Toxoplasma gondii infection: seroprevalence and associated risk factors among primary schoolchildren in Lagos City, Southern Nigeria

Introduction: Toxoplasma gondii infection has been described as the most widespread zoonotic infection of humans and other animals. Information concerning T. gondii infection among schoolchildren is unavailable in Lagos City, Nigeria. Methods: This cross-sectional study investigated the seroprevalence and risk factors associated with T. gondii infection among primary schoolchildren (PSC) from a community located in the center of Lagos, southern Nigeria, from November 2013 to March 2014. A total of 382 PSC were screened for the presence of sera anti-T. gondii antibodies using a latex agglutination test (TOXO Test-MT, Tokyo, Japan). A cutoff titer of >= 1:32 was considered positive, while titers >= 1:1,024 indicated high responders. Questionnaires were also used to obtain data on possible risk factors from parents/guardians. Results: The overall seroprevalence was 24% (91/382), and 83.5% (76/91) of seropositive PSC were classified as high responders. Among the risk factors tested, including contact with cats and soil, consumption of raw meat and vegetables, and drinking unboiled water, none showed statistical significance after multivariate adjustment. No associations were observed among age, gender, body mass index (BMI), and parents' occupation/educational level. Conclusions: The findings in this study show evidence of active infection, and hence, there is need for urgent preventive measures in this city. Further investigation is required to clarify the transmission routes. Policy makers also need to initiate prevention and control programs to protect pregnant women and immunocompromised patients in particular because they are more severely affected by T. gondii infection.