Trypanosomes

Trypanosoma cruzi is the protozoan parasite that causes American trypanosomiasis or Chagas disease. Chagas disease is a major cause of cardiac and gastrointestinal disease in endemic areas of Mexico and Central and South America. The infection is usually vectorborne but can also be acquired by other routes such as blood transfusion, organ transplantation, ingestion of contaminated food or drink, and congenital transmission. This parasite invades any nucleated cell but the cells of the cardiovascular musculoskeletal, reticuloendothelial, and autonomic systems are most commonly involved. The disease is divided into acute, indeterminate, and chronic phases. Chronic Chagas disease may be associated with rhythm disturbances, dilated cardiomyopathy, and/or megasyndromes such as megaesophagus and megacolon. Treatment with available drugs generally is not effective. Human African trypanosomiasis or sleeping sickness is caused by infection with the parasites Trypanosoma brucei gambiense and T. b. rhodesiense. These parasites are vector-borne and can invade the central nervous system (CNS). Whereas T. b. gambiense generally results in a chronic infection that may persist for years, infection with T. b. rhodesiense more often than not is manifest as an acute fulminant systemic and CNS disease. Effective treatment is available. No vaccines are available for preventing Chagas disease or sleeping sickness. Defining Statement.