RESUMO
Little is known about the Anopheles fauna of Saint-Georges de l'Oyapock, a persistent malaria-endemic municipality in French Guiana. This study aimed to update the knowledge of local Anopheles diversity, and their ecology and role in malaria transmission. Sampling sessions were implemented between September 2013 and October 2014. Four species were identified from the 3,450 specimens collected: Anopheles darlingi Root, An. braziliensis, An. triannulatus s.l., and An. nuneztovari s.l. Anopheles darlingi was the predominant species. Its involvement in malaria transmission was suspected due to 1) its abundance, 2) the presence of a density peak during the malaria emergence period, and 3) a dynamic correlated with malaria cases observed two months later. Present and past studies show that the influence of environmental conditions on malaria vector dynamics is high, and may vary drastically according to the local context. This supports evidence that control strategies must be designed at fine scales.
Assuntos
Anopheles/fisiologia , Insetos Vetores/fisiologia , Animais , Meio Ambiente , Guiana Francesa , Malária/transmissão , Densidade Demográfica , Estações do AnoRESUMO
Between 2008 and 2014, there were 1070 malaria cases reported in French Guiana among members of the armed forces. Most of the malaria outbreaks investigated were multifactorial and followed missions conducted at illegal gold mining sites. For example, a malaria outbreak occurred in September 2013, three weeks after the deployment of 15 soldiers at Dagobert, which is such a site. The attack rate was 53%, with seven Plasmodium vivax infections and one coinfection with both Plasmodium vivax and Plasmodium falciparum. Two months later, an entomological investigation in the field caught 321 anopheles by the human landing catch method. Among them, 282 were Anopheles darlingi. One specimen was PCR-positive for P. vivax, for an infection rate of 0.4% (1/282). In 15.7% of these cases, the An. darlingi was caught during the day. The existence of daytime biting activity by An. darlingi in the Guianese forest might play a key role in malaria outbreaks among military personnel. This finding requires that the Army Health Service adapt its recommendations concerning malaria prevention in French Guiana.
Assuntos
Malária/transmissão , Animais , Anopheles , Comportamento Animal , Guiana Francesa , Humanos , Malária/epidemiologia , Mosquitos Vetores , Floresta Úmida , RiscoRESUMO
Anopheles darlingi, one of the main malaria vectors in the Neotropics, is widely distributed in French Guiana, where malaria remains a major public-health problem. Elucidation of the relationships between the population dynamics of An. darlingi and local environmental factors would appear to be an essential factor in the epidemiology of human malaria in French Guiana and the design of effective vector-control strategies. In a recent investigation, longitudinal entomological surveys were carried out for 2-4 years in one village in each of three distinct endemic areas of French Guiana. Anopheles darlingi was always the anopheline mosquito that was most frequently caught on human bait, although its relative abundance (as a proportion of all the anophelines collected) and human biting rate (in bites/person-year) differed with the study site. Seasonality in the abundance of human-landing An. darlingi (with peaks at the end of the rainy season) was observed in only two of the three study sites. Just three An. darlingi were found positive for Plasmodium (either P. falciparum or P. vivax) circumsporozoite protein, giving entomological inoculation rates of 0·0-8·7 infectious bites/person-year. Curiously, no infected An. darlingi were collected in the village with the highest incidence of human malaria. Relationships between malaria incidence, An. darlingi densities, rainfall and water levels in the nearest rivers were found to be variable and apparently dependent on land-cover specificities that reflected the diversity and availability of habitats suitable for the development and reproduction of An. darlingi.
Assuntos
Anopheles/parasitologia , Insetos Vetores/parasitologia , Malária/epidemiologia , Animais , Anopheles/classificação , Ecossistema , Feminino , Guiana Francesa/epidemiologia , Humanos , Incidência , Malária/transmissão , Plasmodium/isolamento & purificação , Chuva , Rios , Estações do AnoRESUMO
In French Guiana, malaria transmission is mainly due to Anopheles darlingi Root, but other species also are involved. Investigation and surveillance must be carried out on all the species to unravel malaria transmission patterns. In this study, we aimed to compare the ability of Mosquito Magnet- and CDC-Light Trap-based methods and human landing collection for evaluating abundance of Anopheles species. Human landing collections exhibited the best results, followed by the Mosquito Magnet and the CDC-Light Trap methods. Studies have to be done to further investigate these methods and other traps have to be tested.
