Serologic cross-reactions with sera from patients with echinococcosis and cysticercosis.

Serum specimens from persons with pathologically confirmed Echinococcus granulosus hydatidosis and Taenia solium cysticercosis were tested in indirect hemagglutination tests using both Echinococcus and Taenia antigens. There were cross-reactions with most sera, and it was not possible to distinguish specific reactions by comparing titers with the homologous or heterologous antigens. Using immunoelectrophoresis or double diffusion tests with E. granulosus antigens, the Echinococcus-specific arc 5 was demonstrated in 11 of 21 hydatidosis sera and in 1 of 20 cysticercosis sera.