// A 7^ .' ^^^ Agriculture Handbook No. 202 ACTIVITIES HANDBOOK ..^^^iCT^S**^^' Animal Disease Eradication Division 4 Agricultural Research Service U.S. DEPARTMENT OF AGRICULTURE i From the collection of the z ^ Prelinger V I J-i"h-PQ ibrary San Francisco, California 2008 Agriculture Handbook No. 202 ACTIVITIES HANDBOOK '"^'"Veference division Animal Disease Eradication Division Gtowlli Through Agncullural Progress p^jf H»i,-. 3 c; Agricultural Research Service U.S. DEPARTMENT OF AGRICULTURE Washington, D.C. issued 1961 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. — Price 50 cents (paper) "We may thoughtlessly reckon our animal tragedies, the visitations of terrifying, wealth-sapping diseases, in terms of fiscal economy only; but in the annals of history, animal diseases influence the destiny of Nations. They are at the roots of famines, plagues, wars, overturned governments and the lapse of civilizations." Merillat and Campbell Foreword The continued high level of the United States economy is due in part to the larjre number of livestock in the Nation, and their relatively healthy condition. Although losses to the live- stock industry in the United States due to ani- mal diseases and parasites have been estimated to be more than $2 billion each year, our Na- tion is relatively lietter off than are most other countries of the world in the prevalence of ani- mal diseases. Many livestock plagues of other lands do not exist here. Conversely, some na- tions have successfully eradicated diseases that are widespread in this country and for which no eradication programs have been authorizeil or undertaken. The Animal Disease Eradication Division of the Agricultural Research Service is responsi- ble to the people of the United States and to the livestock industry for the control and eradi- cation of diseases in livestock and poultry. Progress has been gratifying. A milestone in State-Federal cooperative ef- forts was passed with announcement on Octo- ber 22, 1959, of the eradication of vesicular exanthema. Before the 7-year campaign ended, the dis- ease had spread into 43 States. Ten countries had placed embargoes on our pork products. Losses ran into millions of dollars. Incident to the VE campaign, with raw gar- bage incriminated as the source of many dis- ease organisms, each of the 50 States enacted a mandatory garbage-cooking law. Enforce- ment of these laws will assist in preventing the introduction and spread of livestock and poul- try diseases in the United States. Screwworms, it is encouraging to report, were not found during the entire year in the Southeastern sterile fly release area. On No- vember 14, 1959, less than 2 years after the start of the campaign, cooperating authorities and scientists ceased the rearing and release of sterile screwworm flies in the Southeast. Tills insect i)('st annually had rolibed live- stock growers of $L*() million. The cost of com- bat has boon le.ss than the livestock losses for a single year. A victory has boon won — but the battle against roinfestation continues. In the brucellosis program a new landmark was reached when on April 25, 1960, New Hampshire became the fir.st brucellosi.s-free State. In addition to New Hampshire, 12 coun- ties in 4 States were brucellosis-free. At year's end, 23 States and ()3 percent of the counties in the Nation, Puei'to Rico, and the Virgin Is- lands were modified-certified brucellosis areas. Renewed interest in bovine tuberculosis eradication has sparked additional research and was responsible for many meetings in dif- ferent States throughout the Nation. Forces are being consolidated and a concerted effort is being made toward finding methods to rid the country of this disease. The State-Federal program for the eradica- tion of scrapie has prevented this disease from becoming established in the sheep of the Na- tion. Sheep scabies is once again the subject of considerable attention, and programs are be- ing activated to reduce losses from this disease. Man has catapulted into a jet age. But dis- ease germs have zoomed along with him. The Division stays alert to the shifting pattern of animal diseases. Liaison with scientists throughout the world has been maintained for the development of plans to cope with emer- gency situations should exotic diseases find their way into the Nation's livestock. It cannot be overemphasized, nor too often reiterated, that success in the protection of the country's livestock depends on constant vigi- lance. To this end we have sought to strengthen the regulations governing the interstate move- ment of livestock and poultry. Division veterinarians mu.st be proficient in the basic knowledge of their profession. They Foreword — (Continued) must also have stimulus for growth. And in society's increasing complexity they must be given the means to cope with the mounting de- mands for specific skills and specialized infor- mation. We recognize these needs. Our varied training programs are designed to meet the challenge. Periodically, in order to perform effectively in the present, as well as to plan for the future, it becomes necessary to pause for an examina- tion of the past. This handbook, intended for the use of those intimately concerned with the health of the livestock of the Nation, is dedi- cated to that purpose. R. J. Anderson, Director Animal Disease Eradication Division Contents Page COOPERATIVE DISEASE ERADICATION PROGRAMS 1 Brucellosis 1 Scabies 7 Scrapie 12 Screwworms 14 Cattle Fever Tick 20 Tuberculosis _ 24 Emergency Disease Activities 26 Anaplasmosis 29 Cattle Grubs 3 1 Hog Cholera __ _ 32 Viral Encephalitis 33 Poultry Diseases 34 LABORATORY SERVICES 37 Looking Back in Laboratory Services 37 Achievements 38 Diagnosticians and Epidemiologists 41 Cooperative Projects With Other Laboratories 42 Looking Ahead in Laboratory Services 44 INTERSTATE MOVEMENT OF LIVESTOCK -... 45 Interstate Regulations 45 Public Stockyards 47 DISEASE REPORTING 51 ACCREDITATION OF VETERINARIANS 55 Standards for Accredited Veterinarians 56 Violation of Standards 57 The Colleges and Regulatory Veterinary Medicine 57 TRAINING 59 PROGRAM APPRAISAL 61 COOPERATIVE ACTIVITIES WITH MEXICO 63 ACTIVITIES HANDBOOK Animal Disease Eradication Division Cooperative Disease Eradication Programs BRUCELLOSIS Early efforts Brucellosis of livestock in the United States has been a serious problem for half a century. Losses have exceeded hundreds of millions of dollars. The first real efforts to control brucellosis under independent State programs were under- taken in 1922, but little progress was made until 1934 when the problem was attacked on a national scale. In that year the cooperative State-Federal bovine brucellosis eradication program was launched as part of an emergency cattle-reduction project because of drought in many sections. All States cooi)erated in the plan, and initial testing indicated that approxi- mately 10 percent of the adult cattle in the United States were infected. As the drought emergency subsided, the project was continued on a limited scale as a desirable disea.se-eradication program. It was found to be more economical to eradicate bru- cellosis than to live with it ; and in 1954, funds were made available by the Congress and the various States for an adequate program. Many States were quick to take advantage of the opportunity to participate in a cooperative eradication program, while others lagged and still others have only recently inaugurated com- plete area eradication efforts. All 50 States now have cooperative eradication programs on an area basis. Innovations through the years Considerable progress in eradication was made prior to World War II, but the program was hampered by lack of uniformity in pro- cedures and the fact that a suitable vaccine had not yet been develoi)ed. During the war years, the program suffered from lack of personnel. On the brighter side was the introduction in 1941 of strain 19 BniccJId vaccine. In the en- suing years it has proved dependable and sta- ble, conferring a serviceable, if not absolute, immunity. In 1947, the United States Livestock Sani- tary Association adopted Uniform Methods and Rules for the eradication of brucellosis, which were then approved by the Division. Additions and improvements in the Uniform Methods and Rules have been made from time to time until today the program is similar in all States. One of the most important developments in brucellosis eradication was the introduction in 1952 of the milk-ring test, which has made pos- C/) UJ ■a ^ I- So: to u. < 5^ § 11* ^ _ o o -^ z ^ to Q; > cr. o 5 < to < O li- o < I- C/) I o z z « COS IE < (o O »t cv I/) Ul % (0 o o 5 fc- *n F Z > « I u o E • c M C E -2 5 -) o * - E U- UJ i ^ ■o < ij_ c u. o 1/1 o < 3 , Q ^ u o> 111 «i S • (J — UJ o CD S2 in tn i^ t/) >- 5 o^ o u n- n _I z o _l UJ * LU o * (J q: UJ u _) UJ or Ul q: S u n m UJ uo i-O < o < < on CO 7 I 1-1 LU Z O _J < O > 1 r r on o _J LU o Q -- '^: s LU UJ 00 — ) o :c <: 2 ^ 0) < to on CO U B 0^ -a o □ I < t5 ^- '^ O CO 00 ci: O GD CD LU O o O Ui Z on ^ >; rd O) ,^- > w 3 > 3 E TO ^: Ll. — » S ■< ^ o 00 CD — t CC* Ct z —I . 00 to D_ >-' -; t/T S a> ^ OO 2: z QL QL -0" To = iB ^ = - < < _p OJ J3 E CO 0. z X t^ t^ 3 Qfl c: Xo ^ u (t: Z2 TC 0^ n: tt: -' CD LU ^ CD LU <: z: ct \— ^ ct: >- LU >- LU XT. 1 <: q: cc LU s <: CD CD CD 03 _J O. Of O < z LU < a. slble the frequent, comparatively low-cost screening of commercial dairy herds. Milk samples from dairy herds are obtained at the milk-processing plants and tested in central laboratories. Suspicious reactions are related to the herds from which the samples were CALVES VACCINATED Cooperohwe Stale federal Bfuce/loi'S Efod-catron Pfooror 1943 ^iCOll III 1 1 II ?ll Hi? ^1 — 1 J — 1 r\ ION 1953 >^ June 17, 1960 l^ 775?--^ /^ ^ \ \ 1 r~^^HBi 1^^- m1 PUIITO IICO ALASKA HAW"'' V.^;.V^ AREAS v|i|ia ^1 Infected RSiiil Eradication OH Free /:• OAHU VltGIN ISLANDS IT. THOOAl IT. JOHM ^^ ^^*«AII ^^^^- Ti TITLE 9, CODE OF FEDERAL RECUL-tTIOWS, PART 7< U.l. OEPABTWENT OF ACRICULTUBE NEC. «o (t)-sme *CBKULTURAt BE5EABCH SfBVICe Durinjr the year, outbreaks of mange — first thoiipht to be psoroptic cattle scabies — were reported from Alabama, Oklahoma, and Wyoming. Chorioptic mange was also reported from Oregon. The outbreaks occurred in two flocks of sheep in Benton County and in three herds of goats in Clackamas and Lane Counties. The situation in cattle scabies Psoroptic cattle scabies was reported in a large feedlot in Weld County, Colo. ; a dairy herd in ^Marshall County, Ind. ; a feedlot in Pot- tawattamie County, Iowa ; and a ranch in Baker County, Oreg. Infected and exposed cattle were treated, and an effort was made to locate the source of the outbreaks. In November 1959, mites were found in a shipment of four bulls and one cow trucked to the Ogden Union Stockyards in Utah from Sub- lette County, Wyo. Specimens submitted to the Utah State University and to the ADE Diagnostic Laboratory were identified as sar- coptic. Additional infected animals were found in the Sublette County herd and on adjacent ranches. An eradication program was started immediately. The disease may have been pres- ent in the area for some time. The Bureau of Land Management cooperated b\' refusing entry of undipped cattle from quar- antined areas to lands administered under the Taylor Grazing Act. A State quarantine was placed on a large area in Lincoln, Sublette, and Sweetwater Counties. Additional inspectors from Colorado, Nebraska, Texas, and Utah were assigned to assist in the eradication ef- fort. Inspection of all cattle in the quarantined area — about 14.5.000 — revealed infection in 14 herds. Cattle in all herds in the quarantined. 9 area were considered exposed. About 100,000 cattle were dipped in lindane, including some 5,000 outside the quarantined area dipped at owners' requests. Thirty dipping vats were used, 20 of them newly constructed because of the outbreak. Infected herds were dipped twice — exposed herds once — in temperatures as low as —38 F. Reported losses were one cow and six calves. One calf drowned, and five were sick when dipped. Many of the animals were in very poor physical condition when treated. Movements from infected herds were traced to destinations in California, Colorado, Idaho, Illinois, Kansas, Nebraska, Utah, and Wyo- ming. Cattle from infected Wyoming herds had been moved to several premises in Idaho and Nebraska. Inspections revealed one in- fected herd in Bingham County, Idaho, and one in Keith County, Nebr. Both herds were dipped twice. Inspections did not reveal any evidence of the disease in other Idaho and Nebraska herds involved. The Idaho herds were treated twice, except those in feedlots. They were in- spected and held under quarantine until treated or slaughtered. Cattle from infected Wyoming herds received in other States were inspected and no scabies was found. Mites on elk During 1960, mites identified as Psoroptes equi var. cervinae were found on elk in Idaho and in Wyoming. A skin condition was noticed on the elk, which had been shot in Benewah County, and a veterinary practitioner was called. The veterinarian sent specimens to the laboratory, where they were identified as psor- optic. In Wyoming, scabies lesions were ob- served w^hen members of the Game and Fish Commission were putting elk through chutes for tagging and identification purposes at the Jackson Hole feeding grounds. Laboratory studies confirmed that mites harvested from a dead elk were psoroptic. Psoroptic mites have been found over a period of many years on elk and on bighorn sheep in several Western States. The presence of scabies in wildlife suggests that they may be a reservoir from which the disease may spread to domestic animals. How- ever, there has been no good evidence, at least during the recent years, that this has occurred. Two requirements are necessary for this to happen: (1) Mites on wildlife must be able to propagate on domestic animals, and (2) they must have the opportunity to spread from wild to domestic animals. In this country, scabies has not been observed to spread to domestic animals from bighorn sheep or elk, and out- breaks during recent years in cattle and sheep are not believed to have been caused in this manner. The problem deserves further study. Field trials — cold lime-sulfur dips During recent years, public attention has been drawn to the problem of chemical resi- dues laid down in tissue through treatment of animals. It is also recognized that some acari- cides made available for the control of scabies, ticks, or both might not be effective eradica- tion agents. Following careful study of these related problems, it was decided to conduct field trials in an effort to prove the efficacy of dips as eradication agents and to determine whether a variation of dipping methods or procedures might reduce the tissue-residue hazards to hu- man health. Consequently, in March and April 1960, field trials were conducted in Iowa to de- termine whether cold liquid lime-sulfur plus a wetting agent could be used effectively in sheep scabies eradication. Eight infected and quar- antined flocks totaling 411 sheep wei'e selected in widely scattered communities. Sheep were dipped twice at 10- to 13-day intervals regard- less of temperature and weather, or age and physical condition of the animals. The trials indicated that healthy lambs and adult sheep could be dipped in cold liquid lime- sulfur bath at 29 F., in an atmospheric tem- perature of 16°, with no deleterious effects. The addition of the wetting agent Triton GR 5 at 13 ounces to 100 gallons of water gave complete dip penetration and kept fleece damp for 4 to 5 days thereafter. Farm waters, re- gardless of degree of harshness, did not disturb the equilibrium of the lime-sulfur solution. Im- mersion of adults for 3 minutes and lambs for 1 to I'o minutes in a bath maintained at not less than 2-percent "sulfide-sulfur" concentra- tion, killed mites within 24 to 48 hours follow- ing first dipping. Inspections were made at 10 % n Typical scabby shet'p. Scab lesion. BN-11612 Vat-side test to determine the percentage of "sulfide- sulfur" in dip solution. Scabby sheep being marked and tagged, to aid in post- dipping inspections. I v# Sheep being dipped for 3 minutes in cold liquid lime- sulfur. 30-day intervals, and live mite.s had not been found 90 days later. Inspections at 3-month intervals are to continue for 1 year. Additional field trials with cold lime-sulfur will be conducted during 1961. Decision con- cerning the use of cold lime-sulfur in scabies eradication activities will await completion of these trials. 