Familial aggregation of Leishmania chagasi infection in northeastern Brazil.

A sample of 1,604 individuals belonging to 243 nuclear families from an endemic area of visceral leishmaniasis (Jacobina, Bahia State, Brazil) was studied to disclose the intrafamilial pattern of infection. Significant father to offspring, mother to offspring, and sibling to sibling associations, in contrast a with nonsignificant father to mother association, clearly indicate a familial aggregation of the infection, with a strong suggestion of at least partial genetic involvement.