Estimation of the regional distribution of congenital toxoplasmosis in Brazil from the results of neonatal screening

Abstract

AIMS: To determine the prevalence of congenital toxoplasmosis in Brazil from samples of dried blood on filter paper from neonates attended by a private program of neonatal screening. METHODS: Blood samples collected from neonates by puncturing the heel and dried on filter paper, received from all Brazilian states from September 1995 to July 2009, were tested for Toxoplasma gondii-specific IgM antibodies. For each positive screening test, confirmatory tests were performed in sera of mothers and newborns, obtained by venipuncture. The infants were monitored and classified as infected according to one of the following criteria: presence of Toxoplasma gondii specific IgM and IgG in the newborn and the mother; Toxoplasma gondii-specific IgM and IgG in the newborn only; Toxoplasma gondii-specific IgM and IgG in the mother only; or increasing amount of Toxoplasma gondii-specific IgG in the infant. RESULTS: A total of 800,164 blood samples were tested. The overall prevalence of congenital toxoplasmosis was found to be 1/1,613 (6/10,000) in the country, ranging from 1/5,447 to 1/495 (2/10,000 to 20/10,000) in different states. CONCLUSIONS: Neonatal screening on a large scale is an important tool for determining the prevalence of congenital toxoplasmosis. The high prevalence of the infection in Brazil and the wide variability of its epidemiology among the states support the need to develop policies on health and education to prevent and control congenital toxoplasmosis across the country, respecting the peculiarities of each state.