BACKGROUND : Factors related to the natural transmission of Ebola virus (EBOV) to humans are still not well defined.
Results of previous sero-prevalence studies suggest that circulation of EBOV in human population is common in
sub-Saharan Africa. The Efé pygmies living in Democratic Republic of the Congo are known to be exposed
to potential risk factors of EBOV infection such as bush meat hunting, entry into caves, and contact with
bats. We studied the pygmy population of Watsa region to determine seroprevalence to EBOV infection and
possible risks factors.
METHOD : Volunteer participants (N = 300) aged 10 years or above were interviewed about behavior that may
constitute risk factors for transmission of EBOV, including exposures to rats, bats, monkeys and entry into
caves. Samples of venous blood were collected and tested for IgG antibody against EBOV by enzyme-linked
immunosorbent assay (ELISA). The χ2-test and Fisher’s exact test were used for the comparison of proportions
and the Student’s t-test to compare means. The association between age group and anti-EBOV IgG prevalence was
analysed by a nonparametric test for trend.
RESULTS : The prevalence of anti-EBOV IgG was 18.7 % overall and increased significantly with age (p = 0.023). No
association was observed with exposure to risk factors (contacts with rats, bats, monkeys, or entry into caves).
CONCLUSIONS : The seroprevalence of IgG antibody to EBOV in pygmies in Watsa region is among the highest ever
reported, but it remains unclear which exposures might lead to this high infection rate calling for further ecological
and behavioural studies.