Chagas disease in Canadian blood donors: 15 years of selective testing

Chagas disease (Trypanosoma cruzi), prevalent in Mexico, Central and South America, can be transfusion-transmitted. Selective serological testing of blood donors was implemented over 15 years ago. We describe the trends in infections and characteristics of donors selected for testing.

Donor selection for testing was based on birth in Latin America and/or mother/grandmother born in Latin America and/or travel to Latin America (30 days duration at Héma-Québec [HQ], 6 months at Canadian Blood Services [CBS]). All first-time donors (2010-2024) were analysed. Frequencies were compiled by gender, age group, region and residential material deprivation and ethnocultural composition indices. Multiple logistic regression compared donors with risk factors (tested) versus those without risk factors (not tested).

Of the 67,490 tested donors, most were born in Mexico, Central or South America (71% at CBS). Of the 27 donors positive for T. cruzi antibodies, more were from Ontario, materially deprived and ethnocultural concentrated neighbourhoods. One had mother/grandmother birth, but none had travel as the sole risk factor. Tested donors were similar to non-tested donors except more likely to be aged 30-49 (odds ratio [OR] 1.4, 1.37-1.44 CBS, 1.57, 1.51-1.63 HQ) and live in more ethnoculturally concentrated neighbourhoods (OR 2.09, 2.01-2.18 CBS, 3.46, 3.29-3.64 HQ).

Birth in Latin America captures most T. cruzi antibody positive donations. Mother/grandmother risk occasionally yields a positive donation, but travel history does not. Infections in donors are rare, but selective testing interdicts a small risk of T. cruzi positive blood products being released into inventory.