11 SCRAPIE Scrapie in history Scrapie has been known in Great Britain and Western Europe for more than 200 years. There is evidence that Spanish Merino sheep may have carried the disease into Europe. The disease has been reported in Australia. Austria, Canada, England, France, Germany, Hungary, Iceland (where a similar disease is called Rida), New Zealand, Norway, Poland, Scot- land, Spain, and Wales. The first report in the United States was from Michigan in 1947. Scrapie was again re- l)orted in October 1952 when, in two related California outbreaks, 21 sheep showed symp- toms. The United States Livestock Sanitary Association and segments of the sheep industry urged immediate eradication action. And on October 31, 1952, with an emergency declara- tion by the Secretary of Agriculture, the coop- erative Scrapie eradication program was es- tablished. All sheep in the two California flocks and all exposed sheep moved from them were slaugh- tered, as were the immediate progeny. The 55 premises involved were cleaned and disin- fected. More than 7 years have passed with no extension of infection fi'om these outbreaks. California has since suffered six additional out- breaks that were not associated with those in 1952. The source of the earlier outbreaks is believed to have been a Canadian flock. Sheep rubbing against fence rail — an early symptom, from which the disease derives its name. The di-sease .struck next in Ohio where, in 1953, five infected flocks were found. The eradication program in Ohio included slaughter of infected flocks but not exposed sheep moved from them or the immediate progeny of the ex- po.sed sheep. Certain of the.se animals in Ohio and Tennessee were later found to have scrapie. During the same year, scrapie was diagno.sed in three Illinois flocks. These flocks and exposed sheep moved from them were slaughtered. In both Ohio and Illinois it appeared that the disease had been introduced from the Canadian flock involved in the first California outbreaks. Indiana has had 23 infected ttock.s — more than any other State. The earliest case was in August 1954, and the most recent in April 1959. Eight of these flocks, as well as two in Alabama, two in North Carolina, and one in Missouri, acquired the disease through move- ments of exposed sheep from one of the Indiana flocks. These 13 outbreaks in 4 States resulted from the movements of 322 exposed sheep into 85 flocks in 14 States — a classic example of spread. Had the remaining expo.sed .sheep not been slaughtered, additional cases would un- doubtedly have developed. It became obvious that scrapie could not be eradicated unless both source and infected flocks were slaughtered ; and that exposed sheep from those flocks and their immediate progeny should be slaughtered also. Source flocks were defined as those determined on am- ple evidence, and after careful consideration and consultation, to be disseminating scrapie; but in which no animals were found that showed symptoms of the disease. In the United States, 91 infected flocks have been reported in the following 24 States: Ala- bama 2, California 8, Connecticut 2, Georgia 1, Illinois 15, Indiana 23, Iowa 1, Kentucky 1, Maryland 2, Michigan 2, Mississippi 1, Mis- souri 1, New York 3, North Carolina 2, Ohio 12, Oregon 4, Tennessee 2, Texas 1, Utah 1, Virginia 1, West Virginia 1, Wisconsin 2, and Wyoming 2. There were 10 outbreaks in 1953; 3 in 1954; 11 in 1955; 23 in 1956; 12 in 1957; 7 in 1958; 1 1 in 1959 ; and 13 in 1960. 12 SCRAPIE-lnfected Flocks Reported 1947-59 78 Flocks 21 States Fiscal Year NE9CO(rO)-sl29 Cooperative scrapie eradication The cooperative eradication proj^ram is based on procedures long used to eradicate other diseases, with modifications required by the unusual nature of scrapie. Prompt report- ing of suspicious cases is stressed. Tentative clinical diagnosis is confirmed by histopathological studies of brain tissues. Sus- pect animals are maintained under observation and are slaughtered until symptoms are fully developed. Scrapie in other countries In August 1959, the Canadian Scrapie eradi- cation program was broadened so that Canada and the United States, whose regulatory offi- cials had worked closely, now have equivalent programs. Canadian oflficials have given assur- ance that sheep which would have been slaugh- tered under the current program, had it been in eff'fct in April 1957, will not be certified for export to the United States. Australia and New Zealand — where it is be- lieved scrapie had been newly introduced by imported sheep — also instituted an eradication program. Officials in both countries believe their efforts to eradicate scrapie have been suc- cessful. One outbreak among imported sheep in Norway is l)eing similarly handled. In certain countries where .scrapie is en- demic, owners attempt to reduce the incidence of the disease and the .stigma of having an in- fected Hock by slaughtering selected animals of certain bloodlines. These do not represent or- ganized efforts to eradicate the disease. Infected flocks and source flocks are quaran- tined. All .sheep and goats in such flocks are slaughtered under supervision at authorized slaughtering plants. E.xpo.sed animals moved from these flocks and their immediate progeny are slaughtered. Premi.ses and vehicles are cleaned and disinfected. Principles of eradication Research efforts to produce a vaccine to in- crease resistance have been discouraging. If either breed resistance or individual animal re- sistance exists, it might be possible to develop strains of scrapie-resistant sheep. Even if pos- sible, this would be a long and laborious under- taking. Preventing exposure of susceptible sheep is the only method now known of avoiding addi- tional outbreaks. Until research proves conclu- sively whether scrapie spi-eads from parent to oflFspring, or by some form of contact, any ef- fective program must follow appropriately modified conventional methods which embrace both possibilities of .spread. Since the agent is known to exist in visibly affected sheep, it is clear that they mu.st be de- stroyed. There is no diagnostic test for the disease in an animal not showing symptoms; consequently, there is no way of knowing how many exposed animals may harbor the infec- tious agent. This factor, linked with the long incubation period, necessitates the slaughter of all exposed animals. 13 An advanced case of scrapie. Scrapie studies Each outbreak is carefully studied to estab- lish the epidemiology of the disease. Particu- lar attention is given to symptoms, laboratory findings, age, sex, breed, history, and pedigree of each infected animal, movements from in- fected flocks, and the possible source of the outbreak. During the 7 years the eradication program has been in effect in this country, it has not been possible to identify the source of several outbreaks. The majority, however, fall into a pattern and indicate spread from a limited number of common foci. Such foci — usually identified as source flocks — are now being slaughtered. Approximately 80 percent of the infected sheep in this countiy either were imported or were the immediate progeny of sheep of for- eign registry. The broadened Canadian pro- gram should materially reduce the possibility for further introduction of scrapie through sheep imported from Canada. Exposed sheep and their immediate progeny from 1,800 flocks have been slaughtered. Pres- ently, some 1,500 flocks are receiving the re- quired 6-months' inspection. In November 1956, more than 2,000 flocks were under inspec- tion. These routine inspections have helped locate infected animals. Almost 50 percent of the 91 outbreaks were found in this manner. Sheep under 18 months of age seldom show symptoms of natural scrapie. Only one of the IGl infected sheep in this country was 18 months old ; the others were older. Three were more than 71a> years old. The great majority were from 2\-^ to 4 years old with most being about 3 years of age. Mortality rates are difiicult to determine with certainty. When an outbreak occurs, the entire flock is slaughtered before additional cases have time to appear. Of the 161 confirmed cases in the United States, 151 were Suffolk sheep and 10 were Cheviots. Although the majority of cases have occurred in one breed, it is generally believed that sheep of any breed can develop the disease. The manner in which scrapie spreads is not well understood. Both experimental and field evidence suggest it can spread from the dam, and perhaps the sire, to the progeny. The evi- dence, however, does not explain how the dis- ease spreads from one breed to another. Eradication and research The 91 outbreaks in the United States illus- trate the potential danger of an insidious dis- ease like scrapie in a country where lively trade among growers results in wide distribution of sheep and their diseases. We look forward to additional research re- sults — particularly those designed to explain natural transmission. Precise information will permit moi'e exact identification of poten- tially dangerous animals and may require slaughter of fewer sheep. Experience is convincing that the elimination of infected and exposed animals has effectively controlled the disease, prevented it from be- coming widely established in Cheviot and Suf- folk sheep, and prevented spread into other breeds. The chances for ultimate success appear good if sound eradication procedures, sup- ported by ample research, are continued. SCREWWORMS The screwworm, Callitroga hominivorax (Cqrl.). is an obligatory parasite on warm- blooded animals and causes myiasis. Myiasis is defined as "any disease caused by the pres- ence of the larvae of flies in or on the body of an animal." Since screwworm attack, or 14 myiasis, is a disease of domestic animals, the Animal Disease Eradication Division was as- signed the responsibility of effectuatinK a pro- gram to eradicate this insect pest from the Southeastern United States. Screwworm flies: Left, male; riyhl, female. Early investigations Screwworms have been known in Texas since 1842. During the summer months infe.stations spread to adjoining States but subsequent cold, winter weather usually killed all but those in southern Texas. Screwworms were unknown in the Southeast until the summer of 19:):>, when the first infestations were reported in the Larvae of screwworm. vicinity of Boston, Ga. They .spread rapidly and within 2 years were found throughout Florida. Each summer, infestations spread into Georgia, Alabama, and occasionally far- ther north, but they were subsequently killed by cold, winter weather in all Southeastern areas except peninsular Florida. Heavy losses sustained by the livestock in- dustry of the Southeast due to screwworm at- BN-4376 BN-4380 Eggs of screwworm. Pupae of screw^vorm. 15 tack had stimulated 20 years of agitation for an eradication program. However, although good control methods were available, they were not considered sufliciently effective to justify an eradication effort until the development of a revolutionary approach to insect control. This concept envisioned the elimination of an insect pest by overwhelming the native popu- lation with sterile male flies. Since female screwworm flies when mated with sterile male flies laid only infertile eggs, race suicide seemed possible. Research entomologists of the Agricultural Research Service conceived and developed the sterile-fly method of insect control. Basic tech- niques for the rearing, sterilization, and dis- tribution of screwworm flies were perfected and field trials demonstrated that screwworms could be eliminated from localized areas. Early in 1957, a team of a veterinarian and an entomologist surveyed the screwworm situa- tion in the Southeast. Their purpose was (1) to determine losses due to screwworms, (2) to evaluate the probability of success of an eradi- cation program using the sterile-fly technique, and (3) to estimate the cost and duration of such a program. The survey revealed an an- nual loss of approximately $20 million in the Southeast, half of which was in Florida. The surveyors concluded that screwworms prob- ably could be eradicated in 2 years at a cost of about $10 million. Further investigation revealed that an area of some 50,000 square miles, mostly in penin- sular Florida, would require weekly dispersals of .sterile male flies averaging 500 per square mile. This called for a building of sufficient size, and with adequate equipment, to produce a minimum of 50 million flies per week. Ex- pansion from an experimental fly-rearing plant, with production of about 2 million flies per week, required the design and construction of new equipment, improvement and mechani- zation of all operations synchronized to the life cycle of the fly, a method of automatically pack- aging irradiated pupae, and development of an apparatus for airplane dispersal of packaged flies. gram became available during the summer of 1957. Plans were immediately made to con- vert an airplane hangar at Sebring, Fla., into a huge fly-rearing establishment. Because of the time required to remodel the hangar and to design and build suitable equipment, operation was not expected before July 1, 1958. In the interim, it was decided to use the small, experi- mental fly-rearing facility near Orlando, Fla., to train personnel, and to test and develop new methods and materials. The winter of 1957-58 was one of the coldest and wettest in Florida histox'y. Low tempera- tures in the north and excessive moisture in the south decimated the screwworm population, and restricted the pest to a comparatively small part of southern Florida. In an attempt to halt the northward movement of flies until the new fly-rearing establishment could come into operation, an artificial barrier was established by dropping sterile male flies over the northern part of the State. Production at the small plant was soon in- creased to approximately 10 million flies per week — a sufficient number to maintain an effec- tive barrier and prevent widespread northward migration of native flies. By late spring a State quarantine line had been established across peninsular Florida, extending east and west from Ocala, to prevent the northward movement of infested livestock. Animals in transit from south of the quarantine line were inspected and sprayed before they moved into uninfested northern areas. iSL^SfeS'^Ei^ Eradication in operation Federal-State funds for an eradication pro- Mechanized fly-reai-ing facility converted from airplane hangar, Sebring, Fla. 16 Scre\v«\jini laivae growing on meat-blood-waler mix- ture in electrically heated vats. The .SeioriiiK ll\-reiiriiiK facility was com- pleted on July 10, 1958. Within a short time, 50 to 70 million tlies per week were beinjr pro- duced and dispersed. Larvae were reared on a mixture of ground meat, blood, and water in shallow, heated vats maintained at a constant temperature of 98" F. Approximately 80,000 pounds of meat, 4,500 uallons of blood, and 9, GOO gallons of water were needed to rear 50 million larvae. Mature larvae crawled from the vats and dropped into trays of sand where they pupated. Pupae were separated from sand and stored under optimum One of si.x cobalt-OO units lor sterilizing jnipae of screwworm.s. temperature and humidity conditions. At 5'/2 days ±6 hours of age, pupae were sterilized by being placed in a cobalt-60 unit where they were irradiated with 8,000 roentgens of gamma rays. After irradiation, pupae were packaged in cardboard cartons. The cartons were first stored for a day or two until the flies emerged and then were transported to dispersal centers and loaded in aircraft, from which they were dr()i)ped over the screwworm-infested areas. Twenty airplanes, each equipped with an auto- matic carton-dispersing apparatus, were used in this oi)eration. N H0216 Pupae being separated from larvae by sifting. Pui)ae are automatically measured into cardboard cai'tons. 17 N-28349 Airplane releasing carton of sterile flies. The greatest numbers of sterile flies were dispersed in tiie most heavily infested areas and lesser numbers in the lightly infested areas. Federal and State livestock inspectors throughout the Southeastern States examined livestock and maintained close cooperation with livestock owners to determine the inci- dence and relative abundance of screwworms. The native screwworm population gradually declined, and by the end of 1958 screwworms could be found only in Broward and Dade Counties, Florida, where a localized infestation persisted. This pocket of screwworms was finally eliminated. The last case in the region was found and destroyed February 19, 1959. The only infestation that has been found in Florida since that date was in a dehorning wound, in Highlands County, on June 17, 1959. Challenge and termination The apparent absence of screwworms in Florida for several weeks prompted program officials to test the effectiveness of the eradica- tion effort by discontinuing release of sterile flies in a large part of the formerly infested area. Accordingly, in mid-July 1959, release of sterile flies was discontinued in that portion of Florida south of an east-west line through Lake Okeechobee. The number of livestock inspectors in the untreated area was doubled. and livestock owners were urged to make fre- quent inspections and promptly report any evi- dence of screwworms. When no infestations were reported in the test area in the ensuing 3 months, rearing and release of sterile flies were progressively diminished in the remainder of the Southeast. Screwworm fly rearing operations ceased, and the last sterile flies were dispersed on No- vember 14, 1959. The building then was sealed and sprayed with an activated pyrethrin insec- ticide, and on the following day fumigated with DDVP and TEPP. These precautions were taken to ensure destruction of any fertile screwworm flies tliat might escape from the heretofor fly-secure building and repopulate the area. The establishment was then placed on a standby basis to remain available for emergency use. Continuous alert Continuing systematic animal inspections for evidence of screwworms, and trapping and identification of flies in areas over which sterile flies had been released, ensured rapid detection of wild flies or larvae that might .still survive in the eradication area. An insurance screwworm colony is main- tained at a Department laboratory in Texas. Stock from this parent colony could be used in an emergency to combat future localized out- breaks. During and following eradication efforts in the Southeast, it has been necessary to guard rigidly against reintroduction of screwworms on animals moving interstate from the screw- worm-infested Southwest. This protection has come, through Federal regulation, from the establishment of 13 livestock inspection sta- tions along the eastern borders of Arkansas and Louisiana. All livestock entering the Southeast from the Southwest must be unloaded and inspected at one of the stations. All wounds on livestock are treated with an approved smear. This is fol- lowed by thorough application of an organic phosphorus insecticide to all animals except those specifically exempted. A number of screwworm-infested animals have been inter- cepted and treated at these stations before be- ing permitted to enter the Southeast. 