Comparative evaluation of native 8 kDa antigen based three immunoassays for diagnosis of cystic echinococcosis in sheep

The dog tapeworm Echinococcus granulosus is the causative agent of cystic hydatid disease in domestic/wild herbivores and man. Accurate immunodiagnosis of the infection requires highly specific and sensitive antigens. The aim of this study was to develop and evaluate various immunoassays with principles of precipitation, agglutination and enzyme immunoassays for the identification of sheep infected with hydatid cyst which would allow the monitoring of animals from endemic areas and identifying infected animals prior to slaughter. The immunoassays were developed and validated using hydatid specific, non cross reactive low molecular weight 8 kDa hydatid cyst fluid protein. Sera used for the assay validations were obtained from 150 sheep infected naturally with hydatid cyst and 150 non-infected sheep. The highest diagnostic sensitivity was obtained in Enzyme linked immune electro transfer blot (EITB) at 92.5% followed by Latex agglutination test (89%) and Counter immuoelectrophoresis(78.8%). The study demonstrated that EITB was most sensitive immunological test for detection of cystic echinococcosis in sheep.