Clinical and molecular features of human cystic echinococcosis in Tehran, Iran, 2011-2019

Objective: To evaluate the clinical and molecular features of human cystic echinococcosis in Tehran, Iran. Methods: In this cross-sectional study, all human cystic echinococcosis patients admitted to Tehran’s hospitals from 2011 to 2019 were enrolled, and demographic characteristics, clinical findings, and laboratory data were collected. Formalin-fixed, paraffin-embedded and fresh tissue samples of 175 cystic echinococcosis patients were evaluated for molecular characterization. The samples’ isolated DNA was used to amplify cytochrome c oxidase I and NADH dehydrogenase subunit I genes. Also, the morphological features of fresh samples were examined. Results: In total, 175 patients with a mean age of 45 (9-98) years were admitted to Tehran’s hospitals diagnosed with cystic echinococcosis. Moreover, the highest (26.9%) and the lowest (2.9%) prevalence of cystic echinococcosis cases were in the 16-30 and 1-15 years range, respectively. Male/female ratio was 0.96 (49.1% vs. 50.9%). The liver was affected in 92 patients (52.6%), and two or more organs were infected in 7 patients (4.0%). The cysts’ diameter varied from 1 to 25 cm, and 96.0% of the patients had a single hydatid cyst. All patients underwent radical surgery and the PAIR technique was applied for all cases. No significant difference was observed between the protoscolex hooks of pulmonary and hepatic cysts. G1-G3 had the highest percentage (99.4%) over other identified G6 genotypes (0.6%). Conclusions: The sheep-dog cycle plays an important role in transmitting the human cystic echinococcosis infection in Tehran.