Analysis of Seroconversion Rate and Factors Associated with Toxoplasmosis in a Rural Area of an Extra-Amazonian Region in Brazil: A Cohort Study

Background: Toxoplasmosis is caused by the intracellular protozoan Toxoplasma gondii, which has a worldwide distribution. Here, in the first study of asymptomatic infection by this protozoan in the state of Espírito Santo, Brazil, we present an analysis of the prevalence and annual incidence of asymptomatic cases of toxoplasmosis in a rural area of this state. Methods: Plasma samples from 79 individuals who had responded to questionnaires were analyzed by IgG ELISA, and positive cases were subjected to an IgG avidity test. Follow-up lasted one year and consisted of quarterly visits. Results: Of the 79 individuals assessed, 67.1% were positive for IgG anti-Toxoplasma gondii, and the incidence was 6.2 per 100 person-years of observation. No statistically significant association was found between toxoplasmosis and contact with cats or between toxoplasmosis and consumption of pork, mutton or lamb, even if these were undercooked or raw. According to the multivariate analysis, the only risk factor related to infection appears to be increasing age (OR = 1.086). Confirming the data in the literature, the statistical analysis showed that with every additional year of age the risk of contracting toxoplasmosis increase by 8.6%. Conclusion: The inhabitants of rural communities in the mountainous region of Espírito Santo are very exposed to Toxoplasma gondii and know very little about the disease, making them vulnerable to exposure.