High prevalence of toxoplasmosis in free-range chicken of the Fernando de Noronha Archipelago, Brazil.

The present study aimed to determine the prevalence of toxoplasmosis in free-range chickens of the Fernando de Noronha Archipelago, Brazil and to identify risk factors associated with Toxoplasma gondii infection. Blood samples were collected from all the adult chickens raised in the Archipelago and screened by Indirect Fluorescent Antibody Test (430 samples, in total). Univariate analysis (Chi-square) and logistic regression were used to investigate the relationship between various variables possibly predictive of an increased likelihood of T. gondii infection. The overall prevalence of T. gondii infection in chickens of the Fernando de Noronha Archipelago was 88.4% (380/430; 84.6%-91.0%; 95% CI), ranging from 57.1% to 100.0% among the studied properties. The risk factors associated with T. gondii infection were the number of domestic cats in the properties (p=0.022), the presence of feral cats (p=0.006) and the presence of an open water source (p=0.046). Domestic and feral cats should be prevented from accessing the water and food supplied to chickens.