Tuberculosis in Free-ranging and Captive Hoofed Animals
The major wildlife reservoirs of Mycobacterium bovis infection in addition to cervids are African buffalo, wood bison, North American bison, white-tailed and mule deer, lechwe, and elk. Also, brushtail possums and European badgers are considered reservoirs of M bovis infection. Other species in which M bovis infection has been reported but not implicated as reservoirs and are considered spillover hosts include fennic fox, coyote, Arabian oryx, muntjac, impala, sitatunga, springbok, moles, voles, hares, eland, yak, bactrian camel, wildebeest, European wild goat, large spotted genet, tapir, moose, otters, feral water buffalo, hedgehogs, European wild boar, greater kudu, tiger, white and black rhinoceros, and giraffe. M tuberculosis has been isolated from oryx, black rhinoceros, Asian elephant, addax, and Rocky Mountain goats. Tuberculous lesions vary in consistency from purulent to caseous and often involve the lungs and regional lymph nodes, with liver, spleen, and serosal surfaces as other potential sites. Tuberculin skin tests are conducted in the cervical region using M bovis purified protein derivative (PPD) containing 5,000 tuberculin units prepared for veterinary use. Nonspecific responses may occur in some species with no history of tuberculosis. Therefore, it may be necessary to use biologically balanced PPDs prepared from M avium and M bovis injected at separate injection sites. Skin tests are observed for swelling and induration at 48 and 72 hr.