POLYMERASE CHAIN REACTION-BASED DIAGNOSIS OF ONCHOCERCA-VOLVULUS INFECTION - IMPROVED DETECTION OF PATIENTS WITH ONCHOCERCIASIS

Definitive diagnosis of Onchocerca volvulus (Ov) infection requires th e identification of the parasite in either the skin or subcutaneous no dules. These parasitologic approaches suffer from poor sensitivity. To assess the efficacy and utility of a polymerase chain reaction (PCR)- based diagnosis for Ov infection, skin snips were examined from 94 per sons in an Ov-endemic region of Ecuador, and results were compared in a blinded fashion with those of a PCR assay based on the Onchocerca-sp ecific repetitive DNA sequence, O-150. All 60 patients microfilaria-po sitive on skin snip examination were positive in the PCR-based assay. In addition, 13 of 34 who were microfilaria-negative by skin snips wer e positive in the PCR assay. This suggests that the PCR-based assay is significantly more sensitive than current methods and overcomes many deficiencies of parasitologic and serologic methodologies in diagnosin g active onchocerciasis.