American Trypanosomiasis or Chagas Disease

June 2001

Know before you go!

Infectious diseases not necessarily common in Canada can occur and may even be widespread in other countries. Standards of hygiene and medical care may differ from those at home. Before departure, you should learn about the health conditions in the country or countries you plan to visit, your own risk of disease and the steps you can take to prevent illness.

The risk is yours
Your risk of acquiring a disease depends on several factors. They include: your age, gender, immunization status and current state of health; your itinerary, duration and style of travel (e.g., first class, adventure) and anticipated travel activities (e.g., animal contact, exposure to fresh water, sexual contact); as well as the local disease situation.

Risk assessment consultation
The Public Health Agency of Canada strongly recommends that your travel plans include contacting a travel medicine clinic or physician 6 to 8 weeks before departure. Based on your individual risk assessment, a health care professional can determine your need for immunizations and/or preventive medication (prophylaxis) and advise you on precautions to avoid disease.

Some facts from the experts
The information below has been developed and is updated in consultation with Public Health Agency of Canada's Committee to Advise on Tropical Medicine and Travel (CATMAT). The recommendations are intended as general advice about the prevention of American trypanosomiasis for Canadians travelling internationally.

Disease profile

American trypanosomiasis is a serious disease that leads to chronic progressive heart disease in approximately 20% to 40% of infected persons. It is also known as Chagas disease, having been named after the Brazilian physician Carlos Chagas who first described it in 1909. It is one of the leading causes of sudden death after coronary heart disease. Chagas disease occurs in roughly 150 species of wild and domestic animals and is transmitted to humans by the Trypanosoma cruzi parasite. Chagas disease exists only on the American Continent. A related disease called African trypanosomiasis, or sleeping sickness, is limited to sub-Saharan Africa.

Transmission

Chagas disease is transmitted to humans in three ways:

1) through the bite of an infected triatomine insect (a blood-sucking, predatory bug of the Reduviidae family), popularly known as "vinchuca", "barbeiro", "chipo", "assassin bug", etc. The insects tend to infest poor housing, especially made of mud, adobe or thatch. The infected bug deposits its feces, which are laden with the T. cruzi parasite at the time of biting, usually at night. The feces can then be rubbed accidentally by the individual into the bite wound or another open wound, the eyes or mouth.

2) by transfusion of infected blood or organ transplants;

3) during pregnancy or at delivery, an infected mother can pass on the disease to her baby.

Geographic distribution

Chagas disease is endemic in 21 countries in the southern Western Hemisphere (Mexico, Central and South America), where 16 to 18 million people are infected and 100 million people are at risk. The insects that transmit the parasite live in wall crevices and roofs of houses in poorer rural areas and urban slums. With the rural/urban migrations of the 1970s and 1980s in Latin America, Chagas disease has become an urban infection as a result of blood transfusion transmission.

Symptoms

Chagas disease occurs in two phases: the acute stage appearing shortly after infection and the chronic stage appearing 10 to 20 years after infection. Most people who have been infected with Chagas disease do not have symptoms until they reach the chronic stage, and some never develop symptoms at all.

Acute symptoms occur rarely and mostly in children, lasting 4 to 8 weeks before disappearing even without treatment. Symptoms may include fever, fatigue, enlarged liver or spleen and swollen lymph glands. In some cases, eye swelling (or, Romaña sign) may occur usually where a bite was received or where feces were rubbed into the eye. Infants in the acute stage of Chagas disease may experience brain swelling, which can lead to death.

Chronic symptoms develop after a long symptom-free (or silent) period. Irreversible damage to the internal organs - the heart, esophagus, colon and to the peripheral nervous system - can occur. For individuals with compromised immune systems (such as those living with HIV/AIDS), the effects of Chagas disease can be severe.

Treatment

Medication is available for the treatment of Chagas disease. Treatment should begin as soon as possible following exposure as it is most effective during the acute stage of the infection. Once the chronic stage is reached, there is no effective treatment; only the related conditions, such as heart disease, can be treated or managed. The disease is diagnosed through blood tests.

Prevention and personal precautions

There is no vaccine for the prevention of American trypanosomiasis or Chagas disease.

Recommendations

Public Health Agency of Canada advises travellers to Chagas-endemic areas (e.g., rural areas of Mexico, Central and South America), particularly with accommodation in sub-standard housing made of mud, adobe or thatch, are at the greatest risk for illness and should take personal insect precautions. Travellers intending on staying in well-constructed facilities, such as resorts and hotels, are not at high risk for this disease.

Personal insect precautions
Measures to reduce exposure to biting insects include:

Housing:

• Avoid staying in poorly constructed housing such as mud, adobe or thatch structures.

Protective clothing:

• Wear thick clothing that reduces the amount of exposed skin, such as heavy long-sleeved shirts, long pants, socks and shoes.

Screens and bed nets:

• Sleep inside screened areas, under a bed net or in an air-conditioned room.
• Use bed nets that are rectangular in size, impregnated with permethrin* every 6 months and tucked tightly under the mattress before dusk (note: treated bed nets are available in Canada).

Other measures:

• Avoid blood transfusions in countries where Chagas disease is endemic.
• Insect repellent has not been proven to prevent the triatomine insect bites.

Some things to think about...

Travellers to a Chagas disease-endemic country and intending on staying in rural areas in poor accommodations should ensure they meet with a physician or travel medicine clinic for a personal risk assessment before departure.

For more information...

• World Health Organization (WHO): Chagas disease
• Chagas disease (Special Programme for Research and Training in Tropical Diseases, TDR)
  
• For more Know before you go! information, click here.