Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2009
Publication Date: 7/1/2009
Citation: Rhyan, J.C., Aune, K., Roffe, T., Ewalt, D., Hennager, S., Gidlewski, T., Olsen, S.C., Clarke, R., Jones, L., Sweeney, S. 2009. Pathogenesis and Epidemiology of Brucellosis in Yellowstone Bison: Serologic and Culture Results from Adult Females and their Progeny. Journal of Wildlife Diseases. 45(3):729-739.
Interpretive Summary: Brucella abortus is a disease that causes abortion and associated economic losses in infected cattle herds. The prevalence of B. abortus within bison in Yellowstone National Park pose a risk to the completion of the Brucellosis Eradication Program for cattle. Due to the controversy regarding the pathology of bison in bison, we determined the epidemiologic characteristics of brucellosis in free-ranging bison. Our data suggest that the epidemiologic characteristics of brucellosis in bison mimic the disease in cattle. This data will be of benefit to the National Park Service and the states of Montana, Wyoming, and Idaho in their efforts to resolve the brucellosis problem in the Yellowstone National Park and surrounding areas. This data will also benefit regulatory personnel in their efforts to prevent transmission of brucellosis to cattle herds and direct the Brucellosis Eradication Program.
Technical Abstract: The objective of this prospective study was to follow the natural course of Brucella abortus infection in cohorts of seropositive and seronegative female bison and their offspring in Yellowstone National Park over a 5 year period. Specimens were collected from 53 adult, female bison at least once and from 45 of the bison more than once. Specimens were collected from 25 calves once and from 22 calves more than once. Of the original 45 cows from which specimens were collected more than once, 17 remained seronegative for their entire time in the study; 18 remained seropositive or suspect; eight converted from seronegative to seropositive; and two converted from weak positive or suspect to seronegative. Of the 22 calves that were captured more than once during the study, seven converted from seronegative to seropositve and two from weak or suspect to strongly seropositive. Brucella abortus biovar 1 was isolated at least once from blood, milk, feces or vaginal swabs or exudate from eight of the bison that seroconverted during the study and from blood or milk from three other seropositive bison. Following seroconversion, some bison had one or more reproductive failures; others bore live calves. Calves born to seropositive and seronegative cows converted to seropositive during the study.