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.当前非洲大型类人猿的分布范围覆盖了若干全球人类结核病（Tuberculosis, TB）发病率最高的国家。栖息于自然栖息地的非人类灵长类动物（Non-human primates, NHPs）理应不会感染结核病。然而，结核病已成为圈养非人类灵长类群体的已知威胁。我们采用基于海绵的非侵入性环境DNA（environmental DNA, eDNA）采集方案，在环境复杂的刚果民主共和国（Democratic Republic of the Congo, DRC）东部开展人兽界面横断面调查。本次研究的采样点包括一家灵长类动物康复中心、当地卫生区域，以及附近栖息着极危物种东部低地大猩猩（Gorilla beringei graueri）的国家公园。我们针对两个PCR靶标IS6110与mpb70对海绵样本开展检测，阳性样本进一步通过间隔区寡核苷酸分型（spoligotyping）、菌种鉴定以及利福平与异烟肼的分子耐药性检测完成特征分析。我们在全部3个采样点的172份样本中检出45份（占比26%）结核分枝杆菌（Mycobacterium tuberculosis）环境DNA，样本来源涵盖人类、野生大猩猩与圈养非人类灵长类相关样本。其中14份样本可鉴定出间隔区寡核苷酸分型型别，所有采样点均检出分型型别SIT130，相关样本包括人类与大猩猩的环境样本。本次研究未检测到分子耐药型别。上述结果强烈提示，赤道非洲地区的人类与非人类灵长类结核病之间存在流行病学关联。 关键词：环境传播、东部低地大猩猩（Gorilla beringei graueri）；人兽界面；非侵入性采样；反向人畜共患病；南基伍省。