Assuntos
Anopheles , Controle de Mosquitos/métodos , Animais , Guiana Francesa , Humanos , Insetos Vetores , Malária/transmissãoRESUMO
The border area between Suriname and French Guiana is considered the most affected malaria area in South America. A one-year cooperative malaria vector study was performed by the two countries, between March 2004 and February 2005, in four villages. Anopheles darlingi proved to be the most abundant anopheline species. Human biting rates differed between villages. The differential effect of high rainfall on mosquito densities in the villages suggests variation in breeding sites. Overall parity rates were low, with means varying from 0.31 to 0.56 per study site. Of the 2045 A. darlingi mosquitoes collected, 13 were found to be infected with Plasmodium: ten P. falciparum, two P. malariae and one mixed P. malariae/P. vivax. The overall annual entomological inoculation rates in the villages ranged from 8.7 to 66.4. There was an apparent lack of relationship between number of malaria cases and periods of high mosquito density. The tendency of Anopheles darlingi to bite during sleeping hours provides opportunity for malaria control using impregnated bed nets, a strategy just introduced in Suriname that may also find its way into French Guiana.
Assuntos
Anopheles/parasitologia , Mordeduras e Picadas de Insetos , Insetos Vetores/parasitologia , Malária/transmissão , Animais , Guiana Francesa , Humanos , Mordeduras e Picadas de Insetos/parasitologia , Malária/prevenção & controle , Densidade Demográfica , Rios/parasitologia , Estações do Ano , Suriname , VacinaçãoRESUMO
Description of a new tropical species of French Guiana: Lutzomyia (Trichopygomyia) depaquiti. The principal character is the aedeagus morphology that presents lateral expansions like a marine anchor. An other particularity is centered on the complex paramere with a lateral lobe. Holotype is deposited at the National Museum of Natural History of Paris.
Assuntos
Psychodidae/anatomia & histologia , Psychodidae/classificação , Animais , Feminino , Guiana Francesa , Masculino , Filogenia , Caracteres SexuaisRESUMO
Twenty-seven samples of Aedes aegypti (F1 generation) from French Guiana were tested for their susceptibility to dengue serotype 2 virus. Very high infection rates were observed by indirect fluorescent antibody (IFA) test. Ae. aegypti samples were pooled according to two groups: the first group (N=10) represented mosquitoes from the urbanized area of Cayenne and surroundings, and the second group (N=17) corresponded to mosquitoes collected in the countryside. Infection rates were found to be similar in these two cases. These findings are discussed in relation with the history of Ae. aegypti in this part of the world.
Assuntos
Aedes/virologia , Vírus da Dengue/classificação , Vírus da Dengue/isolamento & purificação , Animais , Suscetibilidade a Doenças , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Guiana Francesa , Humanos , MasculinoAssuntos
Antimaláricos/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/isolamento & purificação , Amodiaquina/farmacologia , Animais , Cloroquina/farmacologia , Resistência a Medicamentos , Guiana Francesa , Humanos , Malária/sangue , Malária/diagnóstico , Malária/tratamento farmacológico , Malária/epidemiologia , Mefloquina/farmacologia , Quinina/farmacologiaRESUMO
General epidemiological and entomological aspect studies of the dengue fever (DF) situation and the mosquito vector, Aedes aegypti, in French Guiana were studied for two years, between 1st October 1993 and 30th September 1995. The methodology included epidemiological data gathered from patients recently infected by a dengue virus, and entomological investigations with sampling of all stages (eggs, larvae, pupae and adults) of Ae.aegypti in the suspected dengue-infected places. DF cases were reported from all parts of the country, mostly from the main city of Cayenne and its surroundings. Likewise, Ae.aegypti was found in all investigated inhabited areas, and infected vectors were collected in four locations. Sampling of immature Ae.aegypti showed that the small outdoor containers were the most important breeding-sites in French Guiana. The duration of development of Ae. aegypti was significantly different according to the type of breeding-site. The vertical transmission of Df viruses under naturual conditions in French Guiana was demonstrated and 2 DEN-2 and 2 DEN-4 strains were isolated. We conclude that DF viruses are endemic in French Guiana, all inhabitied areas of the country are susceptible to epidemic DF and the reponsible vector, Ae.aegypti, can also act as a reservoir for the dengue virus (AU)