ABSTRACT
The performance of an enzyme linked immunosorbent assay [ELISA] for detection of antibodies to Cyclospora cayetanensis in human sera was evaluated by using Eimerian antigens. Accoding to close phylogenetic relationship between C. cayetanensis and Eimerian species, Sporulated oocysts of Eimeria tenella [E.t.s.o] and Eimeria zurnii, [E.z.s.o] were used to purify antigens. Specific lgG antibodies in patients serum quantitatively detected by them. The results show that patients with cyclosporiosis develop an immune response that is detectable using Eimeria antigens. The ELISA assay using Eimeria tenella antigen alone was very sensitive [91.1%] but shows a low specificity [77%], particularly against sera positive for cryptosporidiosis [36%]. On the other hand, bovine Eimeria antigen did not cross-react with Cryptosporidium [100%] but give many false negatives [sensitivity of 56%]. Finally, a combination of both bovine and avian antigens showed a good specificity [85%] without significant loss of sensitivity [91.3%]