Serological screening for toxocariasis, strongyloidiasis and fascioliasis in individuals with eosinophilia in Khuzestan, Iran.

BACKGROUND

Eosinophilia is an important marker of helminthic infection. This study evaluated the seroprevalence of Toxocara spp., Strongyloides stercoralis, and Fasciola spp. among eosinophilic patients in Khuzestan, southwestern Iran.

METHODS

From 2022 to 2024, 482 individuals (aged ≥5 y) with eosinophilia (>500 cells/µl) were recruited. Serum samples tested by ELISA for IgG antibodies against Toxocara spp., S. stercoralis, and Fasciola spp.

RESULTS

Seroprevalence of S. stercoralis was 34.5% (166/482; 95% CI 30.338.9), whereas seropositivity for Toxocara spp. was low (0.8%; 4/482), and no Fasciola spp. infections were detected (0.0%; 0/482). Strongyloidiasis was most frequent among patients aged >60 y (59.4%, 129/217; p<0.001) and was strongly associated with illiteracy (60.5%, 78/129; vs. 17.5%, 22/126 in educated individuals; p<0.001), agricultural or maritime occupations (59.4%, 41/69; in farmers; 59.5%, 25/42; in sailors; p<0.001), history of soil exposure (58.9%, 103/175; vs. 22.6%, 37/164 in unexposed individuals), and metabolic disorders (64.9%, 37/57). Seropositive patients showed significantly higher absolute (1,473 vs. 1,182 cells/µl) and relative eosinophil counts (18.97% vs. 15.04%).

CONCLUSIONS

The results highlight S. stercoralis as the predominant helminth cause of eosinophilia, attributable to the adult cohort and regional ecological and sociocultural factors. The strong associations with age, occupation, and soil contact delineate high-risk groups. Routine serological screening for S. stercoralis is recommended in endemic areas, particularly before immunosuppressive therapy, to prevent sever complications.