heart disease.

  There are several species of trypanosomes, which are single-celled organisms. Some affect primarily animals, but some are a significant cause of human illnes. Trypanosomes are transmitted by insect bites; Chagas disease is transmitted by bites of the reduviid bug. It is estimated that 16 to 18 million people are infected with T. cruzi and that 30 to 40 percent will develop heart symptoms as a result of their infection. In parts of the world where Chagas disease is endemic, most notably South America, the disease is the largest single cause of cardiovascular death. Chagas disease is very rare in the United States; only eight cases have been reported, and all of these in Latin American immigrants.Conditions resulting from Chagas disease also include atrioventricular block, which is a failure of the normal conduction of the electrical impulses which control the heartbeat. Eighteen of the 25 patients with Chagas disease were under treatment for heart disease prior to their proper diagnosis. In one case, a patient had been treated for 10 prior to the diagnosis.