Selective testing for Trypanosoma cruzi: the first year after implementation at Canadian Blood Services.

BACKGROUND: Various testing strategies may reduce the risk of Chagas disease transmission in nonendemic, low-prevalence countries. Results of the first year of selective testing of at-risk donors at Canadian Blood Services are reported. STUDY DESIGN AND METHODS: Since February 2009, platelets were not produced from at-risk donors. Since May 2010, at-risk donors were tested for Trypanosoma cruzi antibodies. Donors testing positive were interviewed about risk factors, and lookback studies were initiated. RESULTS: There were 7255 at-risk donors of 421,979 donors screened (1.72%). Risk factors were born in Latin America (50.6%), mother or maternal grandmother born in Latin America (28%), and 6 months or more travel history or residence in Latin America (19%). Sixteen (16) at-risk donors had T. cruzi repeat-reactive test results of whom 13 confirmed positive. Eleven of 13 were born in Latin America (nine in Paraguay and two in Argentina), and the other two were born in Canada but had short-term travel history and mothers who had been born in Latin America. Ten of the donors spoke German as their first language (all of those born in Paraguay and one born in Canada). There were 148 previous donations (176 components transfused) evaluated by lookback, of which 28% of recipients could be tested. None were positive. CONCLUSION: Selective testing has mitigated a small risk to the blood supply with very few false-positive results. Most positive donors were born in a risk country, with a concentration of German-speaking immigrants from Paraguay. Residency or travel alone were not clear risk factors.

A case of vertical transmission of Chagas disease contracted via blood transfusion in Canada.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is endemic in many countries in Latin America, where infected bugs of the Triatominea subfamily carry the parasite in the gut and transmit it to humans through fecal contamination of a bite. However, vertical transmission and transmission through blood transfusion and organ transplantation is well documented. Increasing immigration from endemic countries to North America has prompted blood operators, including Canadian Blood Services and Hema Quebec, to initiate blood donor testing for Chagas antibody. In the present report, an unusual case of vertical transmission from a mother, most likely infected through blood transfusion, and detected as part of a concurrent seroprevalence study in blood donors is described.

La maladie de Chagas est causée par le parasite protozoaire Trypanosoma cruzi. Elle est endémique dans de nombreux pays d'Amérique latine, où des insectes infectés de la sous-famille des Triatominea sont porteurs du parasite dans leur intestin et le transmettent aux humains par contamination fécale secondaire à une morsure. Cependant, la transmission verticale, par transfusion sanguine et par transplantation d'organe, est bien étayée. L'immigration croissante de pays endémiques en Amérique du Nord a incité les organismes transfusionnels, y compris la Société canadienne du sang et Héma-Quebec, à amorcer le dépistage de l'anticorps de la maladie de Chagas dans le sang des donneurs. Dans le présent rapport, les chercheurs décrivent un cas inhabituel de transmission verticale par la mère, probablement infectée par une transfusion sanguine, dépistée dans le cadre d'une étude concomitante sur la séroprévalence chez les donneurs de sang.