Another decision we had to make was what to do about the numerous unpublished reports on brucellosis in bison. Most of these are committee or agency reports from organizations such as the United States National Park Service, the United States Department of Agriculture, The Canadian Department of Agriculture or other State or Province agencies. The reports contain excellent data and are of great value but frequently are too lengthy to be included with this bibliography. Therefore, we have decided not to include such reports except in a few instances where a report was of reasonable size and of some special significance. We would like to compile a bibliography of all these reports at a later date.
This volume contains the earliest journal articles, e.g. Mohler, 1917; Creech, 1930; Rush, 1932; and Tunnicliff and Marsh, 1935 on through papers published in early 1993. In some cases, because of the length and substance of a paper, we have included only the parts that mention bison. Also, permission has been obtained to use certain chapters from books on wildlife diseases. The volume contains a bibliography numbered and alphabetized by author(s). The subject index covers general topics that occur in each paper.
We are indebted to the Dr. Ken Throlson American Bison Foundation for the generous support that has helped to make these publications possible.
SUBJECT REFERENCE PAPER # Alaska 42, 80 Anthrax 7, 19, 25, 61, 63 Arkansas 13 Bang's Disease 5, 18, 30, 31, 32, 35, 36, 52, 73 Bighorn Sheep 33 Bio-bullets 5, 12, 58, 65 Biovar 1 17, 48, 64, 77 Buffalo National Park 14, 45 Canadian Arctic 70 Canadian Wildlife Service 4, 7, 44, 50, 70 Caribou 5, 12, 19, 33, 34, 42, 43, 48, 49, 62, 70, 80 Cattle 1-12, 19-22, 24, 27, 28, 31, 33, 36, 39, 41, 43, 48, 51, 52, 54, 56, 58, 60, 65, 68, 71, 72, 74, 75, 76, 79 Conception Rates 7, 9, 11 Control: 1, 3, 4, 5, 7-9, 30, 31, 33, 36-38, 43, 45, 62, 65, 68 72, 75, 76 Boundary 37, 38, 45, 65 Hazing 38, 58 Physical Barriers 38, 58 Scare Devices 38 Deer 8, 12, 13, 27, 29, 33, 35, 38, 41, 49, 51, 53, 56, 57, 59, 60, 71 Depopulation 7, 8, 14, 37, 38, 46, 65 Elk 1, 5, 6, 8, 12-14, 19, 22, 30-35, 38, 40, 41, 43, 45, 46, 46, 49, 52-54, 56, 58, 61, 62, 64-68, 70, 73, 76, 78 Elk Island National Park 9, 10, 14, 33, 41, 50, 61 Epidemiology 5, 6, 18, 19, 22, 25-29, 31, 33, 42, 43, 48, 51, 58, 62, 64, 65, 67, 68, 70, 74 Epididymitis 11 Eradication Program 2, 3, 5, 11, 12, 18, 21, 22, 24, 25, 26, 28, 30, 33, 34, 37, 45, 50, 55, 58, 60, 62, 65, 68, 72, 74, 75 Experimental Infection 16, 17, 43, 62, 67 Game Ranching 24, 61, 63 Grand Teton National Park 1, 5, 31, 45-47, 76 Greater Yellowstone Ecosystem 65 Grizzly 80 Indemity Rates, Federal 2 Infection Rates 50 Jackson Elk Herd 5, 65 Leptospirosis 71, 80 Mackenzie Bison Sanctuary 4, 19, 24, 25, 45, 50 Management 5, 7, 9, 10, 24, 25, 36, 38, 44-47, 50, 57, 58, 74 Metritis 10, 11, 42, 44 Minnesota 30 Missouri 29, 59 Moose 13, 14, 28, 30, 33, 41, 43, 61, 70, 80 National Bison Range 15, 16, 30, 33, 41, 46, 47, 54, 58, 73 National Brucellosis Eradication Program 3, 5, 12, 18, 26, 27, 33, 34, 65, 68, 72, 74, 78, 79 National Elk Refuge 6, 45, 46, 58, 65, 66, 76 National Parks: Buffalo National Park 14, 45 Elk Island National Park 9, 10, 14, 33, 41, 50, 61 Grand Teton National Park 1, 5, 31, 45-47, 76 Wood Buffalo National Park 4, 7, 9-11, 19, 23, 33, 44, 45, 50, 62, 64 Yellowstone National Park 1, 3, 6, 12, 15-18, 20, 22, 26, 30, 31, 33, 36-39, 45- 47, 52, 54, 55, 58, 65, 72, 73, 76 National Park Service 1, 46, 65, 72 New Hampshire 30 North Dakota 21, 35 Orchitis 7, 10, 11, 14, 15, 42, 44, 68, 73, 78 Parker Land & Cattle Company 1, 76 Pathology 44, 62, 68, 78 Pronghorn 33, 53 Recovery 25, 50 Reindeer 19, 34, 42, 48, 49, 70, 78 Review Papers 16, 41, 46, 62, 63, 68, 78 Serological Tests 5-9, 11, 13-17, 20, 21, 28- 33, 35, 39-42, 44, 45, 52- 54, 57, 59, 62, 64, 66, 67, 69-71, 73, 77, 80 Slave River Lowlands 4, 7, 24, 25 Strain-19 5, 6, 17, 18, 22, 31, 43-46, 58, 65, 74 Efficiency 46, 65, 74 Susceptibility 73 Transmissibility of B. Abortus 8, 11, 12, 41, 45, 47, 57, 65, 75 Bison to Bison 2, 3, 19, 25, 45, 46 Bison to Cattle 1, 3, 14, 16-22, 26, 36-38, 45, 46, 54, 58, 65, 72 Bison to Elk 31 Caribou & Reindeer to Cattle 43 Cattle to Bison 17, 24, 31, 52, 78 Cattle to Cattle 16 Cattle to Elk 5 Deer to Cattle 43 Elk to Bison 6, 46, 58 Elk to Cattle 1, 5, 22, 31 Moose to Cattle 28 Tuberculosis 4, 7-10, 18, 19, 23-25, 44, 45, 50, 56, 61-64 USDA (United States Department of Agriculture) 2, 3, 5, 17, 18, 22, 27, 36, 37, 45, 46, 55, 63, 65, 74, 76, 79 Utah 69 Vaccination 1, 5, 6, 9, 12, 17, 18, 30, 31, 36, 43-47, 54, 56, 65, 74, 78 Bio-bullets 5, 12, 58, 65 Strain-19 5, 6, 17, 18, 22, 31, 43-46, 58, 65, 74 Wainright, Alberta 4, 7, 24, 45 Wisconsin 71 Wood Buffalo National Park 4, 7, 9-11, 19, 23, 33, 44, 45, 50, 62, 64 Wyoming 1, 5, 6, 12, 22, 53, 62, 66, 67, 77
(note: the entire text of the article follows) A federal judge has ruled that two U.S. agencies were at fault in not restricting movement of brucellosis-infected bison and elk herds roaming the Grand Teton and Yellowstone National Parks in northwestern Wyoming. The ruling, handed down here by Judge Clarence Brimmer, found that the National Park Service and U.S. Fish & Wildlife Service did not sufficiently limit the herds' sizes. He explained that the herds grew larger than the parks could support, forcing infected bison and elk outside the parks in search of food. Brimmer's ruling came on a suit brought by the Parker Land & Cattle Co., which claimed the bison and elk infected its cattle, causing them to abort fetuses and requiring their destruction. However, Brimmer did not award damages to Parker, saying the ranch, which grazes on adjacent forest service land, did not prove the cattle were infected by the wildlife. The ruling also could turn out to be contrary to Parker's and other ranchers' interests, according to government officials and public lands ranchers who submitted supporting briefs or testified in the case. The park and wildlife services suggested that the ruling means they either must destroy bison and elk because brucellosis vaccines effective for cattle are not proven to work for bison and elk, or they must withdraw public grazing permits on nearby land.
(note: the entire text of the article follows) In the Federal Register of November 26, the Animal and Plant Health Inspection Service published final rules that make cutbacks in the maximum amounts payable to owners of cattle that are destroyed to control the spread of brucellosis. The changes were effective on the date of publication. Under the old rates, the owner was reimbursed through a formula. He received 90% of the difference between the fair market value of the healthy animal and the slaughter value, which would be quite different figures for registered, purebred cattle. There were limits on this. The federal indemnity could not exceed $1,000 for registered animals, $750 for non- registered dairy cattle, or $250 for other non-registered cattle. There was also a floor for the federal payment: not less than $250 for registered animals, not less than $150 for nonregistered dairy cattle, and not less than $50 for other nonregistered cattle. The new rules generally convert the floors to ceilings. Now, the federal payment for dairy cattle or any registered cattle cannot exceed $250 per head. For other nonregistered cattle, the ceiling is $50. APHIS offers reasons for the change. As might be expected, there is waste, fraud, and abuse: "...overcompensation unavoidably occurred in some locations making it profitable for herd owners to maintain the disease in the herd." The second reason seems to be that the financial incentive to induce individual herd owners to be disease free has caused an intolerable drain on appropriated funds, to the point where the true goal of the program -eradication- is being jeopardized. In the Federal Register of November 26, APHIS notes that there are somewhere between 500 and 1,000 private bison herds in the country and that brucellosis transmission from one to another is becoming a significant problem. So, APHIS has amended the brucellosis program regulations to permit indemnification of bison owners for animals that are killed. The indemnity rate is the same as that for nonregistered cattle.
