Epidemiological and entomological surveillance of the co-circulation of DEN-1, DEN-2 and DEN-4 viruses in French Guiana.
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We surveyed the disease epidemiology of dengue in French Guiana after the first dengue haemorrhagic fever epidemic from 1991 to 1993 and during an endemic period from 1993 to 1995. DEN-1, DEN-2 and DEN-4 viruses were isolated from patients and DEN-4 was also isolated from Aedes aegypti mosquitoes. Cases of dengue were reported from all over the country, not only from urban areas, but also from rural areas and isolated human settlements, indicating widespread circulation of the viruses. The mosquito vector A. aegypti was found in all inhabited areas of French Guiana and small outdoor containers were the most common breeding grounds. Some ecological features of A. aegypti, such as larvae breeding in Bromeliad plants in the rainforest, a non-exclusive anthropophily and a high vertical transmission rate for dengue viruses, indicate that A. aegypti can behave as a reservoir for dengue viruses in silent areas. Dengue viruses may survive at an endemic level and cause outbreaks when unknown conditions become more favourable. This finding adds to our knowledge of the natural history of dengue viruses in the Americas. (+info)
Plasmodium falciparum in vivo resistance to quinine: description of two RIII responses in French Guiana.
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The resistance of Plasmodium falciparum to antimalarial drugs is one of the most worrisome problems in tropical medicine, but few clinical studies or observations have described confirmed cases of therapeutic failure. We report two cases of in vivo P. falciparum resistance (RIII response) to quinine in French Guiana, an Amazonian focal zone in which multi-resistant malaria is endemic. Both patients presented with uncomplicated malaria and were initially treated with intravenous quinine. Although absorption was normal, the treatment was not effective and the patients still had fever and significant parasitemia three days after the onset of treatment (day 3). The addition of intravenous tetracycline completely resolved the parasitemia within approximately 96 hours. These clinical reports confirm the necessity to combine quinine with tetracycline in this area, as recommended by the recent French regional antimalarial policy. (+info)
High seroprevalence of human T-cell lymphotropic virus type 1 in blood donors in Guyana and molecular and phylogenetic analysis of new strains in the Guyana shelf (Guyana, Suriname, and French Guiana).
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The prevalence of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 in blood donors in Guyana has never been estimated. We evaluated the prevalence of these viruses in blood donors by enzyme-linked immunosorbent assay and Western blotting and showed a prevalence of HTLV-1 of 1.3%; no HTLV-2 was detected. Female donors had a much higher HTLV-1 seroprevalence (3.6%) than male donors (0.7%). HTLV-1-seropositive donors tended to be slightly older than the average age for the total pool of donors. We also investigated the phylogenetic and molecular characteristics of HTLV-1 strains in Guyana and compared them with those identified in Suriname and French Guiana. Analysis of portions of the env and long terminal repeat nucleotide sequences showed that all the strains in Guyana and Suriname, like those in French Guiana, belonged to the transcontinental group of cosmopolitan subtype A. The similarities were greater between strains from Suriname and Guyana than between strains from Suriname and Guyana and those from French Guiana. Nevertheless, our results confirm that the HTLV-1 strains in all three countries have a common African origin. (+info)
Dengue spatial and temporal patterns, French Guiana, 2001.
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To study a 2001 dengue fever outbreak in Iracoubo, French Guiana, we recorded the location of all patients' homes and the date when symptoms were first observed. A geographic information system (GIS) was used to integrate the patient-related information. The Knox test, a classic space-time analysis technique, was used to detect spatiotemporal clustering. Analysis of the relative-risk (RR) variations when space and time distances vary, highlighted the maximum space and time extent of a dengue transmission focus. The results show that heterogeneity in the RR variations in space and time corresponds to known entomologic and epidemiologic factors, such as the mosquito feeding cycle and host-seeking behavior. This finding demonstrates the relevance and potential of the use of GIS and spatial statistics for elaborating a dengue fever surveillance strategy. (+info)
Antibacterial resistance, Wayampis Amerindians, French Guyana.
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Drug resistance in fecal bacteria was high in Wayampis Amerindians who did not take antibacterial agents and were not hospitalized for 1 year. In the Wayampis Amerindians, an isolated traditional community in French Guyana, antibacterial use was 0.64 treatments per person per year. Hospitalization rate was 6.1% per year. Antibacterial drug-resistant bacteria can spread in persons who are not taking antibacterial agents. (+info)
Limited pollen dispersal and biparental inbreeding in Symphonia globulifera in French Guiana.
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In this paper, we report a study of the mating system and gene flow of Symphonia globulifera, a hermaphroditic, mainly bird-pollinated tree species with a large geographic distribution in the tropical Americas and Africa. Using three microsatellites, we analysed 534 seeds of 28 open pollinated families and 164 adults at the experimental site 'Paracou' in French Guiana. We observed, compared to other tropical tree species, relatively high values for the effective number of alleles. Significant spatial genetic structure was detected, with trees at distances up to 150 m more genetically similar than expected at random. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, tm, was 0.920. A significant level of biparental inbreeding and a high proportion of full-sibs were estimated for the 28 seed arrays. We estimated mean pollen dispersal distances between 27 and 53 m according to the dispersal models used. Although the adult population density of S. globulifera in Paracou was relatively high, the joint estimation of pollen dispersal and density of reproductive trees gave effective density estimates of 1.6 and 1.3 trees/ha. The parameters of the mating system and gene flow are discussed in the context of spatial genetic and demographic structures, flowering phenology and pollinator composition and behaviour. (+info)
Plasmodium falciparum malaria in splenectomized patients: two case reports in French Guiana and a literature review.
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Some of the immunologic mechanisms involved in malaria physiopathology remain unclear. In animals, the spleen seems to play a key role in protecting the host against malaria. However, little is known about the effect of spleen dysfunction on human malaria. We report two severe cases of Plasmodium falciparum infection with unusual clinical and parasitologic features in two splenectomized men living in French Guiana. The peripheral blood of these cases showed hyperparasitemia, with a high proportion of mature parasites and leukocytes with malaria pigment. Despite appropriate treatment and adequate absorption, hyperparasitemia persisted. Parasite clearance was delayed and one patient died. Only the patient who died had the merozoite surface protein 1 allele B-K1 and the varD gene genotype, which is considered to be a probable parasite virulence factor. These uncommon cases differ from most of those described in the literature, illustrating the complexity of the mechanisms underlying the protective function of the spleen in human malaria. (+info)
Disseminated cutaneous leishmaniasis due to Leishmania guyanensis: case of a patient with 425 lesions.
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Disseminated cutaneous leishmaniasis is characterized by the presence of a large (> or =10) number of lesions at several anatomic sites (head, limbs, and trunk). Most of the lesions are small, papular, and appear simultaneously with or secondarily to one or several ulcerated lesions of localized cutaneous leishmaniasis. We report the first case of disseminated cutaneous leishmaniasis in French Guiana. It concerns a 24-year-old woman who tested negative for human immunodeficiency virus (HIV). The disease began with three lesions that became ulcerated. One week later, multiple papulo-nodular lesions appeared. We counted a total of 425 lesions. Leishmania were observed in the lesions. The species involved was L. guyanensis, which has never been described in a case of disseminated cutaneous leishmaniasis. The patient was rapidly cured by a single course of pentamidine. Disseminated cutaneous leishmaniasis should be distinguished from other types of leishmaniasis with multiple lesions. These include anergic diffuse cutaneous leishmaniasis, post-kala-azar leishmaniasis, and leishmaniasis associated with HIV infection. (+info)