Transmission of brucellosis from reindeer to cattle.

Sixteen reindeer (Rangifer tarandus tarandus) naturally infected with Brucella suis biovar 4 were penned with 6 male and 2 female cattle for 30 days, then removed and euthanatized. During this period, 5 reindeer had fawns, and 2 reindeer aborted. Brucella suis biovar 4 was recovered from all adult reindeer at necropsy. Nine reindeer had B suis biovar 4 in uterus, udder, and/or milk. The cattle were euthanatized 2 months after the reindeer were removed. Clinical or pathologic signs of disease were not observed in the cattle. Brucella suis biovar 4 was isolated from 2 male and from both female cattle at necropsy. The female cattle had positive reactions on the buffered plate antigen test, brucellosis card test, tube agglutination test, complement fixation test, and indirect enzyme immunoassay for most of the experiment, but the males had inconsistent reactions on these tests. The indirect enzyme immunoassay was the only test to detect all cattle from which bacteria were cultured. This study revealed that caution is warranted before moving reindeer or caribou into areas of traditional agriculture.