American Trypanosomiasis (Chagas disease)

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What is American trypanosomiasis (Chagas disease)?

American trypanosomiasis, more commonly known as Chagas disease, is caused by a parasite spread by infected triatomine bugs.

Chagas disease has two phases. The first phase occurs right after infection and can be mild. The second phase can occur decades later and can cause disability or even death.

Cause 

  • Chagas disease is caused by a parasite called Trypanosoma cruzi.

Risk to Travellers     

  • Risk for most travellers is low.
  • Risk is higher for travellers who are:
    • visiting or living in rural areas.
    • sleeping in poorly-constructed housing (for example, housing with cracked walls, mud walls, or thatched roofs).
    • sleeping outdoors.
  • There is also a minimal risk of being infected with Chagas disease by eating/drinking contaminated food or drinks.

Severity

  • The first (acute) phase of the disease is usually mild.
  • The second (chronic) phase of the disease can be severe, with infected people developing chronic heart and digestive problems that can be life-threatening.
  • Chagas disease can be more severe in immunosuppressed individuals.

Prevention

  • There is no vaccine or medication that can prevent Chagas disease.
  • Preventing triatomine bug bites is the best way to prevent this disease.
    • Avoid sleeping in poorly-constructed housing or sleeping outdoors.
    • If sleeping in poorly-constructed housing or sleeping outdoors cannot be avoided, sleep under a bed net, preferably one treated with insecticide.
  • Practise safe food and water precautions.
  • Avoid blood transfusions and organ transplants in areas where Chagas disease occurs, if at all possible.

Treatment

  • There are medications available to treat Chagas disease.
  • The medical problems that can develop in the chronic phase of Chagas disease cannot be treated, but there are medications available to manage some of the symptoms.  

Symptoms

Chagas disease occurs in two phases. Each phase has different symptoms.

First (acute) phase:

  • Symptoms of the disease occur one or more weeks after the triatomine bug bite.
  • Symptoms are usually mild or do not occur at all, but can cause death in rare cases.
  • Acute symptoms include:
    • swelling around the infected bite (called a chagoma)
    • swelling around the eye (called the Romaña’s sign)
    • fever
    • headache
    • swollen lymph nodes
    • muscle pain
    • enlargement of liver and spleen (hepatosplenomegaly)
    • difficulty breathing
    • in rare cases, swelling of the heart or brain. These symptoms generally occur more often in children, the elderly, and the immunocompromised.

Second (chronic) phase:

  • Most people do not have symptoms, but still remain infected.
  • Some people will have symptoms but these usually appear many years (10-30 years) after the initial infection.
  • These symptoms, which can be life-threatening, include:
    • enlargement of the esophagus (throat)
    • enlargement of the colon
    • enlargement of the heart, which can cause heart failure and abnormal heart beat rhythms (arrhythmia)

Transmission

  • Chagas disease is most commonly spread through the infected feces of a triatomine bug, also called a “kissing bug” or reduvid bug.
    • Triatomine bugs are most active at night and hide in cracks in poorly-constructed houses.
    • Triatomine bugs feed on human blood. After they bite, they deposit feces close to the bite.  
    • The feces of infected triatomine bugs carry the Trypanosoma cruzi parasite that causes Chagas disease.
    • When a person touches the bite, they accidentally rub the infected feces into the bite. A person can also inadvertently rub infected triatomine feces into any skin break, like a scratch or open wound, or into the eyes, nose, or mouth.
  • Less commonly, Chagas disease can also be spread:
    • through a blood transfusion or organ transplant from an infected donor.
    • from an infected mother to her baby during pregnancy or delivery.
    • by food or drinks contaminated with infected triatomine feces.

Where is American trypanosomiasis (Chagas disease) a concern?

Chagas disease occurs in Mexico, Central America, and South America.

The triatomine bug is found mainly in areas with poorly-constructed housing.

Recommendations for travellers

Consult a doctor, nurse or health care provider, or visit a travel health clinic preferably six weeks before you travel.

  1. Protect yourself from triatomine bug bites. 
  2. Practise safe food and water precautions.
  3. In areas where Chagas disease occurs, avoid blood transfusions and organ transplants unless it is an emergency.
    • If you must receive a blood transfusion while travelling, try to ensure the donated blood has been tested for Chagas disease.
    • If you cannot ensure the blood or organ has been screened, and you do not require emergency care, return home for treatment.
  4. Know the symptoms of Chagas disease and see a health care provider if they develop.
    • Chronic symptoms of Chagas disease may develop years after visiting a region where the disease occurs.
    • Tell your healthcare provider that you have travelled to a region where Chagas disease occurs.

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