RESUMO
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.
Assuntos
Doença de Chagas/diagnóstico , Animais , Brasil/epidemiologia , Doença de Chagas/epidemiologia , Doença de Chagas/prevenção & controle , Emigração e Imigração/estatística & dados numéricos , Europa (Continente)/epidemiologia , Humanos , Programas de Rastreamento/métodos , América do Norte/epidemiologia , Paris/epidemiologia , Prevalência , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
The diagnosis of Chagas disease during the chronic phase is based on serology. Outside South America the use of two methods is recommended by WHO. A third method must be available for inconclusive results but there is no gold standard. A pilot study of screening in 254 Bolivian people living in the Paris area (France) was made. Serological study was performed using IIF and three Elisa, Elisa Cruzi (BioMérieux Brésil), BioElisa Chagas (Bio-kit), and Chagatest Elisa recombinante v. 3.0 (Wiener Lab). 165 patients were negative, 69 positive and 20 inconclusive. PCR-based assays appear to have a better sensitivity than parasitological methods, but not more than 70% that do not justify their use for primary testing. There are no standardized and commercial assays. The primer pairs based on the nuclear sequence TCZ1-TCZ2 seems to be the more specific (no cross reaction with others Trypanosomatidae) and the most sensitive with the strains of the two lineage of Trypanosoma cruzi. PCR would have a role in inconclusive serological cases or in the evaluation of treatment failure.
Assuntos
Doença de Chagas/fisiopatologia , Animais , Antígenos de Protozoários/sangue , Doença de Chagas/epidemiologia , Doença Crônica , Doenças Endêmicas/estatística & dados numéricos , Ensaio de Imunoadsorção Enzimática , Geografia , Humanos , América do Sul/epidemiologia , Trypanosoma cruziRESUMO
BACKGROUND: Screening for human T-lymphotropic virus type I (HTLV-I) infection became systematic in 1989 in the French West Indies for blood from all donors and in France for blood from natives of endemic areas; in 1990, it was extended to blood from donors with at-risk sex partners and in July 1991 to blood from all donors. STUDY DESIGN AND METHODS: The epidemiologic characteristics of individuals found through the screening of donated blood to be HTLV-I infected were compared for an endemic region (Guadeloupe, French West Indies) and a nonendemic region (Paris area) over a 3-year period (1989 through 1991). RESULTS: In Guadeloupe, 131 HTLV-I-infected individuals were detected in the screening of 28,801 units; in the Paris area, 38 HTLV-I-infected donors were detected in the screening of 109,824 units. All Guadeloupean HTLV-I-infected donors were natives of endemic areas. Among the 38 Parisian HTLV-I-infected donors, 21 were natives of endemic areas, 10 were natives of endemic areas and had received transfusions, 2 were whites who had received transfusions, and 5 were whites who had had heterosexual contact with natives of endemic areas. The percentage of HTLV-I-infected individuals whose blood would have been excluded because of positivity for one or more markers for other viruses did not significantly change over the study period and did not significantly differ between regions (41%). Among the eight Parisian HTLV-I-infected blood donors detected after July 1991, six would not have been detected without the biologic screening. CONCLUSION: The generalization of biologic screening of HTLV-I-infected donated blood in France was useful for the prevention of HTLV-I and HTLV type II infections through transfusion.