Résumé : Penaeus stylirostris shrimp imported from Hawaii for a genetic program and kept at the Saint-Vincent research facility had progressively developed a high sensitivity to IHHNV, the etiological agent of the Infectious, Hypodermic, and Hematopoietic Necrosis. Fears were that the virus could not only be transferred to their offspring, but also that the New Caledonian strain of Penaeus stylirostris, so far considered as resistant, could become sensitive by an off balance of its hosts/pathogen equilibrium. In October 2008, a joint decision between Uprac (shimp owner), Davar (New Caledonian Animal Health Authority) and Ifremer (scientific partner) was taken to terminate all pure breed and hybrid Hawaiian populations remaining in the ponds, and to implement an intensive fallowing protocol, and controlled restocking. IHHNV was also suspected to trouble experiments carried out in the research facility (mortalities, deformities, slow growth), thus affecting research programs. Difficulties pointed out by IHHNV have triggered since 2008 some awareness on biosecurity issues at some level of the New Caledonian shrimp industry. At the St-Vincent research station, it led to a risk assessment and implementation of biosecurity procedures (fallowing, propagation, grow out and use of screened animals) which minimizes the risk of expression of IHHNV. The use of a brand new hatchery building on site also helped in resetting routine hygiene procedures during production and in controlling incoming and outgoing items (shrimp, water, feed, personnel, equipment, pests and wastes). IHHNV has not been detected on analysed samples since then nor have any symptoms been found during experimental or broodstock growout. Keeping this control alive is considered as a useful tool to lower the risk of potential health threats, to get a better understanding in case of an outbreak, and to increase the reliability of experimental results.
Les crevettes originaires d’Hawaii et conservées au LEAD St-Vincent, dans le cadre du programme d’introduction de variabilité génétique dans le cheptel Calédonien, ont progressivement montré une sensibilité importante au virus IHHNV, agent de la Nécrose Hypodermale et Hématopoïétique Infectieuse (mortalité, croissance ralentie, déformations). Les risques d’une transmission génétique de cette sensibilité à leur descendance à moyen terme, et de son développement par rupture de l’équilibre hôte/pathogène sur la souche dite « Calédonienne » jusqu’alors considérée comme résistante à l’IHHN, ont conduit à partir d’octobre 2008, avec l’accord et l’appui de l’UPRAC et de la DAVAR, à la suppression des animaux hawaiiens ou hybrides encore présents dans les bassins de terre du LEAD St-Vincent, au vide sanitaire de ces derniers, et au repeuplement contrôlé du site. D’autre part, le virus IHHN est soupçonné d’avoir pu affecter les animaux utilisés dans les expérimentations menées au LEAD-St-Vincent (mortalités, déformations, croissance réduite), influençant donc potentiellement leur bon déroulement et celui des programmes de recherches. Les obstacles soulevés par l’expression du virus IHHN ont donc initié depuis 2008 une prise de conscience et la mise en place de démarches de biosécurité dans certains points de la filière. A la station de St-Vincent, cette démarche s’est traduite par une identification/évaluation des risques et l’application de mesures (vide sanitaire, reproduction, élevage et utilisation des animaux contrôlés) chacune dotée de procédures qui regroupées, minimisent le risque d’introduction et de dissémination de l’IHHNV. La prise en main de la nouvelle structure d’écloserie sur le site de la SASV a également été mise à profit pour revoir les procédures d’hygiène de routine dans la conduite des productions et dans le contrôle des flux intrants et sortants (animaux, eau, aliments, personnel, équipement, nuisibles, déchets). Aucune détection d’IHHNV sur les échantillons prélevés n’a depuis été observée, de même qu’aucun symptôme de l’expression de cette maladie sur les animaux en élevage sur le site de Saint-Vincent. La poursuite de ces mesures est envisagée comme un outil d’aide à la minimisation des problèmes potentiels, à leur compréhension en cas d’apparition, et à la fiabilisation des résultats.

