Introduction and Objectives: Diagnosis of hydatidosis is based on immunodiagnostic methods along with radiological and ultrasound examinations. The principal intermediate host of E. granulosus in most endemic regions of the world is sheep. A great number of immunological assays have been developed for detection of anti-hydatid cyst antibodies. Antibodies to various antigens of E. granulosus are detectable in the sera of some, but not all infected sheep. The objective of the present study was to develop a specific and simple antigen-based ELISA method for diagnosis of hydatidosis in sheep with different antigens extracted from E. granulosus. Materials and Methods: A total of 100 sheep sera were collected from sheep with hydatidosis proven by inspection of hydatid-infested livers and lungs of the sheep slaughtered in Mashhad abattoir. A total of 10 negative control sera were also obtained from healthy young lambs. Hydatid fluid and protoscolex were isolated from livers or lungs of sheep with hydatid cyst in sterile conditions. Whole body of Echinococcus granulosus was isolated from intestine of infected dogs. Sera samples were examined by ELISA with different antigens. Statistical significance for differences in antibody level against different antigens was determined by One-Way variance analysis method (ANOVA). Results: The results of antibody detection by indirect ELISA, using different antigens, showed that the hydatid fluid was the most effective antigen of those assessed for detection of infection with hydatidosis in sheep. According to our results, the most significant differences between antibody levels of infected versus negative control group was obtained with hydatid fluid antigen as compared with protoscolices and whole body of E. granulosus (P<0.05). No significant difference was observed between hydatid fluid or protoscolices antigens with positive control. However, whole body of E. granulosus antigen showed significant difference with positive control. Conclusion: According to our results, findings of this study indicated that antibody detection assay based on hydatid fluid is a sensitive and simple approach for diagnosis of hydatid cyst in sheep.

Keywords