There are scarce reports about lesions and pathological alterations by Trypanosoma cruzi infections on opossums (Didelphis virginiana), considered some of the most important reservoir hosts for T. cruzi in western Mexico. After two serological analyses (Serodia and IHA), 12 (24%) of 50 collected opossums in two small towns in western Mexico were positive for the presence of T. cruzi. Eight had some kind of organ alterations: four with alterations in only one organ, three in two organs and one with alterations in three organs. Splenomegaly was the most common alteration in the examined opossums. In light of the present findings, it is possible that organ alterations on studied opossums may have been associated with T. cruzi infections