(note: the entire text of the article follows) Brucellosis in bison herds in Yellowstone National Park and the hazards of wild and exotic animals as pets are two of several regulatory medicine and public health problems on which the Council on Public health and Regulatory Veterinary Medicine took further action at its spring meeting, March 15-16. After reviewing the response of the U.S. Department of Interior to AVMA's recent urgent appeal that steps be taken by the department and USDA to eradicate the disease from Yellowstone's bison, in conformity with the National Brucellosis Eradication program, the Council drafted the following recommendations: 1) Request the Secretary of Agriculture to establish a brucellosis eradication program for bison in Yellowstone National Park. 2) Emphasize that the program will eradicate the disease, and not the bison herds. 3) Request the Conference of Public Health Veterinarians to evaluate the public health danger of permitting brucellosis to remain in the bison at Yellowstone Park. 4) Request that the U.S. Animal Health Association's Brucellosis Committee be advised of the Council's recommendations concerning the establishment of a brucellosis eradication program in bison in Yellowstone, and that the Committee seek support for the program from animal health officials of each state. The Council recommended further that, if support for additional action is necessary, the AVMA suggest to USDA that it conduct studies of transmissibility of Brucella abortus from Yellowstone bison to susceptible pregnant cattle and bison.
In 1985, Canada's national cattle herd was declared free of bovine brucellosis, and bovine tuberculosis is expected to be eliminated in the future. The veterinary and public health benefits, and the resulting economic gains, have increasingly offset the high cost and effort needed to achieve the eradication of these major diseases. Extraneous sources of brucellosis and tuberculosis have become correspondingly more important because of the risk of reintroducing the disease back into cattle. The free-ranging bison population in and around Wood Buffalo National Park is considered the final reservoir of both diseases in Canada. Tuberculosis and brucellosis were introduced into the park between 1925 and 1928 when 6,672 plains bison were shipped there from an infected herd near Wainwright, Alberta. Cumulative data from commercial bison slaughters in the park during the 1950's and 1960's show positive Brucella titres in 714 (36%) of 1,999 bison tested, and report TB lesions in 1,079 (34%) of 3,181 bison. At this date, there are ca. 5,000 bison in the Wood Buffalo National Park and 400 in the Slave River Lowlands. A recent survey found evidence of brucellosis in 18 (25%), and TB in 15 (21%), of 72 bison killed in and around the park. The potential for spread of brucellosis and TB is discussed.
Brucellosis is of the greatest management significance in the Jackson elk herd because 50% of the time it cause abortion or stillbirth of the first calf following infection. While infected cows successfully raise later calves, this results in reduced herd productivity, which may be viewed as detrimental for maximum-sustained-yield elk harvest objectives. Although elk are more resistant to brucellosis, the disease can be transmitted between the two species. Refined serological techniques exist for reliable detection of brucellosis in elk. Identification of brucellosis infection in elk requires that two of four tests be positive; these include plate agglutination, complement fixation, rivanol, and Brucella buffered antigen rapid card tests. Programs for the brucellosis eradication are discussed, including vaccination and biobullet inoculation.
In February 1989, a slaughter MCI reactor was traced to the Parker Land and Cattle Company herd headquartered in Fremont County just west of Dubois, Wyoming. A complete herd test of 622 head of eligible cattle in the herd revealed it to be a brucellosis reactor herd. The isolation of biovar 1 from several titered cattle in the herd confirmed it to be infected with brucellosis. The State of Wyoming obtained its Class Free Brucellosis status in April 1985. The potential exists for this status to be suspended if the field strain infection is found to be imported, and brucellosis has spread to other herds in the area.
Bison in the Slave River lowlands (SRL) and Wood Buffalo National Park (WBNP) have shown high rates of disease infection, primarily with tuberculosis, brucellosis, and anthrax. Examinations and/or testing for tuberculosis and brucellosis in bison were conducted in WBNP between 1950 and 1974 and in the SRL between 1964 and 1974. Tuberculosis infection rates averaged 40% in WBNP (range 15-56%) and varied from 25 to 40% in the SRL. Field examination of bison shot by recreational hunters in 1974 in the SRL revealed a high level of tuberculosis-like lesions. Brucellosis infections rates averaged 30% in WBNP (range 6-62%) and 38% in the SRL. The first outbreak of anthrax killed 281 bison at Hook Lake, Northwest Territories, in July 1962. Attempts to control the disease included depopulation and vaccination. Anthrax and associated control measures have resulted in the death of approximately 1,600 bison in SRL and WBNP since 1962.
Canada eradicated brucellosis from the national cattle herd in 1985 and the eradication of tuberculosis is imminent. In recent years, an increasing number of wild ungulates such as bison, elk, deer, etc., have been introduced into the more heavily populated areas of Canada and, as a consequence, are coming into close contact with domestic livestock and people. These animals may be infected with brucellosis and/or tuberculosis. Game farms and bison ranches situated among cattle ranches or farms are potential sources of infection to domestic cattle. Also, Agriculture Canada is expected to provide the public with protection against zoonotic threats, epecially in petting zoos or roadside exhibits where young children may have intimate contact with animals.
A study in collaboration with the Animal Diseases Research Institute, Canada Department of Agriculture was undertaken in late in 1961. A total of 1,878 bison in Wood Buffalo National Park were tested with tuberculin. A positive reaction was secured in 224 cases, or 11.9% of the animals tested. A total of 491 young animals was also vaccinated against Brucellosis. Altogether, 390 animals, including 224 reactors, were slaughtered and examined thoroughly. All lesions and abnormalities were recorded. The tuberculin test and meat inspection were conducted by officers of the Department of Agriculture. Three hundred and seventy-eight samples of sera collected during the slaughter were tested for Brucellosis and other conditions. A reaction indicating Brucellosis was secured in 161 or 42.32% of the cases.
Tuberculosis and some other pathological conditions in bison at Wood Buffalo and Elk Island National Parks in the fall and winter of 1959-1960 are discussed. In 1959, 1,116 animals were tested with bovine tuberculin and 151 or 13.5% showed a positive reaction. There were 436 animals slaughtered, and 219 or 50.2% showed tuberculous lesions, and 168 or 76.7% of these showed evidence of infection in the lymph nodes of the head. Metritis was noted in 9 animals, 7 of which were tested with tuberculin and 3 tested positive. Eleven cases of orchitis were recorded in bulls. Nine of these had been tested for brucellosis (rapid serum agglutination technique) and 7 tested positive.
Serum samples collected from 2,365 free-roaming hybrid bison (Bison bison bison x Bison bison athabascae) in Wood Buffalo National Park and adjacent areas in the Northwest Territories were tested for brucellosis during the period 1959 to 1974. A positive reaction was obtained in 739 (31.2%) of the animals tested. The overall effect of brucellosis on this free- roaming bison population is unknown. The authors also dealt with some of the actual and possible consequences of the disease in this population.
Tracking and controlling diseases in wildlife may be important regarding conservation efforts. Wildlife health researchers are investigating the relationship between brucellosis in wild animals such as elk, caribou, and bison and livestock including cattle and swine. An eradication program has been in effect since the 1940s and has decreased the disease significantly. However, in the area around Yellowstone National Park, ranchers feel their cattle may become infected from elk and bison when they share feeding grounds. A vaccine developed for cattle was tested on 18,000 elk, and a reported 70% reduction in abortions was documented. Research has been conducted with white-tailed deer and it is concluded that they do not play a role in transmitting the disease.
Tissues from 1572 specimens belonging to 46 species of mammals, reptiles, or birds were cultured for species of the genus Brucella. All species of wild mammals found in Arkansas were included except the following: the Red Wolf, the Bobcat, the Missouri Weasel, the Armadillo, and the Arkansas Mole. Neither Brucella melitensis nor B. suis were encountered, but B. abortus was isolated from two species, the white-tailed deer and the old field race of the house mouse. This evidence strengthens previous reports of antibody titers in deer against Brucella, and, furthermore, implicates house mice as a possible reservoir for B. abortus.
Serological specimens from 343 bison, 221 elk and 124 moose slaughtered in Elk Island National Park in the winter of 1956-1957 were examined for brucellosis. The moose were all negative, 42.27% of the bison were reactors, and 13.12% of the elk were reactors. The occurrence of reactor bison in Wood Buffalo National Park and Riding Mountain National Park in Manitoba is mentioned as well as reactor elk in Waterton Lakes National Park in southwestern Alberta.
While infectious abortion, caused by Brucella abortus, is common among cattle, it has been uncertain whether bison are also susceptible to the bacterium. In 1917, blood samples from three bison cows from Yellowstone National Park which had aborted, were tested and two were positive using the agglutination test. This report describes a case history of a male bison from the National Bison Range at Moiese, MT. The animal in question had developed enlarged testicles and was castrated. The testicles were examined and the gross changes found were similar to lesions caused by B. abortus in cattle. The lesions are described. Bacteriological studies revealed pure cultures of a small bacillus typical of B. abortus.
