A serological survey of Ebola virus infection in central African nonhuman primates.

We used an ELISA to determine the prevalence of IgG antibodies specific for the Zaire subtype of Ebola virus in 790 nonhuman primates, belonging to 20 species, studied between 1985 and 2000 in Cameroon, Gabon, and the Republic of Congo. The seroprevalence rate of Ebola antibody in wild-born chimpanzees was 12.9%, indicating that (1) Ebola virus circulates in the forests of a large region of central Africa, including countries such as Cameroon, where no human cases of Ebola infections have been reported; (2) Ebola virus was present in the area before recent outbreaks in humans; (3) chimpanzees are continuously in contact with the virus; and (4) nonlethal Ebola infection can occur in chimpanzees. These results, together with the unexpected detection of Ebola-specific IgG in other species (5 drills, 1 baboon, 1 mandrill, and 1 Cercopithecus), may help to narrow the search for the reservoir of Ebola virus. They also suggest that future Ebola outbreaks may occur anywhere in the central African forest region.