18 Slate -Fedeml Scremom Eradicati on Program THOUS LB, so - TLY REARINO FACILITY, SEBRING, FLA. J,3. DEPARTMENT OF flOBICULTUne f(EO 60 (7) JiOS AGRICULTURAL RESEARCH SERVICE Larvae of s;-i-e\v\viiiin in wnum: Stale-Federal Scremmrm Eradication Program EGG PRODUCT ON THOUS. GRAMS SON DJ FMA M J JA SO 1958 ! 1959 FL.Y REARING TACH-lTY, SEBRING, FLA us OEPADTMENT OF AORiCULtURE NEG 60|T)9IOO ACRiCULTiJIUl RESEftRCM SCftVICE State - Federal Screwwarm Eradication Program MEAT COST PER MILLION FLIES DOLLARS A r. A n. 1 SONDJFWAMJJAS 1958 1959 FLY REARING FACILITY, SEBRING, FLA U 5 DEPAHTME^T OF AGRICULTURE NE0 60IT15tO2 AGRICULTURAL RESEARCH State-Federal Screwworm Eradication Program PUPAE PER LITER lO s 6 4 2 O r- 1 '" mill I.I. Ill 1 1 1 ,, 1, 1 . .1 1.. i SOISID J FMAMJJ A 1958 1 1959 FLY REARING FACILITY. SEBRING, FLA us DEPARTMENT OF AGRICULTURE NEC 60(7)5101 AGRICULTURAL RESEI Stole -Federal Screwworm Eradication Program FLIES RELEASED PER 10.000 LB. OF MEAT MIL FLIES s o SON DJ FMA M J J A S O 1958 1959 FLY REARING FACILITY, SEBRING, FLA BCM SERVICE O.S OEPARTMENI Of AGRICULtuRE NEC 60 H) 5t04 AGRICULTURAL nESflRCM SERVICE 19 During the warm months, when screwworms can establish themselves in the North and Mid- west, livestock from those areas are inspected to prevent screwwoi-m-infested animals from entering the eradication area. Air, rail, and ocean shipments of livestock also must be cer- tified free of screwworms before they are per- mitted to enter the eradication area. Durinjr the late summer and fall of 1958 and 1959 screwworms succeeded in establishing themselves in several Mississippi counties ad- joining the Mississippi River. Probably these infestations were started by flies entering the eradication area from Louisiana or Arkansas under their own wing-power. The outbreaks were controlled by intensive animal inspec- tions, treatments, and State quarantines. Looking ahead in eradication The success of the eradication program in the Southeast has stimulated considerable in- terest among livestock growers and others in the Southwestern United States. During 1959, a screwworm survey was made in the Southwestern United States and North- eastern Mexico to learn more about screwworm habits and to evaluate the practicability of using the sterile-fly technique in those ai"eas. The survey in Mexico failed to reveal any natural barriers comparable to the water bar- rier that encloses, on three sides, the screw- worm overwintering area in Florida. An eradi- EAST-WEST LIVESTOCK MOVEMENTS Through Screwworm Inspection Stations THOUS 75 50 25 75 50 25 MOVING EAST LiU mMmMR iluULuul MOVING WEST m iuuiiili UlUu 1958 1959 I 1960 & 0(MJI»[V Ciaa'CUlTJUt •WCULniatl. M tiucn Itovict cation eff'ort would not be practicable without a perpetual program to prevent reinfestation of the Southwestern United States through the migration of screwworm flies northward from Mexico. The vast territory involved, the climatologi- cal and topographical differences from the Southeastern United States, and the need for additional information, indicate that any joint United States-Mexican pi'ogram should first be directed toward research, field trials, and meth- ods development. CATTLE FEVER TICK A tale of ticks The theory is that cattle tick fever spread to the Southern United States from the West Indies and Mexico. The earliest report of the disease in this country was made in 1796. In the middle 19th century, there were frequent reports of the infection in the South and South- west. The nature of the disease was not under- stood until 1889, when scientists of the U.S. Department of Agriculture discovered that the causative agent was a protozoan, Babesia bige- niiua, transmitted by the cattle fever tick (Bo- ophilus a)nnihif!is; and BoophilM^ microphts) . The first step in control of the disease was to quarantine the infested area. The order con- trolling movement of southern cattle was is- sued on July 3, 1889. By 1907, cattle tick fever (bovine piroplas- mosis, Texas Fever, splenetic fever) was prevalent in the Southern States, and had been reported in California, Kentucky, Missouri, Oklahoma, and Virginia. Except for a narrow buifer zone along the Texas-Mexican border and sporadic reinfestations in other places, the Tick Eradication Program had eliminated fever ticks from the United States by December 1943. All Mexican territory adjacent to the inter- national boundary along the lower Rio Grande River is tick infested. Reinfestations in Texas by tick-infested Mexican animals illegally en- tering the United States occur regularly. The river boundarv is not an effective barrier 20 against illegal movements or stray animals. The buffer area under Federal and State quar- antine extends 500 miles from Del Rio to the Gulf of Mexico. This zone is patrolled con- stantly by Department inspectors in coopera- tion with Texas livestock sanitary authorities. The area under quarantine includes parts of Cameron, Hidalgo. Kinney, Maverick, Starr, Val Verde, Webb, and Zapata Counties. The cattle fever tick was eradicated from California many years ago. However, this State also has a common border with infested areas in Mexico, and animals illegally entering the United States reintroduce ticks from time to time. In October 1941, fever tick infestation was discovered adjacent to the Mexican border in the Tijuana Valley of San Diego County and on a few farms in Los Angeles County to which cattle had been moved from San Diego County. Infested areas were quarantined and cattle were systematically inspected and dipped. In- festations in small areas in San Diego County were also reported in 1948, 1944, 1949. and 1950. In each in.stance the ticks were eradi- cated by following customary procedures. The most recent infestation in San Diego County was in Marron Valley in June 1956. A State hold-order was placed on the affected area, and an inspection and dipping program inaugurated. No additional ticks were found after official dippings were started, and the hold-order was lifted in June 1957. A double fence was constructed across the valley. Plans were made to chute-inspect cattle and horses in Marron Valley periodically at least four times a year. In Puerto Rico a tick eradication program, in operation for a number of years, is coming to an end. Here the tropical variety of the fever tick was prevalent, and it was necessary to treat sheep and goats as well as equines and cattle. Troublesome ticks in Florida Florida was the last State, aside from Texas, to be freed of fever ticks. The Federal quaran- tine in Collier and Hendry Counties in the Big Cypress Swamp area was lifted in December 1943. Deer, which served as hosts for the tropical tick, delayed final eradication. It was only after the Florida Legislature provided author- ity to eliminate this host that the vector was eradicated. In 1947, slight infestations were found in Broward, Charlotte, Collier, Dade, Hendry, Lee, and Palm Beach Counties. Systematic eradication efforts continued during 1947 and 1948. In October 1948, a heavy infestation of ticks was discovered in Volusia County. Invc-^tiga- tion of this outbreak disclosed additional in- festations in Alachua, Brevard, Flagler, Jack- .son. Lake, Madison, Orange, Osceola, Putnam, and St. Johns Counties in Florida and on one premise in Brantley County, Ga. All these in- festations were caused by movement of cattle from Volusia County. Systematic inspection and dipping brought the outbreak under control, and all remaining Federal quarantines were removed in Decem- ber 1950. No additional infestations were found until 1957. On April 23, 1957, a State inspector found cattle fever ticks at the Okeechobee Livestock Market at Okeechobee, Fla. The ticks were identified as Boophilus microplua. This was the first outbreak of fever ticks in Okeechobee County since the wintc of 1945, when quaran- tines were placed on that county and on Glades, Highlands, and parts of Osceola and Polk Counties. Since the 1945 infestation in Florida, cattle passing through all auctions in the State had been examined for ticks by experienced inspec- tors, and all cattle except those selling for slaughter had been dipped. It was as a result of this routine check that the ticks were found on cattle from two Okeechobee ranches. Immediate steps were taken to treat infe.sted and exposed herds and place a State quarantine on the area likely to be affected. Action was also taken to trace animal movements in and out of the area during the previous 2 or 3 years, to place the premises involved under State quarantine, and to investigate the po.ssible source of the ticks. In all, more than 100 ranches in 10 Florida counties were quaran- tined. Counties involved were Broward, Dade, Glades, Hendry, Martin, Highlands, Okeecho- bee, Palm Beach, and St. Lucie. Premises un- 21 STORY OF TICK ERADICATION 1920 1^ AREAS INFESTED WITH CATTLE FEVER TICKS U S DEPARTMENT OF AGRICULTURE NEG 60 (10) "5126 AGRICULTURAL RESEARCH SERVICE der State quarantine Included those to which cattle had been moved from ranches where ticks were discovered and also premises that had supplied cattle to ranches known to be in- fested. Additional experienced State and Federal tick inspectors were assigned to the eradication project. During the summer of 1957, 8 infested herds were found in Okeechobee County, 3 in Broward, 2 in Highlands, and 1 each in Dade and Palm Beach Counties. The campaign ended successfully in September 1958, more than a year after the last known infestation. Tick fever sfatus today On May 31, 1960, a State inspector again found Boophihi^ microphis on cattle at the Okeechobee Livestock Market. The lot of 21 cattle had been trucked from Palm Beach County. Additional infested cattle were found in the herd of origin. The Animal Disease Eradication Division cooperated with the State of Florida in instituting a vigorous eradication program. Tick inspectors traced movements from infested areas and began the inspection of cattle and horses throughout central and southern Florida. Many owners spray their cattle regularly, which makes it difficult to find ticks. Sixteen infested herds were reported in the following Counties: Palm Beach 10, Martin 4, Hillsborough 1, and Indian River 1. A triangular area of approximately 600 square miles including parts of Palm Beach and Martin Counties was placed under State 22 Inspectors closely examine infected and suspect animals for evidence of cattle fever ticks. tie and horses are systematically inspected south of the line. The propram also includes inspection of cattle at slaughter houses and inspection and dipping of cattle at auction markets. In a tick-eradication program, the pe.st can lit' attacked in two locations — in the pasture and on the cattle. Animals may be freed of ticks in one of two w^ays — by treating with a tickicide that destroys the ticks, or by pasturing at proper intervals on tick-free fields until all the ticks have dropped. Dipping is the method generally used. The pasture-rotation method is more complicated and tick-free fields are seldom available. quarantine. Infested and exposed herds in other areas were also quarantined. During 19(50, 91 Mexican livestock were caught in the Texas-Mexican buffer area by tick inspectors; also, 31 native American live- stock that had strayed into Mexico were caught on their return. Of the Mexican livestock, 41 were horses of which ?, were found to be tick infested, and 50 were cattle of which 31 were infested. Also, animals in 4 United States hei'ds were found to be infested, and 21 herds were held for further treatment. In 1960, 12,- 435 certificates were issued for the intrastate movement of 70,659 livestock from the area. In addition, 172 certificates were issued for the interstate movement of 21,390 livestock. Also 48,151 herds of 1,045,876 live.stock were in- spected for ticks, and 9,938 herds of 53,790 livestock were dipped. Plans for the future Effective July 1, 1960, a Federal quarantine was placed on Hillsborough, Martin, and Palm Beach Counties. The eradication program includes e.stablish- ing a State tick quarantine line crossing Flor- ida at Ocala. This is identical with the former screwworm quarantine line established in May 1958 and discontinued November 1959. Florida regulations require inspection and dipping of animals moving north across the line. All cat- CATTLE FEVER TICK SITUATION JUNE 30, I960 Arso Under Federal ana Slate Ouorontine UJ OfMRTIKHT OF tMICULTURE Proposed Slole Ticit Quoranlme Lme eeeicuLtuBAL eEecARcH iervici In freeing pastures, the method followed may be either direct or indirect. In the direct method, cattle, horses, mules, and other host animals are excluded from pastures until all ticks have died of starvation. This plan is seldom followed because owners are reluctant to give up even temporary use of pastures. In the indirect plan, cattle and other animals re- main on infested pastures but are treated with tickicides at regular intervals to prevent en- gorged females from dropping and reinfesting the field. All seed ticks on the pastures, or those that hatch from eggs laid by females already there, eventually die. Those that get on the cattle from time to time are destroyed by the treat- ment. Those in the pastures that fail to find a host starve to death. 23 BN-12793 Dipping cattle for tick eradication TUBERCULOSIS The road to eradication The American consumer has enjoyed in- creased freedom from the danKer of acquiring tuberculosis from animal products since the inception of the cooperative State-Federal pro- gram in 1917. The considerable reduction in slaughtering plant condemnations due to tuber- culosis bear out the progress of field efforts to eradicate the infection. When the program was initiated, about 5 percent of the cattle in the country were tuber- culous. The disease was causing approximately 50,000 whole beef carcasses, and an even greater number of swine carcasses, to be con- demned annually as unfit for human consump- tion. This was equivalent to a 20-mile-long trainload of live animals. The number of whole beef carcasses condemned in 19.59 was 91. The number of reactors found throughout the United States declined steadily from the advent of the program until a low point in dis- ea.se incidence w^as reached in 1952. The in- fection rate in 1952 was 0.11 percent of all cattle tested, or 11 in every 10,000. In spite of the impressive drop in infection rate since the start of the program, tubercu- losis has yet to be eradicated. During 1953 and 1954, the percentage of reactors remained the same as in 1952. Beginning in 1955, the number of reactors in some areas of the country began to increase until in 1959 a total of 23 of every 10,000 cattle tested were identified as reactors. It is apparent that eradication of tubercu- losis — and elimination of the last tuberculous cow — is still a formidable problem. To wipe out this menace to the livestock industry and to public health, the Division is pursuing a broad program of attack. A year of increasing activity During 1960, greater awareness of the need to completely eliminate tuberculosis resulted in increased attention to the following aspects of the program: (1) Training in uniform test- ing techniques; (2) more effective tracing pro- cedui'es to locate exposed cattle; (3) greater emphasis on field study projects; (4) addi- tional work in laboratory diagnostics; and (5) training in post-mortem examination. Training in uniform testing techniques National conferences and tuberculosis work- shops have afforded opportunities for further training of field veterinarians in the use of proper equipment and approved techniques in the uniform application and interpretation of the tuberculin test. Division personnel have conducted annual testing demonstrations for seniors at colleges of veterinary medicine. This phase of the program provides qualified per- sonnel for continued improvement of the eradi- cation effort. More effective tracing procedures An important adjunct to the regular testing program is the location of infection by tracing 24 Makiiif? the tuberculin test. infected and exposed animals to the herds of origin. This involves — (1) Tracing to herds of origin animals found with lesions of tuberculosis on regular kill at slaughtering plants. (2) Tracing the origin of reactor animals found in tuberculin tests. (3) Tracing and follow up on exposed ani- mals associated with infected herds. Success of the tracing system depends upon close cooperation of many individuals — the vet- erinary meat inspector, the stockyards veteri- narian and stockyards officials, the livestock hauler, the livestock market operator, State and Federal livestock sanitary officials and their respective field veterinarians, the veteri- nary practitioner, the livestock dealer, and the livestock grower. Greater efficiency in tracing operations are borne out in figures for the 5 years 1955-59, during which 72,005 tubercu- losis reactors were slaughtered. Of these, 5,539 or a total of 7.6 percent were found as a result of tracing to herds of origin animals with le- sions reported on regular kill. These reactors were found by testing 164,824 cattle, or only 0.38 percent of the 43,922,211 cattle tested dur- ing the 5-year period. It is anticipated that an even greater percentage of cases will be traced as better identification and more complete rec- oi'd systems are developed. Emphasis on epidemiology (field study projects) Epidemiology in tuberculosis has received increased attention. In cattle this involves other species of animals, as well as man, as potential sources of infection. As the incidence of tuberculosis in cattle has been reduced, the close study of the interspecies relationship of the various types of tubercu- losis has become increasingly important. Avian and human tuberculosis, for example, must be considered in disclosure of possible sources of infection to cattle. Special field investigations being conducted in cooperation with State officials may aid in developing still more effective procedures. Additional work in laboratory diagnostics As increased study and attention is given to the epidemiological aspects of tuberculosis, laboratory and diagnostic work has increased. Specimens from reactor animals in problem herds are processed through the laboratory, where tissues are examined pathologically and bacteriologically. This type of work in diagnosis of tuberculosis is among the mo.st involved and time-consuming of medical diag- nostic procedures. However, as comprehensive investigational studies are made, the laboratory l)ecomes increasingly important in determining the type of tuberculosis involved. Training in post-mortem examinations The Meat Inspection Division has developed a guide that provides specific instructions and information on post-mortem examination of tuberculosis reactors. This guide makes possible the uniform ex- amination of all tuberculosis reactors, whether their slaughter is supervised l^y municipal. State, or Federal inspectors. Special training, under the direction of the Meat Inspection Di- vision, has been given to ADE veterinarians to achieve uniformity in the post-mortem ex- amination of tuberculosis reactors. 