Seroprevalence and risk factors associated with ovine toxoplasmosis in Northeast Brazil.

Serum samples of 930 sheep were tested by ELISA to assess the prevalence of anti-Toxoplasma gondii antibodies and to identify risk factors associated with the presence of toxoplasmosis in two regions of Rio Grande do Norte (Northeast Brazil), with different climatic conditions. The overall estimated prevalence was 22.1%, with 26.3% and 17.8% positive sheep in Leste Potiguar and Central Potiguar regions, respectively. Among the positive sheep, 18.1% had low-avidity IgG antibodies, suggesting the occurrence of recent toxoplasmosis. The risk factors for toxoplasmosis in sheep were: presence of cats (odds ratio (OR) = 1.55; confidence interval (CI) 95% = 1.11-2.16), age of the animals, with adults presenting a greater chance of infection (OR = 2.44; CI 95% = 1.58-3.75), and the use of running water (OR = 1.61; CI 95% = 1.25-2.09), characterizing the existence of transmission by sporulated oocysts of T. gondii in the environment.