In monkeys and large apes, Mycobacterium tuberculosis, M bovis, and M avium complex can cause severe disease of the lungs and other organs. Epidemics in primate colonies may be caused by contact with infected human caregivers. Transmission is usually by aerosol with respiratory infection, but the oral route is also possible. Bacilli may also be shed in urine. Old tuberculin is used in skin tests in preference to purified protein derivative (PPD), because it provides greater sensitivity in detecting animals infected with M tuberculosis or M bovis. Biologically balanced PPDs prepared from M bovis or M avium can be injected intradermally at separate sites on the abdomen to conduct a comparative test. Skin tests are observed at 24, 48, and 72 hr for induration and swelling. Tuberculins prepared for use in people are not of sufficient potency to elicit a response in nonhuman primates. Treatment of cases of tuberculosis in nonhuman primates has been attempted using drugs that have had success in people, eg, isoniazid, ethambutol, and rifampin. Drug sensitivity tests should be conducted to determine sensitivity of isolates. Efficacy is limited, and there are overriding arguments against therapy, based on the removal of infected animals, zoonotic risks, and the danger of developing drug resistance. Exacerbations may occur.