Seroprevalence and Risk Factors of Toxoplasma gondii Infection in Free-Range Chickens in Senegal, West Africa.

In sub-Saharan Africa, few studies have addressed the environmental determinants of the incidence of Toxoplasma gondii infection. Free-range chickens are regarded as sensitive indicators for environmental contamination with T. gondii oocysts due to their ground-feeding behavior and have been used as sentinels. A cross-sectional study was conducted from January to April 2018 to estimate the seroprevalence of T. gondii infection in free-range chickens from Senegal, West Africa, using the modified agglutination test. Sampling was performed in two regions of the country: Saint-Louis, a Sahelian area in the North, and Kedougou, a forest and rainy area in the South. A questionnaire was administered to chicken owners to assess potential risk factors for T. gondii seropositivity, and univariable and multivariable logistic regression analyses were used to determine the statistical significance of risk factors. The seroprevalence in chickens was 7.67% (51/665; 95% confidence interval [CI]: 5.51-9.52). The multivariable logistic regression model indicated that the odds to test T. gondii seropositive was higher in chickens provided well water (odds ratio [OR] = 3.17, 95% CI: 1.45-6.93; p = 0.004) than in chickens provided tap water, and in hens having chicks (OR = 80.15, 95% CI: 22.79-281.95; p < 0.001) than in chickens (male or female) not having chicks. The possible role of contaminated well water in the acquisition of infection in chickens-and hence in human-merits consideration and should be addressed in future studies.