Two groups of six, non-brucellosis vaccinated, brucellosis seronegative pregnant American bison (Bison bison) were individually challenged with 1 x 107 colony forming units (CFU) of Brucella abortus strain 2308. Three days after challenge, each bison group was placed in a common paddock with six non-vaccinated, brucellosis susceptible, pregnant domestic heifers. In a parallel study, two groups of six susceptible, pregnant cattle were simultaneously challenged with the identical dose as the bison and each group was placed with six susceptible cattle in order to compare bison to cattle transmission to that observed in cattle to cattle transmission. Blood samples were collected from bison and cattle weekly for at least 1 mo prior to exposure to B. abortus and for 180 days post-exposure (PE). Sera from the bison and cattle were evaluated by the Card, rivanol precipitation, standard plate agglutination, standard tube agglutination, cold complement fixation tube, warm complement fixation tube, buffered acidified plate antigen, rapid screening, bovine conjugated enzyme linked immunosorbent assay, bison or bovine conjugated enzyme linked immunosorbent assay, and the hemolysis-in-gel techniques for the presence of antibodies to Brucella spp. At the termination of pregnancy by abortion or birth of a live-calf, quarter milk samples, vaginal swabs, and placenta were collected from the dam. Rectal swabs were collected from live calves, and mediastinal lymph nodes, abomasal contents and lung were taken at necropsy from aborted fetuses for culture of Brucella spp. These tissues and swabs were cultured on restrictive media for the isolation and identification of Brucella spp. Pathogenesis of brucellosis in bison was studied in an additional group of six pregnant bison which were challenged with 1 x 107 CFU of B. abortus strain 2308. One animal was euthanatized each week PE. Tissues were collected at necropsy and later examined bacteriologically and histologically. Lesions of brucellosis in bison did not significantly differ grossly or histologically from those in cattle. There were six abortions and two nonviable calves in the bison group, as compared to nine abortions in the 12 similarly inoculated cattle. As determined by bacterial isolations, transmission of B. abortus from bison to cattle (five of 12 susceptible cattle became infected) did not differ statistically from cattle to cattle transmission (six of 12 susceptible cattle became infected) under identical conditions. No single serologic test was consistently reliable in diagnosing B. abortus infected bison for 8 wk PE. Multiple testing periods in which the Card test was used in combination with the bison conjugated enzyme linked immunosorbent assay and the hemolysis-in-gel proved to be a useful battery of serologic techniques to diagnose brucellosis in bison after the initial 8 wk PE.
Protection against Brucella abortus induced abortion and infection provided by strain 19 (S19) vaccination was evaluated in American bison (Bison bison). Forty-eight pregnant bison were manually inoculated (MI) with S19 vaccine, 44 were ballistically inoculated (BI) with an absorbable hollow pellet containing lyophilized S19, and 46 were manually injected with buffered saline as non-vaccinated controls (NVC). All bison were Brucella spp. seronegative prior to the experiment, in the second trimester of pregnancy, and were randomly assigned to experimental groups. Approximately 60 days post-vaccination, abortions were observed in the vaccinated bison. Brucella abortus strain 19 was recovered from a bison that had recently aborted, her fetus, and from 11 of 12 other aborted fetuses. Fifty-eight percent (53 of 92) of vaccinated bison aborted, and no abortions were observed in the NVC bison. One cow aborted during her second post-vaccinal pregnancy and S19 was identified from the dam and fetus indication that chronic S19 infections can occur in bison. Positive antibody titers were present 10 mo post-vaccination in 73% (66 0f 91) of the bison. Thirteen mo post- vaccination, 30 MI vaccinates, 27 BI vaccinates, and 30 NVC were challenged during the second trimester of pregnancy with 1 x 107 CFU of B. abortus strain 2308 via bilateral conjuctival inoculation. Protection against abortion was 67% (P < 0.0001) for vaccinated bison compared to 4% in NVC. Protection against B. abortus infection was determined to be 39% (P > 0.001) for vaccinates and 0% (zero of 30) for NVC. Persistent antibody titers, vaccine induced abortions, and chronic S19 infections indicate that the S19 vaccine doses used in this study are not suitable for pregnant bison.
Cattle ranchers, mostly in Montana, Wyoming and Idaho, are fearful of the spread of brucellosis from bison to their domestic livestock. A primary concern are the free-ranging bison in Yellowstone Park. While bison infected with the bacterium do not seem to be adversely affected, the problem is that they wander out of the park bounds and possibly infect neighboring cattle, which can physiologically and economically hurt cattle and the cattle industry. The organism may infect not only cattle and bison but also sheep, fowl, horses, dogs, deer, elk, ticks, rodents, flies, and humans. In cattle, treatment is preventive: heifer calves are vaccinated before they are 6 months of age and protection is lifelong. In theory, bison could be vaccinated also. Regarding Yellowstone Park, this is an unlikely event because only 75% of the bison can be located or trapped, thus leaving a reservoir. Officials at the Park developed a program in an effort to keep the bison within the bounds of the Park and thereby not in association with neighboring cattle. Basically, any bison that are observed to wander out of the Park (at 9 frequented exits) would be hazed back into the Park's bounds. If this was not successful, the animal would be shot by Park personnel. To date, none have been destroyed. However, cattle producers still feel better control is in order since bison are strong animals and can probably go where they want, and there is no foolproof way of monitoring their movements. Currently, no acceptable solution to the controversy has been found.
The presence of diseased bison in and around Wood Buffalo National Park (the Park), and proposals for controlling or eliminating the diseases, have generated much interest among Canadians living near the Park and throughout the country. This section describes the present situation and its historical development. It is within this context that the problem must be addressed.
This report discusses the bison emigration out of Yellowstone National Park during the winter of 1988 and 1989. Nearly all of the Northern herd moved into Montana during this time, bringing the threat of brucellosis transmission to Montana cattle. A state-supervised hunt and harvest of 570 bison was successful in preventing the transmission. Serologic testing of cattle in the area produced no reactors. The reports states that the development of acceptable management practices is necessary.
Five adult bison females and one adult bison male originating from North Dakota were slaughtered. All tested positive with the card test for brucellosis testing. The herd of origin, consisting of 21 bison, was tested disclosing 18 reactors, 1 suspect, and 2 negative. There were 77 head of cattle on the same premises and one cow tested positive. All the bison and the one cow were slaughtered and tissues submitted for examination. Abortus Biotype I was isolated from 13 of the bison and the one reactor cow. The entire cattle herd was subsequently depopulated.
This report states that brucellosis eradication in bison in Yellowstone National Park is not essential to eradication in cattle. Cattle are the major reservoir of Brucella abortus in the United States, and an excessive concern about a small number of bison in the Park in not necessary. Transmission of brucellosis from Park bison to cattle has not been documented, and knowledge of brucellosis in bison is insufficient. Bison would have to be eliminated to eliminate the disease. Finally, cattle with potential for exposure can be vaccinated to eliminate the possibility of transmission of Brucella from bison. The current plan for controlling potential transmission of brucellosis from bison to cattle involves: routine monitoring of bison for movement into ranges used by domestic cattle, destruction of bison in such ranges and impoundment of cattle that trespass into the park. Additionally, a bison calf vaccination program could be started, a ban on transportation of live or dead bison from the Park could be implemented and aborted fetuses, fetal membranes could be treated (incineration if possible) and contaminated areas could be disinfected. More research on several areas of brucellosis in wildlife will allow improved programs for control and management.
The historical summary, taxonomy, bison range, reproductive characteristics, mortality factors, and management proposals of the range and bison of Wood Buffalo National Park are discussed. Parasites and diseases are discussed in the context of mortality factors, as well as predation, abnormalities and accidents.
Within a century of the coming of Europeans to western North America in the late 1700's, bison (Bison) were reduced to remnant populations throughout their former range. However by 1919 a restored plains bison (B. b. bison) herd in a small reserve in southern Alberta became overabundant. Despite the knowledge that these animals were infected with tuberculosis (Mycobacterium bovis), nearly 7000 were shipped north into the southern end of the wood bison (B. b. athabascae) range. Tuberculosis and brucellosis (Brucella abortus) were introduced to the northern bison population and the plains bison hybridised with the wood bison. By 1991 the number of disease-exposed hybrid bison had declined to approximately 4000 animals, with a number of factors including disease implicated. During the same period a sub-population of disease-free animals salvaged from individuals morphologically similar to wood bison, has grown to over 2000 in the far northern part of their range. Our paper reviews recent initiatives to develop a management plan to protect domestic stock, disease-free bison and people from brucellosis and tuberculosis. Our Department's goal is to see healthy herds of bison restored as a major component of the regional ecosystem. We describe a co- management structure with majority regional native membership, which we believe will steer management towards this goal. The pros and cons of attempting to restore healthy bison herds from salvaged stock are discussed with reference to the principles of conserving biological diversity.
The saga of the North American bison (Bison bison) is chronicled as one of the most tragic abuses of wildlife on this continent. The bison is the largest terrestrial mammal in North America, and in prehistoric and early historic times it was the dominant herbivore on the grasslands of the central plains. It played an important role in grassland boreal ecosystems and was a principal resource for the indigenous human population inhabiting the interior plains region of the continent. At the close of the nineteenth century, following the onset of European settlement, the bison was nearly driven to extinction. The plains subspecies (B. b. bison Linnaeus) was effectively extirpated in Canada by 1885 and only a few hundred wood bison (B. b. athabascae Rhoads) remained in northern areas between Lake Athabasca and Great Slave Lake. The chronology of depletion was similar for the two subspecies. In this century, the plains bison has been saved from extinction and presently numbers over 100,000 individuals, largely on commercial ranches. The wood bison has achieved more modest abundance, and further recovery of this subspecies is clearly at a crossroads. This article deals with the history of the wood bison, tracing it through three distinct periods, the historic period, the early conservation period, and the recovery period. Major limiting factors to further recovery are identified and discussed.
(note: the complete text of the letter follows) In his Jan. 10 letter concerning the elimination of diseased bison from Yellowstone National Park, Donald J. Barnes of the National Anti-Vivisection Society states, "There has never been a single documented case of brucellosis communicated from buffalo to cattle." On the contrary, there is clear evidence to support the view that infected bison (and more than 50 percent of the Yellowstone herd is infected) can spread brucellosis to cattle. Scientists have shown that the same organism causes the disease in both species. In a number of cases, experienced epidemiologists have concluded that bison were the most probable source of infection for cattle herds in the vicinity. Finally, researchers at Texas A&M University recently demonstrated that infected bison transmit brucellosis to cattle with which they were associated. A nationwide eradication program has succeeded in eliminating this costly disease from 30 states, including Idaho, Montana, and Wyoming, all of which border on Yellowstone Park. My agency is working with the National Park Service to develop mutually agreeable plans to deal with the brucellosis situation in Yellowstone.
