TUBERCULOSIS (Mycobacterium tuberculosis var. hominis, M. tuberculosisvar. botis, M. tuberculosis var. avium)

This progressive disease of primates has been reported in macaques, gibbons, orangutans, chimpanzees, squirrel monkeys, owl monkeys, and other primates. It is marked by caseous lesions (tubercles) that may be found in any organ of tissue. Atypical mycobacteria have been isolated from macaques.

The clinical signs are cough, chronic loss of body weight, dull hair coat, diarrhea, dyspnea, depression, anorexia, and kyphosis.

Diagnosis can be confirmed by a positive tuberculin test, positive thoractic radiographs, and cultures or stains of stomach mucus obtained by gastric lavage, and fecal cultures. Newly acquired primates should be tuberculin tested immediately and at 30 days, and annually thereafter. The tuberculin test is administered intradermally by injecting 10,000 units of mammalian tuberculin (0.05 to 0.1 ml) into the skin of the eyelid with a 12 mm, 2s to 28 gauge needle.

Individuals should be chemically restrained, allowing a complete physical examination at the same time. Test readings should be made at 24, 48, and 72 hours. Erythema and edema of the injected eyelid show a positive reaction to the test. Sputum cultures, gastric lavage, and fecal cultures are recommended in diagnosing and monitoring tuberculosis in former reactors that may be anergic.

Radiographic examination of the thorax will often confirm a diagnosis of tuberculosis but should not be depended upon as the primary criterion, since pulmonary involvement does not always occur in primates and the rate of visceral tuberculosis is high.

Treatment of tuberculosis in nonhuman primates, especially those belonging to private individuals, should be discouraged because of the public health hazard. The veterinary clinician is also obligated to recommend that all people exposed to the animal seek medical attention.

The recommended treatment for rare and endangered species and exceptionally valuable experimental animals may be undertaken if the owners and researchers are made fully aware of the public health hazard and are prepared to adhere to strict quarantine procedures during the extended treatment periods. The agent of choice is isoniazid administered orally in a sweet carrier at a rate of 10 to 20 mg per kg per day for one to two years. Some investigators feel that the animal may be maintained on isoniazid for the remainder of its life. Viable mycobacteria normally disappear from the sputum and feces of isoniazid-treated animals in three to 18 weeks. Isoniazid is a potent inhibitor of vitamin B6; therefore, B6 should be supplemented to primates on chronic treatment.