Persistence of Trypanosoma cruzi in the chronic phase of Chagas disease

MILER N; FERNANDEZ G; BLASCO R; FERRERO M; ASIS L; LO PRESTI S; BAZAN C; RIVAROLA W; PAGLINI P

Congreso; VIII Congreso Internacional de Cardiología por Internet; 2013

One of the most important determinants of congestive heart failure and sudden death in Latin America is Chagas disease, provoked by infection with the intracellular protozoan parasiteTrypanosoma cruzi. It affects approximately 20 million people and represents a serious public health problem in Central and South America. Chagasic cardiopathy appears to carry the worst prognosis and has become the most frequent cause of heart failure and sudden death, as well as the most common cause of cardio-embolic stroke in Latin America. Chagas disease also represents an increasing challenge for clinicians in the United States and some European countries due to the continuous immigration of people from disease-endemic countries . The acute phase, characterized by high intracellular parasite growth, usually affects children or young adults in endemic areas . Between 10 to 30 years after this acute stage, about 30% of the patients develop a myocarditis with electrocardiographic abnormalities  increase in heart size and observed histological alterations, such as necrosis of the cardiac fibers, focal or diffuse inflammatory infiltrates and interstitial fibrosis of varying intensity. The mechanisms involved in the pathophysiology and progression of the chronic chagasic cardiomyopathy are still unclear. The difficulty of finding trypanosomes in patients undergoing the chronic phase, suggested that persistent antigenic stimulation could be implicated in the pathogenesis of Chagas disease, with CD4 + lymphocytes generated in response to the parasite?s proteins also reacting against the myocardial tissue. However, later PCR-based studies have confirmed the presence of the parasite during the chronic phase of Chagas disease. These studies would therefore suggest that the persistence of the parasite in all the stages of the infection and its replication are responsible for the cell destruction. Nevertheless, it is uncommon to find trypanosomes in the cardiac tissue; this has been attributed to the ability of the cardiac muscle cells to control the intracellular multiplication of T. cruzi when they are stimulated with certain cytokines. For all these the indication for treatment in patients infected with T. cruzi beyond the acute phase is a subject of debate because of the knowledge that 30% of infected people progress to heart disease and 70% remain asymptomatic,  and the drugs currently used are  not easily tolerated . The purpose of the present was to study 20 patients with long term positive serology for Chagas disease to make a possible association between clinical symptoms and  T. cruzi presence.