Serological evidence of zoonotic filovirus exposure among bushmeat hunters in Guinea

Abstract Recent human Ebola virus (EBOV) outbreaks caused by persistent EBOV infection raised questions on the role of zoonotic spillover in filovirus epidemiology. To characterise potential historical filovirus zoonotic exposure, we collected cross-sectional serum samples from bushmeat hunters (n = 498) in Macenta Prefecture Guinea, adjacent to the index site of the 2013 EBOV-Makona spillover event. We identified distinct immune signatures (20/498, 4.0%) to multiple EBOV antigens (GP, NP, VP40) using a stepwise ELISA and Western blot analysis and, live EBOV neutralisation (5/20; 25%). Using comparative serological data from PCR-confirmed survivors of the 2013–2016 EBOV outbreak, we demonstrated that most signatures (15/20) were not plausibly explained by prior EBOV-Makona exposure. Subsequent data-driven modelling of EBOV immunological outcomes to remote-sensing environmental data also revealed consistent associations with intact closed canopy forest. Together our findings suggest past exposure to other closely related filoviruses prior to the 2013–2016 west African epidemic and highlight future surveillance priorities.