DETERMINING THE PREVALENCE OF ONCHOCERCA-VOLVULUS INFECTION IN VECTORPOPULATIONS BY POLYMERASE CHAIN-REACTION SCREENING OF POOLS OF BLACK FLIES

An important variable in the epidemiology of arthropodborne diseases i s the intensity of transmission, which is a function of host-vector co ntact and the prevalence of infection in the vector population. This l atter value is often difficult to estimate. It is possible to envision the application of polymerase chain reaction (PCR) assays to this pro blem. To accomplish this, the assay must detect a single infected vect or in a pool containing a large number of uninfected individuals. It m ust also be possible to calculate the prevalence of infection from the number of positive peels. A PCR assay for detecting Onchocerca volvul us in pools of vector black flies is described, and an algorithm is pr esented to calculate the prevalence of infection in the vector populat ion, based upon the proportion of PCR-positive pools. This algorithm s hould be applicable to any disease for which a PCR assay is available.