Fast facts: Chagas Disease
Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening condition transmitted by triatomine bugs, or “kissing bugs.” While Chagas disease is more prevalent in the tropics and Latin America, the Centers for Disease Control and Prevention (CDC) estimates that more than 300,000 persons with Trypanosoma cruzi infection live in the United States.
What is Chagas disease?
Kissing bugs (or the triatomine bug)—aptly named for the region they bite (around the eyes and mouth)—carry the parasite Trypanosoma cruzi (T.cruzi), which causes Chagas. The disease is known as a “silent killer” because the infection can remain dormant in the bloodstream for decades. However, around 30 percent of people with the disease may eventually suffer from serious cardiac or intestinal complications.
How is it contracted?
Transmission is mostly due to a bite from the triatomine bug or “kissing bug.” Kissing bugs become a vector for Chagas after they feed on an animal or person infected with the T. cruzi parasite. At night, they become active and feed on human blood. Kissing bugs normally bite an exposed area of skin, such as the face and then defecate close to the bite. T.cruzi parasites enter the body when a person instinctively smears the bug feces into the bite, the eyes, the mouth or into any skin break. T.cruzi can also be spread through:
- consumption of food contaminated with cruzithrough contact with infected triatomine bug feces,
- blood transfusion from infected donors,
- passage from an infected mother to her newborn during pregnancy or childbirth,
- organ transplants using organs from infected donors, and
- laboratory accidents
What are the symptoms of Chagas disease?
Chagas disease presents in two phases: the acute phase and the chronic phase. Both phases can be symptom free or life threatening.
The acute phase lasts for the first few weeks or months of infection. It usually goes unnoticed because it is symptom free or exhibits only mild symptoms and signs that are not unique to Chagas disease. The symptoms can include:
- body aches,
- loss of appetite,
- and vomiting.
The signs on physical examination can include mild enlargement of the liver or spleen, swollen glands, and local swelling (a chagoma) where the parasite entered the body. The most recognized marker of acute Chagas disease is called Romaña’s sign, which includes swelling of the eyelids on the side of the face near the bite wound, or where the bug feces were deposited or accidentally rubbed into the eye. Even if symptoms develop during the acute phase, they usually fade away on their own, within a few weeks or months. Although the symptoms resolve, the infection will persist if left untreated.
During the chronic phase, the infection may remain silent. However, some people develop:
- cardiac complications, which can include an enlarged heart (cardiomyopathy), heart failure, altered heart rate or rhythm, and cardiac arrest (sudden death); and/or
- intestinal complications, which can include an enlarged esophagus (megaesophagus) or colon (megacolon) and can lead to difficulties with eating or with passing stool.
The average life-time risk of developing one or more of these complications is about 30 percent.
Can it be treated?
There are two approaches to therapy, both of which can be life-saving:
- antiparasitic treatment, to kill the parasite; and
- symptomatictreatment, to manage the symptoms and signs of infection.
Antiparasitic treatment is most effective early in the course of infection but is not limited to cases in the acute phase. In the United States, this type of treatment is available through Centers for Disease Control and Prevention (CDC). Your health care provider can talk with CDC staff about whether and how you should be treated. Most people do not need to be hospitalized during treatment.
Symptomatic treatment may help people who have cardiac or intestinal problems from Chagas disease. For example, pacemakers and medications for irregular heartbeats may be life saving for some patients with chronic cardiac disease.
What should I do if I think I have Chagas disease?
You should discuss your concerns with your health care provider, who will examine you and ask you questions (for example, about your health and where you have lived). Chagas disease is diagnosed by blood tests. If you are found to have Chagas disease, you should have a heart tracing test (electrocardiogram), even if you feel fine. You might be referred to a specialist for more tests and for treatment.
How do I keep kissing bugs out of my home?
Kissing bugs typically live in the cracks of poorly constructed homes in rural or suburban areas, but they are also found beneath porches, between rocky structures, in wood or brush piles, and in outdoor dog houses and kennels or chicken coops.
Long lasting insecticide treated bednets and curtains have been show to kill these bugs. In the United States, a licensed pest-control operator should be consulted if considering the use of insecticides around the home. Roach motels or other “bait” traps do not work against kissing bugs.
Experts stress if a kissing bug is found in your home you should never handle it with your bare hands.
Other precautions to prevent a house infestation include:
- Sealing cracks and gaps around windows, walls, roofs, and doors
- Removing wood, brush, and rock piles near your house
- Using screens on doors and windows and repairing any holes or tears
- If possible, making sure yard lights are not close to your house (lights can attract the bugs)
- Sealing holes and cracks leading to the attic, crawl spaces below the house, and to the outside
- Having pets sleep indoors, especially at night
- Keeping your house and any outdoor pet resting areas clean, in addition to periodically checking both areas for the presence of bugs
To learn more about how to safely identify kissing bugs visit kissingbug.tamu.edu.This site features an interactive map on their whereabouts in Texas and posts updates and precautions associated with kissing bugs and Chagas disease.
Scott Lillibridge, M.D., is a professor at the Texas A&M Health Science Center School of Public Health and deputy principal investigator and chief scientist for the Texas A&M Center for Innovation in Advanced Development and Manufacturing. Dr. Lillibridge is a 30-year veteran in medical and public health preparedness who previously served as founding director of the Centers for Disease Control and Prevention Bioterrorism Preparedness and Response Program and also worked as Special Assistant to the Secretary for the U.S. Department of Health and Human Services. Dr. Lillibridge served as Medical Director of the U.S. Office of Foreign Disaster Assistance. He currently serves on the Institute of Medicine’s Health Threats Resilience Sub-Committee, offering expertise in refugee health and civil conflict, biodefense and bioterrorism, public health preparedness and response, and global health and development. He also serves on the Texas Task Force on Infectious Disease Preparedness and Response, which was created in response to the Ebola outbreak in the U.S.
Featured image credit: Gabriel L. Hamer