Chagas Disease (American trypanosomiasis)

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Page originally published 4/5/2024. Last updated 10/13/2025.

Chagas disease, also known as American trypanosomiasis, is caused by a parasite called Trypanosoma cruzi (T. cruzi). This parasite is spread to people and animals by bugs known as triatomine bugs (sometimes called "kissing bugs").

Chagas disease is mostly found in countries across Latin America, mainly in rural areas. However, because people are moving from rural to urban areas, Chagas disease has been found in other regions around the world, including the United States.

In California, Chagas disease has been reportable in Los Angeles County since 2019 and became reportable in San Diego County in 2024.

On this page:

Prevention
Transmission (spread)
- Kissing Bugs
Symptoms
Diagnosis & Treatment
- Chagas Disease in Animals
Resources
Information for Healthcare Professionals

Prevention

There is no vaccine, or medicine, that can prevent Chagas disease. If you plan on traveling to areas where Chagas is common take these precautions:

Sleep indoors, in safe, well-built places.
Do not sleep in housing made of adobe, mud, or thatch.
Spray places you are staying with long-lasting insecticides.
Sleep under bed nets treated with long-lasting insecticides.
Wear clothes that cover your skin and use bug spray on exposed skin.
Do not eat salads, raw vegetables, unpeeled fruits, or drink unpasteurized fruit juices.

Keeping Kissing Bugs Away from Your Home

Close all openings where bugs can get in.
Fix structural problems that allow bugs to enter. Seal any cracks or gaps.
Put a screen on all windows and vents.
Insect-proof pet entrances.
Turn lights off at night by doors, windows, and patios when not needed.
Remove rodent nests near your home.
Remove firewood piles and trash.
Check beds at night and shake out bedding.
Keep beds a few inches away from the wall.

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Transmission (Spread)

Chagas disease infects people through the bite of a certain type of bug or vector. The bug vectors are called triatomine (tri-atomine) bugs, also known as "kissing bugs" or "conenose bugs." Once the bugs are infected, they pass T. cruzi by biting people’s faces or body when they are sleeping at night. After they bite, they defecate (poop) near the bite.

Someone cannot get infected from the bite of a kissing bug. Chagas disease infection only occurs when the bug's feces get into the bite wound, eyes, or mouth by scratching or rubbing the feces.

Chagas disease can also spread through:

A pregnant woman to her baby (congenital),

Contaminated blood products (transfusions),

Organ transplants from an infected donor,

Eating uncooked food contaminated with feces from infected kissing bugs, and

Accidental laboratory exposure.

Chagas disease does not spread person-to-person through normal contact with infected people or animals.

Kissing Bugs

Kissing bugs are key in spreading Chagas disease. Most kissing bugs are found in Texas, New Mexico, and Arizona but are also found in parts of California, especially in rural foothills and mountainous areas.

In California, the most common kissing bug is called Triatoma protracta.
- About 28% of these bugs in Southern California are infected with T. cruzi.
- This bug differs from other kissing bugs because it bites and defecates (poop) after it leaves, lowering the chances of spreading the disease.
Adult kissing bugs can fly and are attracted to light, especially on warm nights. They can get into homes through cracks or holes in walls or through open windows or doors.

There are 11 types of kissing bugs in the U.S. The most common bugs are about 1-inch long with dark red stripes or yellow-orange stripes. Some, especially those found in California, may have a single, light-brown band around the outer edge of the body.

The bugs have a long, cone-shaped head with a dark brown or black body.
Their legs are thin and long.
Young kissing bugs, called nymphs, are smaller and do not have wings.

Do not touch a kissing bug with your bare hands! Use a glove or plastic bag to catch the bug.

If You Find a Kissing Bug:

If you think a kissing bug has bitten a person and you are concerned about Chagas disease, have the bug identified. There are many other bugs in California that look like kissing bugs.
If you have the bug, or photo of the bug, please contact the Epidemiology Unit at (619) 692-8499 for identification.

Safe Kissing Bug Collection

If a kissing bug is needed for testing or identification, follow safe collection methods including:

Do not touch the kissing bug with bare hands.
Handle gently to avoid crushing the bug.
Use a glove or small plastic bag to catch the bug.
Put the bug in a sealed plastic bag, vial, or small container.
Thoroughly clean all surfaces the kissing bug touched with a 10% bleach and 90% water solution.
Wash your hands thoroughly after catching the bug and dispose of any materials used.
Write down where the bug was found, date and time it was found, if the bug was alive, what it was doing when it was found, and any human exposure (e.g., bites, crawling on you, etc.).

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Symptoms

There are two phases of Chagas disease: acute and chronic. Most people with acute infection have no symptoms (asymptomatic). If left untreated, it will progress to chronic infection.

Acute phase: Occurs in the first few weeks or months after infection. Symptoms are usually mild or not there at all (asymptomatic). Symptoms include:

Fever;
Feeling tired (fatigue);
Body aches;
Headache;
Rash;
Loss of appetite;
Diarrhea;
Vomiting; and/or
Eyelid swelling (Romaña’s sign).
- Due to T. cruzi infecting the eyelid when bug feces are accidentally rubbed into the eye or into a bite near the eye.

Chronic phase: Can last for many years or a lifetime. Most people have no symptoms and remain asymptomatic. However, 20-30% of infected people develop severe problems, which may include:

Heart issues: enlarged heart, heart failure, irregular heartbeat, or sudden death.
Digestive problems: enlarged esophagus or colon, leading to trouble eating or going to the bathroom.

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Diagnosis and Treatment

Chagas disease is diagnosed using blood tests. If Chagas disease is suspected, a doctor will consider the following:

Overall health and medical history,
Signs and symptoms, and
Travel history.

If Chagas disease is diagnosed, the doctor may recommend cardiac function tests including:

Echocardiogram,
Electrocardiogram (EKG, ECG), and/or
X-ray or CT scan of the abdomen or chest.

Treatment for Chagas disease can be life-saving and occur in the acute or chronic phase. This includes:

Antiparasitic treatment to kill the parasite, and
Symptomatic treatment to manage the signs and symptoms of infection.

Most people do not need to be hospitalized during treatment.

If You Have Been Bitten by a Kissing Bug:

Wash the bite area with soap and water or disinfect it with an over-the-counter medicated cream.
Most bug bites occur in the home, often while a person is sleeping.
Bites usually happen on areas of the body that are not covered by clothes (face, neck, arms, and shoulders).
Bites are painless but may cause skin redness, itching, or swelling within 24 to 48 hours.
Call your healthcare provider and discuss your concerns. They will examine you and decide if you need the tests to confirm you have Chagas disease.
- If you do not have a healthcare provider, contact 2-1-1.

For information specific to healthcare providers, visit Chagas Information for Healthcare Professionals.

Chagas Disease in Animals

Animals can also be affected by Chagas disease. Dogs and other animals can be exposed to this disease by eating a kissing bug, being exposed to the feces of the bug, or eating the meat of an infected animal.
Dogs can develop lethargy (tiredness), vomiting, diarrhea, decreased appetite, or sudden death after exposure. Over time, dogs can develop heart disease or other problems with their internal organs. Less is known about the effects T. cruzi can have on other species of animals.
The same prevention methods mentioned above will also keep your pet safe.

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