Chagas Disease

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Overview, Causes, & Risk Factors

Chagas disease is caused by Trypanosoma cruzi, a parasite related to the African trypanosome that causes sleeping sickness. It is spread by reduvid bugs and is one of the major health problems in South America, where 20 million people are infected. Due to immigration, approximately 500,000 people in the United States are believed to be infected.

Risk factors for Chagas disease include living in Central or South America, poverty, living in a hut where the reduvid bugs live in the walls, and receiving a blood transfusion from a person who carries the parasite, but does not have active Chagas disease.

Chagas disease has two phases -- acute and chronic. The acute phase may have no symptoms or have very mild symptoms. Symptoms of the acute phase include swelling and reddening at the site of infection (where the blood-sucking insect caused the initial infection).

This may be followed by swelling of one eye. Lymph nodes that drain the area of the insect bite may become swollen. As the parasite spreads from the bite site, the patient develops fever, malaise, and generalized swelling of the lymph nodes. The liver and spleen may become enlarged.

The disease goes into remission after the acute phase and may become chronic with no further symptoms for many years. When symptoms finally develop, they appear as cardiac disease (cardiomyopathy) and digestive abnormalities.

Patients may develop congestive heart failure. Swallowing difficulties may be the first symptom of digestive disturbances and may lead to malnutrition. Patients who have parasitic infection of the colon may experience abdominal pain and constipation. Death is usually caused by heart disease.