Testing blood donors for Chagas disease in the Paris area, France: first results after 18 months of screening

Abstract

Background: Chagas disease is endemic in Latin America (LA). Currently 10 million people are infected despite World Health Organization efforts aimed at preventing domestic transmission. However, with the migration of infected asymptomatic individuals to nonendemic countries, transmission of Chagas disease by transfusion may become a worldwide problem. The observation that the number of cases of Chagas disease has increased over the past 10 years in French Guiana, together with the results of a previous hospital-based study in the Paris area, confirms the transmission of Chagas disease from patients coming from LA. For these reasons, the French authorities stopped the collection of blood in French Guiana in 2005 and began screening blood donors in the French Caribbean islands and, in 2007, in continental France.

Study design and methods: Data on birth place, mother's birth place, and travel in LA were recorded for at-risk donors. These subjects were tested using two enzyme-linked immunosorbent assays (ELISAs).

Results: Of the 312,458 individuals who gave blood in the Paris area during an 18-month period, 30,837 were tested. Of these, 972 were born in LA, three of whom were positive for the two ELISAs and immunofluorescence tests. The prevalence of Trypanosoma cruzi-positive donors was 9.7 in 100,000 tested donors, but 0.31% among donors born in LA. Serology tests gave discrepant results in 1.02% of the samples.

Conclusion: The efficiency of blood donor screening programs could be improved by screening only blood donors who were born in LA or who have traveled in LA for extended periods, using a single enzyme immunoassay.