Purposes, objectives, and guidelines of this executive committee are outlined through which the USAHA can best be served. Regarding brucellosis, the eradication program was initiated in 1934. Tremendous progress has been made but a problem still exists for the cattle industry due to the known involvement of elk in several western states and bison in Yellowstone Park. The status of wild deer as potential reservoirs of the disease has been investigated and they do not play a significant role in transmission. Records of susceptibility to brucellosis has been documented in rats, rabbits, hares, mink, foxes, coyotes, dogs, guinea pits, sparrows, magpies, crows, pigeons, pheasants, chickens, turkeys, geese, fleas, house flies, mosquitoes, bedbugs, ticks, etc. Piroplasmosis, salmonellosis, swine tuberculosis, pseudorabies, raccoon rabies, and vesicular exanthema are discussed.
A serological survey for Brucella abortus antibodies in mature cow moose (Alces alces) was made in an area of northcentral British Columbia which recently had been heavily infected with bovine brucellosis and in which there was considerable intermixing of moose and range cattle. No evidence of Brucella infection was found in the moose tested and it was concluded that they were probably not of great significance in the epidemiology of bovine brucellosis in the study area and were therefore unlikely to have hindered attempts to eradicate brucellosis from the cattle in that area.
During the hunting seasons of 1979 and 1980, sera were collected from 713 white- tailed deer in Missouri and tested for antibodies to Brucella abortus using the standard tube agglutination, standard plate agglutination, Brucella buffered antigen card agglutination and rivanol agglutination tests. Only one sample was considered to be positive for Brucella antibodies. This study demonstrated that white-tailed deer in Missouri were not an important reservior host of brucellosis.
This paper is intended to bring together as many studies relating to brucellosis in wildlife as possible and to attempt to analyze them from the standpoint of importance in our Bang's disease control and eradication program. In summary of these studies: 1) The bison is susceptible to Brucella abortus infection; 70% of the bulls and 44% of the steers were positive reactors to the agglutination test. 2) The elk is proven to be susceptible to B. abortus infection, as demonstrated by the presence of specific serum agglutinins. 3) One bull moose yielded a culture of B. abortus and a very high blood titer. 4) Deer have been considered a possible reservoir of Brucella infection, but the few blood tests conducted by various states have proved negative. 5) The wild rat is definitely susceptible to natural infection and can pass viable organisms in the feces and urine. 6) The pigeon, the turkey, the duck, the pheasant, and the goose are all susceptible to the various Brucella organisms when fed or injected with them. Only the turkey succumbs to this infection. There is no indication that these birds pass the organisms along to cattle or even among themselves. 7) The English sparrow has not yet been incriminated with the ability to harbor the Brucella organism.
Brucellosis, with emphasis on North American elk, is emphasized in this section of the book. Previous work has shown the disease to be prevalent in bison herds, but many studies show that prevalence is low among elk herds, even ones in close proximity to infected bison herds. One exception is the persistence of the disease in elk using feeding grounds in western Wyoming. Several possibilities exist for management of the disease, although no practical options exist for eradication.
The results of testing 143 elk blood samples for Brucella antibodies are presented, with emphasis on comparing two testing methods. Commercial plate antigen tests have been consistent with the official tube test when testing cattle sera. The results of this study indicate that there is significant difference in the tests when testing elk sera. About 13% of the samples had different results with the tests used. The results indicate that the tube test is more satisfactory in detecting Brucella antibodies in elk sera, than two commercial plate tests. The prevalence of positive samples in this study is higher than previous studies.
Published reports of Brucella abortus infections in wild North American ungulates and domestic cattle herds were reviewed to determine if infection in these species was related. Bison (Bison bison) were frequently found infected, but are probably a minor threat to livestock due to their current limited distribution. Most elk (Cervus elaphus) were free of infection except where their range was shared with infected bison or livestock. Deer (Odocoileus spp.), pronghorns (Antilocapra americana), moose (Alces alces), and bighorn sheep (Ovis canadensis) appeared to be insignificant hosts of Brucella abortus. The lack of significant wild ungulate hosts and the distribution of infected livestock herds in the United States suggests that wild ungulates are of little importance in the epidemiology of infections by B. abortus in cattle.
Brucellosis is an important disease in livestock and also humans. Blood samples have been tested from red, roe, fallow, sika, muntjac, and Chinese water deer and no antibody has been detected. While cattle are infected, deer do not appear to be a transmitter or reservoir, as are cattle, bison and elk. In Russia, maral deer have been found infected. In addition, reindeer, foxes, arctic foxes, impala, desert wood rats, and in some countries such as Denmark, the hare has been found to be infected with a Brucella organism.
A study of brucellosis in white-tailed deer (WTD) was conducted for the hunting seasons of 1947-48. Brucellosis occurs in humans, cattle, hogs, and goats. In wildlife, bison are commonly infected while elk are infrequently infected. Little is known regarding brucellosis in other wildlife. A total of 436 samples from 118 bucks, 136 does, 24 fawns, and 158 unknown aged and sexed deer were examined using the standard plate agglutination test (antigen test). The incidence of infection of the 436 deer was 0.22% (one positive reactor was detected). Because the infection rate in domestic animals is much greater that the incidence detected in this study, it is concluded that brucellosis is not a significant disease in WTD at present, and that WTD are probably not considered important in the transmission of the disease to domestic livestock.
A section on diseases of Yellowstone National Park bison is included from the book. Prevalence of brucellosis in bison has varied in the studies conducted in the Park. Most studies have concentrated on the rate of infection and not the effects of the organism. Limited information suggests that the Brucella organism has little physiologic effect on the bison. It is possible that an equilibrium has established between this organisms and the bison host. Although the disease does not appear to greatly effect the bison of the Park, there is great concern with the potential for transmission of brucellosis to domestic livestock that come into contact with bison. The current management procedures of Yellowstone National Park bison are discussed.
The USDA has been conducting a program for the brucellosis eradication in the U.S. The Department of Interior may be indifferent and non-cooperative efforts by people in Agriculture, farmers, and state officials to eradicate brucellosis from bison in Yellowstone Park warrants comment. It is felt (by Meagher) that an eradication program in the Park would destroy the free-ranging theme of bison there. The bison in the Park are the only ones that survived extermination in historic times. These bison descended from the mountain and plains bison. Bison that die in the park serve as food for meat-eating wildlife. Brucellosis in the park bison does not cause disease conditions for these animals and is suggestive of a symbiotic relationship between organism and host. Past control programs in the park have been in conjunction with population reduction. It is not efficient to capture wild bison for brucellosis control since only 75% of the herd could be captured, tested and vaccinated. Yearly slaughter of bison that are positive reactors may remove dominant lead-females and these animals are required to keep historic patterns of habitat use continual. An eradication program for the Park is outlined and discussed. Transmission of brucellosis from Park bison to domestic livestock is a remote possibility and is addressed.
Efforts made since 1976 to contain bison within the boundaries of Yellowstone National Park proved to be ineffective. Hazing and herding activities demonstrated that bison can be moved only where they want to go. Attempts to block travel routes and harassment with various devices sometimes treated immediate problems at the locations involved, but did not change the overall direction of bison movement down the Yellowstone River. Further, these tactics apparently caused major shifts to other travel routes or sometimes displaced a conflict from one site to another. It appears that, in general, success (if any) in localized displacement of bison by human efforts will decrease and hazards to personnel will increase with these management approaches. Cropping of bison by public hunting outside the park will not change their movements, but may lessen local conflicts.
Infectious abortion (due to Bacillus abortus) in cattle is an important problem. Control of this disease is currently under study. Livestock owners are encouraged to build their herds through breeding rather than purchasing to limit the spread of the disease. Sanitation in infected herds s encouraged. Bacterin treatments are being used in test herds that recently contracted the disease. Subcutaneous injections of live organisms in animals that have shown presence of the disease for a number of years is being done in test animals, although more time will be needed to evaluate the success of this method. Induction of immunity by injection is yet to be determined Three serum samples from Yellowstone National Park buffalo cows were tested for abortion disease. Two of the three animals had aborted. Two samples gave a positive reaction with an agglutination fluid prepared from Bacillus abortus. It appears that the organism is pathogenic for this animal.
(note: the entire text of this report is included below) When Buffalo and Elk were being slaughtered in two National Parks to reduce the size of the herds during the winter of 1946-47, an opportunity was taken to conduct a serological survey by using the tube agglutination test to determine the extent of Brucella infection. The Buffalo and Elk herds roam in separate parks which are situated about 150 miles apart. When culling the respective herds the animals were hunted by attendants and selected animals shot. The hunter carried a supply of sterile bottles. After shooting them he severed the jugular vein and filled a vial from the free flowing blood. This blood was shipped to one of our Branch Laboratories where the serum was removed and forwarded for examination. Because of the conditions under which animals were slaughtered, no attempt was made to isolate Brucella abortus. One hundred and eighty-six samples were received from Elk of both sexes and all ages. All of these were negative. Thirty-seven samples of Buffalo serum were received, the majority being taken from mature males, 6 (16.2%) were positive, 5 (13.5%) were questionable and 26 (70.3%) were negative. A point of interest is that 5 of the 6 positive samples were from male Buffalo.