Droits : 2010 Ifremer
http://archimer.ifremer.fr/doc/00118/22949/20776.pdf
http://archimer.ifremer.fr/doc/00118/22949/

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Author Summary Leptospirosis is a common disease in tropical regions around the world. It is caused by a bacteria excreted in environmental waters by mammals, especially rodents, through their urine. Leptospirosis has symptoms similar to other tropical diseases, including dengue fever, and early laboratory diagnosis is crucial to provide both appropriate treatments for patients and rapid control measures when an outbreak occurs. In 2011, we undertook a study to determine the incidence of leptospirosis in two territories (Guadeloupe and Martinique) in the French West Indies by establishing a surveillance network and implementing new diagnostic assays in order to ensure an exhaustive diagnostic analysis. We concluded that leptospirosis was previously significantly under-reported in the French West Indies and we recommended: 1- access to these new diagnostic tests for the entire population for a better detection of leptospirosis patients and, 2- the implementation of an integrated surveillance, alert and prevention system for the disease in this region. Our findings had raised the awareness of this neglected disease in the French West Indies and, as another consequence; new diagnostic tests are now reimbursed by the social security insurance in France
ISSN: 1935-2727

Droits : http://creativecommons.org/licenses/by/
hal-01324701
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01324701
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01324701/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01324701/file/journal.pntd.0004668.pdf
DOI : 10.1371/journal.pntd.0004668

Résumé : As the emergence of new vibriosis in the European Atlantic coasts has been associated with mass mortalities of molluscs cuasing important economic losses, the project obectives are to provide knowledge and operational tools to evaluate the impact of vibriosis on farmed japenese oyster Crassostrea gigas. Facing the diversity of Vibrio species associated to bivalve disease outbreaks, the difficulties of identification and the detemrination of their pathogenic abilities we propose a double approach to correlate phenotype/geneotype of a bacteria with risk of disease : 1) by genotyping we will evaluate if specific strains are associated with disease. 2) by evaluating likely virulence mechanisms implicated in pathogenesis, we will characterise the genes involved. Therefore, new diagnostic test should be used in an epizootiological study to evaluate the importance of these emerging pathogens in farmed bivalves and will be supplied for further exploitation in aquaculture.
Les vibrioses sont les infections bactériennes les plus courantes chez les espèces marines d'intérêt aquacole. Certaines espèces sont pathogènes et ont été associées à d'importantes pertes économiques pour l'industrie aquacole dans le monde. L'objectif principal de mon projet de recherche est de développer des outils diagnostiques pertinents permettant d'évaluer l'impact des vibrioses dans des élevages d'huîtres creuses Crassostrea gigas. Le problème majeur est l'extraordinaire diversité des espèces appartenant à ce genre bactérien, compliquant considérablement leur caractérisation en terme de spéciation et de virulence. Nous développons une double approche pour corréler le phénotype et le génotype de pathogènes potentiels par : 1) une clarification taxonomique des souches de vibrions nous déterminons si certaines espèces sont systématiquement associées à de maladies; 2) une caractérisation des mécanismes de virulence, nous recherchons les gènes supports de la pathogénie. Les marqueurs génétiques ou de virulence mis au point pourront alors être utilisés pour une étude épidémiologique de ces maladies.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2004/these-3699.pdf
http://archimer.ifremer.fr/doc/00000/3699/

Éditeur(s) : Elsevier Science Bv
Résumé : Shrimp aquaculture in New Caledonia is subject to seasonal mortalities during grow-out due to highly virulent Vibrio nigripulchritudo (Vn). To understand the mechanisms affecting shrimp resistance and leading to significant mortality, a shrimp ecophysiology and immunology survey was conducted on two farms, the first considered as a "control" farm (HC), the second affected by the disease (DF). Mortality observed during the survey at DF started 50 days after stocking and was typical of this disease. The main observations regarding shrimp were: (a) growth was not affected by the disease and was faster in the DF than in the HC pond; (b) disease did not affect one sex more than the other, or a specific part of the population in terms of weight; (c) the physical condition of shrimp did not specifically allow us to foresee disease outbreak; (d) shrimp at late premolt stage D-2 and early postmolt stage A appeared to be at some points of the mortalities - but not continuously - the most sensitive to disease; (e) physiological, immunological and nutritional parameters of uninfected shrimp in the DF pond were altered, suggesting that environmental stress occurred just before the first mortalities; (f) data suggest that Vn-infected shrimp are more stressed than the presumed healthy shrimp. Combined with pathological and environmental knowledge gained in parallel during this survey, a conceptual model is proposed. Results suggest that an unstable environment induced conditions (i) stressful for the shrimp, increasing their susceptibility to bacterial infections and (ii) favoring the proliferation of the pathogen in the pond. The combination of these two processes could lead to significant mortality.
Aquaculture (0044-8486) (Elsevier Science Bv), 2013-04 , Vol. 388 , P. 105-114

