Chagas disease

If you were born outside of Canada or your mother or maternal grandmother was born outside of Canada, or if you have travelled or resided in Latin America, including Mexico, for 30 or more consecutive days, the blood you donate will be tested to determine whether you are a carrier of Chagas disease.

What is chagas disease?

Chagas disease is an infectious illness rife in Central and South America. It is caused by a parasite transmitted by the bite of an hematophagous insect (feeds on blood) called Triatoma infestans.

Endemic areas for this infection extend from Mexico to the south of Argentina (excluding the Caribbean islands). The parasite is found mainly in rural areas, especially in populations living in primitive dwellings (especially those made of adobe, which consists of a mixture of straw and mud).

Latin America countries affected by the selection criterion

• Argentina 
• Belize 
• Bolivia 
• Brazil 
• Chile 
• Colombia 
• Costa Rica 
• Ecuador 
• Guatemala 
• Guyana 
• French Guiana 
• Honduras 
• Mexico 
• Nicaragua 
• Panama 
• Paraguay 
• Peru 
• El Salvador 
• Suriname 
• Uruguay 
• Venezuela

Transmission of the disease

It is transmitted mainly by a bite from Triatoma infestans (insect). The parasite can also be transmitted by blood transfusion, organ transplant, and in the case of pregnant women, from mother to child via the placenta. A person carrying this disease will be contagious for life.

Symptoms

The first symptoms, flu-like (fever, swelling of the lymph glands, etc.), generally appear within thirty days. After this 4-6 week phase, the infection becomes asymptomatic, i.e. the person has no specific symptoms. A mortality rate of 1% in the acute phase has been reported. However, the infected person will remain chronically infected if not treated. Moreover, in the succeeding decades, 10-30% of infected persons will develop severe complications, mainly cardiac and gastrointestinal.

Treatment and prevention

People infected with the disease can be treated with an antiparisitic, for which they will need to be hospitalized. Treatment to relieve the symptoms is also available.

There is no vaccination or preventive treatment against the disease. Apart from eradication of the vector insects (use of insecticides and improved living conditions), the main means of prevention is the use of a mosquito net over the bed.

Measures instituted by Héma-Québec to ensure the safety of the blood supply for Quebecers

Following the introduction of this new selection criterion, ALL blood donors must answer the following questions added to the record of donation:

1. Were you born outside of Canada? 
2. Was your mother or maternal grandmother born outside of Canada?  
3. Have you travelled to or resided in Latin America (including Mexico) for 30 consecutive days or more?

On a first donation, if a blood donor answers yes to any one of these three questions, a sample of the donor’s blood will be sent to the laboratory to be screened for Chagas disease. For subsequent donations, a positive answer to the third question will automatically lead to a laboratory screening test on the donated blood.

If the result is negative, the blood donation can be used for transfusion and the person can continue to donate blood. If the result is positive, the donation will be destroyed, the sample will undergo further tests to confirm the infection, and the donor will be informed and referred to a medical resource for clinical follow-up.

This criterion also applies to donors on the Stem Cell Donor Registry and to human tissue donations. As for cord blood donations, a sample of each donation will be systematically sent to the laboratory for screening.

Will many donors be affected by this new measure?

According to a survey conducted by Héma-Québec, few donors or donor’s mother or maternal grandmother come from the endemic countries. They represent 0.6% of donors. It is also estimated that 2.8% of donors have visited endemic areas for periods of longer than one month.