American Trypanosomiasis (Chagas Disease)

American trypanosomiasis (Chagas disease) is an important cause of human heart disease, megaesophagus and megacolon in Latin America, where the causative organism, Trypanosoma cruzi, is endemic. While this organism occasionally causes an acute illness, most people do not realize they are infected until several years or decades later, when some develop a chronic medical condition. Antiparasitic treatment is most effective in the acute stages of the infection, and may be ineffective once this period has passed. In addition to humans, T. cruzi can infect many other mammals and marsupials, some of which act as reservoir hosts. Clinical cases have been reported mainly in dogs and captive non-human primates, with few illnesses documented in other species. However, cases in animals might be underdiagnosed. Chagas disease is usually transmitted by the bites of triatomine insects, also known as “kissing bugs.” These insects or their feces can also contaminate foods such as fruit juices, resulting in foodborne, sometimes life-threatening, outbreaks of acute Chagas disease in people. In South and Central America and parts of North America, T. cruzi cycles between triatomines in the environment and wild or domesticated animals. Some triatomine species occur in the wild, or invade human homes only opportunistically; others have adapted to live within substandard dwellings, where they hide in cracks during the day and emerge to feed on people and animals at night. Campaigns to eliminate triatomines in domestic cycles, together with diagnostic testing to prevent congenital or blood transfusion associated infections, are gradually reducing the incidence of Chagas disease in Latin America. However, this disease has become an increasing problem in non-endemic regions, where infections may not be recognized in immigrants and travelers, and where the few effective drugs may not be widely available.