25 N-293S6 Inspectors follow uniform post-mortem procedures when examining carcasses of tuberculous reactors. Tuberculosis forecasts Progress has been made. But much remains to be done. The increasing interest and support being given by the cooperating States is encouraging. Division activities in epidemiological studies, laboratory work, and case-finding techniques will be continued. Close cooperation with research workers in both animal and human medicine will hasten the development and use of new and improved diagnostic tools. The support and cooperation of State and Federal officials, the veterinary profession, public health agencies, research workers, live- stock producers, and consumers will enable con- tinued improvement to be made. The goal is: Eradication of bovine tubercu- losis from the United States. EMERGENCY DISEASE ACTIVITIES The former Bureau of Animal Industry was organized in the U.S. Department of Agricul- ture to deal with an animal disease emergency, contagious bovine pleuropneumonia. The Bu- reau became world famous for the tenacious application of slaughter and quarantine pro- cedures that resulted in the eradication of con- tagious pleuropneumonia and several out- breaks of foot-and-mouth disease. These same principals were used more recently by the Ani- mal Disease Eradication Division in eradicat- ing vesicular exanthema. Planning for emergencies The Division is now responsible for continu- ing the development of plans for stamping out any foreign animal disease that may gain en- trance into this country. Such plans must be workable, realistic, and documented for ready use. The planning process is a continuing one. A manual, "Emergency Animal Disease Eradication Guide," wa^^ completed anl dis- tributed to each State in March 1960. It covers both technical and administrative aspects of an emergency disease eradication operation. Through continual revision of this loose-lsaf manual, a practical, up-to-date guide for emer- gency disease operations will always be avail- able. The United States is fortunate in being free of several livestock diseases that are enzootic in other parts of the world, such as foot-and- mouth disease, rinderpest, African swine fever, and Rift Valley fever. These diseases are very destructive and result in great lo.sses in coun- tries where they exist. Freedom from such diseases makes possible more economic produc- tion ; and economic production makes for greater availability of meat for consumption. Maintenance of freedom from disease lies in planning and preparation for animal disease emergencies. Diagnostic personnel and facilities Since 1950, 50 Division veterinarians have received special training in the diagnosis of foreign animal diseases, particularly the vesic- ular diseases. The. veterinarians are available for consultation in any part of the country. The Division maintains a diagnostic labora- tory at Beltsville, Md. This facility will be transferred to the National Animal Disease Laboratory, at Ames, Iowa, when it is com- 26 I)letccl. The Plum Island Laboratory of the Animal Disease and Parasite Research Divi- sion is also available for assistance in diag- nosis. Statutory prohibition exists against the importation of foreign animal disease produc- ing agents to any point in this country except Plum Island. For this reason many of the tests for such diseases can be conducted only at that laboratory. Vesicular diseases During 1960, 64 reports of suspected vesicu- lar conditions were received in Washington. Each of these cases was investigated and serum or tissue specimens were submitted for labo- ratory tests. A positive diagnosis of New Jer- sey type vesicular stomatitis was made in 21 of the 64 cases. In each case in which the diag- nosis was negative, the herd or animal involved was regularly reinspected until it could be sat- isfactorily determined that the condition was not vesicular. Each tissue specimen received was checked by complement fixation test again.st the .seven known types of FMD anti- sera, with negative results. Foot-and-mouth disease With the exception of North America, Cen- tral America, Australia, and New Zealand, foot-and-mouth disease is considered to be en- zootic in the major livestock countries of the world. The disease has been known for more than 100 years. It was not until the latter part of the 19th century, however, that its economic importance was fully realized. There have been nine outbreaks of foot-and- mouth disease in the United States. Not the last, but perhaps the worst, struck in 1914. It started in Berrien County, Mich., in August of that year. For reasons explainable only by lack of alert and trained diagnosticians and an inadequate emergency disea.se reporting sys- tem, the disease went undiagnosed until Octo- ber 15. The Union Stockyards in Chicago were quar- antined on October 28, and the machinery of eradication finally moved into gear. But be- fore the emergency ended, on June 5, 1916, havoc and death had spread to the livestock industry of 22 States. Nine million dollars had been spent; 172,222 cattle, sheep, swine, and goats had been sacrificed. Vesicular stomatitis The dust from the foot-and-mouth disease campaign had hardly settled when "the event of greatest consequence" in 1917 unfolded. From the concentration remount station near Chicago, came word of a disease of the mouths and tongues of horses. The disease was traced to similar remount stations at Grand Island, Nebr., and Denver, Colo., where thousands of horses and mules had been gathered for ship- ment to the armies of France and Britain. Sick animals were immediately isolated, quarantined, and treated. Infected pens were cleaned and disinfected. Then, a carload of horses from Nebraska arrived at Denver. Several animals were re- jected and returned. Four days later the re- jected animals had developed lesions that quickly spread to horses and cattle on neighbor- ing ranches. And before anyone was fully aware of what was happening, inspectors at Kansas City were reporting lesions resembling foot-and-mouth disease in cattle shipped from Nebraska. The lesions were diagnosed as those of vesic- ular stomatitis (VS), a disease well known in Europe and South Africa, but up to that time only occasionally noted in the United States. Before it was controlled, VS had spread from Nebraska and Colorado to ranches and remount .stations in South Dakota and Wyoming, and through the usual trade channels to the At- lantic Coast and to France. In 1917, a prompt and exact differentiation in cattle between foot-and-mouth disease and vesicular stomatitis was accompanied by many difficulties. Not least among them was the awareness that a mistaken pronouncement could lead, on the one hand, to unnecessary and serious economic disturbances and, on the other, to the spread of one of the most dread and readily communicated animal plagues. Vesicular stomatitis is endemic in certain parts of the United States and Mexico. It has occurred sporadically in some parts of Central and South America. In this country, the dis- ease seldom occurs in winter. It appears an- nually during the warmer months in the coastal 27 INCIDENCE OF VESICULAR STOMATITIS Confirmed by Laboratory PREMISES 1960 10 - ^^■■- Porcine JSS^ ••••■•■ Equine ^^ ^W J I I I r I >L J L 60 TOTAL . 1952 60 \ 50 ^ / \ 40 - / y / A \y\ 30 ' 1 1^ \ 1 ' ^ \ / / '• \ 20 - 1 ! \ .* \ :^C\ \ 10 // / \ \ / ' •'' * ^N \ n 1 1 ty . . •-•;^>\ M J J MONTH plains areas of Georgia, Louisiana, North Caro- lina, and South Carolina. Sporadic outbreaks occur in other States. The clinical similarity between VS, foot-and- mouth disease, and vesicular exanthema makes early diagnosis essential. Laboratory tests, ani- mal-inoculation tests, or both, are necessary for a positive diagnosis. It is difficult to maintain interest in report- ing vesicular conditions in the VS-endemic areas. Livestock owners and practicing veteri- narians become so accustomed to seeing lesions that an apathy toward reporting develops. There is danger, therefore, that either foot-and- mouth disease or vesicular exanthema will not be reported immediately if it should appear in a VS-endemic area and its spread would be uncontrolled. A continuing campaign to em- phasize the necessity of early reporting of all vesicular lesions is essential. Vesicular exanthema \'esicular exanthema (VE) is a disease of swine characterized by formation of vesicles in the mouth and on the snout and feet. The teats and udders of sows may also be affected. Clini- cally, VE cannot be distinguished from foot- and-mouth disease and vesicular stomatitis. VE, which had not been previously diagnosed in any other part of the world, first appeared in California in 1932, where it remained con- fined for 20 years. In 1952 and 1953, the dis- ease spread to 42 States and the District of Columbia. The first appearance of the disease outside the State of California was at a gar- bage-feeding premise in Wyoming. Sixty days prior to the outbreak the owner started feeding raw garbage from trains originating in Cali- fornia. The time-tried eradication measures of in- spection, prompt reporting, diagnosis, slaugh- ter, cleaning and disinfecting, and testing of premises, together with cooking of garbage, made possible the eradication of VE. Its com- plete eradication from the United States was announced by the Secretary of Agriculture in October 1959. Present program With the announcement of the eradication of VE came immediate requests for cessation of inspection of garbage-feeding premises and garbage-fed swine. The knowledge gained during the eradication program, however, clearly indicates the importance of garbage cooking to control swine diseases. In most areas, regular periodic (but less frequent) in- spections of garbage-feeding premises and gar- bage-fed swine are being maintained. Search for a laboratory test When VE was eradicated, it became a dis- ease foreign to the United States. Re.search within the continental limits was discontinued and all VE virus was either destroyed or shipped to the Plum Island Laboratory. Re- search at Plum Island will continue in an ef- fort to develop a laboratory test for VE and 28 to learn more about the disease and its effect on swine. ANAPLASMOSIS The early account Anaplasmosis is an infectious and transmis- sible disease of cattle that apparently has been in this country for many years. Some have theorized that it was introduced with the first cattle brought by the Spaniards. Theobald Smith and Fred L. Kilborne in 1893 made first mention of the disease in their report on the cause and transmission of Texas cattle fever. Frequently encountering another entity, they questioned whether they were deal- ing with Texas fever alone or with two dis- tinct diseases. In 1910, Arnold Theiler, in South Africa, presented evidence that two diseases were in- volved, piroplasmosis and another which he named, anaplasmosis. K. F. Meyer, in 1913, confirmed observation of anaplasma-like bodies in California cattle. Thereafter, little atten- tion was given to the disease. Most people be- lieved that it would be controlled with the eradication of the fever tick. However, in 1921), Dai'lington reported that although ana- plasmosis was a troublesome disease in south- eastern Kansas, he had failed to find fever ticks on infected animals. This was the first indica- tion that eradication of the fever tick might not eliminate anaplasmosis. Much has been learned since then. Nature of the agent The causative agent of anaplasmosis is Ana- pkisnia marginale, a parasite that destroys the red blood cells of infected animals. Research workers are not in complete agreement as to the nature of the agent. During recent years, a number of investigators have tried to show that it is a filterable virus ; however, their woi-k has been either negative or inconclusive. Recently, Espana and coworkers reported that examination by phase contrast and elec- tron microscopy of hemolyzed erythrocytes from infected cattle showed the parasite to be more complex than was generally believed. Ring, match, comet, and dumbbell-like forms were observed. They found AnaplaJima mar- (/ivale to be motile, a property not previously described. This may be impoi-tant in cla.ssify- ing the parasite as well as explaining the mech- anism of cell penetration and the typical mar- ginal position. They believe it is justifiable to consider A. marginale a true parasite, prob- ably belonging to the Protozoa. Antibiotics and insecticides Weapons have not yet been developed for planned eradication or control of the disease and anaplasmosis still costs the cattle indus- try millions of dollars annually. Some prog- ress has been made in combating bovine ana- plasmosis on a herd basis. It was found that several broad-spectrum antibiotics inhibit the organism. Development of the comi)lement- fixation test has given one of the best tools for identification of infected or carrier animals. Encouraging results in stemming transmission of the disease by control of vectors have also been obtained through the systematic use of insecticides on infected herds. Anaplasmosis can be treated. But if tetra- cycline antibiotic therapy is to be used bene- ficially, it must be given early in the period when anaplasma bodies are increasing in num- ber. The antibiotic suppresses formation of additional bodies. Blood transfusions are in- dicated during the period of anemia and espe- cially before the crisis is reached in RBC de- -struction. Ticks in the west; fh'es in the south The anaplasmosis syndrome is similar wher- ever the disease occurs. However, the vectors thought to be chiefly responsible for the trans- mission of the disease in the Southeast are dif- ferent from those in the West. In the Rocky Mountain and West Coast Regions, the natural vectors of primary importance are believed to be the spotted fever tick (Dermacentor ander- s())ii), and the Pacific Coast tick {D. occiden- tiilis) ; biting insects are considered of second- ary importance. In the Southea.st, horseflies and mosquitoes are believed to be the primary vectors. Natural wild animal reservoirs have not been implicated in this region as have deer in California. 