Serodiagnosis and seroepidemiology of human unilocular hydatidosis in Jordan

A total of 2182 serum samples from 38 patients with surgically confirmed unilocular hydatidosis, 19 clinically assessed patients, 15 patients with parasitic infections other than hydatidosis, 104 hospital outpatients, and 2006 normal Jordanians were serodiagnosed for the presence of IgG antibodies against hydatid fluid, circulating immune complexes (CIC), and/or hydatid circulating antigen (CA). Anti-hydatid IgG antibodies were detected in the sera of 77.4% of patients with hydatid disease and persist for very long periods postsurgery. As many as 54.1% of patients with hydatidosis had positive levels of CIC, and 16.1% had circulating antigen in their sera. The search for circulating antigen and CIC decreased the number of false-negative hydatid cases from seven to three, and the combined sensitivity of the assays thus increased from 77.4% to 90.3%. Using the immunoblot technique, 16- and < 14.4-kDa Echinococcus granulosus-specific bands were detected in sera from 54.1% and 61.5% of patients with hydatid disease who were tested before and after surgery, respectively. The seropositivity rate for anti-hydatid IgG antibodies was 2.4% for the general Jordanian population and 5.8% for hospital outpatients.