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Search Results: 1 - 10 of 6307 matches for " Nicolas Degallier "
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Environment, arbovirus transmission and control of epidemics
Cordellier, Roger;Degallier, Nicolas;
Cadernos de Saúde Pública , 1992, DOI: 10.1590/S0102-311X1992000300004
Abstract: in order to illustrate the relationships between the biotopes (or phytogeographical zones), arbovirus vectors and vertebrate hosts (including man), and epidemiology, current knowledge on the transmission of yellow fever virus in west africa is reported. a dynamic scheme has been devised to integrate the observed geographical distribution of cases and the timing of their occurrence. two principal areas, endemicity and epidetnicity, were defined according to the presence or absence of sylvatic monkey-mosquito transmission. the intensity and potential of contacts between humans and vectors depends on the degree of man-made changes in the environment, often increasing the extension of ecotone areas where the mosquitoes are easily biting at the ground level. prevention and/or control of arbovirus diseases require detailed eco-epidemiological studies to determine: (1) the effective role of each potential vector in each phytogeographical region; (2) the risk factors for the people living in or near areas with a sylvatic transmission cycle; (3) the priorities - vaccination and/or control - for preventing the expansion of natural foci.
A revision of the genus Mecistostethus Marseul (Histeridae, Histerinae, Exosternini)
Michael Caterino,Alexey Tishechkin,Nicolas Degallier
ZooKeys , 2012, DOI: 10.3897/zookeys.213.3552
Abstract: We revise the genus Mecistostethus Marseul, sinking the monotypic genus Tarsilister Bruch as a junior synonym. Mecistostethus contains six valid species: M. pilifer Marseul, M. loretoensis (Bruch), comb. n., M. seagorum sp. n., M. carltoni sp. n., M. marseuli sp. n., and M. flechtmanni sp. n. The few existing records show the genus to be widespread in tropical and subtropical South America, from northern Argentina to western Amazonian Ecuador and French Guiana. Only a single host record associates one species with the ant Pachycondyla striata Smith (Formicidae: Ponerinae), but it is possible that related ants host all the species.
Imported and autochthonous cases in the dynamics of dengue epidemics in Brazil
Degallier,Nicolas; Favier,Charly; Boulanger,Jean-Philippe; Menkes,Christophe;
Revista de Saúde Pública , 2009, DOI: 10.1590/S0034-89102009000100001
Abstract: objective: to estimate the basic reproduction number (r0) of dengue fever including both imported and autochthonous cases. methods: the study was conducted based on epidemiological data of the 2003 dengue epidemic in brasília, brazil. the basic reproduction number is estimated from the epidemic curve, fitting linearly the increase of initial cases. aiming at simulating an epidemic with both autochthonous and imported cases, a "susceptible-infectious-resistant" compartmental model was designed, in which the imported cases were considered as an external forcing. the ratio between r0 of imported versus autochthonous cases was used as an estimator of real r0. results: the comparison of both reproduction numbers (only autochthonous versus all cases) showed that considering all cases as autochthonous yielded a r0 above one, although the real r0 was below one. the same results were seen when the method was applied on simulated epidemics with fixed r0. this method was also compared to some previous proposed methods by other authors and showed that the latter underestimated r0 values. conclusions: it was shown that the inclusion of both imported and autochthonous cases is crucial for the modeling of the epidemic dynamics, and thus provides critical information for decision makers in charge of prevention and control of this disease.
A revision of the genus Kaszabister Mazur (Histeridae, Histerinae, Exosternini)
Nicolas Degallier,Slawomir Mazur,Alexey Tishechkin,Michael Caterino
ZooKeys , 2012, DOI: 10.3897/zookeys.199.3245
Abstract: We revise the four species of Kaszabister Mazur, 1972, one of which, Kaszabister barrigai sp. n., is described as new. The other species in the genus are K. rubellus (Erichson, 1834), K. ferrugineus (Kirsch, 1873) and K. carinatus (Lewis, 1888). The species are principally known from the subtropics of South America, with one in Central America. Lectotypes are designated for K. rubellus and K. ferrugineus, and a key is provided for all the species. Ants of the genus Solenopsis Westwood, mainly S. invicta Buren and S. saevissima (Smith), are documented as hosts of three of the four species.
