Mycobacterium tuberculosis infections in cynomolgus monkey transplant recipients and institution of a screening program for the prevention and control of tuberculosis

BACKGROUND: Tuberculosis is a major health concern in not only humans, but also in non-human primates. In this paper, we report recent cases of Mycobacterium tuberculosis in cynomolgus monkeys from Cambodia used in transplantation research in a Korean facility and describe a program instituted to prevent and control subsequent infections. CASE PRESENTATION: All monkeys were antibody negative for tuberculosis during quarantine; however, suspected tuberculosis gross lesions were observed in two cynomolgus monkeys who underwent allograft kidney transplantation. Lung tissue from one monkey was found to be weakly positive by PCR for detection of M. tuberculosis. After PCR confirmation of tuberculosis, we decided to sacrifice the remaining animals and instituted a program for preventing subsequent infections. During necropsy of the remaining monkeys, two additional suspected tuberculosis cases were observed. A total of four monkeys with nodular lesions in the respiratory tract, suspected to be tuberculosis, demonstrated no clinical signs. Acid-fast bacilli were identified on slides from the lung or liver in all four monkeys. Two of four monkeys tested PCR positive. We decided that new monkeys entering from Cambodia should undergo a single gastric aspiration PCR and tuberculin skin testing (TST) every 2 weeks until four consecutive negatives to detect latent tuberculosis are obtained before starting experiments. Monkeys should then undergo a chest X-ray monthly and TST every 6 months. CONCLUSIONS: Detection of latent tuberculosis by an effective preventive screening program before starting experiments is an essential process to reduce the risk of reactivation of tuberculosis, especially in studies using immunosuppressive drugs. It also serves to protect the health of captive non-human primates, their caretakers and researchers.