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[Chagas disease and blood transfusion: an emerging issue in non-endemic countries]
1Établissement français du sang (EFS), 20, avenue du Stade-de-France, 93218 La Plaine Saint-Denis, France. azzedine.assal@efs.sante.fr
Insights
French Blood Services screened donors for Chagas disease (Trypanosoma cruzi) antibodies. A prevalence of 1 in 32,800 was found, leading to strategy revisions for donor screening.
Area of Science:
- Infectious Diseases
- Parasitology
- Public Health
- Transfusion Medicine
Background:
- Chagas disease, caused by Trypanosoma cruzi, is endemic in Latin America and poses a transmission risk via blood transfusion in non-endemic countries.
- Imported Chagas disease cases necessitate robust screening protocols in blood services to prevent transfusion-transmitted infections.
Purpose of the Study:
- To evaluate the seroprevalence of anti-Trypanosoma cruzi antibodies among blood donors in France.
- To assess the effectiveness of the French Blood Services' (EFS) screening strategy implemented in May 2007 for at-risk donors.
Main Methods:
- Systematic screening of at-risk blood donors (originating from or having lived/traveled in endemic areas) for anti-T. cruzi antibodies.
- Simultaneous use of two ELISA tests (purified parasite lysate antigens and recombinant antigens), with positive/discrepant results confirmed by immunofluorescence assay.
- A seroprevalence assay conducted across 17 French blood centers over an 18-month period (May 2007 - December 2008).
Main Results:
- Out of 4,637,479 donations, 163,740 (3.5%) were tested, identifying a seroprevalence of anti-T. cruzi antibodies at 1 in 32,800 donations.
- Five positive donors were identified, all originating from endemic areas.
- An indeterminate result rate of 0.85% was observed, prompting a review of the screening strategy.
Conclusions:
- The implemented screening strategy detected Chagas disease in a small but significant proportion of at-risk blood donors.
- The high rate of indeterminate results indicated a need for strategy revision to minimize unnecessary donor deferrals while maintaining safety.
- Ongoing surveillance and strategy optimization are crucial for preventing transfusion-transmitted Chagas disease in non-endemic settings.
Abstract:
Chagas disease or American human trypanosomiasis, is a parasitic disease due to Trypanosoma cruzi, which is endemic in Latin America. The parasite is transmitted by haematophagous vectors from reduviidae family. In some patients, the parasite is responsible for severe complications such as cardiac manifestations, gastrointestinal involvement and neurologic disease. Imported Chagas disease by immigration in non-endemic countries poses the threat of the infection transmission by blood transfusion. In order to prevent this risk, the French Blood Services (EFS) introduced systematic screening of at-risk blood donors for anti-T. cruzi antibodies, in May 2007. The concerned donors are people originating from an endemic area, donors with mothers originating from such an area and individuals who had lived in or travelled to endemic areas. Donors were screened with two different Elisas simultaneously: one Elisa using purified parasite lysate antigens and the second one composed of recombinant antigens. Positive results and discrepant results were further assayed with an immunofluorescence assay. A seroprevalence assay was performed in the 17 French blood centres after an 18-month testing period from May 2007 to December 2008. During this period 4,637,479 million donations were collected. Out of these 163,740 donations were tested (3.5%). The prevalence of anti-T. cruzi antibodies was one in 32,800 donations. Five positive donors were identified. All of them were originating from endemic areas. A rate of 0.85% indeterminate results was found. Screening strategy revision was decided to reduce the number of donors unnecessarily deferred.
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