Aedes albopictus may not be vector of dengue virus in human epidemics in Brazil
Degallier Nicolas,Teixeira José Marcus Sócrates,Soares Sidinei da Silva,Pereira Regilene D
Revista de Saúde Pública , 2003,
Abstract: Over 60,500 dengue cases were reported in the state of Espírito Santo (ES), Brazil, between 1995 and 1998. The study's purpose was to identify whether Aedes albopictus was transmitting the dengue virus during an epidemic in the locality of Vila Bethania (Viana County),Vitória, ES. From April 3 to 9, 1998, blood and serum samples were collected daily for virus isolation and serological testing. Four autochthonous cases were confirmed through DEN 1 virus isolation and two autochthonous cases through MAC ELISA testing. Of 37 Ae. aegypti and 200 Ae. albopictus adult mosquitoes collected and inoculated, DEN1 virus was isolated only from a pool of two Ae. aegypti female mosquitoes. The study results suggest that Ae. albopictus still cannot be considered an inter-human vector in dengue epidemics in Brazil.
Yellow fever virus envelope protein expressed in insect cells is capable of syncytium formation in lepidopteran cells and could be used for immunodetection of YFV in human sera
Maria CES Barros, Tatiane GCM Galasso, Ant?nio JM Chaib, Nicolas Degallier, Tatsuya Nagata, Bergmann M Ribeiro
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-261
Abstract: Insect cells infected with vSynYFE showed syncytium formation, which is a cytopathic effect characteristic of flavivirus infection and expressed a polypeptide of around 54 kDa, which corresponds to the expected size of the recombinant E protein. Furthermore, the recombinant E protein expression was also confirmed by fluorescence microscopy of vSynYFE-infected insect cells. Total vSynYFE-infected insect extracts used as antigens detected the presence of antibodies for yellow fever virus in human sera derived from yellow fever-infected patients in an immunoassay and did not cross react with sera from dengue virus-infected patients.The E protein expressed by the recombinant baculovirus in insect cells is antigenically similar to the wild protein and it may be useful for different medical applications, from improved diagnosis of the disease to source of antigens for the development of a subunit vaccine.Yellow fever (YF) is an haemorragic disease caused by a virus and transmitted by mosquitoes through two distinct cycles: the urban YF, transmitted by Aedes aegypti and the sylvatic YF, maintained in a enzootic cycle by Haemagogus and Sabethes mosquitoes with monkeys as main hosts [1]. No cases of urban YF have been reported in Brazil since 1942 [2]. The sylvatic YF is mostly restricted to wild and rural areas but recent outbreaks amongst human visitors and travelers together with the reinfestation of urban areas with the vector mosquito Aedes aegypti have concerned health authorities about the reurbanization of YF.The main mechanisms for YF control consists of vaccination and insect vector control in urban areas. Yet, in 2008, 228 YF epizootic cases were reported and 64 cases of dead monkeys ocurred just in January. These are more than the 104 YF epizootic cases and the 17 cases of dead monkeys during the whole year of 2007. Until July of the same year, 45 cases of YF amongst humans were confirmed with 25 deaths, which represents 55,6% case fatality rate [3]. Similar to w
Suscetibilidade de larvas de Aedes aegypti ao inseticida temefós no Distrito Federal
Carvalho Maria do Socorro Laurentino de,Caldas Eloísa Dutra,Degallier Nicolas,Vilarinhos Paulo de Tarso Ribeiro
Revista de Saúde Pública , 2004,
Abstract: OBJETIVO: Estudar o padr o de suscetibilidade do Aedes aegypti ao inseticida organofosforado temefós. MéTODOS: Amostras de larvas de Ae. aegypti foram obtidas com armadilhas para oviposi o, em oito cidades do Distrito Federal, nos anos 2000 e 2001. As larvas foram submetidas à dose diagnóstica de 0,012 mg/l de temefós, segundo metodologia padronizada pela Organiza o Mundial da Saúde. As popula es de campo foram testadas em paralelo com a cepa de referência Rockefeller e a cepa DIVAL, do insetário da Diretoria de Vigilancia Ambiental. A concentra o e a pureza das solu es de temefós foram analisadas por cromatografia gasosa. Os cálculos de correla o foram determinados pelo programa StatView - SAS Institute Inc., vers o 5. Utilizou-se o teste t de Student para verificar diferen as de suscetibilidade, com níveis de significancia, alfa=0,05. RESULTADOS: Em 2000, as popula es de larvas de Ae. aegypti nas cidades de Taguatinga, Guará e Núcleo Bandeirante apresentaram-se resistentes ao temefós, com mortalidade de larvas entre 54,1 e 63,4%. As popula es do Gama, Planaltina e Sobradinho apresentaram altera es nos níveis de suscetibilidade (mortalidade de 83,6 a 92,8%). A popula o de Ceilandia foi a única suscetível, com 98% de mortalidade. Em 2001, todas as popula es testadas mostraram-se resistentes (44,4 a 66,4% de mortalidade). Nenhuma correla o significativa foi encontrada entre a suscetibilidade das popula es e a distancia entre essas cidades ou a quantidade de inseticida aplicado nos anos anteriores ao estudo. CONCLUS ES: Os níveis de suscetibilidade do Ae. aegypti ao temefós vêm se alterando no Distrito Federal. é essencial a continuidade de programas de monitoramento da resistência desse vetor aos inseticidas para se garantir a eficiência dos programas de controle e a prote o da saúde humana.
