Chagas disease

Overview

Chagas (CHAH-gus) disease is an inflammatory, infectious disease caused by the parasite Trypanosoma cruzi. This parasite is found in the feces of the triatomine (reduviid) bug. This bug is also known as the "kissing bug." Chagas disease is common in South America, Central America and Mexico, the primary home of the triatomine bug. Rare cases of Chagas disease have also been found in the southern United States.

Also called American trypanosomiasis, Chagas disease can infect anyone. Left untreated, Chagas disease later can cause serious heart and digestive problems.

During the acute phase of infection, treatment of Chagas disease focuses on killing the parasite. In people who have chronic Chagas disease, it's no longer possible to kill the parasite. Treatment in this later phase is about managing signs and symptoms. You can also take steps to prevent infection.

Symptoms

Chagas disease can cause a sudden, brief illness (acute), or it may be a long-lasting (chronic) condition. Symptoms range from mild to severe, although many people don't experience symptoms until the chronic stage.

Acute phase

The acute phase of Chagas disease, which lasts for weeks or months, is often symptom-free. When signs and symptoms do occur, they are usually mild and may include:

Swelling at the infection site
Fever
Fatigue
Rash
Body aches
Eyelid swelling
Headache
Loss of appetite
Nausea, diarrhea or vomiting
Swollen glands
Enlargement of your liver or spleen

Signs and symptoms that develop during the acute phase usually go away on their own. In some cases, if the infection isn't treated, Chagas disease will advance to the chronic phase.

Chronic phase

Signs and symptoms of the chronic phase of Chagas disease may occur 10 to 20 years after initial infection, or they may never occur. In severe cases, Chagas disease signs and symptoms may include:

Irregular heartbeat
Heart failure
Sudden cardiac arrest
Difficulty swallowing due to enlarged esophagus
Stomach pain or constipation due to enlarged colon

When to see a doctor

See your doctor if you live in or have traveled to an area where Chagas disease is widespread and you have signs and symptoms of the condition. Symptoms may include swelling at the infection site, fever, fatigue, body aches, rash and nausea.

Causes

The cause of Chagas disease is the parasite Trypanosoma cruzi, which is spread from an insect known as the triatomine bug, or "kissing bug." These insects can become infected by this parasite when they swallow blood from an animal that is infected with the parasite.

Triatomine bugs live primarily in mud, thatch or adobe huts in Mexico, South America and Central America. They hide in crevices in the walls or roof during the day and come out at night — often feeding on sleeping humans.

Infected bugs defecate after feeding, leaving behind parasites on the skin. The parasites can then enter your body through your eyes, mouth, a cut or scratch, or the wound from the bug's bite.

Scratching or rubbing the bite site helps the parasites enter your body. Once in your body, the parasites multiply and spread.

You may also become infected by:

Eating uncooked food contaminated with feces from bugs infected with the parasite
Being born to a person who is infected with the parasite
Getting a blood transfusion or an organ transplant from someone who was infected with the parasite
Being accidentally exposed to the parasite while working in a lab
Spending time in a forest that contains infected wild animals, such as raccoons and opossums

Risk factors

The following factors may increase your risk of getting Chagas disease:

Living in poor rural areas of Central America, South America and Mexico
Living in a residence that contains triatomine bugs
Receiving a blood transfusion or organ transplant from a person who carries the infection

It's rare for travelers to the at-risk areas in South America, Central America and Mexico to catch Chagas disease because travelers tend to stay in well-constructed buildings, such as hotels. Triatomine bugs are usually found in structures built with mud or adobe or thatch.

Complications

If Chagas disease progresses to the long-lasting (chronic) phase, serious heart or digestive complications may occur. These may include:

Heart failure. Heart failure occurs when your heart becomes so weak or stiff that it can't pump enough blood to meet your body's needs.
Enlargement of the esophagus (megaesophagus). This rare condition is caused by the abnormal widening (dilation) of your esophagus. This can result in difficulty with swallowing and digestion.
Enlargement of the colon (megacolon). Megacolon occurs when your colon becomes abnormally dilated, causing stomach pain, swelling and severe constipation.

Prevention

If you live in a high-risk area for Chagas disease, these steps can help you prevent infection:

Avoid sleeping in a mud, thatch or adobe house. These types of residences are more likely to harbor triatomine bugs.
Use insecticide-soaked netting over your bed when sleeping in thatch, mud or adobe houses.
Use insecticides to remove insects from your residence.
Use insect repellent on exposed skin.

Diagnosis

Your doctor will conduct a physical exam, asking about your symptoms and any factors that put you at risk of Chagas disease.

If you have the signs and symptoms of Chagas disease, blood tests can confirm the presence of the parasite or the proteins that your immune system creates (antibodies) to fight the parasite in your blood.

If you're diagnosed with Chagas disease, you'll likely have more tests. These tests may be done to determine whether the disease has entered the chronic phase and caused heart or digestive complications. Tests may include:

Electrocardiogram, a test that records your heart's electrical activity
Chest X-ray, an imaging test which lets your doctor see if you have an enlarged heart
Echocardiogram, a test that uses sound waves to capture moving images of your heart, allowing your doctor to see any changes to the heart or its function
Abdominal X-ray, a test that uses radiation to capture images of your stomach, intestines and colon
Upper endoscopy, a procedure in which you swallow a thin, lighted tube (endoscope) that transmits images of your esophagus onto a screen

Treatment

Treatment for Chagas disease focuses on killing the parasite and managing signs and symptoms.

During the acute phase of Chagas disease, the prescription medications benznidazole and nifurtimox (Lampit) may be of benefit. Both drugs are available in the regions most affected by Chagas disease. In the United States, however, the drugs can be obtained only through the Centers for Disease Control and Prevention.

Once Chagas disease reaches the chronic phase, medications won't cure the disease. But, the drugs may be offered to people younger than age 50 because they may help slow the progression of the disease and its most serious complications.

Additional treatment depends on the specific signs and symptoms:

Heart-related complications. Treatment may include medications, a pacemaker or other devices to control your heart rhythm, surgery, or even a heart transplant.
Digestive-related complications. Treatment may include diet changes, medications, corticosteroids or, in severe cases, surgery.

Preparing for your appointment

You're likely to start by seeing your family doctor. Depending on his or her findings, your doctor may refer you to an infectious disease specialist.

It's a good idea to prepare well for your appointment. Here's some information to help you get ready for your appointment, and what to expect from your doctor.

What you can do

Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
Write down key personal information, including travel to other countries, major stresses or recent life changes.
Make a list of all medications, vitamins and supplements that you're taking.
Write down questions to ask your doctor.

Preparing a list of questions will help you make the most of your time with your doctor. For Chagas disease, some basic questions to ask your doctor include:

What's the most likely cause of my symptoms?
What kinds of tests do I need?
Is my condition likely temporary or long lasting?
What treatments are available?
I have these other health conditions. How can I best manage these conditions together?
Am I contagious? Are others who traveled with me likely infected?
Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

When did you first begin experiencing symptoms?
Have your symptoms been continuous or occasional?
How severe are your symptoms?
Does anything improve your symptoms?
What, if anything, appears to worsen your symptoms?
Have you lived or traveled anywhere, such as Mexico, where the triatomine bug or Chagas disease is common?