An Overview of Chagas Disease

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Chagas disease is an infectious disease caused by the Trypanosoma cruzi (T. cruzi) parasite. Since the bug that transmits it lives in Central America, South America, and Mexico, this is where the vast majority of infections are seen, 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 being unaware of the infection. If it's left untreated, Chagas disease can become lifelong and cause serious heart and digestive issues.

Symptoms

Chagas disease has two phases: the acute phase and the chronic phase. In either, the infection can cause mild symptoms or none at all, or it can end up being life-threatening.

Acute Phase

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

These symptoms can persist for weeks or months and usually resolve on their own, but the infection doesn't go away without treatment. It can move to the chronic phase, causing life-threatening complications later, which is why treatment during the acute phase is so important.

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

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 percent even die from cardiac disease during the acute illness.

Chronic Phase

After the acute phase of Chagas disease resolves, most untreated people enter what is called the chronic indeterminate (or latent) form of the disease. The indeterminate form of Chagas' disease is characterized by a complete lack of illness or symptoms.

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 form of Chagas disease affects around 20 percent to 30 percent of people and can appear as many as 10 or 20 years after you've been infected, lasting for decades. Signs and symptoms that chronic Chagas disease has become severe and potentially life-threatening may include the above-mentioned cardiac symptoms, as well as:

  • Irregular heartbeat
  • Heart failure
  • Heart enlargement
  • Colon enlargement, which can cause severe constipation and abdominal pain
  • Enlargement of your 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 percent. 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.

Causes

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 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.

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 your face at night while you're sleeping, which is why they're also known as "kissing bugs." They defecate immediately after biting you, so the parasite is left on your skin where it can get inside your body through the bite, or by unknowingly rubbing the parasites into your 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

Diagnosis

If you think you might have Chagas disease, your doctor will first give you a physical exam and then ask you about your symptoms and potential exposure to the T. cruzi parasite. He or she will then likely do a blood test to check for antibodies to the parasite, which can confirm or rule out whether or not you have Chagas disease. If your blood test is positive, your doctor 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, chest X-ray, abdominal X-ray, or upper endoscopy.

Treatment

The treatment of Chagas disease includes killing the T. cruzi parasite and treating the signs and symptoms of any potential complications like heart failure or cardiac arrhythmias, as well as working to prevent sudden death. Experts agree that it's important to treat patients with acute Chagas disease, and possibly with early indeterminate Chagas disease, with antiparasitic drug therapy aimed at T. cruzi.

The two drugs that may be effective against T. cruzi are called benznidazole and nifurtimox. Both of these drugs often 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 doctors 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 percent 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, doctors do give these drugs to people who are under 50 and have either the indeterminate or chronic forms of Chagas disease because the drugs may slow down the complications the disease can cause, though they won't cure it.

Preventing Chagas disease is typically not a concern for Americans unless they are living in or traveling to rural Latin American countries. For those who are concerned, 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 percent 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 when aggressive, modern treatment strategies are employed.

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