29 Prospects for controlling or eradicating ana- plasmosis are less encouraging in the Western States than in the Southeast since the causative agent can survive longer in the body of a tick than in a i\y or mosquito. It also has been shown that anaplasmosis may be transmitted from one generation of ticks to the next and then into a susceptible bovine host. The key to control Since the infection is easily spread by me- chanical transfer of infected blood, man, through carelessness in performing blood-let- ting operations, becomes an important poten- tial agent of conveyance. Prevention of nat- ural, mechanical disease transmission is the key to control. This, in turn, is conditioned by four factors: (1) The infectivity level of the blood of carrier cattle; (2) the biting insect vector density population for any given area; (3) the lapse of time between insect feeding on infected and susceptible cattle; and (4) pre- cautions against carelessness in blood-letting operations. Control of any of these factors has an immediate, favorable effect on reducing the disease transmission rate. In certain areas of the country, herds have been cleared of the disease by application of the complement-fixation test and segregation or disposal of reactors. If segregation is prac- ticed, carrier or reacting animals should be sufficiently I'emoved from the susceptible group to insure that interrupted vector feedings are not resumed on the susceptible animals. These practices have been found feasible in Virginia, and the State is offering a voluntary program to livestock owners. Suspect herds are tested and owners given the choice of re- moving reactors for immediate slaughter or holding them under segregation pending slaughter. A similar project on a limited scale is being offered in Tennessee. No indemnity is paid under the voluntai^j' programs. Halting the disease in Hawaii Hawaii has had a program since November 1955. It was initiated as a pilot project to see if anaplasmosis could be eradicated by use of the complement-fixation test. The essentials of the program are — (1) Application of the complement-fixation test for the detection of carrier ani- mals. (2) Identification and immediate slaughter of positive animals. (3) Testing of herds (including all cattle 2 months of age and over) at not less than 60-day intervals until two nega- tive tests are obtained. (4) Testing of blood samples collected from all cattle slaughtered in the Islands to detect foci of infection. Since anaplasmosis was brought to the Is- lands by importation of carrier animals from the mainland, only animals negative to the com- plement-fixation test are now permitted entry. Cattle must pass two negative tests — one be- fore shipment from the mainland and a second on arrival, before release from quarantine. They are retested 60 days after introduction into a herd. In the absence of a serious vector problem, Hawaii ofl[icials believe that their pro- gram provides a practical means of eradicating anaplasmosis. Field trials in Mississippi In January 1959, field trial studies were started in the Delta Region of western Missis- sippi. The situation there is different from that in the Hawaiian Islands, in that biting insect populations build up during the warm months from spring to fall. Of the nearly 15,000 head of cattle tested in 79 herds in 16 counties, slightly more than 60 percent of the animals were classed as reactors or suspects. Individual herd incidence patterns varied from no reactors in a few herds to almost 100-per- cent reactors in several herds. Unfortunately, because of lack of funds, it was necessary that owners pay for the collec- tion of blood samples. Hence, herd retests gen- erally were not made at desired intervals dur- ing the nonvector winter months. Neverthe- less, overall results, from the standpoint of reduction of losses from anaplasmosis and new transmission, were encouraging. During the summer of 1959, there were fewer losses in herds in which control measures were practiced than there had been the pre- vious year. Some clinical cases appeared in the susceptible segregation groups. But in 30 every instance, it was shown that sufficient testing had not been done to insui'e that all carrier cases had been removed prior to the vector season. Clinical cases and death losses were extensive in the nonsegregated and non- tested herds in the area. This indicated that conditions for natural spread of the disease were present. Several herds in the area are being studied for the effects of insecticide and antibiotic con- trol. Preliminary findings indicate that I'egular use of insecticides and antibiotic feeding sup- port the segregation program. Trials to continue Field trial studies in the Delta Region will be continued until more detailed recommendations on control can be made. Research and field studies will also be continued in the sections of the country where ticks are the primary vector. Where anaplasmosis is not too prevalent and the natural vectors of primary importance are biting insects, the disease can be controlled by application of the complement-fixation test, re- moval of reacting carrier animals by segre- gation or slaughter, and proper herd manage- ment practices. CATTLE GRUBS Cattle grubs, also called "warbles" or "wolves," are the larval stage of the heel fly or warble fly. This pest of economic impor- tance has plagued domestic animal producers throughout recorded history. The two species present in this country — Hypoderma lineatum, the common cattle grub, and H. hovis, the northern cattle grub — were probably imported with the fii'st cattle brought in by the early American settlers. Their sub- sequent spread paralleled movement of cattle accompanying settlers during their westward migration. The common cattle grub is found throughout the United States. The northern grub, for- merly limited to the Northern States, is gradu- ally spreading south. The grub story The two species have a similar life history. Eggs are attached near the base of the hair on the host. The adult of the northern species de- posits her eggs singly. Her buzzing approach panics cattle, and the fly in pursuit strikes the thighs and the rump. The adult of the com- mon species — more stealthy in its approach — manages to place several eggs on the heels or the underside of the host. Eggs hatch in 3 to 6 days and the newly hatched larvae penetrate the skin. They mi- grate through the host to the gullet, dia- phragm, and abdominal viscera. Nine months after penetration of the host the grubs appear under the skin of the animal's back. They come to rest near the median line between the shoulders and hips, cut a breathing hole through the skin, and encyst. The injury at this site is considered most damaging by the leather industry. Soon after the larva reaches the back, it molts into the second instar. During this stage, which lasts about 3 weeks, the larva grows and causes considerable tissue inflammation, us- ually accompanied by pus, in and around the cyst. A second molt follows, and the larva enters the third and final stage of its develop- mental period. After some 20 days, the mature larva emerges from the cyst and falls to the ground. It crawls under a protective object and pupates. The pupal period lasts fi'om 16 to 75 days, depending on temperature and humidity. At the end of this period, the adult fly emerges from its pupal case and immediately seeks a mate. Adults do not feed, and egg laying promptly follows mating. Losses Livestock Conservation Incorporated reports annual losses from cattle grubs of over $55 million to growers and feeders; $32 million to the tanning and leather industry; and $13 mil- lion to the meat packing industry — a total of more than $100 million annually. Control The effectiveness of rotenone in controlling cattle grubs has long been recognized. Some workers rate it at a little less than 80 percent as compared with the 85- to 90-percent effec- tiveness claimed for more recently developed 31 organic phosphate systemic insecticides. The latter have been used extensively in field trials during the past few years with encouraging results. The future The National Cattle Grub Committee reports as follows: "Research in grub control now un- derway and recommended includes a study of the ecology and life cycle of the parasite in various regions, effects of movement of cattle from one climate to another on the life cycle of grubs, the apparent resistance of older cat- tle to grubs, and the possibility of induced im- munity to grubs." The Animal Disease Eradication Division does not envision a national cattle grub eradi- cation program in the immediate future. How- ever, available reports on each new develop- ment in research and field trials are constantly examined and analyzed in light of possible ap- plication to cattle grub eradication. HOG CHOLERA The cholera chronicle Hog cholera is reported to have been in this country since the early 1830's. Some reports indicate that it was here before then. During the latter part of the 19th century it devastated the swine population of the country. As late as 1913 an epidemic of this disea.se was responsi- ble for killing 10 percent of the hogs in the United States. After much trial and error, research scien- tists of the former Bureau of Animal Indu.stry identified a virus as the cause of hog cholera. Following this, vaccination with live hog chol- era virus and serum was started. This type of immunization saved the swine indu.stry of the country. Periodic outbreaks, however, con- tinued to occur. Investigations revealed that they were due to no vaccination or. in some cases, were directly attributable to the virulent virus used in the immunization. HOG CHOLERA REPORTED Fiscal Year 1960 PUERTO RICO U S DEPARTMENT OF AGfitCUlTuBf ■^EG 60 (n> S057 AGBICUIIUBAI SESEAHtCM SfBviCE 32 Because of the annual incidence of the dis- ease, as well as the fact that the immunizing agent itself was capable of introducing infec- tion on premises, no State or Federal programs were proposed for the eradication of the dis- ease. Its control, consequently, remained with the owner and the practicing veterinarian. In 1951, modified live virus vaccines were perfected, which considerably reduced the haz- ard of virus introduction from immunization. The trend since then has been reduction in the use of virulent virus and its replacement with modified live virus and serum. Also in 1951, the United States Livestock Sanitary Associ- ation outlined procedures in a recommended hog cholera eradication program. Status and stimulus Increased use of newer immunizing agents and the prohibition against feeding raw gar- bage, now imposed by all the States, have stim- ulated the drive for eradication. Additional impetus has come from Livestock Conservation Incorporated, which represents various segments of the swine indu.stry. At its annual meeting in February 1960, the organi- zation noted that losses and damage from hog cholera justified an all-out eradication effort. It recommended an educational approach and regional meetings by the U.S. Department of Agriculture to urge States to start eradication programs. Following that suggestion, the Division and the Federal Extension Service held meetings in Chicago, New Orleans, and New York dur- ing March and May. Industry reaction was enthusiastic. A fourth regional meeting was held in Denver, Colo., in August. The future of hog cholera Additional regional and State meetings will be held to acquaint the various interests with the factors and problems involved in an eradi- cation program. If industry then is still sufficiently interested to give its support, it is expected that State programs for the eradication of hog cholera will be started. VIRAL ENCEPHALITIS Like many other diseases, the encephalitides were present and inflicting widespread spo- radic damage for many years before they were identified. From Boston in 1854, Texas in 1882 and 1897, North Carolina in 1902, and Louisi- ana in 1906 and 1907, came reports of a neu- rologic disea.se in horses. It was variously called "forage poisoning," "blind staggers," and "brain fever." The disease was differentiated from a num- ber of others and established, in 1930, as a definite clinical entity called equine encephalo- myelitis. The identification of its viral nature came as the result of an investigation in Cali- fornia that year of G.OOO affected horses and mules, half of which died. Serological distinction of the disease into two types. Eastern and Western, was made in 1933. The Eastern type has remained localized along the Atlantic Seaboard and the Gulf of Mexico, with isolated occurrences in Tennessee, Mi.ssouri, Michigan, and Wisconsin. The West- ern type has occurred in every State west of the Mississippi. EQUINE ENCEPHALOMYELITIS Reported During Calendar Year 1959 From 1935 through 1959, the total number of horses reported affected with eastern and western encephalitides in the United States was 503,725. Of this number, 38,258 died. Considerable difference of opinion still exists concerning the natural history of the virus. There is general agreement, however, that neither humans nor horses are necessary to the life cycle of the disease. Both are accidental 33 dead-end hosts. The virus is most commonly transmitted from bird to bird, with mosquitoes the principal vector. Sometimes horses are infected without the involvement of man. When both horse and man are involved, horse cases generally pre- cede the human by 2 weeks. What factors are responsible for this periodic "spill-over" from birds into horses and man is not known. With our present knowledge that the virus affects the horse, mule, ass, deer, pheasant, wild birds, and humans, it seems more appro- priate to designate the disease viral encepha- litis. In horses, following incubation of several days to 3 weeks, the disease produces typical symptoms of an encephalitis, including fever of 107° F., rapid paralysis, sleepiness, eventual respiratory failure, and death. With the more virulent eastern type there may be 90 percent fatality. Horses can be protected by preseason inoculation with a bivalent vaccine, and mos- quito control. In pheasants, symptoms resemble the paraly- sis of botulinus intoxication. Outbreaks among pheasants in the Northeast generally accom- pany those in horses — suggesting involvement of the same vector. Mortality can exceed 60 percent. Present knowledge of viral encephalitis re- moves the stigma from the horse as a danger to public health. The Division has no eradication program for viral encephalitis, nor is one contemplated. Nevertheless, in these times of alertness to the threat of biological warfare, a prompt diag- nosis is essential — not only for recognition of viral encephalitis, but also to be sure that it is not .something else, more deadly and more difficult to control. POULTRY DISEASES Poultry progress Throughout the pages of history, man has waged constant war against disease. Next to those directly affecting him and his family, the diseases that threatened his food supply have been of greatest importance. As the re- sult of improved husbandry practices and eco- nomic pressures on the producers, the place of poultry in this food supply has increased many- fold since the days of chicken for "Sunday din- ner." The housewife now has a choice between poultry or red meat products never before achieved in food logistics. Conscious of the ever-present possibilities of economic disaster and loss of this vital seg- ment of the Nation's food supply due to disease, the U.S. Department of Agriculture, at the in- dustry's reque.st, establi.shed a Poultry Disease Section July 9, 1956. Its purpose was to coor- dinate national poultry disease control and eradication. The section cooperates closely with State Livestock Sanitary officials, research workers, the poultry industry, and other inter- ested governmental agencies. To provide its veterinarians witli additional experience in poultry disease work, the Divi- sion, in 1956, started a training program at Iowa State University. Poultry disease diag- nostic courses conducted in 1957, 1958, and 1959 made available for immediate field work 49 Federal, 12 State, and 2 veterinary prac- titioner poultry diagnosticians. Graduates have at their disposal a poultry diagnostician's kit of equipment plus detailed instructions in ADE Division Memorandum No. 501.4, Supple- ment 2, entitled "Investigation of Suspected Emergency Poultry Disease Outbreaks." Ornithosis outbreaks The immediate problem facing the new Poul- try Disease Section was the alarming increase in the number of cases of ornithosis in turkey flocks in Oregon and Texas. Ornithosis in poultry and other species, or "psittacosis" as the disease is known in the parrot bird family and man, was first described in 1874 in Euro- pean literature. Evidence obtained since 1950 has indicated that ornithosis is fairly widespread among domestic turkeys. It has also been diagnosed in ducks and chickens. Numerous epidemics in humans have been traced to exposure of processing plant employees to diseased poultry or to recent importations of infected parrots or psittacine birds. Human cases of psittacosis have been most severe in Oregon and Texas; death has resulted in several instances. A regulation to control ornithosis or psit- tacosis was published in the Federal Register 34 ORNITHOSIS IN TURKEYS AND DUCKS f^-^ __ Reported, 1945 - Januory 1958 ^JJj VIRUS ISOLATION '■■ ; SEROlOGICAl (VIDENcE ^ V on March 7, 1957. This regulation (Part 82, Title 9, CFR) restricts interstate movement of poultry affected with psittacosis or ornithosis and their carcasses, parts, and offal. It also requires disinfection of coops and vehicles used in transporting affected poultry. Management factors in condemnations When compuls()r\- inspection of dressed \wi\\- try moving in interstate traffic became law on •January 1, 1959, there arose the problem of high condemnation rates, particularly from chronic respiratory disease. In an effort to find some solution for this economic loss, the Division in cooperation with the Agricultural Mai-keting Ser\ice conducted surveys in se- lected flocks in Arkansas, Louisiana, Missis- sip])i, and East Texas. These limited sui'veys indicated that the high condemnation rates wei'e caused by lack of good management, in- atlequate housing, and substandard or no disease control plans by producers. Similar coojjerative studies with State and industry representatives have been conducted in Georgia and the Delmarva Peninsula. Poultry prospects Eradication of oi-nithosis or psittacosis can- not be planned at this time because of the unavailability of a reliable, practical field di- agnostic test. The immediate objective is the di.ssemination of information regarding the nature and clinical manifestations of the di- sease. After treatment, recovered flocks may be marketed when deemed safe by State and Federal officials. In 1958, the National Plans Confei-ence of the National Poultry and Turkey Improvement Plans adopted a resolution reque.sting that the Animal Disease Eradication Division i)i'omul- gate a Federal Regulation limiting the inter- state movement of poultry except from those flocks and hatcheries that meet the minimum requirement of the NPIP and NTIP in regard to jndlorum disease and fowl typhoid control. The regulation was published, and comments from industry groups are being reviewed be- fore further action is taken. The Division is engaged in cooperative studies on poultry diseases with State universi- ties and State departments of agriculture in Georgia, Maine, Minnesota, and Virginia. In future plans and operations the watch- word is vigilance. Through the Poultry Di- sease Section, the Division is in a better posi- tion to deal with any foreign poultry disease that may gain entry into this country. Con- cui'rently. close scrutiny will be kept on changes in the epidemiological patterns of di- seases now present in the United States. This work will be accompli.shed by recording data reported by the individual States, conducting epidemiological surveys concerning chronic respiratory di.sease, and gathering information on the latest research developments. 