Droits : 2013 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00176/28764/27567.pdf
DOI:10.1016/j.aquaculture.2013.01.010
http://archimer.ifremer.fr/doc/00176/28764/

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : International audience
Coral disease outbreaks have increased over the last three decades, but their causal agents remain mostly unclear (e.g., bacteria, viruses, fungi, protists). This study details a 14-month-long survey of coral colonies in which observations of the development of disease was observed in nearly half of the sampled colonies. A bimonthly qPCR method was used to quantitatively and qualitatively evaluate Symbiodinium assemblages of tagged colonies, and to detect the presence of Vibrio spp. Firstly, our data showed that predisposition to disease development in general, and, more specifically, infection by Vibrio spp. in Acropora cytherea depended on which clades of Symbiodinium were harbored. In both cases, harboring clade D rather than A was beneficial to the coral host. Secondly, the detection of Vibrio spp. in only colonies that developed disease strongly suggests opportunistic traits of the bacteria. Finally, even if sporadic cases of switching and probably shuffling were observed, this long-term survey does not suggest specific-clade recruitment in response to stressors. Altogether, our results demonstrate that the fitness of the coral holobiont depends on its initial consortium of Symbiodinium, which is distinct among colonies, rather than a temporary adaptation achieved through acquiring different Symbiodinium clades.
ISSN: 2045-7758

hal-01270779
https://hal-univ-perp.archives-ouvertes.fr/hal-01270779
https://hal-univ-perp.archives-ouvertes.fr/hal-01270779/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01270779/file/41080.pdf
DOI : 10.1002/ece3.1895

Éditeur(s) : HAL CCSD
Résumé : The mosquito species Aedes (Stegomyia) aegypti (Linnaeus 1762) was introduced into the Americas some 400 years ago from the African continent. Currently, this species is the primary agent behind dengue and chikungunya outbreaks in the pan-tropical area and its widespread distribution has likely played an important role in the recent expansion of the Zika virus. The biology of Ae. (Stg.) aegypti is particularly well known, which is not the case for its ecology. By adopting a cross-disciplinary approach I attempted to understand the relative contribution of biotic and abiotic factors as well as some evolutionary processes in the distribution of this species at the local and regional scales in French Guiana.Initially, I was interested in revising the core knowledge concerning the diversity of mosquitoes in French Guiana. By combining traditional and molecular taxonomy, this step allowed my colleagues and I to discover several new species and to create the appropriate tools to manage this type of entomological data.Secondly, we studied the spatio-temporal structure of resident aquatic macroinvertebrate communities in urban areas. This highlighted the existence of antagonistic and mutualistic interactions. In particular, the native mosquito Limatus durhamii Theobald 1901 appears to prevent the sustainable establishment of Ae. (Stg.) aegypti in slightly urbanized environments via a mechanism of competitive exclusion.
Le moustique Aedes (Stegomyia) aegypti (Linnaeus 1762) a été introduit dans les Amériques depuis le continent africain il y a environ 400 ans. Actuellement, cette espèce est la principale responsable des épidémies de dengue et de chikungunya dans la zone pantropicale et sa large répartition a très probablement joué un rôle important dans l’expansion récente du virus Zika. La biologie d’Ae. (Stg.) aegypti est particulièrement bien connue, ce qui n’est pas le cas de son écologie, en particulier de ses interactions avec les communautés résidentes. En adoptant une démarche pluridisciplinaire je me suis intéressé à la contribution relative des facteurs biotiques et abiotiques ainsi que de certains processus évolutifs dans la distribution de cette espèce à différentes échelles en Guyane française.Dans un premier temps j’ai participé à la révision des connaissances fondamentales sur la diversité des moustiques de Guyane. En alliant la taxonomie classique et moléculaire, cette étape a permis de découvrir plusieurs nouvelles espèces et de mettre en place des outils adaptés à la gestion de ce type de données, notamment pour une utilisation future.Dans un second temps la structuration spatio-temporelle des communautés résidentes de macro-invertébrés aquatiques a été étudiée en milieu urbain. Cela a permis de mettre en évidence l’existence d’interactions antagonistes et mutualistes avec les taxons des communautés résidentes. En particulier, le moustique autochtone Limatus durhamii Theobald 1901 semble empêcher l’établissement durable d’Ae. (Stg.) aegypti dans les milieux faiblement urbanisés via un mécanisme d’exclusion compétitive.
https://tel.archives-ouvertes.fr/tel-01405425

