Chagas disease

Alternative names:

American trypanosomiasis

Definition:

An insect-transmitted parasitic disease common in South and Central America.

Causes, incidence, and risk factors:

Chagas disease is caused by Trypanosoma cruzi, a parasite related to the African trypanosome that causes sleeping sickness. It is spread by several families of blood-sucking insects (Rhodnius, Panstrongylus, and Triatoma) and is one of the major health problems in South America.

Chagas disease has two phases, acute and chronic. The acute phase may be without 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 is followed, in about half of the infected people with 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. Abnormal or rapid heart rhythms develop in half of the patients. The liver may become enlarged. About 1 out of 10 infected people die during the acute phase.

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. Death is usually from heart disease.