35 Laboratory Services LOOKING BACK IN LABORATORY SERVICES In June 1955 a committee of scientists in- spected Agricultural Research Service disease laboratories in WashinRton, D.C., and at Belts- ville, Md. ; Auburn, Ala. ; and Denver, Colo., and reported that the laboratories were not adequate to safeguard employees from expo- sure to disease or the experimental work from cross-contamination. Much of the laboratory woik in research and regulatory fields at Washington, Auburn, and Denver was discon- tinued. Also, in 1955, laboratory programs which had been performed by the Pathological Division of the former Bureau of Animal In- dustry, were assigned to Animal Disease Erad- ication in 1955. The.se laboi'atory programs were placed under the staff position of Labora- toi-y Services, which now has been enlarged to a staff of 45. In addition to maintaining facilities in Washington, D.C.. and at Beltsville, Md., and Ames, Iowa, Laboratory Services maintains a close working relationship wiih all diagnostic laboratoi'ies in the United States and in many foreign countries. There are 155 animal diag- nostic laboratories in this country. Biological cultures, reference materials, and direct assist- ance are provided to these laboratories on request. A Manual and Directory of Animal Diagnostic Laboratories in the L'nited States was completed in 1958 and distributed to field stations, State animal diagnostic laboratories. State livestock disease control officials, and others interested in State-Federal programs. Diagnostic services for the detection of dis- eases that might be introduced into the United States are cooperatively administered with the Plum Island Animal Disease Laboratory. A staff member is stationed at the Plum Island Animal Disease Laboratory for this purpose and to become experienced in recognizing ex- otic animal diseases. Training for Division personnel at colleges and universities is supervised by Laljoi-atory Services. This includes approval of graduate programs as well as supervision and guidance given to individuals in such programs. Staff members of Laboratoi-y Services have an opportunity to become experienced in many fields related to the control and eradication of animal diseases. The functions of the staff of- fice are practical, and often provide the great satisfaction of applying knowledge on a pilot ANIMAL DISEASE DIAGNOSTIC LABORATORIES JUNE 30. 1960 u % MMnTufPiT (y*e«icu.Tut «<; €0 If '-cy: L'>^li "t««PCH S(*V<( scale for disease eradication which has been established only through many years of scien- tific research. The staff office provides a corps of technical personnel having a broad range of experience with a wide variety of animal di-seases. Division programs actively supported by Laboratory Services are those for the eradica- tion of brucellosis, tuberculosis, screwworms, vesicular diseases, scabies, and scrapie. Lab- oratory programs are also in progress to sup- port activities in anaplasmosis, leptospirosis, enzootic abortion of ewes, and enteric infec- tions. 37 ACHIEVEMENTS Washington, D.C. The staff of Laboratory Services was instru- mental in compiling and editing material for inclusion in a publication requested by the subcommittee on Reorganization and Inter- national Organizations of the Senate Commit- tee on Government Operations. Entitled "Veterinary Medicine of the United States and its Contribution to Man's Health and Welfare," it deals with both national and international organizations and agencies in which veterinary medicine of the United States plays a part. It will be used mainly for congressional review but should serve as an invaluable documentary of information on the services veterinary medi- cine has rendered to mankind. The semiannual check test kits for brucel- losis were supplied to all of the principal State- Federal laboratories. These tests check agree- ment between laboratories. The results on the last series showed agreement on 92 percent of the samples tested. The chemistry unit, although an integral part of the Division, performs services for both Animal Disease Eradication and Animal Inspection and Quarantine Division pertaining to (a) acaricides, (b) disinfectants, (c) ani- mal tissues and other matter suspected of containing poison, (d) animal byproducts of- fered for entry from areas having or suspected of having foot-and-mouth disease or rinder- pest, and (e) diagnostic agents. Two hundred and eighty-seven chemical analyses on products and materials were com- pleted in 1960. In addition to chemical analy- ses, the laboratory develops apparatus and methods for vat-side testing of dijjs used in the Division's regulatory work. To maintain this testing of dipping baths, chemicals for 16,872 tests were furni.shed field inspectors. Also supplies for 967 tests were furnished inspec- tors for determining the preservatives in serums, vaccines, and diagnostics manufac- tured under the supervision of the Veterinary Biologies Inspection Section of Animal Inspec- tion and Quarantine. All pullorum antigen employed for official testing under the National Poultry and Na- tional Turkey Improvement Plans must meet the chemical and sensitivity standards estab- lished by Laboratory Services. Te.sts repre- senting a production total of 1,349,488 milliliters of K polyvalent pullorum whole- blood antigen, 1,021,751 milliliters of Redigen whole-blood antigen, and 37,605 milliliters of pullorum tube antigen were performed in 1960 in support of this program for the control of salmonellosis. Belt-sville laboratory Brucellosis. — All diagnostic materials used to conduct Brucellosis serological tests are pro- duced at Beltsville. A total of 702,240 milliliters of Brucellosis plate antigen, 119,500 milliliters of concen- trated tube antigen, and 114,060 milliliters of Brucella Ring Test antigen were produced during 1960. The amounts of the three an- tigens produced each year reflect the activi- ties of the brucellosis eradication program since 1950. Brucella abortus Stroin 1119 ANTIGENS PRODUCED AND DISTRIBUTED THOUS.ML. 1950 1953 1956 1959 US DEMRTHENTOFaCRICULlUHE i3BiCyi,Tu««^ KESEAHCH SIBvi:£ Antigens are distributed for the most part to State-Federal Cooperative Laboratories. Small amounts are furnished on request to re- search institutions and foreign countries des- ignated for use as standard antigens for comparative testing or research purposes. More than 10,000 agglutination tests for brucellosis were made on samples from cattle and swine from Federal herds during 1960. Commercially prepared Brucella plate anti- gens totaling 119,600 milliliters were tested for sensitivity, total cell concentration, purity and sterility and were found to be satisfactory foi- diagnostic purposes. 38 All EniciUa abortus strain 19 vaccine pro- duced in the United States for use in State- Federal brucellosis eradication is examined at Heltsville before release. Vaccines that do not meet the rigid requirements for purity, hy- drogen ion concentration (pH), total cell con- centration, viability, and colonial characteris- tics are rejected. During the year, 1,516 serial lots, i-epresenting 8,604,946 do.ses, were tested. Of this amount, more than 7,949,876 doses (92.4 percent) were released as safe and reli- able for use. There has been a gradual in- crease in volume production of desiccated strain 19 vaccine (lyophilized) since the re- lease of this i)roduct in 1945. Eighty-six per- cent of the 43,024,733 milliliters produced in 1960 were desiccated vaccines. Brucella abortus Strain 19 VACCINE RELEASED FOLLOWING TEST Ml I. DOSES 1950 1953 1959 US oeParthcmto^aomiculTure ■ SHICULtUtttL HtSCKCH SCKVlCC In addition to the Brucella strain 19 vaccine (liquid) produced at Beltsville for reference purposes, 840 doses were distributed for vac- cinating calves in 19 Federal in.stitution herds. On numerous occasions, cultures of the or- ganism causing brucellosis have been supplied to private and Government laboratories in the United States and in many foi'eign count I'ies. To replace stock cultures for use in produc- ing the vaccine, continuous since the jjrocedure was inaugurated in 1940, 107 selected Brucella abortus strain 19 cultures were supplied to 17 commercial laboratories and 2 State in.stitu- tions during 1960, and 106 selected cultures were sent to 17 foreign countries. Of the 213 cultures di.'^tributed, 50 percent were furnished for distribution outside the continental United States. Thirty-six selected cultures of Brucella abortus antigen strain 1119-3 were distributed to 1 States and 10 foreign countries for use in producing antigens and for research pur- poses. Stock cultures of Brucella abortus .strains 19 and 1119-3 (lyophilized) are main- tained at the Division laboratories at Beltsville for immediate distribution to approved insti- tutions throughout the world. The Division al.so extends technical assist- ance and training to scientists from many foreign lands interested in the brucellosis erad- ication program of the United States. As a result of those exchanges, a close working re- lationship has been e.stabli.shed with .scientists in many parts of the world. Through arrangements with the Interna- tional Cooperation Administration and other agencies, 26 individuals rei)re.senting 16 foreign countries and the Pan American Sani- tai\- Bureau were approved for visits to the Beltsville Laboratories in 1959. The various l)ha.ses of production, .standardization, and control of Brucella antigens and vaccine and the diagnosis of brucellosis in animals were demonstrated and discussed. During the year, 1,716,460 milliliters of mammalian contract tuberculins i)roduced com- mercially for the Agricultural Ke.search Serv- ice were tested and released as satisfactory for use in the State-Federal program for diag- nosis of tuberculosis. Vesicular Diseases. — Serological testing is another important function of Laboratory Services at Beltsville. Of special importance is the diagnosis of vesicular exanthema, in- fectious bovine rhinotracheitis, and vesicular .stomatiti.s, and their differentiation from foot- and-mouth disease. Vesicular stomatitis of the New Jersey type was the only vesicular disease diagnosed in 1959 from 36 tissue and 257 sei'um samples received. The first cases again were reported during May from the enzootic coastal i)lain areas of North Carolina, South Carolina, Georgia and Louisiana. Simultaneously, ve- sicular stomatitis appeared in six counties bordering the Texas side of the Rio Grande River. The Texas outbreak was part of an epidemic that progressed northward through Mexico, crossed the Rio Grande into Texas, and finally abated. 39 LABORATORY DIAGNOSES OF VESICULAR STOMATITIS Count, rt. Jonuory 1 - D*i*mb«r 31 1959 The epidemiology' of this Texas outbreak is comparable to that of 1949, which also started early in the season and progressed from Texas and Arizona into Colorado, Utah, Wyoming, and Wisconsin before it stopped in the fall. The possible reservoirs of infection and vectors remain unknown. The infection frequently spreads from the Carolina-Georgia and Louisiana-Mississippi endemic coastal plain areas northward into Virginia, West Virginia, and Maryland. Anaplasmosis. • — Serological diagnosis of anaplasmosis of cattle is another activity of the Beltsville laboratory. Interest in the pos- sibility of establishing a control program for this disease is increasing. Since the Agricul- tural Research Service is no longer in a posi- tion to produce anaplasmosis antigen in its own laboratories, a cooperative agreement has been established for its production at the Texas Agricultural Experiment Station. Two million test doses of anaplasmosis com- plement-fixation antigen were delivered to the Division's Beltsville laboratory on June 7, 1960, by the Texas A & M College. This delivery completed phase I of the cooperative project between the Division and Texas A & M College for the production of anaplasmosis antigen. The antigen is now available for distribution to cooperating laboratories. Under phase II, another 2 million test doses are scheduled for delivery by June 30, 1961. The Beltsville laboratory is responsible for distributing antigen, complement, standard sera, and other diagnostic materials related to performance of the complement-fixation test for anaplasmosis in the various field labora- tories. It also maintains general supervision of testing efficiency and accuracy of the 16 Fed- eral, State, or University laboratories engaged in the testing of serum for anaplasmosis. A composite report of the results on a large number of unknown serum samples forwarded to these 16 laboratories for comparative test has recently been made. A total of 21 State or Federal serologists have completed training at the laboratory in the complement-fixation test for anaplasmosis. The new "small" tube technique for anaplas- mosis has been inaugurated and all labora- tories engaged in anaplasmosis testing have been so informed. Each laboi-atory was fur- nished the new publication, "Manual and Directory of Animal Diagnostic Laboratories in United States," standard serums, hemolysin, standard complement, and antigen. The serology' unit also tests for dourine and glanders all equine serum samples submitted from the various quarantine stations and other points. During 1960, 11.085 tests were made for dourine and 11,075 for glanders. Ames diagnostic laboratory The Diagnostic Laboratory at Ames, Iowa, was established in 1957 under a cooperative agreement with Iowa State University to serv- ice the Division's programs in tuberculosis, brucellosis, scrapie, and other diseases of na- tional interest. The staff of 20 will be transferred to the National Animal Disease Laboratory in 1961. Tuberculosis. — Many new types of bacterial organisms closely resembling Mycobacterium tuberculosis are being recovered from human patients thought to be tubercular. In order to maintain the confidence built up in the tuberculin test over the years, it was important to get more information about the causes of reactions to mammalian tuberculin in no-gross- lesion cases under field conditions. A project was established for this purpose in 1957. Specimens collected from animals that re- veal NGL reactions as well as specimens from regular kill are studied. Procedures include direct culturing of specimens, animal inocu- lations for initial recovery of organisms and 40 typing, and staining of smears and histological sections for evidence of acid-fast organisms. Isolations of soil acid-fast organisms are capable of producing allergens which cross- react with mammalian and avian strains. These allergens usually produce low sensitivity when injected intramu.