Immunodiagnosis of polycystic hydatid disease/polycystic echinococcosis due to Echinococcus vogeli.

A crude antigenic metacestode extract from Echinococcus vogeli was assessed by enzyme-linked immunosorbent assay (ELISA) and showed strong binding activity with serum antibodies from patients with polycystic echinococcosis. Major cross-reactions occurred with serum antibodies from patients with cystic and alveolar echinococcosis and from patients infected with other species of helminths. An E. vogeli antigen fraction, Ev2, was subsequently purified by immunosorption. The respective Ev2 ELISA demonstrated improved specificity, allowing discrimination of non-Echinococcus infections from polycystic echinococcosis. Based upon the calculation of a comparative (Ev-crude ELISA versus Ev2 ELISA) reactivity index, it became possible to discriminate all cystic echinococcosis cases, but only some alveolar echinococcosis cases, from polycystic echinococcosis. Immunoblot analyses revealed an antibody banding pattern highly conserved among polycystic, cystic, and alveolar echinococcosis. However, immunoblotting reliably distinguished between echinococcosis and all non-Echinococcus infections.