Experimental American leishmaniasis and Chagas' disease in the Brazilian squirrel monkey: cross immunity and electrocardiographic studies of monkeys infected with Leishmania braziliensis and Trypanosoma cruzi

, and 1988. Experimental American leishmaniasis and Chagas' disease in the Brazilian squirrel monkey: cross immunity and electrocardiographic studies of monkeys infected with Leishmania braziliensis and Trypanosoma cruzi. International Journal for Parasitology 18: 1053–1059. Adult, laboratory-bred squirrel monkeys (Saimiri sciureus) previously infected with either Leishmania braziliensis braziliensis or L. b. panamensis were challenge infected with blood-form trypomastigotes of Trypanosoma cruzi (Brazil strain). Monkeys previously infected with T. cruzi were challenged with stationary phase promastigote forms of L. b. braziliensis. Monkeys were examined during the course of challenge for evidence of infection, electrocardiographic alterations and parasite-specific antibody responses. T. cruzi epimastigotes were cultured from the blood of monkeys up to 3 months after challenge with this parasite. Unulcerated cutaneous lesions appeared and persisted in monkeys challenged with L. b. braziliensis. The formation of satellite lesions was observed in one monkey. Increased QRS intervals were not observed in T. cruzi challenged monkeys without prior cardiac irregularities and QRS left axis shifts were observed in only two of these monkeys. Elevated titers of parasite binding IgM and IgG specific for both T. cruzi and L. braziliensis were observed in all monkeys following challenge. These results indicate that prior infection with T. cruzi or L. braziliensis does not protect against heterologous challenge infection with these organisms. However, prior infection with Leishmania parasites may provide some protection against chagasic cardiopathies.