Indeterminate Chagas' disease: Trypanosoma cruzi strain and re-infection are factors involved in the progression of cardiopathy

• Published in: Clinical science (1979) Vol. 104; no. 4; pp. 415 - 420
• Main Authors: BUSTAMANTE, Juan M, RIVAROLA, Héctor W, FERNANDEZ, Alicia R, ENDERS, Julio E, FRETES, Ricardo, PALMA, José A, PAGLINI-OLIVA, Patricia A
• Format: Journal Article
• Language: English
• Published: London Portland Press 01.04.2003
• Subjects: Animals; Biological and medical sciences; Chagas Cardiomyopathy - mortality; Chagas Cardiomyopathy - parasitology; Disease Progression; Electrocardiography; Female; Heart - parasitology; Host-Parasite Interactions; Human protozoal diseases; Infectious diseases; Medical sciences; Mice; Mice, Inbred Strains; Models, Animal; Parasitemia; Parasitic diseases; Protein Binding; Protozoal diseases; Receptors, Adrenergic, beta - metabolism; Recurrence; Survival Rate; Trypanosoma cruzi - physiology; Trypanosomiasis; Protozoal disease; Insecta; Chagas disease; Cardiovascular disease; Electrodiagnosis; Histopathology; Transmission from animal to animal; Heart disease; Electrocardiography; Trypanosomiasis; Kinetoplastida; Protozoa; Rodentia; Parasitosis; Reinfection; Survival; Trypanosoma cruzi; Infection; Pathology; Symptomatology; Vertebrata; Mammalia; Mouse; Arthropoda; Animal; Risk factor; Invertebrata
• ISSN: 0143-5221; 1470-8736
• DOI: 10.1042/CS20020245

Chagas' disease is caused by Trypanosoma cruzi, which is transmitted by reduviid bugs. The World Health Organization has estimated that about 16-18 million people in the Americas are infected, and that more than 100 million are at risk. In the present study we have used a murine model to analyse if particular T. cruzi strains (Tulahuen strain and SGO-Z12 isolate from a chronic patient) and/or re-infection may determine, during the indeterminate phase of experimental Chagas' disease, changes that could explain the different evolution of cardiac lesions. Re-infected mice reached higher parasitaemias than those infected for the first time. The survival in the indeterminate phase of mice infected with Tulahuen strain was 50.0%, while the SGO-Z12-infected group presented a significantly higher survival rate (77.1%; P <0.01). The SGO-Z12-re-infected group showed a survival rate (70.9%) significantly higher than that of the Tulahuen-re-infected group (37.0%; P <0.01). Electrocardiographic abnormalities were found in 66% of Tulahuen-infected mice, while in SGO-Z12-infected group such abnormalities were found in only 36% of animals ( P <0.01). The two groups exhibited similar percentages of electrocardiographic dysfunction on re-infection, although intraventricular blocks were more frequent in Tulahuen-re-infected mice ( P <0.01). Hearts from infected or re-infected mice with either parasite showed mononuclear infiltrates. The SGO-Z12-re-infected and Tulahuen-re-infected groups exhibited a significantly diminished affinity ( P <0.05) and a significantly increased density ( P <0.05) of cardiac beta-adrenergic receptors compared with the infected and non-infected groups. The indeterminate phase of Chagas' disease is defined as a prolonged period that is clinically silent, but the present findings show that different T. cruzi strains and re-infection are able to alter the host-parasite equilibrium, and these factors may be responsible for inducing progressive cardiopathy.