Detection of Onchocerca volvulus infection by O-150 polymerase chain reaction analysis of skin scratches.

The standard assay for onchocerciasis diagnosis is microscopic detection of parasites in skin snips. Skin snipping is painful and may potentially transmit bloodborne infections. Thus, an alternative method for the diagnosis of onchocerciasis that does not require skin snipping is needed. A polymerase chain reaction (PCR)-based assay was shown to detect the presence of parasite DNA in superficial skin scrapings. Detection of parasite DNA in both skin snips and skin scratches was found to be more sensitive for detecting low-density infections than was microscopic examination of skin snips. The skin scratch PCR assay is minimally invasive and painless and does not present the risk of transmitting bloodborne infections. These properties make the skin scratch an attractive alternative to the skin snip for detecting O. volvulus infection.