Chagas disease is widely endemic throughout Central and South America, and parts of Mexico, where the main mode of transmission is exposure to infected triatomine (or riduviid) bugs; in these regions. The parasite (a Protozoan flagellate) can also be transmitted in utero although this is rare. Most initial infections occur in childhood, are asymptomatic or cause non-specific, flu-like symptoms and are not diagnosed. Chronic T. cruzi infection can cause serious complications of the heart and gastrointestinal tract in approximately 30 per cent of infected individuals. Treatment which may alter the natural course or progression of the disease is available.

Canadian Blood Services has implemented three additional questions to the blood donor screening questionnaire, to assess a donor's potential risk of exposure to Chagas' disease. Donors are asked if they have spent at least six continuous months in Mexico, Central or South America, and if they, or their mother or grandmother were born in these regions. If a donor answers yes to a Chagas risk question, then as a precaution, platelets and frozen plasma for transfusion are not produced from that donor. Donors who answer yes to a Chagas risk question also have their blood tested for the presence of T. cruzi antibodies.