Detection of tuberculosis in cynomolgus macaques (Macaca fascicularis) using a supplementary Monkey Interferon Gamma Releasing Assay (mIGRA).

Cynomolgus monkeys (Macaca fascicularis; MF) are commonly used as nonhuman primate models for pharmaceutical product testing. In their habitat range, monkeys have close contact with humans, allowing the possibility of bidirectional transmission of tuberculosis (TB) between the two species. Although the intradermal tuberculin skin test (TST) is used for TB detection in MF, it has limitations. Herein, we established the mIGRA, combining human QuantiFERON-TB Gold-Plus and monkey IFN-γ ELISA systems, and used it to investigate 39 captive MF who were cage-mates or lived in cages located near a monkey who died from the naturally TB infection. During a 12-month period of study, 14 (36%), 10 (26%), and 8 (21%) monkeys showed TB-positive results using the mIGRA, the TST, and TB culture, respectively. Among the 14 mIGRA-positive monkeys, 8 (57.1%) were TST-positive and 7 (50%) were culture-positive, indicating early TB detection in the latent and active TB stages with the mIGRA. Interestingly, 3 (37.5%) of the TST-negative monkeys were culture-positive. Our study showed that the mIGRA offers many advantages, including high sensitivity and high throughput, and it requires only one on-site visit to the animals. The assay may be used as a supplementary tool for TB screening in MF.