Symptoms of Chagas Disease

The symptoms of Chagas disease, an infection caused by a protozoan parasite called Trypanosoma cruzi (T. cruzi), resemble those of the flu—at least at first. When the acute phase of the disease resolves, however, the T. cruzi parasite can persist in the body for many years, even in people who appear entirely healthy. Many years later, often after decades, a chronic form of Chagas disease can develop, producing cardiac problems, gastrointestinal problems, or both.

Chagas disease is transmitted to people by the bite of an insect called the triatomine bug. It's most commonly seen in rural areas of Latin America. In that region of the world, complications of Chagas disease are a major cause of cardiac death, as well as disability from both heart and gastrointestinal disease.

chagas symptoms

Acute-Phase Symptoms

After a person has been exposed to T. cruzi, they can become sick anywhere from a week to several months later.

Flu-Like Illness

Most people with the acute form of Chagas disease have either no symptoms or relatively mild symptoms. They can develop mild flu-like symptoms including fever and myalgia (muscle pain).

While these symptoms can persist for as long as a few months, most people with acute-phase Chagas disease never seek medical help and never know they have had Chagas.


Some people with acute Chagas disease develop an area of persistent swelling and inflammation at the site of the bite of the triatomine bug, often around the eyes or elsewhere on the face. This is known as a chagoma, and if recognized, is an important clue that Chagas disease may be present.


In a small proportion of individuals—fewer than 1 percent—the acute phase of Chagas disease can develop into a very serious illness. These people may develop myocarditis (inflammation of the heart muscle), pericardial effusionmeningitis, and/or encephalitis. The mortality rate associated with this severe form of acute-phase Chagas disease is quite high.

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Late-Phase Symptoms

Once the acute phase of Chagas disease resolves (usually within 12 weeks of the initial infection), people infected with T. cruzi enter the chronic phase of the disease.

Unless a person with acute-phase Chagas disease has received successful treatment with antitrypanosomal drugs, the T. cruzi parasite usually persists in the body for the life of the patient.

The chronic phase of Chagas disease is divided into two forms: The indeterminate form, and the determinate form.

The Indeterminate Form

Virtually everyone infected with T. cruzi who is not treated during the acute phase of the infection will enter the indeterminate form of the disease for many years—at least 10 to 30 years. During the indeterminate phase, there are no symptoms at all. However, the infection persists, and the parasite is still present in the blood.

This means that people with the indeterminate form of Chagas disease who look and feel entirely healthy can still pass the disease on to others by blood donation or organ donation. Also, pregnant women can pass T. cruzi to their fetus by transplacental transmission.

Up to 70 percent of people infected with T. cruzi will remain in this indeterminate form of Chagas disease for the rest of their lives, without ever developing any more symptoms.

The Determinate Forms

After a decade or more of living with the indeterminate form of Chagas disease, up to 30 percent of people infected with T. cruzi will eventually manifest one of the “determinate forms” of the disease.

There are two major determinate forms of Chagas disease: Chagas heart disease and Chagas gastrointestinal disease.

Chagas Heart Disease

Chagas heart disease is a form of dilated cardiomyopathy, in which the heart enlarges to try to compensate for the weakness of the heart muscle. Eventually, the cardiac weakness leads to heart failure.

Consequently, people with Chagas heart disease experience the entire range of symptoms common to those with heart failure.

These include:

  • Dyspnea (shortness of breath). Dyspnea often occurs most prominently with exertion, but may also occur when lying down (orthopnea), when bending over (bendopnea), or may cause sudden awakening from deep sleep (paroxysmal nocturnal dyspnea).
  • Edema. Swelling of the legs, and possibly of the abdomen, often results from water and salt retention that occurs with heart failure.
  • Weakness and fatigue. Reduced cardiac pumping ability can cause significant weakness and fatigue.
  • Lightheadedness. Lightheadedness can result from low cardiac output due to the weakened heart muscle, or to a cardiac arrhythmia.
  • Palpitations. The cardiac arrhythmias commonly associated with heart failure often produce palpitations.
  • Syncope. Loss of consciousness may result from dangerous cardiac arrhythmias.
  • Stroke. Stroke is associated with heart failure of any type, because of an increased propensity for blood clotting.
  • Sudden death. Sudden death from ventricular tachycardia or ventricular fibrillationis distressingly frequent in people with heart failure.

Chagas Gastrointestinal Disease

Gastrointestinal disease caused by chronic T. cruzi infection is less common than cardiac disease and causes death much less frequently. However, the gastrointestinal form of Chagas can produce severe symptoms and can make daily life very difficult. These symptoms often include:

  • Nausea and vomiting
  • Dysphagia (difficulty swallowing)
  • Odynophagia (painful swallowing)
  • Gastrointestinal reflux
  • Severe constipation
  • Megacolon and megaesophagus. Advanced Chagas gastrointestinal disease can lead to massive, flaccid dilation of the colon (megacolon) or esophagus (megaesophagus). In these cases, symptoms of constipation or dysphagia can become so severe as to be life-threatening.

These kinds of gastrointestinal symptoms are disturbing for anyone, but the severity of these symptoms in people with Chagas disease can reach astounding proportions and can be very difficult to treat. The gastrointestinal form of chronic Chagas disease can have a devastating effect on a person’s life.

Frequently Asked Questions

  • How many people develop swelling in one eye as a result of Chagas disease?

    According to the World Health Organization, fewer than 50% of people will develop this characteristic symptom of a triatomine (kissing bug) bite. However, the reaction does not prove infection with T. cruzi—it is, in fact, possible to develop swelling in an eye after a triatomine bug bite while testing negative for Chagas disease.

  • What does a kissing bug bite look like?

    Some people may barely notice a triatomine bug bite, while others may develop itchy, raised bumps at the location of bites. The bugs often bite numerous times in one area—often around the mouth or eyes, but sometimes in other areas.

  • Can I contract Chagas disease and not know it?

    Yes. Bites can go unnoticed, and immediate symptoms—which could include fever, fatigue, body aches, headache, or rashes—may be mild. However, even after initial symptoms fade, the infection will remain. If you live in an area where kissing bugs are common, getting tested during regular medical checkups is an important precaution.

6 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.
  1. Bonney KM. Chagas disease in the 21st century: a public health success or an emerging threat?. Parasite. 2014;21:11. doi:10.1051/parasite/2014012

  2. Centers for Disease Control and Prevention. Parasites - American Trypanosomiasis (also known as Chagas Disease).

  3. Bern C, Martin DL, Gilman RH. Acute and congenital Chagas disease. Adv Parasitol. 2011;75:19-47. doi:10.1016/B978-0-12-385863-4.00002-2

  4. Nguyen T, Waseem M. Chagas disease (American trypanosomiasis). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Updated March 13, 2019.

  5. Chatelain E. Chagas disease research and development: Is there light at the end of the tunnel? Comput Struct Biotechnol J. 2017;15:98-103. doi:10.1016/j.csbj.2016.12.002

  6. World Health Organization. Chagas disease (also known as American trypanosomiasis).

Additional Reading

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.