Parasite persistence correlates with disease severity and localization in chronic Chagas' disease.

The protozoan parasite Trypanosoma cruzi infects up to 20 million people in Latin America, and the resulting disease (Chagas' disease) is a leading cause of heart disease and death in young adults in areas endemic for the parasite. The clinical symptoms of Chagas' disease have been attributed to autoimmune reactivity to antigens shared by the parasite and host muscle or neuronal tissue. In the present study, in situ polymerase chain reaction analysis was used in murine models of Chagas' disease to demonstrate an absolute correlation between the persistence of parasites and the presence of disease in muscle tissue. Clearance of parasites from tissues, presumably by immunologic mechanisms, correlated with the abatement of inflammatory responses and the resolution of disease. These data provide strong evidence for parasite persistence as a primary cause of Chagas' disease and argue for efforts to eliminate T. cruzi from the host as a means for prevention and treatment of Chagas' disease.