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Chagas Disease/American Trypanosomiasis

Chagas Disease, also known as American trypanosomiasis, is not a reportable disease in Oklahoma; however, the Oklahoma State Department of Health investigates outbreaks of  Chagas Disease to control the spread of this disease.  Chagas disease is caused by the parasite Trypanosomac cruzi.  An estimated 16 to 18 million people worldwide are infected with Chagas disease.  Of those infected, 50,000 will die each year.  It is most commonly seen in South America, Middle America, and Mexico.

Anyone living in or visiting Chagas endemic areas is potentially susceptible.  Persons at highest risk of getting the disease include laboratory personnel working in Chagas disease research and people who regularly sleep in poorly constructed housing made from mud, adobe, or thatch found in the rural areas of Central and South America.

American trypanosomiasis is spread by Triatome bugs (or “kissing’ bugs) that live in cracks and holes of substandard housing from the southern United States to southern Argentina.  Unlike other arthropod-borne diseases, the parasite is not passed to humans directly by the bite of the infected insect.  Triatome bugs defecate while blood-feeding, and if the insect is infected with the parasite, the parasite can enter the bloodstream when the host scratches the bite wound.

People can also become infected with Chagas by:

  • Unknowingly touching their eyes, mouth, or open cuts after having come into contact with infective triatome bug feces,
  • Bugs directly depositing infected feces in their eyes,
  • Eating uncooked food contaminated with triatome bug feces,
  • Receiving infection from mother during pregnancy or at birth, and
  • Receiving an infected blood transfusion or organ transplant.

The disease can cause different symptoms depending on the location of the parasite in muscle tissue.  Acute symptoms only occur in about one percent of infected individuals.  Symptoms of acute disease include fever, malaise, swollen lymph nodes and Romanas sign, an obvious swelling of the eye and surrounding area at the site of exposure.  Asymptomatic infections are thought to be common.  Chronic symptoms of the disease develop in approximately 20 to 30 percent of infected individuals.  This stage occurs years after the exposure and may include abnormal enlargement of the esophagus or colon and congestive heart failure.  Persons with weakened immune systems may have more severe symptoms.

If symptoms develop, they may occur between 5 and 14 days after the insect bite. If exposed through a blood transfusion, symptoms may develop in 30 to 40 days. Most people do not have symptoms until the chronic stage of infection, 10 to 40 years after first being infected.  T.cruzi, the parasite that causes American trypanosomiasis, may remain in the body throughout the person's lifetime.

Medication for Chagas disease is usually effective when given during the early acute stage of infection. Once the disease has progressed to later stages, medication may be less effective. In the late chronic stages of infection, treatment focuses on managing the symptoms associated with the disease.

How to prevent Chagas disease:

  • Avoid sleeping in thatch, mud, or adobe houses.
  • If traveling to a country with high levels of disease, sleep inside screened areas, under a permethrin-impregnated bed net, or an air-conditioned room.
  • Avoid insect bites.
  • Use insecticides to kill bugs and reduce the risk of transmission.
  • Wash and cook any food that could be contaminated with insect feces.
  • Remain aware that, in some countries, the blood supply may not always be screened for American trypanosomiasis and blood transfusions may carry a risk of infection.

American Trypanosomiasis Fact Sheets and Information:

American Trypanosomiasis/Chagas Disease Fact Sheet (67k.pdf)

External American Trypanosomiasis Resources:

American Trypanosomiasis - Chagas Disease (CDC)

Chagas Disease (Medline Plus)
African Trypanosomiasis - Sleeping Sickness (CDC)
African Trypanosomiasis (WHO)


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