Comparison of the usefulness of hydatid cyst fluid, native antigen B and recombinant antigen B8/1 for serological diagnosis of cystic echinococcosis.

For serodiagnosis of cystic echinococcosis (CE), the usefulness of three native antigens, a hydatid cyst fluid (HCF) obtained from infected sheep in China, two types of antigen B prepared from each HCF obtained in Iran and China, and one recombinant antigen B8/1 (RAgB), were evaluated by ELISA using a total of 155 serum samples from Iran, Turkey, China and Japan. Both the Iranian native antigen B and RAgB had high sensitivity, but RAgB showed an excellent specificity in comparison with native antigens because none of the serum samples of healthy people from Iran and Japan became positive with this antigen except one case of taeniasis. The taeniasis case exceptionally showing cross reactivity with all antigens was considered to be co-infected with Echinococcus granulosus and Taenia saginata. The recombinant antigen showing a high diagnostic odds ratio in comparison with other evaluated antigens might be recommended for diagnosis of CE in different CE-endemic areas.