Seroprevalence, disease awareness, and risk factors for Toxocara canis infection among primary schoolchildren in Makoko, an urban slum community in Nigeria

In this study, we investigated the seroprevalence of Toxocara canis infection in southern Nigeria, which previously was unknown, in addition to evaluating disease awareness and potential risk factors for schoolchildren in an urban slum community. In total, 366 primary schoolchildren were investigated for the presence of anti- Toxocara IgG antibodies. Blood was collected and screened by a Western blot analysis based on the excretory-secretory antigens of larval T. canis (TcES), targeting low molecular weight bands of 24-35. kDa specific for T. canis. Children were considered seropositive if their serum reacted with TcES when diluted to a titer of 1:32. Questionnaires concerning possible risk factors were given to the schoolchildren to acquire data on this infection. The overall seroprevalence of Toxocara infection was 86.1% (315/366). The logistic regression analysis of risk factors showed that children's age (odds ratio (OR) = 2.88, 95% confidence interval (CI) = 1.08-7.66, p= 0.03), contact with dogs (OR = 0.51, 95% CI = 0.28-0.94, p= 0.03), the age of the dog (OR = 0.34, 95% CI = 0.18-0.68, p= 0.002), the feeding location of the dog (OR = 0.31, 95% CI = 0.12-0.79, p= 0.01), the consumption of raw vegetables (OR = 0.89, 95% CI = 0.54-1.48, p= 0.004), and the drinking of unboiled water (OR = 0.48, 95% CI = 0.26-0.90, p= 0.02) were risk factors associated with Toxocara infection. Although there was a high awareness of dogs being hosts of some parasites in this study, not much was known about T. canis. This is the first serological investigation of T. canis infection among primary schoolchildren in southern Nigeria. The high seroprevalence recorded is an indication of high transmission with the consequent risk of visceral or ocular larval migrans and neurologic toxocariasis in these children. Our findings suggest the need for prompt interventional measures, particularly health education on personal hygiene.