Parasitological detection and seropositivity for Strongyloides stercoralis among individuals attending public health centers in Shoushtar County, southwestern Iran

Abstract Objective Strongyloides stercoralis is a soil-transmitted helminth (STH) that is prevalent in tropical and subtropical regions. This study aimed to determine the occurrence of Strongyloides stercoralis using parasitological methods and assess antibody seropositivity among individuals attending public health centers in Shoushtar County, southwestern Iran. Blood and single stool samples were collected from participants attending two main public health centers. Stool samples were examined using direct smear, formalin–ethyl acetate concentration, and agar plate culture. Serum samples were tested using an indirect ELISA (NovaLisa ® Strongyloides antibody kit). Data were analyzed using R version 4.5.2. Results A total of 277 participants were enrolled, with a mean age of 33.4 ± 11.33 years. The prevalence of S. stercoralis detected by direct smear, formalin–ethyl acetate concentration, and agar plate culture was 1.44%, 1.44%, and 3.24%, respectively. Serological testing revealed that 6.9% ( n = 19) were positive for S. stercoralis antibodies. Gender, age, literacy level, occupation, residence, contact with soil, and gastrointestinal and respiratory symptoms were significantly associated with S. stercoralis seropositivity. ELISA yielded a higher positivity rate than parasitological methods, however, antibody positivity does not necessarily indicate active infection. These findings highlight the complementary epidemiological information provided by parasitological and serological methods.