This review covers over 100 studies and publications on brucellosis in wild mammals. Included are tables of over 120 ruminant and nonruminant mammals with corresponding infection rates, source and testing method. Attempts were made in most of these studies to correlate the prevalence of Brucella abortus infection in wild animals with the disease status of local livestock. Ingestion of aborted fetal or placental material appears to be the most probable means of exposure for wild animals, although proof of this has not been demonstrated. Transmission of Brucella organisms from wildlife to livestock or man is of greater concern but difficult to document. Wild ruminants such as elk, bison, and African buffalo, which are affected by abortion or birth of nonviable or weak calves, provide potential sources of B. abortus to wild and domestic animals. Roles of other wild species in transmission of the agent have not been determined. Rats are capable of contracting the disease after contact with infected rats and they then shed the organism in their urine and feces. However, available evidence indicates that brucellae travel to rodents but not from them to domestic animals. Abortions have been observed in mink and coyotes. Brucellae have been isolated from vaginal exudate in the latter, which provides another potential source of infection for wild animals. In utero transmission has been documented in mink and coyotes. Wild animals are likely to be involved in mechanical transmission of B. abortus by scattering contaminated material around farm or pasture areas as they feed.
Data on brucellosis in several Alaskan caribou herds during 1962-65 is summarized. During this time agglutination-reactor prevalence rates (1:20 or higher) gradually declined in the Nelchina (6.5 percent to 1.0 percent) and Arctic (30 percent to 12 percent) caribou herds. A simultaneous decline (5 percent to 3.4 percent) in the prevalence of placental retention and/or excessive bleeding at parturition was also observed on the Arctic calving grounds in northwest Alaska in 1963 and 1965. Various additional conditions have been observed, from each of which brucella organisms were isolated on several occasions. These include orchitis- epididymitis, bursitis-synovitis and metritis, singly or in combination. In some cases, the observed lesions no doubt resulted in one or more of the following signs: sterility, lameness, and/or abortion with (probable) subsequent death of the female following putrefaction of retained placental structures. During 1963 about 25% of 107 cows showing placental retention and/or "excessive bleeding" were unaccompanied by calves when seen a few days post-partum. The Russian and American points of view regarding naming the causative organism of rangiferine brucellosis are briefly reviewed. Brucella suis biotype rangiferi is proposed as a compromise, based on both the principles of bacterial taxonomy and the natural ecology of the organism.
The epidemiology of bovine brucellosis is often complex and influenced by several nontechnical and techinal phenomena. The evolutionary changes in animal husbandry toward larger herds and greater cattle commerce result in increased exposure potential of herds to brucellosis. The effectiveness of surveillance methods is reduced. The intricate host-parasite relationship of Brucella abortus and cattle may cause a highly variable incubation period, latent infection, and seronegative cattle which abort. These complicate control of the disease. A large variety of diagnostic procedures are available. The sensitivity and specificity vary and results should be evaluated by bacteriologic and epidemiologic information. Serologic tests which depend upon qualitative antibody determinations should be emphasized. Strain 19 remains the most widely used immunogenic agent for the control of bovine brucellosis. The disadvantages of its use can be largely overcome by reducing the dose and proper application of supplemental diagnostic tests. Vaccination without regard for age (whole herd) should gain wider acceptance in many areas. Individual herd plans should have wide flexibility. The goal must always be to reduce infection to the lowest possible, yet economically feasible level. Many nonbovine species have been studied as hosts for B. abortus. Infection in these animals is not common and clinical symptoms are infrequent. It appears that cattle are sources of these infections but the reverse situation is rare. The complexities of the epidemiology of bovine brucellosis will assure the existence of the disease for many decades.
The testing, tagging and slaughter of bison in Wood Buffalo Park was carried out in October and November, 1958, at the Sweetgrass abattoir and corral site. The program this year consisted of testing the animals for tuberculosis reaction by injection, testing of blood samples of live animals for brucellosis by the rapid agglutination test, facilities for which were set up in the abattoir, tagging all animals thus tested and finally slaughtered all reactors of either or both diseases. This program was carried out as planned with the exception of the taking of some animals by open-field shooting to complete the meat requirements. The results of the work done is presented using data taken by the Health of Animals representative, Dr. F.G. Gallivan and by the writer. A complete physiological examination was done on slaughtered animals and is reported.
Wildlife managers lack a scientifically sound basis from which to formulate management policy regarding many host-parasite interactions. One contributing factor to this problem is the paucity of hypothetico-deductive (H-D) research concerning the ecological consequences of host-parasite interactions. A comparison of justifications used for wildlife brucellosis management policy in Wood Buffalo National Park (NP) (Canada) and the Greater Yellowstone Area (U.S.) demonstrates how perspective (with or without science) can drive policy formation. If wildlife scientists consistently used the H-D method to gather reliable knowledge pertinent to an ecological perspective of wildlife brucellosis (or other host-parasite interactions), their contribution toward the formation of disease management policy would be more significant. In situations where disease management must commence prior to the completion of manipulative experiments (which admittedly can be difficult to apply with free- roaming wildlife), adaptive resource management, as suggested by Walters (1986), could profitably be used to test hypotheses.
We examined via simulation 3 representative types of bison (Bison bison)-brucellosis management schemes that have been proposed for the Grand Teton National Park (NP) bison herd: (1) vaccinating female calves, (2) vaccinating females of all ages, and (3) testing and removing seropositive animals, combined with vaccinating female calves or females of all ages. Sensitivity analysis demonstrated that model predictions are relatively robust to likely errors in estimates of key parameters under assumptions representing Grand Teton NP. Simulations predict that, after 20 years, the proportion of the Grand Teton NP herd seropositive for Brucella could be reduced from 69% (current level) to, at best, 20% under any of the 3 management schemes evaluated. Our examination of the relationship among brucellosis transmission rate, vaccine efficacy, and vaccine delivery rate indicated that reducing the percentage of seropositive animals to <10%, a stated goal for this herd, would require reducing the B. abortus transmission rate to <5%, which is unlikely with currently available vaccines and without also limiting contact with B. abortus infected bison and/or elk (Cervus elaphus).
We describe development of a simulation model representing bison (host)-brucellosis (parasite) interactions within a natural resource management framework. We document three phases in model development which focus on the simulation of bison population dynamics in (1) a brucellosis-free herd, (2) a brucellosis-infected herd, and (3) an infected herd subjected to different vaccination schemes. The first phase represents bison population dynamics based on age-specific rates of natural mortality and natality and rates at which animals are harvested. The second phase represents the influence of brucellosis-induced abortions, brucellosis transmission, and naturally acquired immunity. The third phase represents acquired immunity to brucellosis (or lack thereof) due to immunization, which is a function of vaccine efficacy and the percentage of bison to which the vaccine can be delivered. The model accurately simulated historical changes in herd size, annual recruitment, population age structure, and survivorship of individual cohorts over a 17-year period in a brucellosis-free bison herd on the National Bison Range, U.S.A. (Phase I). The model also accurately simulated historical changes in herd size, and predicted the most likely year of infection, in a bison herd in Grand Teton National Park, U.S.A., that contracted the disease during a 20-year period (Phase II). Finally, the model was used to evaluate a proposed bison brucellosis management plan for the Grand Teton National Park herd which involves annual vaccination of female calves (Phase III). Simulations suggested that, after 20 years, the proportion of the herd infected with brucellosis might be reduced from 69% (current level) to between 50% and 20%, depending on the (currently unresolved) vaccine efficacy.
Brucellosis is caused by the Brucella spp. bacterium and is contagious in animals and humans. The primary manifestations may include abortion, retained placenta, orchitis, epididymitis, and impaired fertility in animals, and in humans the characteristics of infections include weakness, fever, chills, sweating, joint pain, headaches and body aches. Six species of Brucella are listed and their associated hosts. This chapter discusses the disease characteristics, etiologic agent, host range, distribution, and specifically the disease in cattle, swine, yaks, bison, horses, dogs and humans. The general mode of spread, epidemiology, diagnosis in animals and humans is reviewed. Prevention and control in cattle, swine, and humans is addressed.
The existence of the focuses of brucellosis of wild animals in numerous countries is demonstrated. These wild focuses, whatever be the origin of their contamination, implicate the possibility of the transmission of Brucellosis to domestic animals and the human being from such reservoirs. The Brucellosis of the hare appears quite to be a disease spread in Europe. This animal, infected easily, should in this way be an important natural reservoir of Brucellosis capable of transmitting this disease to the Suidae the Ovine animals and two Bovines who grazed near the customary lairs of this leporine. The role of the wild rodents appears almost as important, irrespective of whether they are or are not the commenslas of man. The dissemination of Brucellosis by the arthropods, and the long preservation of Brucella in ticks are facts that must be taken into consideration for the campaign against Brucellosis. Apart from the standard modes of transmission of Brucellosis from animal to animal and from animal to the man (dust, contact, ingeston, etc.) the time has come when a study must be made, not a trifling one, of the share of these new modes of preservation and transmission.
