RESUMO
Multiple factors, both dependent on the host and the parasite are involved in determining resistance or susceptibility to infection with T. cruzi, but the influence of the sex of the host is a factor that has not been clearly established. In this paper we analyzed the influence of this factor upon the infected individuals. We used Swiss albino mice infected with 50 trypomastigotes / mouse of T. cruzi, strain Tulahuen: males (n = 73) and females (n = 64). The highest parasitemia was detected on day 21 post-infection (pi) in both males and females and became negative on day 56 pi, and males exhibited significantly higher levels of parasitemia. The highest mortality occurred between day 21 and day 28 pi; by day 270 pi (chronic stage) one male (3%) survived every 7.6 females (23%). In skeletal muscle of male and female mice on days 90, 180 and 270 pi, lympho-monocitary infiltrates were found nests of amastigotes, whereas the myocardium of these animals showed inflammatory infiltrates only. We conclude that males showed greater susceptibility to infection and higher mortality than females in this mouse model infected with T. cruzi, Tulahuen strain, but the characteristics of the infection and cardiomyopathy development are similar in nature.