NNT : 2016YANE0001
tel-01405425
https://tel.archives-ouvertes.fr/tel-01405425
https://tel.archives-ouvertes.fr/tel-01405425/document
https://tel.archives-ouvertes.fr/tel-01405425/file/These_Def_Talaga.pdf

Éditeur(s) : Elsevier
Résumé : in this study we evaluated the effects of the probiotic Pediococcus acidilactici MA18/5M on shrimp, Litopenaeus stylirostris (also called Penaeus stylirostris), first on antioxidant defences and secondly on the oxidative stress status in the shrimps' haemolymph and digestive gland. We conducted two experiments with the same protocol in which shrimps were fed two diets for three weeks: a control diet and a probiotic diet containing 1 g of live P. acidilactici MA18/5M kg(-1). In the first experiment, the shrimps were found to be healthy over the trial period; no mortalities and non-detectable signs of infection were recorded. These resulted in high final survival rates (above 90% in both treatments). On the other hand, during the second trial, carried out at a period of increased risk for an outbreak of the summer syndrome, higher mortalities were recorded, associated with high V. nigripulchritudo prevalence and loads in the shrimp haemolymph. In healthy shrimps (trial 1), no detectable response of the antioxidant defence system and of oxidative stress bio-indicators were observed. However, feeding the probiotic significantly increased the total antioxidant status (TAS) and glutathione peroxidase activity, while all other parameters remained significantly unchanged. In the shrimps exposed to V nigripulchritudo (trial 2), the antioxidant response was characterized by higher antioxidant enzyme activities (superoxide dismutase and catalase) and higher oxidative stress level in the digestive gland (higher oxidized/reduced glutathione ratio, higher malonclialdehyde and carbonyl protein contents) compared to levels found in trial 1. However, shrimps fed the probiotic diet exhibited (i) significantly higher final survival rates (67 +/- 3%) compared to the control (47 +/- 4%) and (ii) a lower prevalence of V nigripulchritudo throughout the trial. Moreover, the antioxidant response and the oxidative stress level recorded in the digestive gland with shrimps submitted to the probiotic diet were lower. In the light of these results, we confirm that P acidilactici enrichment in shrimps' diet seems an effective way of reducing the susceptibility of shrimps to bacterial pathogens. (c) 2009 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2009-09 , Vol. 294 , N. 3-4 , P. 306-313

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6780.pdf
DOI:10.1016/j.aquaculture.2009.06.016
http://archimer.ifremer.fr/doc/00000/6780/

Résumé : Dans cette thèse, nous présentons deux modèles mathèmatiques qui simulent la dynamique d'une épidémie de dengue à Cuba. Le premier modèle est décrit par un système d'équations différentielles ordinaires dans le but d'estimer certains paramètres essentiels dans l'évolution de l'èpidérnie. Le deuxième modèle utilise une inclusion différentielle afin de simuler la dynamique sous incertitudes. Nous passons aussi en revue une famille de modèles d'équations différentielles pour l'épidémie de VIH/SIDA à Cuba et nous reformulons l'un de ces modèles en une inclusion différentielle. En outre, pour analyser le comportement de ces deux épidémies et l'effet de l'intervention nous développons un algorithme pratique pour le calcul des ensembles atteignables des inclusions différentielles, qui fournit un cadre mathématique nous permettant de faire des prédictions appropriées de toutes les variables d'état des modèles
Ln this work we present two mathematical models that simulate the dynamics of an epidemic outbreak of dengue disease in Cuba. The i first model is described by a system of ordinary differential equations with the purpose of estimaling some essential parameters in the evolution of the epidemie. The second model uses a differential inclusion in order to simulate the dynamic under uncertainties. Also, we review a family of ordinary differential equations models of HIV/AIDS epidemic in Cuba and one of these models is reformulated as a differential inclusion. In addition, to analyze the behavior of these two epidemies and the effect of intervention, we develop a practical algorithm for the computation of the reachable sets of the differential inclusions, providing a mathematical framework allowing us to make suitable predictions of aII state variables of the models at a future time.