A cooperative interagency program was established in western Canada in 1975 to recover wood bison (Bison bison athabascae) in areas of historic range. Wood bison were classified as endangered in 1979 and were downlisted to threatened in 1988. A recovery plan is being drafted to ensure the survival of wood bison as a wild subspecies. Four wild herds with at least 200 animals in each is the minimum requirement. Currently, there are more than 2,900 wood bison with about 75% of the total population located in the Mackenzie Bison Sanctuary (MBS). Bovine diseases present in the wild bison in and around Wood Buffalo National Park pose a threat to wood bison recovery and to the MBS herd. Fifty percent of the historic range is unavailable for recovery because of diseased bison. With disease elimination, the scope for recovery in a large portion of the historic range would be significantly increased. In 1990, the Northern Diseased Bison Enviromental Assessment Panel recommended eradication of diseased bison and herd replacement. The introduction of plains bison into the core range of the wood bison in the 1920's nearly caused extinction of the wood bison. Today, western Canadian provinces and territories lack consistency in wildlife policies regarding transfers and establishment of ranched and/or free-roaming bison of either subspecies within the historic range of the other. Conservationists cannot rely on the agricultural industry to ensure recovery and preservation of the genetic integrity of wood bison in the long term. Additional herds of wood bison are required to secure survival of the subspecies and to insure full recovery within its historic range. For a successful recovery program, protection of the MBS wood bison resource from disease and genetic contamination and establishment of additional herds of healthy wood bison in healthy habitats are required management actions.
Brucellosis occurs in domestic livestock and wild species including bison, caribou, elk, Russian antelope, European hares, desert wood rats, and possibly moose and hippopotami. Only 0.16% of white-tailed deer tested positive serologically. Etiological agents, epizootiology, clinical signs, pathologic manifestations, diagnosis, and prevention and control are discussed. Implications regarding wildlife, domestic livestock, and human health are also addressed.
Surplus bison from Yellowstone National Park in December, 1930, were tested for brucellosis. The results show 58 positive and 25 suspicious animals of 110 tested. The results are further broken down into sex and reproductive state. Speculation was made on the possibility of transmission from cattle to the bison. More study on the effect of the disease on the bison herd needs to be done, and control measures need to be implemented. Results of elk testing show 3 of 67 samples positive while 10 were suspicious.
This letter begins with a short review of brucellosis, with emphasis on different effects of the disease on different animals. The results of brucellosis testing of hunter-killed wild game is presented. Samples from antelope, deer and elk were negative for brucellosis. The author finishes the article with a short review of other papers dealing with brucellosis in big game.
Comments regarding a commentary by Dr. Tufts: Dr. Safford feels that pathology of brucellosis in bison in Yellowstone Park is not minimal and that testicular lesions and lesions in the genital tract is a common association with infection. He also feel thats brucellosis could be a likely cause of a poor reproductive rate of bison in the Park. Selling and distribution of bison from the Park to other parts of the U.S. in the 1960s probably enhanced the spread of the disease to domestic livestock. Another consideration is the public health concern and risk of infection to humans that are visiting the Park every year. He suggests selective slaughter of bison and calfhood vaccination as a means to eliminate brucellosis and preserve the bison gene pool. This would aid in decreasing the infection in elk as well.
(note: the complete text of the letter follows) Dear Sir: I read with dismay the Jan. 15, 1974, J.A.V.M.A. article on page 131 stating that the Council on Public Health and Regulatory Veterinary Medicine agreed to continue efforts to persuade the USDA to proceed immediately with eradication of brucellosis from Yellowstone bison. Attempts to brucellosis-test bison or other wild species would almost necessarily entail a high mortality and great expense. When threatened species of wildlife whose contribution to disease perpetuation is not well defined are to be included in eradicaton progams of questionable benefit at great hazard to that species and at great expense to the public, then it is time to call for a moratorium. I strongly urge that the Council discontinue efforts to promote brucellosis eradication in the Yellowstone bison.
Most of the studies of diseases of wildlife have been carried on primarily in relation to human welfare and the transmissibility of these diseases to domestic livestock rather than for the benefit of wildlife itself. Today the emphasis is changing somewhat, and wildlife diseases are being studied as a necessary part of conservation. Despite the views of many older writers, losses among wild species from disease are very considerable. The isolation of many wild animals in places remote form human habitations and their general tendency to scatter rather than to concentrate make it difficult to obtain information on the mortality from disease among them. It is also a characteristic of wild animals, when they are sick, to secrete themselves in dense cover or in burrows, thus making their discovery unlikely; and scavenger insects, birds, and animals rapidly dispose of carcasses in exposed places, so that shortly after their death little trace of them remains. Nevertheless, from time to time epizootics, or severe outbreaks of disease, of varying degrees of destructiveness have been found to occur in practically all species of wildlife thus far studied. In this article, cross references will be made to other articles in the Yearbook in which specific diseases are discussed at greater length in relation to domestic animals.
The need has been discussed for more information on those diseases transmissible from wildlife to domestic animals. In compliance with this necessity, a preliminary survey of the incidence of brucellosis and leptospirosis among the white-tailed deer of the Southeast has been conducted. By plate-agglutination techniques, the results of this investigation indicate a prevalence of only 0.25 per cent brucellosis and 1.73 per cent leptospirosis among the animals surveyed. Continued studies on these diseases are anticipated in 1958 and 1959.
"Brucella abortus is relevant to the ecology and management of elk." The host range is wide for transmission but the disease occurs primarily in cattle, bison and elk. Transmission of brucellosis from wildlife to domestic cattle makes the disease significant. Evidence of infection in elk and bison has existed for 62 and 75 years, respectively. Brucellosis was first detected in elk in 1930 and in bison in 1917. Attention has been drawn to brucellosis after 569 bison were killed in Yellowstone National Park and a rancher's cattle herd became infected in Wyoming. The disease may by perpetuated in elk when food is limited and the herds concentrate. Infected female elk play a significant role in transmission of the disease to susceptible hosts because aborted fetuses, vaginal fluids, newborn young, birth byproducts, and milk is contaminated with the bacteria. In Yellowstone Park during the 1960s, 1.7% of elk killed there tested positive. Since 1970, 28% of 1,600 elk tested reacted positively. Regarding bison in the park, 54% of several hundred tested reacted positively. Continued interaction between these species may provide the opportunity to perpetuate the disease. Under experimental conditions, brucellosis has been transmitted from elk and bison to cattle. However, there have been no cases reported of wildlife infecting cattle with the disease in the field. Thus, the problem is the potential of wildlife infecting domestic livestock. Most of the cases of brucellosis in humans (undulant fever) occurs from contaminated milk and milk products with Brucella melitensis, which is found in goats and sheep. Pasteurization kills the bacteria. Occupational contact with infected animals ranks second in humans becoming infected. The risk of human infection by elk, bison or other big game is remote. Controlling brucellosis in livestock (vaccination) and controlling transmission from wildlife to livestock is discussed. Strategies to lower the risk of transmitting the bacteria to livestock include 1) increase cattle's resistance to the disease, 2) decrease the number of potential transmitters of the disease, and 3) decrease the opportunity for transmission to occur. The future of the impact of brucellosis on wildlife and livestock is discussed.
Previous studies have revealed Bang's disease in bison, elk, moose, and white-tailed deer (WTD). A few mule deer and pronghorn antelope that were tested were negative. Brucellosis seems to be a rarity in WTD (in North Dakota 1/436 tested positive, and in many other studies all were negative). This article's objective was to determine whether Missouri deer were infected with brucellosis due to the possible effects that brucellosis may have on deer herd productivity and the potential danger in spreading of the disease, if present, to domestic livestock. Blood samples were collected from WTD killed during the hunting seasons of 1950-1953. All but one (this one had a non-characteristic reaction) of 996 deer sera tested negative using the standard plate agglutination test.
The value of an Official Calfhood Vaccination (OCV) program in regard to eradicating brucellosis is debated by cattlemen. While Bang's disease is rapidly decreasing in beef herds in the U.S., there are differences of opinion on how to effectively manage its eradication, specifically OCV. The primary problem with a highly decreased incidence of the disease is that some commercial cattlemen feel it is safe to bypass the OCV for their replacement heifers. The other problem is the use of the live vaccine which is not a very good immunizing agent, only 65% effective, which also masks the symptoms of the disease. However, in spite of the flaws, a consensus of veterinarians and cattlemen feel the OCV program should be continued. Transmission of brucellosis from wildlife vectors may be an important consideration. In regard to Yellowstone National Park, biologists from the Interior Department are comtemplating how the Brucella organism fits into the scheme of things as far as wildlife vectors, especially bison, may contribute to cattle infections.
Portions of western Canada, which include the boreal mixedwood, aspen parklands, lower foothills, and the monatane forest regions, contain large expanses of aspen. These regions are favorable for consideration as game ranching areas because of a shallow snow cover, productive soils, variety of vegetative types, and a variety of native wild ungulates, including bison (Bison bison), moose (Alces alces), elk (Cervus canadensis), mule deer (Odocoileus hemionus), and white-tailed deer (O. virginianus). Those parameters discussed, which are relevant to game ranching, include range carrying capacity, sex ratio, management during winter, scale of operation, interspecific competition, and behavioral intolerance, disease and parasites, harvesting, and multiple use management.
As the campaign to eradicate bovine brucellosis (Brucella abortus) and tuberculosis (Mycobacterium bovis) in Canadian livestock nears completion, the importance of extraneous sources of these diseases increases. This review summarizes the literature on brucellosis and tuberculosis in Canadian wildlife species to determine existing and potential hosts. Canadian caribou (Rangifer tarandus) are reservoirs of Brucella suis biotype 4 which is pathogenic in caribou, humans and muskoxen but reportedly nonpathogenic in livestock. Bison (Bison bison) and elk (Cervus canadensis) are significant reservoirs of B. abortus and M. bovis. The bison in and around Wood Buffalo National Park have both diseases and are the only wildlife reservoir in Canada. Free-ranging elk are important reservoirs of brucellosis in Wyoming, and captive elk initiated the recent outbreak of bovine tuberculosis in 20 American states which has also involved bison and cattle herds. If bison and elk ranching continues to develop in Canada, the industry will have to be monitored to prevent the introduction and spread of infectious diseases like brucellosis and tuberculosis. This requires the evaluation and/or development of effective diagnostic methods for use in these animals.