Spatial Studies on Vector-Transmitted Diseases and Vectors
Maria Goreti Rosa-Freitas,Nildimar Alves Honório,Cláudia Torres Code?o,Guilherme Loureiro Werneck,Nicolas Degallier
Journal of Tropical Medicine , 2012, DOI: 10.1155/2012/573965
Abstract:
Climate-Based Models for Understanding and Forecasting Dengue Epidemics
Elodie Descloux ,Morgan Mangeas,Christophe Eugène Menkes,Matthieu Lengaigne,Anne Leroy,Temaui Tehei,Laurent Guillaumot,Magali Teurlai,Ann-Claire Gourinat,Justus Benzler,Anne Pfannstiel,Jean-Paul Grangeon,Nicolas Degallier,Xavier De Lamballerie
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001470
Abstract: Background Dengue dynamics are driven by complex interactions between human-hosts, mosquito-vectors and viruses that are influenced by environmental and climatic factors. The objectives of this study were to analyze and model the relationships between climate, Aedes aegypti vectors and dengue outbreaks in Noumea (New Caledonia), and to provide an early warning system. Methodology/Principal Findings Epidemiological and meteorological data were analyzed from 1971 to 2010 in Noumea. Entomological surveillance indices were available from March 2000 to December 2009. During epidemic years, the distribution of dengue cases was highly seasonal. The epidemic peak (March–April) lagged the warmest temperature by 1–2 months and was in phase with maximum precipitations, relative humidity and entomological indices. Significant inter-annual correlations were observed between the risk of outbreak and summertime temperature, precipitations or relative humidity but not ENSO. Climate-based multivariate non-linear models were developed to estimate the yearly risk of dengue outbreak in Noumea. The best explicative meteorological variables were the number of days with maximal temperature exceeding 32°C during January–February–March and the number of days with maximal relative humidity exceeding 95% during January. The best predictive variables were the maximal temperature in December and maximal relative humidity during October–November–December of the previous year. For a probability of dengue outbreak above 65% in leave-one-out cross validation, the explicative model predicted 94% of the epidemic years and 79% of the non epidemic years, and the predictive model 79% and 65%, respectively. Conclusions/Significance The epidemic dynamics of dengue in Noumea were essentially driven by climate during the last forty years. Specific conditions based on maximal temperature and relative humidity thresholds were determinant in outbreaks occurrence. Their persistence was also crucial. An operational model that will enable health authorities to anticipate the outbreak risk was successfully developed. Similar models may be developed to improve dengue management in other countries.
Aedes albopictus may not be vector of dengue virus in human epidemics in Brazil
Degallier,Nicolas; Teixeira,José Marcus Sócrates; Soares,Sidinei da Silva; Pereira,Regilene D; Pinto,Santuzza C F; Chaib,Antonio de Jesus Melo; Vasconcelos,Pedro F C; Oliveira,Enilce;
Revista de Saúde Pública , 2003, DOI: 10.1590/S0034-89102003000300019
Abstract: over 60,500 dengue cases were reported in the state of espírito santo (es), brazil, between 1995 and 1998. the study's purpose was to identify whether aedes albopictus was transmitting the dengue virus during an epidemic in the locality of vila bethania (viana county),vitória, es. from april 3 to 9, 1998, blood and serum samples were collected daily for virus isolation and serological testing. four autochthonous cases were confirmed through den 1 virus isolation and two autochthonous cases through mac elisa testing. of 37 ae. aegypti and 200 ae. albopictus adult mosquitoes collected and inoculated, den1 virus was isolated only from a pool of two ae. aegypti female mosquitoes. the study results suggest that ae. albopictus still cannot be considered an inter-human vector in dengue epidemics in brazil.
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