-^cularly. Guinea pigs inoculated intramusculai-ly with soil acid-fast isolates were .still reacting 3'.j to 4 months after inoculation; only avian and mammalian tuberculin were used on the .second test. The greatest reaction was obtained with avian tu- berculin. Field evidence indicated the soil acid-fast produced sensitivity may be of short duration, and the time between exposure and testing will be shortened to less than 2 months in future laboratory trials. Microscopic .study of 417 cases of suspected tuberculosis lesions on regular cattle kill was made. Thirty-one percent were positive for acid-fast bacteria, and another 10 percent con- tained atypical acid-fast oi'ganism. Of the remainder, 33 percent were mycotic, parasitic, or neoplastic, and 26 percent were negative. This compares favorably with lesions selected from tuberculosi.s-reactor animals. Out of 160 such lesion cases, 23 percent showed typical organisms and 17 percent showed atypical acid-fa.st bacilli. Of other causes, 22 percent were mycotic, parasitic, or neoplastic, and 38 percent were completely negative. While in- dicating the general effectiveness of the tuber- culosis control program, these figures reflect the difficulties that will be encountered in the final phase of tuberculosis control. They stress the importance of careful meat inspection and laboratory procedures in detecting tuberculous animals on regular kill, and tracing them back to source herds, which may then be tuberculin- tested. Studies were completed on the use of media versus laboratory animals for primary isola- tion of acid-fast oi-ganisms from bovine tis- sues. These studies revealed that certain media are as good as laboratory animals, or possibly better, for the primary isolation of Mycobacterium tubercidosis organisms. This has resulted in a saving of time and laboratory animals. Brucellosis. — Correlation of .serological and bacteriological results in reactor herds is in progress. Attempted isolations from 63 vac- cinates in 10 herds were positive in 18 (29 percent) of the animals, although 4 of the infected vaccinates were in the negative or suspect serological range. In nonvaccinated cattle, isolations were possible in 19 (46 per- cent) of 41 animals in 8 herds, and only 2 of these were classed as suspects. In herds containing both vaccinated and nonvaccinated animals, 45 percent of the isolations were from vaccinated cattle, while 5.5 percent were from nonvaccinates. Only 1 of the 15 herds that were shown to contain infected cattle had a negative Brucella Ring Te.st (BKT) hi.story. An isolation of a Brucellalike organism was made from tissues submitted by the New Mexico field station from a ram with a history of loss of viability of sperm. Preliminary serological and biochemical studies revealed that the organism has certain characteristics of all three of the Brucella species but is dis- similar to any one in particular. Trichinosis. — The cooking of garbage fed to swine was initiated as a measure to control vesicular exanthema; however, other diseases are also reduced by this measure. One of these is trichinosis. To evaluate the incidence of Trichina, 64 lots of 1,896 diaphragms were examined for the isolation of Trichinella i^piralis. Trichina were found in 188 dia- phragms of 21 of these lots. Since diaphragms were submitted only from Northeastern States, the study did not show national distribution. Scrapie. — Pathological evidence is used to diagno.se scrapie, as no virological means are available. Diagnosis is based on the history and findings of characteristic vacuoles in the brain. Twenty-seven laboratory confirmations of the disease were made at the Ames Labora- tory from January 1958, to August 4, 1960. Studies have been started to evaluate the present methods of histopathological diagnosis. DIAGNOSTICIANS AND EPIDEMIOLOGISTS Specialized training programs are being utilized to e.stablish teams of diagnosticians and epidemiologists for investigating and studying animal di.sease outbreaks. These groups w'ill function for field investigational work when diseases of unusual nature or pro- 41 portions are encountered. This service will include diagnosticians and epidemiologists for vector-transmitted diseases, industrial and phytotoxicological diseases, radiation diseases, mycotic, protozoal, and viral diseases. Other teams will be trained in the investigation of such exotic diseases as rinderpest, foot-and- mouth disease, and virulent strains of New- castle disease of poultry. Records of past anthrax outbreaks suggest that alternate wet weather and drouth, where the organism is established in the soil, may cause increased incidence of the disease. The prediction of a 1959 increase in the Southern Great Plains was followed by the identification of at least four foci of infection. The impor- tation of infected cattle from Mexico caused a fifth outbreak. Studies of hog cholera and immunization procedures in the Corn Belt indicated that weather may also favor complications follow- ing vaccination with modified viruses. Seque- lae were reported more common during hot, humid weather. The need to continue use of virulent virus was not established. COOPERATIVE PROJECTS WITH OTHER LABORATORIES Salmonellosis Because of the importance of serological typ- ing in a program to control salmonellosis in domestic farm animals and poultry, a coopera- tive program was established with U.S. Public Health Service. A bacteriologist has been assigned by the Division to the Communicable Disease Center in Georgia to conduct typing and identification of enteric organisms of animal origin. This has enabled State animal disease diagnostic labora- tories to submit more cultures for study and typing. This laboratory activity will be trans- ferred to the National Animal Di.sea.se Labora- tory in 1961. Lept-ospirosis The relationship between leptospirosis in wildlife and livestock is under study by an epi- demiological team in cooperation with the New Bolton Center of the University of Pennsyl- vania. It is important to establish the role of wild- life leptospirosis in the study area because of many favorable opportunities for the transmi.s- sion of infection to domestic animals and to humans. This team is using the agglutination- lysis test and several nutrient media to isolate and identify leptospira from livestock, the water supply, and from wildlife in the vicinity of the diseased herds. The motility of leptospira and their lack of resistance to drying makes water a principal means of spread. Investigators have found leptospira are adversely affected by acidic wa- ter; they lose motility at a pH below 6.0. They prefer alkaline water. Stream pH in the area of study varies from 6.9 to 8.5. Many streams and pools persist throughout the year, and dur- ing their low stages in summer, animals stand- ing in them may become infected. Although the project has been active for less than 6 months, much information regarding the role of wildlife has accumulated. The dem- onstration of Leptospira poniona infection in a woodchuck indicates the importance this com- mon inhabitant of pastures might assume in control of bovine leptospirosis. One outbreak was investigated in which blood cultural isola- tions were made from 8 of the 22 cattle in the herd. The source of infection was found to be carrier animals which were introduced into the herd less than a month before the blood isola- tions were made. A national survey of serological techniques used in the diagnosis of leptospirosis was com- pleted this year. Check samples were submitted to all laboratories conducting leptospii'osis tests. The results indicated considerable variation in procedures. Adoption of a standard test with strict adherence to details of procedure would improve the uniformity of results. Efforts are being made to encourage the adoption of a standard serological technique. The various tests, such as the agglutination-lysis te.st, are being studied to determine the sources of their inherent variation. A serological method for detecting dairy herds infected with leptospii'O- sis by means of the composite herd milk sam- ple has been developed. Serum samples of ani- 42 nials, inc-ludiiiK wilcilife, submitted from all parts of the United States are examined for antibodies apainst at least 12 leptospiral sero- types. This service is of particular value where signs of leptospirosis are observed, but routine testing with Lcptn?:pira pomona antigen yields negative results. Where infection with the less common serotypes is indicated locally (Iowa), field investigations are performed in an effort to isolate the causative agent. Enzootic abortion Record of the Decade. — The virus of en- zootic abortion in ewes was first discovered in Scotland in 1950. Since then it has also been reported in several European countries. In the spring of 1958, the Montana Veteri- nary Research Laboratory isolated and identi- fied the virus in ewes in Montana. This was the first report of the disease in this country. It confirmed the belief that many of the hith- erto undiagnosed cases of abortion in sheep in the United States may have been due to this viru.s. Its similarity to the enzootic abortion virus of Scotland was subsequently established i)y a Scottish research group. Although exact distribution and prevalence of the disea.se in the United States were unknown, it was sus- I)ected to be widespread. A Study of Incidence. — The Division en- tered into an agreement with Montana State College on January 2G, 1959 to study the preva- lence of enzootic abortion in ewes in this coun- try and to improve the antigen u.sed in the com- plement-fixation test for the disease. The survey was initiated by soliciting sam- ples from flocks in which ewes had aborted and had a negative history as regards vibrio in- fection. During the period January 25, 1959 to April 21, 19()(), the following results were i-ejiorted by Montana Veterinary Research Laboratory, Montana State College : Incidence of enzootic abortion reported during the period January 26, 1959-May 16, 1960 State Arizona California Colorado Idaho Montana Nebraska North Dakota. Oregon South Dakota Tennessee Utah West Virginia. Wisconsin Wyoming Minnesota New Mexico.. New York Iowa Totals'. Percent. Flocks Total 1 6 1 22 18 2 4 2 1 2 5 1 1 9 1 1 1 1 79 Positive 1 18 7 1 1 4 3 35 44.3 Suspicious o 6.0 Sheep Total 38 61 6 1,416 587 26 42 11 35 19 293 1 15 86 4 15 7 9 :,67i Positive 1 152 78 1 1 22 16 Suspicious 271 10.7 2 83 24 3 1 30 15 158 5.8 ' Positive flocks were found in 7 of 18 States submitting samples. Suspicious flocks were found in 1 additional State. 43 Survey work conducted thus far indicates that EAE has been in this country for some time. This work has been biased to some ex- tent by the sampling of suspected flocks. A more accurate indication of the prevalence of this disease could be had by testing random samples collected from ewes at time of slaugh- ter. Vaccination .studies have not yet been com- pleted. Future Aims. — A psittacosis-lymphogranu- loma group antigen is produced from enzootic abortion virus. The current complement-fixa- tion test is not specific and not too effective in individual animals. It is fairly accurate when used to diagnose the condition in flocks pro- vided 30 percent of the flock is tested. Additional survey work is needed to more accurately determine the prevalence of enzootic abortion in ewes. Further studies also are necessary to refine the antigen and increase its specificity. The disease is not the type, such as foot-and- mouth disease, rinderpest, or African Swine Fever, that compels drastic action. Considei'ing the economic eifect of the dis- ease in other countries, and the additional studies that are necessary, present circum- stances do not warrant Division participation in a control program. The World Picture. — This is not a report- able disease in countries such as England, Scot- land, and France. Regulatory officials do not believe that its economic effects in sheep in those countries warrant an eradication pro- gram. A voluntary vaccination program is followed. The vaccine is reported to be effective. Even in infected flocks, the rate of abortion appears to decrea.se rapidly following vaccination of all ewes. LOOKING AHEAD IN LABORATORY SERVICES Laboratory Services must look toward pro- viding even broader diagnostic programs to meet the varied and changing needs of the Di- vision. Speciali.sts in the epidemiological study of most major diseases of animals must be available to meet the challenge of this highly technical field. Expanded and modern facili- ties and ecjuipment will soon be available at the National Animal Disease Laboratory. Funds totaling $16,250,000 were granted in July 1956 for establishment of the laboratory. Construction began in late summer of 1958 on a 318-acre farm tract east of Ames, Iowa. The national laboratory will include an Admin- istration Building, large and small animal labo- ratory buildings, a central heating and emer- gency power plant, sewage decontamination plant, and \arious types of support structures and animal quarantine barns. Most of the activities of Laboratory Services will be transferred to the new laboratory in the spring or summer of 1961. Regulatory functions will occupy approximately 20 per- cent of the total space, of which about one- half will be devoted to diagnostic services for Division programs. The remaining space will be used for laboratory functions in support of the biologies control programs of the Animal Inspection and Quarantine Division. The diagnostic services programs at the Na- tional Animal Disease Laboratory will require a staff of about 50, of which 18 will be veteri- nary specialists. The remainder will be tech- nical employees, animal caretakers, and others required to service the various programs. Re- cruitment for the laboratory staff at Ames has been limited almost exclusively to present Di- vision personnel having an interest in the labo- ratory service programs of the Division. The staff will move into these new facilities with a continuing determination to provide the best possible diagnostic services to meet the program needs of the Division. 44 Interstate Movement of Livestock INTERSTATE REGULATIONS Many regulations are considered by the pub- lic as a burden imposed on commerce for pur- poses they do not readily comprehend. However, regulations fill an important gap in animal disease control and eradication pro- grams. Methods of disease dissemination are thoroughly studied, and regulations are di'awn to prevent spread of the diseases. If these reg- ulations were not enforced, mo.st programs would be ineffective. Interstate Regulations administers two pro- grams : (1) Enforcement of regulations promul- gated under authority of the Animal Quarantine Laws. (Acts of May 29, 1884; February 2, 1903; and March 3, 1905) (2) Enforcement of the 28-Hour Law. (Act of June 29, 1908) Animal quarantine laws The regulations promulgated pursuant to the Animal Quarantine Laws are contained in Parts 71 through 83 of Title 9, Code of Federal Regulations. These regulations are designed to prevent the spread of communicable diseases by controlling the interstate movement of live- stock, including poultry, which are apparently free of disease or exposure thereto. Special provisions permit the interstate movement of reactors to the tuberculosis, brucellosis, and paratuberculosis tests, but only under certain carefully supervised conditions which insure their proper handling until final disposition. The regulations also provide for the proper cleaning and disinfection of all cars, boats, and other vehicles used in the interstate transpor- tation of diseased live.stock and poultry. These sanitary precautions apply likewise to yards and other premises used in connection with such shipments. Inspection for compliance with the laws is conducted throughout the United States at highway and railroad points, stockyards, and livestock centers. Apparent violations are re- ported to the Dei)artment for further investi- gation and possible prosecution. During 1960, reports were received of 367 violations of the AQ Laws. Twenty-eight of these cases, together with 8 on hand at the be- ginning of the year, were closed when further investigation revealed that either a violation did not occur or there were insufficient grounds on which to prosecute. Of the 225 cases sent to the Office of the General Counsel, 180 were recommended for prosecution. Because of ex- tenuating circumstances it was recommended that the remaining 45 cases be disposed of by letters of warning. In the same period, notice was received of 199 dispositions as follows: 99 — by Court action (including 2 dismis- sals). 29 — declined for prosecution by the Depart- ment of Justice ; however, 27 of these ca.ses with the concurrence of the De- partment of Justice had been recom- mended for disposition by letter of warning. 71 — declined for prosecution by various United States Attorneys ; however, warning notices were issued to the alleged violators. 28-hour law With the advent of railroads there began a new epoch in the delivery of livestock to mar- kets. "The first cars employed were crude af- fairs, built of slats without overhead protec- tion and without means provided for watering. . . . car roofs were built, hot for shelter, as might be supposed, but to prevent the cattle from jumping out, as the railroads had in- curred considerable losses from that cause." 