Chagas disease

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American trypanosomiasisLast 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.

References

1. Kirchhoff LV. Trypanosoma species (American trypanosomiasis, Chagas' disease): Biology of trypanosomes. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 277.

Review Date: 9/15/2010.Reviewed by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital.