Familial Analysis of Seropositivity to Trypanosoma cruzi and of Clinical Forms of Chagas Disease

A cross-sectional study was carried out in Água Comprida, MG, Brazil, a region previously endemic to Chagas disease whose vectorial transmission was interrupted around 20 year ago. A total of 998 individuals were examined for anti-Trypanosoma cruzi antibodies. Seropositivity was observed in 255 subjects (25.5%), and 743 subjects were negative. Forty-one families with 5–80 individuals with similar environmental conditions were selected for familial analysis. In 15 families, seropositivity to T. cruzi was observed in > 50% of individuals. The segregation analysis confirmed family aggregation for the seropositivity to the T. cruzi. Heart commitment was the major clinical form observed, and in six families, > 50% of the individuals display cardiopathy that may be attributed to T. cruzi infection. Our results support the hypothesis that there is a family aggregation for the seropositivity but without the effect of one major gene