Interaction on an additive scale between the effects of parasites on the prevalence of ACE.

*Interaction could not be determined for O. volvulus and P. falciparum co-infection as there were no cases of ACE with exposure to O. volvulus infection without exposure to P. falciparum. +RERI adjusted for age, sex, study site, education (none, primary, or secondary and above), employment, marital status and exposure to other assayed infections. A positive RERI indicates that the combined effect of the two parasites is greater than the sum of the individual effects.