45 This mode of transportation was attended with much cruelty. As reported from several sources in 1871 : "Cars are terribly over- crowded, and animals are carried great dis- tances without food or water." . . . "Cattle trains yield the road to most others, and pass hours on sidings ; the animals are without food or water, and often with insufficient ventila- tion in summer or shelter in winter; they are jolted off their legs and then goaded till they struggle up, for they cannot be permitted to lie down ; they thus arrive at destination trampled upon, torn by each others' horns, bruised, bleeding; having in fact suffered all that ani- mals can suffer and live. The whole system of cattle transportation in the United States as at present conducted is an outrage on the first principles of humanity." A monotonously deadening repetition of these practices and a mounting public clamor culminated in the Act of June 29, 1906. This is essentially a law to prevent cruelty to animals while in transit interstate. It prohibits the confinement of animals m a car for a period longer than 28 consecutive hours without un- loading them in a humane manner into prop- erly equipped pens for rest, water, and feeding for a period of at least 5 hours. In some in- stances animals may be fed and watered with- out unloading them into pens, provided ade- quate space is available for rest in the cars. And in some cases written request, accidental causes, or acts of nature, which cannot be an- ticipated or avoided by the exercise of due dili- gence and foresight, may excuse continuous confinement for 36 hours or longer. Although the law is applicable only to railroad and wa- ter shipments, attempts have been made to ap- ply its humane principles to motortruck ship- ments as well. The 28-Hour Law does not provide for the issuance of regulations ; thus, its administra- tion is governed by the language of the law itself and Court decisions subsequently ren- dered. Enforcement of the overconfinement provi- sions of the 28-Hour Law is performed by ex- amination of records maintained by the car- riers (waybills and similar documents). Peri- odic inspections are made at the more than 800 feed, water, and rest stations throughout the United States to insure that the facilities BN-77S4-X Hogs being reloaded after a period for feed, water, and rest, in compliance with the 28-hour law. and equipment are adequate and properly maintained. Railroads operating such facili- ties are promptly notified to correct unsatis- factory conditions. Apparent violations of the 28-Hour Law are reported to the Department for further inve.stigation and possible prose- cution. In 1960, 482 reports were received of alleged violations of the 28-Hour Law. Prosecution was recommended in 252 cases. During this period reports were received on 176 prosecutions in which penalties of $18,450 and costs were im- posed. Interstate Regulations was also instrumental in developing and distributing the following publications : (1) ARS 91-13, "A Guide for the Enforce- ment of Regulations Governing the Interstate Movement of Livestock and Poultry." This comprehensive manual was issued as a source of information to field representatives and as a guide to uniform procedures to be used in in- vestigating and reporting apparent violations of the 28-Hour Law and the Animal Quaran- tine Laws. (2) "Regulations and Laws Administered by the Animal Disease Eradication Division." This publication contains a reprint of subchap- ters B and C of chapter 1, title 9, Code of Fed- eral Regulations, and also certain Acts of Con- gress that are the basic laws upon which the rules and regulations of the Animal Disease Eradication Division are based. (3) ARS 91-17, "Health Requirements and Regulations Governing the Interstate and In- 46 ternational Movement of Livestock and Poul- try." This is a loose-leaf compilation of all the State and Federal regulations and also includes the Animal Inspection and Quarantine regula- tions and the Canadian import regulations. Objectives A well-informed field organization is essen- tial for the proper enforcement of our pro- grams. As before, meetings will be held as conditions warrant for the purpose of improv- ing operating procedures. Changes in regu- lations and other information having wide- spread application will likewise be promptly brought to the attention of our inspectors. Contact will be maintained by field represen- tatives with individuals and organizations en- gaged in livestock activities to keep them in- formed of the laws and regulations pertaining to their activities. Such contacts should do much to prevent or reduce the number of in- advertent violations. A more effective enforcement of the inter- state regulations and laws has resulted from close cooperation with State and local livestock oflicials. It is expected that this cooperation will continue with increasing advantages to all agencies engaged in animal disease control programs. PUBLIC STOCKYARDS The first record An Act of Congres.s dated May 29. 1884, authorized the Commissioner of Agriculture to organize a Bureau of Animal Industry, ap- point a Chief "who shall be a competent veteri- nai-y surgeon," and to employ a force "not to exceed 20 persons at any one time." The same Act, Section 4, authorized special investigations of pleuropneumonia, or any con- tagious, infectious, or communicable disease, "alo)ig the lines of transportation from all parts of the United States. . . ." In this general language lies legal authority for public stockyards inspection. For several years Texas fever was the only disea.se subject to .stockyards control. In 1897, inspection was extended to sheep scabies and in 1903, to cattle scabies. By 1905, activities were enlarged to embrace inspection for com- municable disea.ses of all livestock received at public stockyards. Since its beginning, public stockyards in- spection has been important in controlling or eradicating Texas fever in cattle, dourine and glanders in horses, scabies in sheep and cattle, foot-and-mouth disease, and vesicular exan- thema. The stockyards service proved its importance in controlling and eradicating vesicular exan- thema. Since mo.st major markets were in- volved, the manner in which VE was handled unque.stionably prevented the development of additional foci of infection. On many occa- sions stockyards inspection not only stopped the spread of infection but also helped the Division locate farm sources where the disease was not known to exist. The cooperation between the management of stockyards companies and the Division in controlling the VE eindemic cannot be overem- I)hasized. It demonstrated that in these days of rapid transit, the Division, by working with marketing interests, can effectively control the spread of livestock diseases. Stockyards inspection activities were en- hanced when, in furtherance of efforts to pre- vent the spread of brucellosis, provision was made, on January 1, 1957, for specifically approved stockyards and slaughtering es- tablishments. These approved establishments operate under State inspection. Cattle may move interstate to them without having to meet certain prior requirements. Subsequent movements from such markets, however, must be in compliance with Federal regulations. As of June 30, 1960, there were 3,430 such estab- lishments. The importance of stockyards inspection From an economic standpoint, no service supplies more information on the health of the Nation's livestock than does the stockyards in- spection service. If efforts were being made to learn which disea.ses existed in livestock, in- spection of premises would be required. This would be an impracticable service. However, a very satisfactory method of making this de- termination is available by inspecting the 60 to 65 million animals that annually move through 56 majoi- marketing centers. 47 PUBLIC STOCKYARDS Operating Under Federal Inspection U. S^ DEPARTMENT OF AGRICULTURE June 30, 1960 NEG 60 (6) 5099 AGRICULTURAL RESEARCH SERVICE 48 This service provides a means of preventing the interstate spread of communicable diseases of animals. It also builds confidence in buyers at inspected markets that they are getting healthy livestock. The statist-ical sfory In 1960, a total of 219 Federal veterinarians and livestock inspectors examined, segregated, and safely handled all diseased animals. Under their supervision, 2,536 cars and 24,882 trucks contaminated b\- diseased animals were cleaned and disinfected. Inspectors directed the dipping for scabies of 53,627 cattle and 374,834 sheep, and super- vised the immunization of 150,043 hogs against cholera. For the interstate movement of livestock found to be apparently free from communica- ble diseases, inspectors issued 296,045 health certificates. The following statistics .show- the compara- tive volume of activities at public stockyards in 1959 and 1960: Stockyards operating Cities in which located Animals inspected: Cattle Sheep Swine 1959 Number 58 56 1!>C0 Number 58 56 21,977,606 21,700,786 11,908,863 12,351,029 28,926,309 31,448,004 Total animals inspected 62,812,778 65,499,819 Animals dipped for scabies: Cattle Sheep 21,456 388,450 Swine immunized against hog chlorea for movement to farms for stocker and feeder jiiir- poses --- - - - 151,613 Total animals iliiiped and immimizi'd 561,519 53,627 374,834 150,043 578,504 Health certificates issued for shipments ^ Infectious cars received -- Cars cleaned and disinfected '.— Trucks cleaned and disinfected Diseased animals received 275,834 296,045 393 235 2,317 2,536 34,683 24,882 434,971 ■-■ 446,493 ' Includes requests by States and railroads. - Includes 91,620 brucellosis, 10,089 tuberculosis and 18() paratuberculosis reactors; and 333,076 other diseased animals. ■• Includes 65,822 brucellosis, 7,077 tuberculosis and 122 paratuberculosis reactors; and 373,472 other diseased animals. 49 Disease Reporting A look at the future Experience gained in the \K epidemic em- phasized the need of keeping personnel alert to the constant threat of disease whose ap- pearance in public stockyards could wreck the livestock industry. Equally essential is com- petence in the early diagnosis of diseases. Inspectors examine livestock for symptoms of disease. Training programs will be improvetl to give inspectors increasing information about dis- ease conditions. Interchange of per.sonnel will be made between stockyards inspection and cooperative disease eradication programs to increase familiarity with all Division activities. A manual is being written that will bring greater uniformity in the handling of live.stock at public yards. Stockyards inspectors stand in the first line of defense in protecting the livestock industry from the ravages of communicable diseases. Continuing efforts to imjjrove ins]:)ection pro- ficiency in the early detection of disease will further assure the public that its food supply is well guarded. Development of reporting When Norsemen landed on North American shores around the year 1004, they brought with them cattle, sheep, horses, and goats. By the time Jamestown was settled, these domestic animals had vanished. The Spaniards brought horses, but they remained in the west. So when a bull and three heifers from Eng- land arrived at Plymouth colony in 1624, they came to an environment that was more nearly disease-free than it has e\er been since. Communities developed, but remained iso- lated. Movement of animals was local. The few early records available indicate that ap- parently serious losses did occur in certain localities. Generally, however, when diseases were introduced they did not become wide- spread. Early agricultural journals, starting with the "American Farmer" in 1819, attempted to l)ublish reports of animal diseases. Soon many of them had regular veterinary columns. Un- til the publication of the "American Veterinary Review" in 1877, these journals were the prin- ciple sources of information on incidence of animal di.seases. When the U.S. Department of Agriculture's Bureau of Animal Industry came into being in 1884, more attention was given to preparing otticial statistical reports showing the incidence of certain livestock diseases and the extent of loss suffered. A substantial part of this infor- mation came from routine program reports by State and Federal inspectors. More than 35 years ago, the Secretary of the United States Livestock Sanitary As.sociation urged that national veterinary vital statistics be collected and distributed. This recommenda- tion was based on the conclusion that such in- formation was essential to disease control. The Association, recognizing the need for a national reporting service, adopted a resolution recom- 51 mendinp that livestock sanitary authorities in the States gather reliable information about the health of livestock and outbreaks of com- municable diseases, and forward it to a central location for summary and publication. More recently, the Association's Committee on Morbidity and Mortality again reviewed the situation, and adopted a plan to assist the U.S. Department of Agriculture in establishing, in cooperation with State livestock sanitary offi- cials, a .system for collecting and disseminating statistics on livestock diseases. This was the beginning of the Animal Diseases Reporting System, established in the Agricultural Re- search Service of the U.S. Department of Agri- culture, in November 1955. Reporting will not, in itself, prevent the spread of disease. But it is an important foundation in building sound programs of live- stock di.sease prevention, control, and eradica- tion. During the past several years, much progress has been made. The individual States have assumed i-esponsibility for collecting in- formation within the State. The U.S. Public Health Service has participated actively in instituting State reporting systems. At the same time, the Agricultural Research Service has cooperated closely with State Livestock Sanitary Ofticials, the U.S. Livestock Sanitary Association, the U.S. Public Health Service, State health departments, veterinary colleges, the American Vetei'inary Medical Association, Poultry Division of the Agricultural Marketing Service, and other Federal and State agencies. Why disease reporting? Why is animal disease reporting important? Its purpose is to furnish continuing informa- tion that will enable us more accurately to estimate disease losses. These reports also alert us to changes in disease incidence and help in program planning. Reporting includes four basic steps: collec- tion of information, processing, use, and co- ordination. To be effective this must be a continuous cycle with each step coordinated with and supporting the others. Shorfcomings Animal disease reporting has its weak spots. Reports rarely show all occurrences of a given disease. Sometimes practitioners fail to cooperate. Some reports do not include all of the diseases observed ; others include some diseases more consistently than they do others, or may have incorrect field diagnoses. These reports have additional weaknesses. The owner of disea.sed livestock may fail to consult a veterinarian, thus, the occurrence is not reported, or the veterinarian may visit the herd only once. Perhaps several cases have occurred before he is called. Others that are not reported to him may occur after his call. No reporting system can reflect all occurrences of every disea.se, particularly those that are common or widespread. Obviously, these and other factors must be considered if disease reports are to be inter- preted properly. Constant effort is needed to improve the system to keep the effects of these shortcomings to a minimum. The veterinary practitioner Since he does daily battle with disease, the practitioner has a definite stake in a report- ing system, and without his help there can be no program. By his cooperation the prac- titioner provides a wealth of disease informa- tion not readily available elsewhere. Although reporting programs are criticized for their inaccuracy of diagnosis and of evalu- ation based on incomplete participation, the means are available to obtain better data. Ac- curacy can be improved as time goes on. And the reports do provide the most realistic in- formation obtainable on county. State, and national levels. This is particularly true if the information is available over a period of years so that broad trends can be recognized. There are also indirect benfits from practi- tioner participation. A working relationship is created which encourages consultation and prompt reporting to regulatory officials of po- tentially serious disease outbreaks. Collection of information This is the most difficult aspect of the re- porting cycle. Obviously, the wide.st possible range of accurate informational sources is needed if the final reports are to have meaning. Practicing veterinarians .... veterinary col- leges .... veterinary science departments of 52 agricultiii'al culleKes and uni\ersities .... diagnostic laboratories .... inspection services at public stockyards and auction markets .... antemortem and po.-^tmortem inspections at slauRhterlng plants operating under Federal, State, and municipal suiiervision .... lns])ec- tion at poultry slaughterinK plants .... i-eports from regulatory officials of the Public Health Service, and State and Federal Departments of Agriculture .... and from Federal and State Wildlife Conservation Services .... all of these are current sources of useful infor- mation. Several survey methods can be used to aug- ment data supplied by routine reporting. One method is to conduct a survey on a herd-by- herd basis or, in a serological sur\e\'. at se- lected laboratories, to determine the prexalence of selected diseases in the field. This method is valuable not oidy as an aid in determining the prevalence of certain di.s- eases but also as a "monitor" for diseases not known to be in the area — particularly foreign diseases. Samples can be obtained l)y veterinarians taking pai't in a field survey or they can be chosen at random or by design from those received at laboratories in the course of routine work. Samples can also be collected from animals at slaughterhouses or concentration points, and in the case of wild- life during organized hunts, trapping pro- grams, or as "kill-specimens" obtained at check stations dui'ing hunting seasons. Another method is to make a comprehensive survey of representative herds to obtain infor- mation on a variety of infectious diseases and other disorders. The survey might include repeat visits and the reports could include valuable data on disease prevalence in a herd ovei' an extended period of time. Still another approach is to organize prac- ticing veterinarians on a selected area basis so that on specified days or during particular periods they make detailed reports of all dis- eases encountered. Also, cooperative owners might be asked to keep accurate records of disease losses in their herds over a period of time. Processing To simplify processing the reports, they should be prepared on standardized forms, con- solidated, summarized, and distributed at ap- propriate intervals. As soon as the quality and quantity of data are adequate, the infor- mation can be placed on machine records to obtain more complete analyses. Processing .should be handled an5^ .o^.^^ /:#^ <^ 0^^ <^ <^ >- cc < OC m _j 2: o o -J CO 3 >■ a. Q X UJ CD O 3 2 o Ul Q: cc O LU u. ca Ul CO tt 2 UJ UJI 3 O \ r > > o < H m X > z CO o o 7^