Clinical Information

Chagas disease (American trypanosomiasis) is an acute and chronic infection caused by the protozoan hemoflagellate, Trypanosoma cruzi, which is endemic in many areas of South and Central America. The parasite is usually transmitted by the bite of reduviid (or "kissing") bugs of the genus Triatoma, but also has been transmitted by blood transfusion, organ transplantation, and apparently also by food ingestion. The acute febrile infection is most often undiagnosed and often resolves spontaneously. The actively motile (trypomastigote) form may be demonstrated in peripheral blood by stained smears during the acute phase. Chronic infections are often asymptomatic but may progress to produce disabling and life-threatening cardiac (cardiomegaly, conduction defects) and gastrointestinal (megaesophagus and megacolon) disease. These damaged tissues contain the intracellular amastigote of Trypanosoma cruzi. The parasite is not seen in the blood during the chronic phase. Diagnosis at this time is made by serology or tissue biopsy. A positive serology is considered presumptive evidence of active infection. Serologically positive asymptomatic persons are capable of transmitting the infection.