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 the bite of 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
- Receiving a blood transfusion from a person who carries the parasite but does not have active Chagas disease
- General ill feeling (malaise)
- Swelling of one eye if the bite is near the 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:
- Digestive problems
- Heart failure
- Pain in the abdomen
- Swallowing difficulties
Signs and tests
Physical examination can confirm the symptoms. Signs may include:
- Enlarged liver and spleen
- Enlarged lymph nodes
- Irregular heartbeat (arrhythmia)
- Rapid heartbeat (tachycardia)
- Blood culture to look for signs of infection
- Chest x-ray
- Electrocardiogram (ECG)
- Enzyme-linked immunoassay (ELISA) to look for signs of infection
- Peripheral blood smear to look for signs of infection
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 children and most 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
- Problems sleeping
- Skin rashes
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.
- Enlargement of the colon (megacolon)
- Enlargement of the esophagus (megaesophagus) with swallowing difficulty
- Heart disease
- Heart failure
Calling your health care provider
Call for an appointment with your health care provider if you think you may have Chagas disease.
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.
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.
Kirchhoff LV. Chagas’ disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 355.
Last reviewed 10/6/2012 by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. 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. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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