http://www.theses.fr/2011AGUY0413

Éditeur(s) : HAL CCSD IGI Global
Résumé : International audience
The social behavior of individuals is an important factor of the transmission and the evolution of many diseases. As such, epidemic studies have attempted to integrate social aspects in dissemination modeling. Since the pioneering works of Klovdahl on AIDS in 1985, epidemiological investigations and interventions increasingly focus on social networks. Significant factors of the transmission and outbreak of many infectious diseases are the structure and nature of human interactions. Network-based modeling approaches have found various applications in epidemiology as a simple yet efficient way to represent the complexity of human relationships implicated in dissemination processes. However, most results have been obtained by considering social networks as steady stage structures. Evolving networks have not been explored. The objective is first to give an overview of network-based modeling attempts in epidemiology to analyze and understand the dissemination processes with an emphasis on dynamic networks. The authors approach is designed to understand the impact of social links dynamics on epidemic spread. The authors present the results obtained by combining network evolution patterns (link creation and deletion) and a typical epidemic model. The speed of link dynamics and the infection time strongly influence the occurrence and value of the epidemic peak.
ISSN: 1947-8186

hal-00700105
https://hal.archives-ouvertes.fr/hal-00700105
DOI : 10.4018/jismd.2012070103

Éditeur(s) : HAL CCSD
Résumé : International audience
—Managing spatial reservoirs of malaria infection plays a crucial role in effective disease control. In this paper, a reservoir of infection refers to one or more interconnected subpopulations that sustain the epidemic at the level of the metapopulation to which applying a (linear) control strategy suffices to eradicate the disease in the whole system. We propose a numerical method to explain the steps for identifying reservoirs of malaria infection within n connected regions with the explicit movement of human population from the previous theoretical results in order to design an efficient computational tool. Furthermore, we determine the minimal percentage (critical vaccination fraction) of susceptible individuals in the reservoirs that should be protected to eliminate malaria. The costs and cost-effectiveness of malaria control interventions were analysed considering two strategies of control. (i) protecting the minimal fraction of susceptible individual; (ii) protecting any fraction greater than the minimal fraction. Cost-effectiveness analysis shows that the less cost and more effective strategy is to vaccinate (or protect) the minimal fraction of susceptible human in the reservoir of infection to halt outbreak. A numerical example provides insight into the efficiency of this approach.
IAENG International Journal of Applied Mathematics

Droits : info:eu-repo/semantics/OpenAccess
hal-01683800
https://hal.univ-antilles.fr/hal-01683800
https://hal.univ-antilles.fr/hal-01683800/document
https://hal.univ-antilles.fr/hal-01683800/file/ZongoDorvilleGouba28Janvier2017.pdf

Éditeur(s) : European Association of Fish Pathologists Seventh International Conference Diseases of Fish and Shellfish
Résumé : Outbreaks of mass mortality occurred since 1993 in penaeid shrimp (Penaeus stylirostris) reared in New-Caledonia. Since then, the disease, called "syndrome 93" (S93) has inflicted serious losses (60 to 100%) during the cold period and thus must be considered as an economically significant disease.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1995/acte-2974.pdf
http://archimer.ifremer.fr/doc/00000/2974/

