Seroprevalence and risk factors of Anisakis simplex in Makoko schoolchildren: insights from a Lagos, Nigeria slum.

Background: Anisakis simplex is a parasitic zoonosis associated with consuming raw or undercooked fish. Despite its global relevance, data from Africa are scarce. This study assessed the seroprevalence and risk factors of A. simplex infection among primary schoolchildren (PSC) in Makoko, an urban slum in Lagos, Nigeria.

Methods: A cross-sectional study was conducted from November 2013 to March 2014 involving 196 PSC from three government schools. Serodiagnosis was performed using enzyme-linked immunosorbent assay (ELISA) with recombinant Ani s 1 and Ani s 7 allergens. Stool samples were examined for soil-transmitted helminths (STHs) using the Kato-Katz method. Structured questionnaires gathered demographic and dietary information.

Results: The overall seroprevalence of A. simplex infection was 12.25%. No significant association was found with gender or raw fish consumption. However, parental education and occupation influenced seropositivity. Interestingly, co-infection with STHs was inversely associated with A. simplex seropositivity. ELISA demonstrated high specificity with minimal cross-reactivity to STHs.

Conclusions: This study provides the first seroepidemiological data on A. simplex in Nigerian children. Public health interventions, particularly fish-handling education, are warranted. Further research is needed to understand the clinical relevance of A. simplex sensitization in African settings.