Noninvasive environmental DNA sampling reveals tuberculosis risks at the human – great ape interface in Africa

The current range of African great apes includes countries with some of the world’s highest incidence rates of human tuberculosis (TB). Non-human primates (NHPs) living in their natural habitats are expected to be free of TB. However, TB represents a known threat to captive NHP communities. We applied a noninvasive sponge-based environmental DNA (eDNA) collection protocol to run a cross-sectional survey at the human-animal interface in a challenging setting: the East of the Democratic Republic of Congo (DRC). The study sites included a primate rehabilitation center, the local health area, and a nearby national park with critically endangered Eastern Lowland Gorillas (Gorilla beringei graueri). Sponge samples were tested for two PCR targets, IS6110 and mpb70. Positive samples were further characterized by spoligotyping, species identification and detection of molecular resistance against rifampicin and isoniacid. We detected Mycobacterium tuberculosis eDNA in 45 of 172 samples (26%) from all three sites including samples linked to humans, wild gorillas and captive NHPs. The spoligotype could be identified in 14 cases. Spoligotype SIT130 was detected in all sites including human and gorilla environment samples. No molecular resistance patterns were found. These findings are strongly suggestive of epidemiological links between human and NHP TB in equatorial Africa. Key words: Environmental transmission, Gorilla beringei graueri; Human-wildlife interface; Noninvasive sampling; Reverse zoonosis; South Kivu.