Chagas Disease

There are two phases of Chagas disease: acute and chronic. Both phases can be symptom-free or life-threatening.

The acute phase of the disease occurs during approximately the first 8 weeks of infection. Symptoms, if present, may include:

• Fever

• Malaise

• Body aches

• Rash

• Headache

• Loss of appetite

• Vomiting

• Diarrhea

• Localized swelling (“chagoma”) where the parasite entered the body

People with acute illness may also have mild enlargement of the liver or spleen. They may also have swollen lymph nodes and other less common findings. The most recognized sign of acute Chagas disease is Romaña's sign. This is swelling of the eyelids on the side of the face near the bite wound or where bug feces entered the eye. Symptoms of acute illness can last weeks to months and then disappear, even without treatment. The acute phase of the disease may go unnoticed because it often causes no symptoms or only mild symptoms.

The chronic phase of the disease follows the acute phase and includes a form without symptoms (“indeterminate” or “latent” infection) and another form with symptoms. The majority of people in the chronic phase will remain symptom-free for life, but 20-30% will develop symptomatic illness, including:

• An enlarged heart (cardiomyopathy), heart failure, altered heart rate or rhythm, or sudden death

• An enlarged esophagus (megaesophagus) or enlarged colon (megacolon), which can cause difficulties eating or having bowel movements

The T. cruzi parasite is transmitted in the feces of blood-feeding triatomine bugs (also called reduviid bugs, kissing bugs, or cone-nosed bugs). The triatomine bug vectors usually become infected after feeding on an infected animal or, more rarely, a person. After the organism reproduces in the bug, it can spread to people if the infected bug defecates while feeding on them. This usually happens while the person is sleeping at night, and the person rubs the feces into the bite wound, an open cut, or a mucous membrane.

People also can become infected through:

• Congenital transmission (from a pregnant woman to her baby)

• Blood transfusion

• Organ transplantation

• Consumption of beverages or uncooked food contaminated with feces from infected bugs

• Accidental laboratory exposure

Chagas disease is not transmitted from person to person like a cold or the flu, or through casual contact with infected people or animals.

Contact your medical provider if you think you have Chagas disease, have been exposed to a triatomine bug, or share risk factors with a family member who has Chagas disease. Your medical provider will conduct a thorough physical exam and ask you about risk factors for infection. It will be important to tell your provider if you traveled to areas where Chagas disease is common. Your provider will also test your heart rhythm and order blood tests. If tests show infection, drugs are available for treatment. A cure is not always possible. These drugs may cause significant side effects that some people may not tolerate.

Blood banks screen first-time blood donors for evidence of T. cruzi infection. Donors who test positive are notified by the blood bank and should consult their medical provider for evaluation and more laboratory testing. Potential blood donors infected with T. cruzi should not donate blood or tissues for the rest of their lifetime.

T. cruzi infection has been reported in dogs in Texas and several other states, including Louisiana and Oklahoma. Infections in domestic cats have been reported in South America, but not in the U.S. In Texas, infection in dogs occurs more often in Central and South Texas. Outdoor dogs are at much higher risk due to their outdoor exposure, the likelihood of infestation of outdoor kennel areas, and the tendency for some dogs to eat triatomine bugs. Studies conducted in South Texas in 1999 found that 7.5% of the stray dogs tested were positive for the parasite. Infection in coyotes has also been reported. If you think your dog may have been infected, contact your veterinarian. Your veterinarian will be able to examine your dog and collect blood samples for laboratory testing. Currently, there are no drugs available in the U.S. to treat dogs infected with T. cruzi.

When traveling to areas with a high risk of infection, it's important to take preventive measures. This can help reduce the likelihood of getting bitten by disease-carrying insects and lower the risk of getting infected.

Some measures include:

• Using bed nets that are treated with long-lasting insecticides

• Wearing protective clothing that covers your skin

• Applying insect repellent to the exposed areas of your body.

To reduce the risk of transmission to animals and humans in the U.S.:

• Keep yard and kennel areas clean to get rid of habitat for the bugs; remove brush piles, rock piles, excessive buildup of leaf litter, etc.

• Control rodents to remove a potential food source that may sustain populations of bugs in the yard

• Turn off outdoor lights at night so that bugs aren’t attracted to the house and yard

• Identify and seal entry points for the bugs into the home and consider the appropriate use of a long-lasting insecticide

• Keep pet food and water bowls inside to prevent contamination with feces from the infected bugs

• Keep dog houses and poultry coops clean, fill in crevices where the bugs might hide, and consider the appropriate use of long-lasting pesticides in and around these structures

For additional information about Chagas disease in Texas, please contact the DSHS Zoonosis Control program at the.vet@dshs.texas.gov.

Find more detailed information about Chagas disease on the following websites:

• U.S. Centers for Disease Control and Prevention (CDC)
• Pan American Health Organization
• World Health Organization

• Downloadable Information Guide – “Kissing Bugs and Chagas Disease: What You Need to Know”

  • English (PDF, 2.3 MB)
  • Spanish (PDF, 1.7 MB)