What is Chagas disease (American trypanosomiasis)?
Chagas disease, also known as American trypanosomiasis, is a tropical parasitic infection transmitted by crawling, blood-sucking insects (kissing bugs). The kissing bug is almost exclusive to continental Latin America.
The infection results from the parasite Trypanosoma cruzi (T. cruzi). In most cases, the disease passes to humans who have been exposed (bitten) by an infected triatomine bug (kissing bug).
Parents may spread Chagas disease to their offspring during pregnancy or delivery. Other exceedingly rare forms of transmission include:
- Infected blood transfusions.
- Sharing needles.
- Consumption of food or beverages contaminated by the insect or its urine or feces that contain the parasite T. cruzi.
- Very rarely, organ transplants or laboratory accidents.
Chagas disease can cause both sudden (acute) and long-term (chronic) symptoms. People can be infected for a long time without showing symptoms. Without treatment, serious complications, including heart and intestinal tract problems, are possible.
Chagas disease is curable if treated soon after infection. Unfortunately, most infected people are unaware of their infection until it’s too late, and they present with complications of chronic heart or bowel problems.
Who gets Chagas disease?
Anyone exposed to the feces or urine of an infected kissing bug (triatomine) can develop Chagas disease.
The infection is most common in rural or impoverished continental South America, Mexico and Central America. Most infections still occur in Latin American cities of 21 countries, with very few cases of chronic disease in other countries. Public health efforts have decreased disease transmission and helped eradicate it from some areas of South America and Central America.
Now infected people live with Chagas in other places, as people with Chagas disease have moved throughout the world. Very few local vector (insect bites) transmission cases occur in the United States from southern states bordering Mexico. There are no published cases of local transmission from insect bites outside continental America.
People at highest risk of developing Chagas disease include:
- People born in or living in adobe (mud walls) houses with thatched (straw) roofs in rural South America, Central America and Mexico.
- People who received a blood transfusion before universal blood screening for American trypanosomiasis began. This screening started in 2004 in South America, Central America and Mexico, and in 2007 in the U.S.
- Children born from people infected with American trypanosomiasis.
Most people can be infected for a long time even a lifetime without showing symptoms. But the disease can still affect you, even if you don’t know you have it. Without treatment, serious complications occur in approximately 20% to 30% of cases, including cardiac (heart) damage and digestive (bowels) or neurological (brain) issues.
How common is Chagas disease?
Chagas disease affects an estimated 6 million people worldwide, with about 300,000 cases per year in the Americas. Approximately 70 million people in America live in areas of exposure and are at risk of contracting the disease.
Symptoms and Causes
What causes Chagas disease?
The disease is caused by a blood infection with a parasite (T. cruzi). In most cases, people who develop Chagas disease are exposed to T. cruzi from the feces or urine of an infected triatomine (kissing bug).
The triatomine is a blood-sucking insect that feeds on animals and humans. They hide during the day and crawl at night to feed.
They usually bite at night while you’re asleep. The bites are frequently on or around your face, this is how they got the name ‘kissing bug.’ While feeding, the bugs pee and poop (depositing the parasite T. cruzi ) close to the bite. You may unintentionally rub or scratch the bite, smearing the parasite into the opening in your skin. This allows the parasite T. cruzi to reach your blood.
Additionally, Chagas disease may spread through:
- Congenital transmission (an infected pregnant person gives the infection to the developing fetus or the baby during delivery).
- Transfusions of infected blood. However, all blood products are now tested for T. cruzi.
- Eating undercooked or unpasteurized food that’s contaminated with infected triatomine bug feces or urine. When this occurs, there are usually outbreaks and multiple people develop severe disease.
- Triatomine bites sustained while eating raw sugar cane sticks.
- Transplantation of infected organs. However, hospitals now screen donors for T. cruzi.
- A laboratory accident. This is very rare.
What are the symptoms of Chagas disease?
Chagas disease occurs in two distinct phases:
The acute (sudden) phase
Symptoms are generally mild or go unnoticed, including:
- Swelling at the site of the bug bite/ contact with the bug feces.
- Flu-like symptoms, such as fever, body aches, fatigue and headache.
- Muscle pain.
- Abdominal pain.
- Enlarged spleen or liver.
- Swollen glands.
The phase may last a few days or a few weeks.
The chronic (long-term) phase
Symptoms may start years or even decades after the initial infection. They include:
Diagnosis and Tests
How is American trypanosomiasis (Chagas disease) diagnosed?
Your healthcare provider diagnoses Chagas disease with a simple blood test. The test looks for the presence of antibodies against the parasite.
After a positive diagnosis and complete history, your provider may recommend cardiac testing to rule out heart or gastrointestinal complications. These tests may include:
- Echocardiogram, which uses sound waves to create a detailed picture of your heart.
- Electrocardiogram (EKG, ECG), which uses electrodes attached to your skin to record your heart’s electrical activity.
- X-ray or CT scan of the abdomen or chest to check for an enlarged colon or esophagus.
Management and Treatment
How is Chagas disease treated?
Treatment for Chagas disease includes antiparasitic medications, such as benznidazole. In addition, if you have cardiac or intestinal complications from Chagas disease, you may need further treatment.
What complications are associated with Chagas disease?
Chronic Chagas disease may cause serious complications that affect the heart and gastrointestinal tract. These complications may be life-threatening if left untreated. Heart complications include:
- Arrhythmia (unusual heart rate or rhythm).
- Cardiac arrest (sudden death).
- Dilated cardiomyopathy (enlarged heart).
- Heart failure.
Intestinal tract complications may include:
- Megaesophagus (enlarged esophagus).
- Megacolon (enlarged colon).
In rare cases, young children or immunosuppressed people infected with Chagas disease develop life-threatening complications, including:
- Myocarditis (severe inflammation and infection of the heart muscle).
- Meningoencephalitis (severe inflammation and infection of the brain).
Can Chagas disease be prevented?
If you live in areas of transmission, there are several things you can do to help prevent Chagas disease. These include:
- Use insecticide spray around houses and other structures.
- Clean your home frequently.
- Use nets around beds to keep the bug away from your face.
- Be sure your food is thoroughly cleaned and fully cooked.
Outlook / Prognosis
What is the prognosis (outlook) for people with Chagas disease?
With timely treatment, most people with Chagas disease recover fully.
Frequently Asked Questions
Who should be tested for American trypanosomiasis or Chagas disease?
The following people should be screened for Chagas disease:
- If your parent had American trypanosomiasis during pregnancy or is from the endemic areas of South America or Central America.
- If you were born in the endemic areas of South America or Central America, or lived there for more than six months.
- If you live in the southern U.S. and recognize a triatomine bug.
When should I call my doctor?
Chagas disease is easily diagnosed with a blood test. Contact your doctor for this test if you:
- Live in an area where Chagas disease is common.
- Travel to areas where triatomine bugs (kissing bugs) cause Chagas disease.
- Develop any symptoms of Chagas disease.
A note from Cleveland Clinic
Chagas disease is an infection transmitted by crawling insects called kissing bugs. They live mostly in South America and Central America. Kissing bugs crawl on your face before and after they bite you, and you can be infected with the parasite if you scratch those bites. Some people develop flu-like symptoms, while others may never notice. Importantly, Chagas disease can lead to life-threatening complications.
If you live in or travel to South America or Central America, you should take precautions like using bug spray and keeping your home clean. If you were born in these areas, or have visited since, be on the lookout for symptoms of Chagas disease and follow up with your primary care provider regularly.
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