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A.D.A.M. Medical Encyclopedia.

Chagas disease
American trypanosomiasis
Last reviewed: September 15, 2010.

Chagas disease is an illness spread by insects. It is 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 reduvid bugs and is one of the major health problems in South America. Due to immigration, the disease also affects people in the United States.

Risk factors for Chagas disease include:

Living in a hut where reduvid bugs live in the walls

Living in Central or South America

Poverty

Receiving a blood transfusion from a person who carries the parasite but does not have active Chagas disease

Symptoms
Chagas disease has two phases: acute and chronic. The acute phase may have no symptoms or very mild symptoms. Symptoms include:

Fever

General ill feeling (malaise)

Swelling of one eye

Swollen red area at site of insect bite

After the acute phase, the disease goes into remission. No other symptoms may appear for many years. When symptoms finally develop, they may include:

Constipation

Digestive problems

Pain in the abdomen

Swallowing difficulties

Signs and tests
Physical examination can confirm the symptoms. Signs may include:

Cardiomyopathy

Enlarged liver and spleen

Enlarged lymph nodes

Irregular heartbeat (arrhythmia)

Rapid heartbeat (tachycardia)

Tests include:

Blood culture

Chest x-ray

Echocardiogram

Electrocardiogram (ECG)

Enzyme-linked immunoassay (ELISA)

Peripheral blood smear

Treatment
The acute phase and reactivated Chagas disease should be treated. Infants born with the infection should also be treated.

Treating the chronic phase is recommended for both children and adults. Adult patients should talk to their doctor about whether to treat chronic Chagas disease.

Two drugs are used to treat this infection: benznidazole and nifurtimox.

Both drugs often have side effects. The side effects may be worse in older people.

Side effects may include:

Headaches and dizziness

Loss of appetite and weight loss

Neuropathy

Problems sleeping

Skin rashes

Expectations (prognosis)
About 30% of infected people who are not treated will develop chronic or symptomatic Chagas disease. It may take more than 20 years from the time of the original infection to develop heart or digestive problems.

Abnormal heart rhythms (arrhythmias, ventricular tachycardia) may cause sudden death. Once heart failure develops, death usually occurs within several years.

Complications
Cardiomyopathy

Enlargement of the colon (megacolon)

Enlargement of the esophagus (megaesophagus) with swallowing difficulty

Heart disease

Heart failure

Malnutrition

Calling your health care provider
Call for an appointment with your health care provider if you think you may be infected with Chagas disease.

Prevention
Insect control with insecticides and houses that are less likely to have high insect populations will help control the spread of the disease.

Blood banks in Central and South America screen donors for exposure to the parasite. The blood is discarded if the donor tests positive. Most blood banks in the United States began screening for Chagas disease in 2007.