Eosinophilia and Helminthic Infections in the Black Sea Region of Türkiye

Introduction: Eosinophils play crucial roles in the cellular and humoral immune responses and usually constitute 1-3% of leukocytes in peripheral blood. Conditions that cause eosinophilia include allergic diseases, drug hypersensitivity, infections, cancers, and immunological or autoimmune diseases. Among parasitic diseases, it has been reported that eosinophilia is most frequently caused by helminth infections such as cystic echinococcosis (CE), fascioliasis, toxocariasis, schistosomiasis, strongyloidiasis, filariasis, and trichinellosis. Methods: The population of the research was taken as the population of Samsun province. A total of 646 sera were taken from patients (278 males and 279 females) with eosinophilia (>5%), and 89 samples were taken from patients (45 males and 44 females) without eosinophilia (<5%) which were referred to the Public Health Laboratory for hemogram analysis from Samsun province were included in the study. An in-house ELISA was used to investigate F. hepatica, T. spiralis, and E. granulosus antibodies in sera collected from the patients in the eosinophilic and non-eosinophilic groups. Results: In the eosinophilic group (n=557), seropositivity rates were 0.9% for echinococcosis, 0.5% for fascioliasis, 72.2% for toxocariosis, and 0.5% for trichinellosis, while they were 0.0%, 0.0%, 64%, and 1.1%, respectively, in the non-eosinophilic group (89 cases). Conclusion: Although the results suggest that helminth infections may be relatively rare causes of eosinophilia in our region, more data are required due to the low number of controls. For this purpose, a comprehensive seroprevalence study with a larger control group will investigate other helminthic agents such as ascariasis, strongyloidiasis, and hookworm infections.