The involvement of veterinarians in the health management of North American bison will continue to increase, particularly in regard to the development of the bison ranching industry. More intensive management of bison will lead to greater recognition of diseases, and will raise concerns about the transmission of diseases between bison and other livestock species. This review of the infectious and noninfectious diseases of free-ranging and captive bison populations indicates that bison are susceptible to a wide range of indigenous and foreign diseases that occur in cattle and other livestock species. Most of the available information is based on necropsy results or serological surveys, and there is much less information on clinical diagnostic and preventive medicine, or on the evaluation of conventional diagnostic tests, therapeutic regimens, or vaccines in bison.
Examinations of complete or partial remains of 72 bison found dead in and around Wood Buffalo National Park, Canada, revealed evidence of brucellosis in 18 (25%) and tuberculosis in 15 (21%), with a combined prevalence of 42%. Urease-positive and urease- negative strains of Brucella abortus biovar 1, and strains of biovar 2, were isolated from tissues of bison, including synovium and exudate from severe arthritic lesions. Mycobacterium bovis was isolated from a range of granulomatous lesions that were similar to those reported in tuberculous cattle. Diseased bison had a broad geographical distribution, and were found outside the park on at least three natural corridors. The diseases have a deleterious effect on this population of bison, and pose a health risk to other bison herds, livestock, and native hunters in the region.
Although generally regarded as a bovine disease, in the Greater Yellowstone Ecosystem (GYE) brucellosis receives more notoriety in wildlife than it does in cattle. Brucellosis is biologically important to wildlife of the GYE, but its significance as a bovine disease gives it great economic and political importance. As an example, 562 bison from Yellowstone National Park were taken during the winter of 1988-1989 in a Montana harvest that was necessary because of concern about brucellosis transmission to cattle; brucellosis also played a role in the March 1989 agency reduction of 16 bison from the Jackson herd in Wyoming. Brucellosis in bison of the GYE cannot be discussed without also considering brucellosis in cattle and elk. Brucellosis has been found in over 50% of the animals in the GYE in several studies. Brucellosis in elk is generally much less prevalent, but concentrated feeding grounds in Wyoming cause brucellosis to be present in an increased number of elk. Bison and elk are very similar in their response to infection with Brucella abortus, with abortion being the most important symptom. Transmission of brucellosis from bison or elk to cattle has not been observed under field conditions, but experimental conditions of close contact suggest that transmission can occur. Transmission of brucellosis is unlikely to occur in the GYE, but current large-scale movements of animals into livestock areas in the brucellosis-free states of Montana and Wyoming increase the possibilities of transmission to occur in the future. Brucellosis eradication is an important concern to the federal government due to the historic losses to the cattle industry. The infection rate in the U.S. has dropped from 11% in 1935 to 0.17% of cattle herds infected in 1991, with 27 states brucellosis-free. Surveillance and vaccination are important controls to the spread of brucellosis, although both are still imperfect procedures. The bison in the GYE are currently under close study, especially to improve understanding of the status of brucellosis. Both Wyoming and Montana have developed management plans to keep populations in control and to prevent the spread of the disease. Control of the disease in the GYE needs to be examined from the following perspectives: (1) the livestock industry and officials responsible for brucellosis eradication, (2) the elk and a wildlife management agency, and (3) ecosystem maintenance and the National Park Service. There is no easy solution to the problem of brucellosis in the GYE that is satisfactory to all concerned parties. Additional research on strain 19 and other vaccines should be conducted with bison, and field trials with the biobullet and strain 19 system should be conducted. The question of whether B. abortus is native to bison should be resolved. Efforts should be made by wildlife and land management agencies and by cattlemen to reduce contact between bison and cattle. Acquiring winter range for wildlife is one possible avenue; delaying movement of cattle to forest grazing allotments until after bison and elk calving periods may be another. Cattle in and around the GYE should be vaccinated against brucellosis, and surveillance for brucellosis in cattle may have to be continued indefinitely. Harvest of bison that could come into contact with cattle will undoubtedly continue to be necessary; but it is hoped that ways can be found to reduce this measure. Finally, compromise and dialogue must be continued and increased, and the matter of brucellosis in bison of the GYE addressed in a sound manner with a minimum of disruption to the ecosystem.
Incidence of brucellosis in elk (Cervus canadensis) on two winter feedgrounds in Wyoming was examined over a 5-year period by testing serum samples using the standard plate agglutination (SPT) buffered Brucella antigen (BBA), rivanol (Riv) and complement fixation (CFT) tests. Thirty-one percent of 1,165 elk were positive by defined criteria. Considering each test individually, only 29% (106) of 370 positive sera would have been classified as reactors by the SPT, 83% (370) by the BBA test and 86% (314) by the Riv test. The CFT would have identified 85% (267) of 332 positive samples on which it was used. Brucella abortus, type 1, was isolated from 17 of 45 elk necropsied. The SPT identified 59% (10) of these as reactors, the BBA test 94% (16) and the Riv test 88% (15). The CFT identified nine of nine (100%) on which it was used. Prevalence of seropositive animals increased with age. Brucellosis has been present in one of the two elk herds since at least 1930, and the incidence of infection among mature females in both herds was approximately 50% during this study. No single serologic test should be relied upon to diagnose brucellosis in elk.
The effects of brucellosis in 60 mature elk (Cervus canadensis) and over 72 of their offspring were determined over a 65-month period. Artificial infections were induced with Brucella abortus type 1 strain 2308. All 27 artificially inoculated and 96% of 24 naturally- exposed mature elk became infected with brucellosis. An additional five cow elk were used to examine the importance of venereal transmission. The average incubation period from artificial exposure until abortion was 89 days among seven cows, and the average incubation period from exposure to development of a serotiter was 39 days among 24 artificially- inoculated cows. The most probable route of infection was oral contact through licking or ingestion of contaminated materials. Fetal fluids, vaginal exudates and aborted fetuses were the most likely sources of contamination. The venereal route of transmission was unimportant. Abortion or birth of nonviable calves was the most improtant and frequent sign of brucellosis, and 48% of 29 cows lost their first calf following infection. Other signs were secondarily infected hygromata and synovitis in the lower legs. Most calves born alive to infected cows demonstrated a serologic titer at or soon after birth, and the majority lost their titer. Many of the calves demonstrating early postnatal titers as well as those born without indication of infection became infected later in life. Although the maximum duration of brucellosis was not determined, one cow had maintained an infection for 56 months prior to necropsy. Five elk apparently recovered, but Brucella was recovered at necropsy from another three which also appeared to be recovering.
This chapter from the book focuses on important bacterial diseases of Wyoming wildlife. Included is a general review of brucellosis. Distribution and hosts affected, transmission, pathogenesis and pathology, diagnosis, control, and implications of brucellosis are covered. Although the focus is on wildlife of Wyoming, brucellosis of elk and bison in the northwest region and Canada is specifically considered.
From 1954 to July, 1964, over 29,100 wildlife serum and tissue specimens, 120,000 ectoparasites, and 4,400 livestock serum samples, collected principally from west central Utah, were examined for evidence of Brucella. Eighteen isolations of Brucella were made: 15 Brucella neotomae from the desert wood rat (Neotoma lepida), 1 Br. neotomae from fleas (Orchopeus sexdentatus) taken from a wood rat, 1 Brucella suis from a black-tailed jack rabbit (Lepus californicus), and 1 possible strain of Brucella melitensis from the same species. Sixty- eight wildlife serum specimens from 13 animal species were found to contain Brucella abortus agglutinins. These species included wood rats, jack rabbits, deer mice (Peromyscus maniculatus), Ord kangaroo rats (Dipodomys ordii), Townsend and white-tailed antelope squirrels (Citellus townsendii and Citellus leucurus), mule deer (Odocoileus hemionus), bison (Bison bison), and a harvest mouse (Reithrodontomys megalotis), a long-tailed pocket mouse (Perognathus parvus), a western porcupine (Erethizon dorsatum), a desert cottontail (Sylvilagus audubonii), and a Nuttall's cottontail (Sylvilagus nuttallii). Numerous cattle and sheep from the region and adjacent areas were also found to have agglutinin titers sufficiently high to be indicative of active Brucella infections.
Seven cases of brucellosis in Eskimos of the Western Canadian Arctic have been identified. In four of the cases the organism was isolated from blood or bone marrow, the other three were diagnosed by agglutination tests. The strains are considered to be Br. melitensis or Br. suis (Danish variety) depending on the interpretation of differential tests. The latter variety has not previously been reported in humans or in North America. Caribou is considered to be the animal source, though investigation to date is limited and other reservoirs may yet be incriminated.
The goal of this study was to obtain evidence of the prevalence and importance of leptospirosis and brucellosis in Wisconsin deer. Three methods of collecting whole deer blood samples for serological examination from Wisconsin white-tailed deer were used. Samples obtained by game biologists and wardens at selected hunting season registration stations provided the best material for serological study. Only one reactor to Brucella abortus was detected among the 600 deer tested. From these results and the reports of other investigators, it appears that brucellosis is not the important disease in white-tailed deer that it is in cattle and has been reported to be in bison, elk and moose. Leptospirosis reactors were found in deer from all areas with heavy deer populations. The average titer of reactors was 1:1,000. The number of leptospirosis reactors was greater among adult deer than among fawns. A higher prevalence of reactors was found in adult males than in adult females, but among fawns positive titers were found only in females. The tissue predilection of the disease in other species, the apparent age and sex prevalence of the disease in deer and the sexual behavior of deer fit the hypothesis that leptospirosis transmission among deer is strongly promoted during the rut by the sexual behavior customary in this animal species. This mode of transmission could help explain the apparent independence of the disease in deer and cattle populations, and the occurrence of the disease in whichever of the two species is present in greatest numbers in an area, irrespective of the occurrence of the disease in the other species.
