Chapter 28: Gap Junctions Are Specifically Disrupted by Trypanosoma cruzi Infection

Abstract

Publisher Summary Chagas' disease is a leading cause of cardiomyopathy in Latin America, affecting an estimated population of 18 million persons in the continent. Of those affected, approximately 30% develop cardiac manifestations that range from electrical and mechanical disturbances to sudden death. The disease is caused by a protozoan parasite, Trypanosoma cruzi , and transmitted by an insect vector, a reduviid or triatomine bug, during blood sucking. The parasite has distinct developmental stages: the trypomastigotes are the nondividing forms that circulate within the blood of the infected hosts; amastigotes are the replicative forms that are found inside the cells of the infected host organs; and epimastigotes are the forms found in the insect midgut. Migration of infected individuals to metropolitan areas within and outside Latin America has spread the disease through blood transfusion. Chagas' disease has both acute and chronic phases, separated by a variable-length indeterminate phase, where patients are usually asymptomatic. The acute phase is characterized by the presence of the parasite in circulating blood and in organs such as the heart and intestines, where the amastigote form of the parasite reproduces inside the cells. Cardiac symptoms, although rare during the acute phase, may include arrhythmias, conduction blockade, and congestive heart failure. In the chronic phase, parasitemia and tissue parasitism are rarely found and distinct processes, including autoimmune, neurogenic, and microvascular mechanisms, have been suggested to be responsible for the cardiac pathological manifestations.