What Is Chagas Disease?

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Chagas disease is an infectious disease caused by the Trypanosoma cruzi (T. cruzi) parasite. The insect that transmits this parasite lives in Central America, South America, and Mexico, where the vast majority of infections occur, though some cases were recently found in the southern United States.

It's estimated that around 8 million people in Latin America have Chagas disease, with most people unaware that they're infected.

If it's left untreated, Chagas disease can persist throughout life and cause serious heart and digestive issues.

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Chagas Disease Symptoms

Chagas disease has two phases: the acute phase and the chronic phase. In each of these phases, the infection can cause mild symptoms or none at all, or it can cause life-threatening effects.

Acute Phase

The acute form of Chagas disease usually begins one to 16 weeks after you've been infected with the T. cruzi parasite. Acute Chagas disease is generally a fairly mild illness, often with no symptoms at all.

Sometimes it causes flu-like symptoms, such as:

  • Fever
  • Fatigue
  • A headache
  • Rash
  • Muscle aches
  • Swollen lymph nodes

You may also notice these symptoms:

  • Swelling where the bug bit you
  • Swollen eyelid(s)
  • Appetite loss
  • Digestive issues such as nausea, vomiting, or diarrhea

The acute symptoms can persist for weeks or months and usually resolve on their own, but the infection doesn't go away without treatment.

This infection can progress to the chronic phase, causing life-threatening complications later—which is why treatment is important during the acute phase.

Heart Involvement: Sometimes acute Chagas disease can affect your heart. People with cardiac (heart) involvement have symptoms of acute myocarditis (inflammation of the heart muscle), and may also have acute pericarditis (inflammation of the tissue around the heart).

Symptoms and signs of cardiac involvement may include:

  • Chest pain
  • Dyspnea (shortness of breath)
  • Changes on your electrocardiogram (ECG)
  • Evidence of a pericardial effusion (fluid collecting around the heart) on an echocardiogram

Most often, the heart problems that are seen with acute Chagas disease resolve completely after a few months. However, some people with acute cardiac Chagas disease will progress rapidly to a chronic form of heart failure, and around 5% die from cardiac disease during the acute phase of the illness.

Chronic Phase

After the acute phase of Chagas disease resolves, most untreated people enter the chronic indeterminate, or latent, phase of the disease. This phase of Chagas disease is characterized by a complete lack of symptoms or effects of illness.

If you have indeterminate Chagas disease, you appear and feel entirely normal, and you have a normal cardiac examination, including ECG and echocardiogram. However, blood testing will show that you have a chronic infection with T. cruzi. Many people stay in this latent phase with no symptoms for the rest of their lives.

The chronic phase of Chagas disease affects around 20 to 30% of people and can last for decades.

Signs and symptoms of severe or life-threatening chronic Chagas disease may include:

  • Irregular heartbeat
  • Heart failure
  • Heart enlargement
  • Colon enlargement, which can cause severe constipation and abdominal pain
  • Enlargement of the esophagus, which can cause pain and difficulty swallowing
  • Sudden death

If you are in the chronic phase of Chagas disease, your lifetime risk of developing one or more of these heart or gastrointestinal complications is around 30%.

Chagas heart disease usually appears at least five years after the acute illness, and it may be delayed much longer than that.

Chagas heart disease is a very significant problem and often results in death or serious disability. In fact, next to coronary artery disease, Chagas disease is the most common cause of heart failure in Latin America.


Chagas disease is caused by the Trypanosoma cruzi (T. cruzi) parasite, which is found in the feces of infected triatomine bugs in South America, Central America, and Mexico. Triatomine bugs are common in rural areas, especially in dwellings made of adobe, mud, straw, or thatch, and they feed on human and animal blood. Chagas disease is not common among city dwellers and is generally limited to the rural areas of Latin America, although there are cases of it worldwide.

T. cruzi parasites have also been found in guts of Reduviid bugs in the Southern United States, and transmission has rarely been reported to have occurred in the Southern US.

Most people contract the disease when they're bitten by a triatomine bug that has picked up the parasite from an infected person or animal.

Triatomine bugs are nocturnal and tend to bite on people's faces at night while they're sleeping, which is why they're also known as "kissing bugs." They defecate immediately after biting, leaving the parasite on the skin where it can get inside the body through the bite, or by rubbing the parasites into the eyes, mouth, or a cut or scratch.

You can also get Chagas disease in the following ways:

  • In utero (infected mothers can transmit it to babies)
  • Receiving an infected organ via transplantation
  • A blood transfusion from an infected person
  • Eating contaminated food that's undercooked or raw
  • Exposure in a laboratory


If you think you might have Chagas disease, your healthcare provider will ask you about your symptoms and potential exposure to the T. cruzi parasite and do a physical examination. They may also order a blood test to check for antibodies to the parasite, which can confirm or rule out whether or not you have Chagas disease.

Chagas Disease Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Man

If your blood test is positive, your healthcare provider may do more testing to see if you're in the active or chronic phase and if you have developed any complications. These additional tests may include an echocardiogram, electrocardiogram (EKG), chest X-ray, abdominal X-ray, or upper endoscopy.


The treatment of Chagas disease includes killing the T. cruzi parasite and treating the signs and symptoms of any complications, like heart failure or cardiac arrhythmias. Acute Chagas disease, and early indeterminate Chagas disease are sometimes treated with antiparasitic drug therapy.

Benznidazole and nifurtimox are the two drugs that may be effective against T. cruzi.

Both of these drugs can cause significant toxicity, and only benznidazole is approved for use by the Food and Drug Administration (FDA). However, neither are available in U.S. pharmacies, so American medical professionals who need to treat a patient for T. cruzi must obtain these drugs directly from the Centers for Disease Control and Prevention (CDC). If they're taken early enough, these drugs are nearly 100% effective in treating Chagas disease.

The evidence is sparse that treating adults who have the indeterminate or chronic forms of Chagas disease with antiparasitic therapy measurably improves the outcome. However, healthcare providers do give these drugs to people who are under 50 and have either the indeterminate or chronic form of Chagas disease because the drugs may slow down complications, though they won't cure the disease.


Preventing Chagas disease is typically not a concern for Americans unless they are living in or traveling to rural Latin American countries.

If you are in a high-risk area, the following strategies can be beneficial:

  • Be mindful of food storage and consumption
  • Keep your living space, especially your bedroom, clean (that goes for a pet's living quarters, too)
  • Have your residence sprayed with insecticides by an extermination professional
  • Ensure that any holes or cracks in your house are filled

A Word From Verywell

If you contract Chagas disease, don't be alarmed. Most cases don't require hospitalization. And if you get treatment right away, the disease can be cured. Even if you don't realize you have the disease and end up in the chronic phase, treatment may still help, and you have more than a 70% chance of not developing any complications at all. If you do have a complication, your symptoms can be substantially reduced, your quality of life can be greatly improved and your survival can be prolonged with treatment.

20 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
Richard N. Fogoros, MD

By Richard N. Fogoros, MD
Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.