This article is a comment to the AVMA Council on Public Health and Regulatory Veterinary Medicine regarding eradication of brucellosis in Yellowstone's wild bison herd, specifically to the following items ver batum: 1) The reservoir of brucelloisis in the Park herd is a hazard to the herd itself, and to the livestock industry of Wyoming and neighboring states. 2) It (brucellosis) jeopardizes completion of the National Brucellosis Eradication Program, target date for end-1975. 3) a. Methods and expertise to test the bison and to remove reactors are available; b. the program could be completed without disturbing Park ecology; and c. such a program would result in maintenance of a healthy bison herd. Dr. Tufts comments on the aforementioned items.
Officials at Yellowstone National Park have slaughtered bison in efforts to reduce the herd size. In 1931, 205 bison were killed and agglutination tests for infectious abortion were conducted: 12/13 bulls, 3/3 steers, and 49/90 cows tested positively. In 1932, 199 animals were slaughtered: 25/60 steers, 30/49 bulls, and 52/90 cows reacted positively. In 1933, 69 animals were slaughtered: 9/10 bulls and 42/59 cows tested positively. Live and somewhat healthier animals were also tested: 4/4 bulls and 55/78 cows tested positively. Testicles of some bulls were also examined: 2 positive-reacting bulls had the organism culturable and identifiable. Officials at the National Bison Range, Moise, MT also slaughtered bison to reduce herd size. In 1932, 4/8 cows and 54/79 bulls classified as reactors. In 1933, 12/20 bulls and 36/66 cows tested positively. In 1931 and 1932, 105 elk sera were tested: 8% reacted positively, and 14% were suspect.
The United States Dept. of Agriculture/Animal Plant Health Inspection Service has compiled information regarding frequently asked questions about brucellosis. Topics and questions (with answers) include the following sections of information which follows ver batum. 1) The disease - symptoms, causes, and effects. What is brucellosis? How serious is brucellosis? What disease agents cause brucellosis? What are the symptoms of brucellosis? Is the infected bull a threat to other cattle? Can brucellosis be in a herd without causing abortions? How is brucellosis spread? Do ponds or streams contribute to the spread of brucellosis? Do other ruminants figure in the spread of brucellosis? What about dogs or predatory animals? 2) The eradication program - how it works. What is being done to fight brucellosis? What is the basic approach to eradication? Have any other countries successfully eradicated brucellosis? What is area testing? How do we keep on the lookout for infection in cattle? What happens when evidence of disease is found? Why do we have quarantine and limitation of movement? How does the brucellosis ring test (BRT) work? How does market cattle identification (MCI) work? 3) More about tests and the disease. What is the blood agglutination test? What is the brucellosis card test? Are there any other tests for brucellosis? How important is research to the eradication effort? What are epidemiologists? What is the incubation period of brucellosis? What are negative, exposed cattle? 4) Good herd management - key to prevention. Can brucellosis in animals be cured? How is brucellosis eliminated from a herd? Are calves from infected dams a hazard to other cattle? How well do disease-causing organisms survive outside the cow? Can brucellosis be prevented? 5) Importance of vaccination. What about calfhood vaccination? How are vaccinated animals identified? Is there anything special about brucellosis vaccine? How effective is Strain 19? Is Strain 19 vaccine safe? What are the problems with vaccine use? How does adult vaccination fit in? 6) The economics of brucellosis. Is brucellosis still costly for the cattle and dairy industry? How are owners of infected cattle compensated? 7) The swine program. What are the plans to eradicate swine brucellosis? Are the owners of infected swine eligible for indemnity? 8) Brucellosis in humans. Generally, how does brucellosis affect its human victims? What are some of the symptoms of undulant fever? What are the main sources of human infection? How common is human brucellosis in this country? Can people get brucellosis by eating meat? How can people avoid becoming infected?
Workers from Texas A&M University are continuing research on brucellosis with the intention of aiding eradication of the disease. The team will explore every facet of brucellosis- ranging from infected coyotes and quarantined commercial cattle herds to use of powerful microscopes and electronic computers. This is an interdisciplinary thrust to determine causes and vectors of transmission of the organism from one animal to another.
There has been friction between government agencies and cattle producers regarding Brucella spp. infection in wildlife in the western states. A federal court ruling has recently established an association between wildlife brucellosis infections and domestic cattle. While the number of domestic, quarantined cattle herds decreases rapidly, a residual pool of brucellosis in cattle exists in the periphery near Yellowstone National Park and Grand Teton National Park. Small areas of privately owned agriculture land surrounds these federally owned lands. Bison and elk roam freely in and out of the national parks. Approximately 60% of the bison and elk are infected with the Brucella organism and are thereby a major concern to livestock producers who are trying to eradicate brucellosis from their cattle herds. The National Park Service, Yellowstone, U.S. Forest Service, Grand Teton National Park, and Game and Fish Departments (MT and WY) are attempting a brucellosis eradication program.
Brucellosis was studied opportunistically in bison (Bison bison) in the free-ranging Jackson herd of approximately 120 in Teton County, Wyoming (USA) in March 1989. Recent abortion was diagnosed in a 2-yr-old cow and Brucella abortus biovar 1 was isolated from vaginal discharge, uterine contents, uterus, and supramammary lymph nodes. Endometritis was characterized by lymphoplasmacytic infiltrates in the lamina propria and neutrophils in uterine glands and within necrotic debris and exudate in the uterine lumen. A 5-yr-old bull had diffuse lymphoplasmacytic infliltrates in epididymis and accessory sex glands; B. abortus was isolated from seminal vesicle and ampulla. Twenty-seven (77%) of 35 bison tested from 1989 to 1990 were serologically positive or suspect on tests for Brucella antibodies. We report the occurrence of abortion due to brucellosis in free-ranging bison in the Jackson herd, suggest that bison in this herd are capable of transmitting brucellosis to other susceptible hosts, and report the first confirmation of brucellosis in this herd.
The bacterium, Brucella spp., causes brucellosis in many animals and also in humans. This disease may be referred to as contagious abortion, Bang's disease, Bang's abortion disease in animals, and Malta fever, Mediterranean fever, and undulant fever in humans. This chapter comprehensively discusses the Brucella organisms and disease, including history, distribution, etiology, transmission, signs, pathogenesis, pathology, diagnosis, prognosis, treatment and control. In addition, the implications of brucellosis in bison in regard to cattle and human health is also discussed.
An opportunity was given to interested parties to present recommendations or ideas regarding the National Brucellosis Eradication Program to the Brucellosis Committee. Eighteen states have achieved Certified Brucellosis-Free status. The USDA is enforcing interstate regulations in an effort to prevent further spread of brucellosis. Some of the regulations include official vaccination ages for cattle: vaccinated heifers of beef breeds tested at 24 months of age, dairy breeds tested at 20 months of age. Additionally, a program for eradication of brucellosis in bison will be developed and conducted in a similar convention to domestic cattle. An outbreak of Brucella melitensis was reported in goats and sheep near the Mexican border in Texas.
Antibodies to Brucella spp. were detected in sera of seven of 67 (10%) caribou (Rangifer tarandus), one of 39 (3%) moose (Alces alces), and six of 122 (5%) grizzly bears (Ursus arctos). Antibodies to Leptospira spp. were found in sera of one of 61 (2%) caribou, one of 37 (3%) moose, six of 122 (5%) grizzly bears, and one of 28 (4%) black bears (Ursus americanus). Antibodies to contagious ecthyma virus were detected in sera of seven of 17 (41%) Dall sheep (Ovis dalli) and five of 53 (10%) caribou. Antibodies to epizootic hemorrhagic disease virus were found in sera of eight of 17 (47%) Dall sheep and two of 39 (6%) moose. Infectious bovine rhinotracheitis virus antibodies were detected in sera of six of 67 (9%) caribou. Bovine viral diarrhea virus antibodies were found in sera of two of 67 (3%) caribou. Parainfluenza 3 virus antibodies were detected in sera of 14 of 21 (67%) bison (Bison bison). Antibodies to Q fever rickettsia were found in sera of 12 of 15 (80%) Dall sheep. No evidence of prior exposure to bluetongue virus was found in Dall sheep, caribou, moose or bison sera.
Thanks are given to Helga Pac of the Montana, Fish, Wildlife and Parks agency; Dr. Donald P. Ferlica, State Veterinarian, Montana Department of Agriculture; Dr. C. Cormack Gates, Wildlife Management Division, Government of the Northwest Territories, Canada; Dr. D. R. Bridgewater, United States Department of Agriculture, Animal, Plant Health Inspection Service; Dr. Mary M. Meagher, National Park Service, Yellowstone National Park; Mike Schlegel, Idaho Fish and Game Department; and Richard Mackie, Department of Biology, Montana State University.
Stuart E. Knapp, Ph.D and Professor of Parasitology, Veterinary Molecular Biology, Montana State University, Bozeman, Montana 59717
Sara E. Marley, Ph.D of Parasitology and Entomology, NIH Post- doctoral Research Fellow, Centers for Disease Control, Atlanta, Georgia 30341
Shawna M. Button, Student Research Assistant, Veterinary Molecular Biology, Montana State University, Bozeman, Montana 59717
Matthew C. Rognlie, M.S. of Biochemistry, Research Specialist, Veterinary Molecular Biology, Montana State University, Bozeman, Montana 59717