[Experience of targeted screening of Chagas disease in Ile-de-France]

Abstract

2009 is marked by the centenary of the discovery by Carlos Chagas of Human American Trypanosomiasis. As a result of international cooperation its incidence has been falling in endemic areas, whereas North America and Europe are witnessing an increase in the number of imported cases. In metropolitan France, 18 such cases were reported between 2004 and 2007. Recently, estimates based on immigration figures have been made and suggest that about 1,500 imported cases can be expected in France. The object of this article is to assess the value of targeted screening of an at-risk population, originally from Latin America and now living in the Ile-de-France (area centred on Paris). The serological techniques employed were indirect immunofluorescence (IIF) and, depending on the case, 2 or 3 Elisa tests (Biomérieux, Biokit and Wiener). Trypanosoma cruzi serology was considered positive when the IIF was superior or equal to 200, or when two Elisa's were > 1, or when the IIF was superior or equal to 100 with at least one Elisa > 1. PCR was performed in 48 cases, which were considered to be positive. The tests were carried out on a voluntary basis after a publicity campaign within the Latin American community in the Ile-de-France. In this article, we present the findings of the first year of screening. Two hundred and fifty-four individuals were screened for Chagas' disease between June 2008 and June 2009. The median age was 33 years [11-63], the male/female ratio 102/152. Overall prevalence of positive serology was 23.6% (60/254). For six patients, the results were classified as "uncertain" (discordant serological tests). Of the seropositive group, 87.4% were Bolivian and 100% presented as a chronic form. Of these, 23.6% presented with functional cardiac manifestations and 22% with gastro-intestinal problems. The PCR was positive in 61% of the seropositive individuals. Clinical evaluation together with other investigations and therapeutic intervention is being carried out at present. These results confirm that metropolitan France is subject to the emergence of Chagas' disease in a non-endemic zone. This confirms the value of screening in at-risk populations, in particular because of the recent broadening of indications for antiparasitic treatment. In addition it is relevant to the prevention of vertical transmission or infection via organ donation, which could arise in France. These results also demonstrate continuing difficulties in the interpretation of serological results and the usefulness of PCR, which might increase sensitivity substantially.