The role of a recombinant hybrid protein based ELISA for the serodiagnosis of Onchocerca volvulus

Aims: Onchocerca volvulus infection is traditionally diagnosed by examination of skin snips for the presence of microfilariae. A disadvantage of this method is the low sensitivity particularly with light or prepatent infection. Serodiagnosis using recombinant-antigen-based assays may provide a more sensitive diagnostic test. An ELISA based on a recombinant antigen OvH3 has previously been validated using sera from endemic areas. This study investigated the role of this ELISA-based assay for use in the serodiagnosis of onchocerciasis in non-endemic areas. Methods: The ELISA-based assay was tested on sera from untreated patients with known onchocerciasis and on untreated and treated patients with definite or probable onchocerciasis identified from a hospital diagnostic database. The assay was also tested on sera from patients with other helminthic infections to determine the sensitivity and specificity of this assay in a tertiary referral laboratory dealing with sera from a variety of patients. Results: The sensitivity and specificity of the OvH3 assay were 93.2% and 93.5%, respectively, when tested on non-endemic patients with clinical diagnosis of onchocerciasis. Conclusions: This study demonstrates the potential role of the assay as a sensitive and specific test for use in the serodiagnosis of onchocerciasis in a reference laboratory dealing with sera from patients in non-endemic setting.