What is Chagas disease?

Chagas disease is a parasitic infection caused by Trypanosoma cruzi. Without treatment, it can remain silent for years and, in some people, lead to serious heart or digestive complications. It is a leading cause of parasitic heart disease in the Americas.

How do “kissing bugs” spread it?

Kissing bugs (also called triatomines) are nocturnal, blood-feeding insects attracted to light and carbon dioxide. They commonly bite exposed skin around the face—hence the nickname. Transmission usually happens when:

• A bug carrying T. cruzi feeds and defecates near the bite, and parasite-laden feces enter through the bite wound, eye, or a mucous membrane—often via rubbing or scratching.
• Less common routes include congenital transmission (during pregnancy), blood transfusion or organ transplantation (US blood supply is now screened), and food contamination in rare outbreaks.

In the US, housing quality and the behavior of local triatomine species reduce (but do not eliminate) the risk compared with some areas of Latin America.

Where is it found in the US?

Triatomine bugs and animal reservoirs (such as opossums, raccoons, armadillos, and dogs) are established across much of the southern half of the country, with species documented in at least two dozen states from the Southwest through the Gulf Coast and into parts of the Southeast and Mid-Atlantic.

Locally acquired human infections have been reported in several southern states (for example, Texas and neighboring regions). The overall risk for the average person in the US remains low, but researchers consider the parasite’s life cycle to be established (endemic) in certain areas.

How common is infection?

Estimates suggest hundreds of thousands of people living in the US may carry T. cruzi, the majority having acquired it in Latin America before moving to the US. A smaller number of infections have been acquired locally. Because early infection is often silent, many people are unaware they are infected.

Who is at highest risk?

• People living in or frequently visiting rural or wooded areas in the southern US where triatomines, wildlife reservoirs, and outdoor shelters (sheds, kennels) provide habitat.
• Homes with gaps, cracks, or unscreened windows/doors that allow bugs to enter, especially structures with outdoor lighting that attracts insects.
• Dogs kept outdoors or in kennels; working and sporting dogs in endemic regions have documented risk.
• People from or who have spent extended time in endemic Latin American countries.
• Pregnant people with current or past exposure (because of possible congenital transmission).

Symptoms: what to watch for

Acute phase (weeks to months after infection)

• Often none or mild, flu-like illness: fever, fatigue, body aches.
• Swelling at the bite site (chagoma) or one-sided eyelid swelling (Romaña sign) if contamination occurs near the eye.
• Enlarged lymph nodes, liver, or spleen can occur.

Chronic phase (years later in a subset of people)

• Heart problems: conduction abnormalities, arrhythmias, cardiomyopathy, heart failure, stroke risk.
• Digestive complications in some: difficulty swallowing (megaesophagus) or severe constipation (megacolon).
• Many remain asymptomatic but still carry the parasite.

Early diagnosis improves chances of clearing the parasite and preventing complications.

What about pets?

Dogs can become infected and may develop serious heart disease. Reduce outdoor kennel exposure, remove harborage (woodpiles, brush), and talk with your veterinarian if you live in or travel to endemic areas. There is no approved vaccine for pets.

Prevention: reducing your risk

• Bug-proof your home: seal cracks and gaps; repair screens; use weather stripping; close gaps around utility lines.
• Manage lighting: reduce outdoor lighting near sleeping areas; use yellow “bug” bulbs where lighting is needed.
• Remove harborage: clear brush, woodpiles, and rock piles near the home; keep yards tidy.
• Protect sleeping areas: in rustic settings, consider bed nets; keep pets’ sleeping areas off the ground and away from walls.
• Handle suspect insects safely: do not crush against your skin. If safe to do so, capture in a container, or take a clear photo for identification.

Found a possible “kissing bug” or think you were exposed?

• Do not touch bare-handed. Use gloves or a plastic bag to avoid contact with potential feces.
• Save the insect (if possible) in a sealed container. Freezing the insect can preserve it for identification.
• Contact local experts: your state or county health department, cooperative extension office, or a nearby university entomology lab may assist with identification and testing of insects.
• If you develop illness after a suspected exposure, seek medical care and mention possible triatomine exposure.

Testing and treatment

• Diagnosis:
  • Acute infection: PCR or parasite detection in blood; time-sensitive.
  • Chronic infection: typically requires two different antibody tests performed at a qualified lab.
• Treatment:
  • Benznidazole and nifurtimox (Lampit) are antiparasitic drugs available in the US. They are most effective in acute and early chronic infection and may benefit many chronically infected people.
  • Side effects can occur; treatment decisions—especially in older adults or those with advanced heart disease—are individualized. Consultation with an infectious diseases specialist is recommended.
• Blood and organ safety: US blood donations are screened for T. cruzi, greatly reducing transfusion risk.
• Pregnancy: People who may have been exposed should discuss testing; infants born to infected mothers can be tested and treated early if needed.

Myths vs. facts

• Myth: All household bugs spread Chagas. Fact: Only triatomines transmit T. cruzi. Common bed bugs do not transmit Chagas disease.
• Myth: A bite alone causes infection. Fact: Infection typically requires contact of parasite-laden feces with a bite, eye, or mucous membrane.
• Myth: There’s nothing you can do. Fact: Home sealing, sensible lighting, yard cleanup, and safe bug handling significantly reduce risk.

When to seek medical care

• You have a suspected kissing-bug exposure followed by fever, facial swelling, or a new skin lesion at the bite area.
• You are from, or spent significant time in, an endemic area and have unexplained heart symptoms (palpitations, fainting, chest pain) or digestive issues.
• You are pregnant and think you may have been exposed in the past.

Tell your clinician about possible Chagas exposure; testing protocols are specific and may require specialized labs.

Learn more

• CDC: Chagas Disease – https://www.cdc.gov/parasites/chagas/
• CDC: Kissing Bugs (Triatomines) – https://www.cdc.gov/parasites/chagas/gen_info/vectors/
• Your state or local health department and cooperative extension programs for insect identification and local risk guidance.