Acquisition of toxoplasma infection by children in a developing country.

The prevalence of toxoplasma infection was studied in 850 healthy children (550 newborn infants and 300 children aged 6 months to 14 years) from a population of low socioeconomic status in Santiago, Chile. Antibodies were detected in 49% of the serum samples in children at birth and in 0% at 6 months, 2% at 1 year, 10% at 2 years, 22% at 4 years, and 32% at 6 years of age, and in 48% of the children aged 7-14 years. In order to determine the rate of infection and associated epidemiological factors, 50 seronegative infants aged 6 months were followed up; 11% and 14% of them showed seroconversion after 1 and 2 years, respectively. The results suggest a significant association between infection and the ingestion of raw or undercooked meat. The role of cats and vectors such as flies and cockroaches in the transmission of infection could not be determined owing to the commonness of these two sources in relation to the small number of subjects studied.