Background: Cystic echinococcosis (CE) is an important zoonotic parasitic disease worldwide. Application of species-specific antigen for serodiagnosis of human CE has not been utilized, so far. In this regard, AgB originated from Echinococcus granulosus sensu stricto (G1-G3) and E. canadensis (G6/G7) CE cysts, confirmed by molecular biology and sequencing was used for evaluation of their ability in the diagnosis of confirmed human CE. Methods: The hydatid cyst fluid (HCF) of E. granulosus sensu stricto and E. canadensis species were separately, used for preparation of AgB during 2017-2018 in Shiraz and Tehran, Iran. A total of 45 sera samples from confirmed CE patients, 102 sera from healthy people as negative control and 44 sera from other parasitic diseases, were used for measurement of the diagnostic ability of antigen B originated from E. granulosus sensu stricto and E. canadensis species of CE, alone or in 50%:50% mixture using ELISA method. Results: Overall, 38 (84.4%) out of 45 confirmed human CE were positive by ELISA using AgB originated from E. granulosus sensu stricto. This items for AgB originated from E. canadensis was 39 (86.6) out of 45 serum samples. A total of 39 out of 45 samples (86.6%) showed positivity by a mixture of antigen B originating from both species. The specificity of the above tests was calculated as 93.15%, 96.58%, and 93.84%, respectively. Conclusion:  Due to the diversity of the cyst species in human population, application of AgB from prevalent species alone or in combination with other species is suggested

Background: To determine the seroprevalence of human cystic echinococcosis/hydatidosis which is one of the most important zoonotic diseases by ELISA using native antigen B in Semnan and Sorkheh, Semnan province, Iran, where no significant information about human infection exists. Methods: Overall, 957 human serum samples were randomly prepared from Semnan, Sorkheh, and its 13 surrounding villages in different seasons from 2017 to 2018. Antigen B was prepared from native hydatid cyst fluid of domestic sheep. All serum samples were evaluated by ELISA while the suspected cases were rechecked. The cut-off was calculated as the X̄±2SD. Results: Overall, 48(5%) out of 957 (422 males and 535 females) were positive for hydatidosis. The seropositivity based on sex showed 20(2.1%) out of 422 in males and 28(2.9%) out of 535 in females. The distribution of seropositive samples based on residence area showed 41 (4.3) out of 882 in urban and 7 (0.7) out of 75 in rural areas. The highest seroprevalence cases was among housewives (2.1%) followed by employers (1.5%). Based on education, source of drinking water, and age groups the highest seropositivity was observed in high school and less, in the plumping water consumers, and 50 to 59 yr old age group, respectively. There was a significant difference between seropositivity with occupation, literacy, and age group (P<0.05). Semnan with 4% seropositivity had the highest prevalence followed by Sorkheh, county. Conclusion: High prevalence of the disease in this area emphasizes the importance of increasing people's awareness about hydatidosis.