Chagas’ disease, also known as American trypanosomiasis, is a life threatening condition caused by the parasite Trypanosoma cruzi. It appears mainly in Latin America, and insects transmit it to humans. Symptoms include skin lesions, swelling of the eyelids, and fever.

Symptoms of Chagas’ disease vary depending on whether the infection is in the acute or chronic phase of the disease. The most common symptoms associated with acute Chagas’ disease are flu-like symptoms, purplish swelling of one eyelid, and skin lesions.

According to the World Health Organization (WHO), up to 30% of people with chronic Chagas’ disease develop cardiac issues while 10% develop digestive or neurological issues. These may include an enlarged heart, enlargement of the colon or esophagus, and ultimately, potential heart failure.

This article will explain what Chagas’ disease symptoms are, including the differences between the acute and chronic phases. It will also explain when to contact a doctor, how to manage symptoms, and overall treatment.

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The WHO estimates that 6–7 million people worldwide have Chagas’ disease. It is an illness that, if not treated at the onset of the acute phase, can be fatal. Chagas’ disease results from the bite of a triatomine bug infected by the parasite, Trypanosoma cruzi.

The specific symptoms someone with Chagas’ disease experiences can depend on:

  • their age at the time of infection
  • ways they acquired the infection
  • the strain of Trypanosoma cruzi involved

Generally speaking, however, the symptoms of Chagas’ disease primarily depend on whether someone is in the acute or chronic phase of the infection.

Acute phase

The acute phase of Chagas’ disease occurs during the first couple of weeks to months after the infection starts while the parasite is circulating in the blood.

During this period, someone may not experience any symptoms or only mild symptoms, such as:

  • Romaña’s sign, which is the swelling of an eyelid when someone accidentally rubs triatomine bug feces into the eye
  • fever
  • fatigue
  • body aches
  • headaches
  • rash
  • a loss of appetite
  • diarrhea
  • vomiting
  • mild enlargement of the liver or spleen
  • swollen glands
  • swelling at the site of the bite

When the infection is acute, many people are unaware they have Chagas’ disease because the symptoms can be so mild, varied, and similar to other common conditions.

But a doctor may be able to recognize that someone has Chagas’ disease if they notice a few particular symptoms during a physical exam, such as:

  • swelling at the site of the bite
  • swollen glands
  • enlargement of the spleen or liver

Chronic phase

The chronic phase of Chagas’ disease can last for decades or even a lifetime.

Around 70–80% of people do not experience symptoms during the chronic phase. During this time, the parasite lives in the digestive and heart muscles. Yet around 10–30% of people with chronic Chagas’ infections experience symptoms one to three decades after initial infection, such as:

  • an enlarged heart
  • altered heart rate or rhythm
  • heart failure or heart attack
  • an enlarged esophagus or colon
  • colon or gallbladder disorders, which can cause problems eating and defecating

The Centers for Disease Control (CDC) estimates that around 8 million people living in Central America, South America, and Mexico have Chagas’ disease.

In the southern United States, Chagas’ disease infections rarely occur. However, the disease is not endemic or native to the U.S. or the Caribbean.

People exhibiting signs and symptoms of Chagas’ disease or any infection should seek medical attention to limit the chances of developing complications. A person should seek medical attention as soon as possible if their symptoms include:

  • trouble breathing
  • changes in heart rate or rhythm
  • severe swelling
  • high fever
  • a loss of consciousness

A person should see a doctor if they have traveled to an area where Chagas’ disease is present or if they have experienced any of the following:

  • a bite from a triatomine bug
  • a bite from an insect they cannot identify
  • any symptoms of Chagas’ disease

It is important to note that, globally, only 1 in 10 people with Chagas’ disease receive a proper diagnosis.

The best treatment for people in the acute phase of Chagas’ disease is antiparasitic medications, most commonly benznidazole and nifurtimox.

Both medications are almost 100% effective at curing the disease, according to the WHO, but only if a person takes them quickly after infection in the acute phase.

Once the infection moves onto the chronic phase, treatments aim to manage or treat specific digestive and cardiac conditions.

Chagas’ disease results from the parasite Trypanosoma cruzi or T. cruzi.

Blood-sucking insects called triatomine bugs that feed on animals infected with the parasite spread most Chagas’ infections. They then spread the parasite to humans through their feces, which can enter the body via bites. Someone may inadvertently infect themselves by scratching their bite and then rubbing or touching their mouth or eyes.

Most triatomine insects live in homes made from materials, such as:

  • straw
  • palm thatch
  • adobe
  • mud

In the daytime, these bugs hide in cracks in roofs and walls. During the night, they emerge and bite people while they are sleeping. Triatomine insects, or “kissing bugs,” tend to bite people’s faces.

Less commonly, people may catch Chagas’ disease via:

  • blood transfusions
  • organ tranplantations
  • laboratory exposure
  • eating uncooked food contaminated with infected insect feces
  • congenital transmission from a pregnant person to their baby

Read more about “kissing bugs.”

Many people recover from the acute phase of Chagas’ disease within a few weeks to months. However, if someone does not take antiparasitic medications during this period, the infection will remain in the body.

Most people with acute Chagas’ disease experience mild symptoms. However, less than 5% of young children die from severe inflammation and infection that spreads to their brain or heart muscles. Acute symptoms may also be more severe in people with weakened immune systems.

If someone does not receive treatment for Chagas’ disease during the acute phase of the infection, more severe conditions of the heart, digestive tract, and nervous system can develop. These conditions can result in severe complications, including:

  • irreversible organ damage
  • coma
  • death

According to the World Heart Federation, around 12,000 people die of Chagas’ disease annually worldwide.

There are no vaccines or medications capable of preventing Chagas’ disease. There are a few measures, however, that someone can take to limit their risk of getting the infection.

The WHO recommends the following:

  • sleeping indoors in well-constructed buildings with air conditioners or screened windows
  • sleeping with a mosquito or bed net that completely covers the bed, particularly those treated with long lasting insecticides
  • spraying infested dwellings with long lasting insecticides
  • wearing protective clothing during the night that covers most of the skin or contains insecticides
  • applying insecticides creams or sprays to exposed skin
  • avoiding eating salads, uncooked vegetables, unpasteurized juices, and unpeeled or boiled fruit

People undergoing a blood transfusion or organ transplantation should ensure the blood and organs they receive come from a location that screens for Chagas’ disease.

Read more about parasite infections in humans.

Chagas’ disease is a parasitic infection transmitted by insects to humans via infected feces that enters damaged skin or mucous membranes. During the acute phase of the infection, someone may experience flu-like symptoms, enlargement of the glands or spleen, and eyelid swelling.

The best treatment for the early stages of Chagas’ infections is antiparasitic medications. When untreated, around 10–30% of people with Chagas’ disease develop cardiac, gastrointestinal, or nervous system symptoms 10–30 years after infection.