GYA Bison Brucellosis
Transmission of Brucellosis from Bison to Cattle
Brucella-induced abortions in both bison and elk have been documented under experimental and field conditions (Thorne et al., 1978a; 1978b; Williams, et al., 1993; Rhyan et al., 1994; Davis, et al., 1990; 1991). Bison have also been shown to transmit brucellosis under range conditions (Flagg, 1983).
Davis, D.S., J.W. Templeton, T.A. Ficht, J.D. Williams, J.D. Kopek & L.G. Adams. 1990. Brucella abortus in captive bison. I. Serology, bacteriology, pathogenesis, and transmission to cattle. J. Wildl. Dis. 26:360-371.
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 month 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 fixtion 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 in the 12 similarly inoculated cattle. As determined by bacterial isolations, transmission of B. abortus from bison to cattle (five of 12 susceptible cattle become infected) did not differ statistically from cattle to cattle transmission (six of 12 susceptible cattle become infected) under identical conditions. No single serologic test was consistently reliable in diagnosis 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 batter of serologic techniques to diagnose brucellosis in bison after the initial 8 wk PE.
Davis, D.S., J.W. Templeton, T.A. Ficht, J.D. Williams, J.D. Kopek & L.G. Adams. 1991. Brucella abortus in bison. II. Evaluation of strain 19 vaccination of pregnant cows. J. Wildl. Dis. 27:258-264.
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 38% (66 of 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 to 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.
Flagg, D.E. 1983. A case history of a brucellosis outbreak in a brucellosis free state which originated in bison. U.S. Animal Health Assoc. Proc. 87: 171-172.
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.
Moore, T. 1947. A survey of the buffalo and elk herds to determine the extent of brucella infection. Can. J. Comp. Med. Vet. Sci. 11: 131.
When buffalo and elk were being slaughtered in the two National Parks to reduce the size of the herds during the winter of 1946-67, 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.
