Use of the recombinant Onchocerca volvulus protein Ov20/OvS1 for the immunodiagnostic differentiation between onchocerciasis and mansonelliasis and for the characterization of hyperreactive onchocerciasis (sowda)

The protein Ov20/OvS1 was used as antigen in ELISA and Western blot in orde r to differentiate onchocerciasis from African mansonelliasis and to charac terize the hyperreactive form of Onchocerca volvulus infection (sowda). The specificity of the IgG4 Western blot was 98% for the differentiation betwe en persons with onchocerciasis and Mansonella microfilariae (mf) carriers ( 125 persons with M. perstans and 92 with M. streptocerca), whereas the IgG4 ELISA showed a specificity of 81% in 137 M. perstans mf carriers and 85% i n 94 M. streptocerca mf carriers. The sensitivity of Ov20/OvS1 in identifyi ng onchocerciasis using the IgG4 ELISA was 75% fur 103 O. volvulus mf carri ers with the generalized and 89% for 44 patients with the sowda form of onc hocerciasis. IgE antibodies against OvS1 were found in 95% of 39 patients w ith hyperreactive onchocerciasis but only in 15% of 47 persons with the gen eralized form. Thus, Ov20/-OvS1 appears a promising candidate antigen for t he diagnosis of onchocerciasis and in particular for the detection of the s owda type of disease.