strongyloides stercoralis: the most prevalent parasitic cause of eosinophilia in gilan province, northern iran

background: eosinophilia occurs in a wide variety of situations such as parasitic infections, aller­gic disorders, and malignancies. most cases of eosinophilia of parasitic origin, especially those with a tissue migration life cycles consists of human infections by helminth parasites. the aim of present study was to determine the parasitic causes of eosinophilia in patients in a major endemic area of human fascioliasis in gilan province, northern part of iran. methods: one hundred and fifty patients presenting with an elevated eosinophilia attending infec­tious disease clinics with or without clinical symptoms, were examined. after clinical his­tory evaluation and physical examination, coprological examinations were performed using the formalin-ether and the kato-katz techniques for detection of fasciola sp. and intestinal parasites. results: forty two percent of patients were infected with s. stercoralis, nine (6%) were found to be infected with fasciola sp. while only a single patient (0.7%) were infected by ttrichostrongy­lus sp. conclusion: local clinicians in gilan may consider eosinophilia as a suggestive indication for diagnosis of human fascioliasis, especially when microscopic stool and/or serological tests are negative. based on the results, local physicians should consider s . stercoralis as the potential causes of eosinophilia in patients with elevated eosinophilia.