SEROLOGIC SURVEY FOR INFECTIOUS PATHOGENS IN FREE-RANGING AMERICAN BISON

From November 1991 through March 1992, we evaluated 101 free-ranging A merican bison (Bison bison) from Yellowstone National Park, Wyoming (U SA) for exposure to infectious organisms that commonly infect: cattle. No titers were detected for bluetongue virus, bovine leukemia virus, or Campylobacter fetus in these 101 bison, Detectable antibodies occur red against Anaplasma marginale (eight of 76, 11%), bovine respiratory syncytial virus (31 of 101, 31%), bovine viral diarrhea (31 of 101, 3 1%), bovine herpesvirus 1 (29 of 76, 35%), Leptospira interrogans icte rohaemorrhagine (four of 101, 4%), L. interrogans hardjo (seven of 101 , 7%), L. interrogans autumnalis (one of 101, 1%), L. interrogans brat islava (seven of 101, 7%), L. interrogans australis (one of 101, 1%), and parainfluenza 3 virus (27 of 75, 36%). The low antibody titers and the lack of gross lesions are evidence that while previous exposure t o infectious organisms may have occurred, none appeared to have active infections.