Résumé : La dengue constitue actuellement l'arbovirose la plus répandue sur la planète avec 40% de la population mondiale exposée, soit environ 2,5 milliards de personnes. La maladie est endémique dans tous les continents excepté l'Europe même si les premiers cas de transmission autochtone ont été observés en France métropolitaine et en Croatie en 2010. L'augmentation régulière de son incidence fait actuellement de la dengue un problème de santé publique majeur dans les pays tropicaux et une menace pour d'autres pays du monde. En raison de son mode de transmission, la dengue constitue une maladie étroitement liée à l'environnement. L'urbanisation constitue un facteur important dans l'émergence ou la réémergence d'épidémies de dengue dans les pays tropicaux. Cette étude menée a pour objet d'analyser les liens existant entre le domaine de la santé (situation sanitaire et épidémiologique de la dengue) et de celui de l'environnement (évolution de l'urbanisation) en Guadeloupe continentale entre 2000 et 2008.Pour ce faire, les cas suspects et confirmés de dengue ont été recueillis. L'incidence pour ces deux types de cas a été calculée puis représentée à deux échelles administratives différentes: communes et sections. Les facteurs environnementaux comprenant les variables physiques et socio-démographiques ont été pris en compte pour la définition, l'identification et l'analyse de l'évolution des contextes d'habitation durant la période étudiée. Deux méthodes ont été utilisées: la classification «Raster» consistant en une analyse régulière basée sur des mailles de taille identique et la classification « Vecteur» s'appuyant sur les limites administratives des sections. Ces classifications ont permis de décrire la répartition des différents contextes d'habitation sur le territoire de la Guadeloupe et d'obtenir des indicateurs qui ont été analysés en relation avec les données sanitaires. Il a été mis en évidence que la situation épidémiologique de la dengue dans le département s'est significativement aggravée au cours de la période étudiée. Des épidémies majeures sont apparues en 2001, 2005/2006 et 2007. Le nord Basse-Terre, la région Pointoise ainsi que le sud-est de la Grande-Terre, de la ville du Gosier à Saint-François le long de la côte, sont les régions les plus concernées par l'augmentation d'incidence de la maladie. Concernant les contextes d'habitation, huit contextes distincts ont été identifiés: touristique, naturel, intermédiaire, agricole, résidentiel, rural, périurbain et urbain. Le contexte intermédiaire correspond à des régions de transition entre les autres contextes d'habitation. La différence entre les contextes agricoles et ruraux réside dans la prédominance de surface agricole pour le premier alors que le contexte rural est caractérisé par les espaces cultivés habités. L'évolution surfacique de ces contextes au cours du temps a été analysée en relation avec les incidences. Les résultats montrent que les contextes d'habitation sont statistiquement.associés à l'incidence de la dengue en Guadeloupe. En particulier, les contextes touristiques, résidentiels et ruraux possèdent une association positive élevée avec l'incidence de la dengue.
At present, dengue fever has become the arbovirose the most wide-spread worldwide with 40 % ofthe exposed population, 2,5 billion people. The disease is endemie in all the continents excepted Europe even though the fust cases ofautochthonoustransmissionwere observedinmetropolitanFranceandCroatiain2010.Because oftherecentincrease of its incidence, dengue fever is now a major public health problem in the tropical countries and a threat for the other countries in the worldwide. Due to its mode oftransmission, the disease is closely linked to the environment. Urbanization is an important factor ofthe emergence or the re-emergence of dengue in the tropical countries. This study aims to analyze the links between health and environment domains, which correspond to the epidemiological situation of the dengue and the evolution ofthe urbanization in Guadeloupe.Information about suspect and confirmed cases of dengue were collected. The incidence of suspect and confirmed cases has been estimated, then represented at two different administrative boundaries: communes and sections. Environmental factors including the physical and socio-demographic variables were taken into account to the definition, the identification and the analyze ofevolution of the housing patterns during the studied period. Two methods were used: Il Raster" consisting of a regular analysis based on squares units and "Vector" based on the administrative limits of sections. These classifications allowed to describe the distribution ofthe different housing patterns ofGuadeloupe and to estimate indicators for the analyzing of sanitary data. The results highlight a worsening ofepidemiological situation ofthe dengue over the time in the department. Major outbreaks occurred in 2001,2005/2006 and 2007. The north Basse-Terre, the Pointe-à-Pitre urban area as weIl as the whole coast (frOID the city of Gosier to Saint-François) ofthe southeast ofGrande-Terre were the most affected regions by the increase ofincidence of dengue. Concerning the housing classes, eight different patterns were identified: tourist, natural, intermediate, agricultural, residential, rural, suburban and urban. The intermediate class corresponds to buffer regions between the other patterns. The difference between the agricultural and rural contexts lies in the predominance ofagricultural surface for the first one while the rural context is characterized by the inhabited farmland. The evolution over time of spatial extend ofthese patterns was described in relation with incidence. Results showed that the housing patterns are statically associated with the incidence ofdengue in Guadeloupe. In particular, the touristic, residential and rural patterns have a high positive association with dengue incidence.

http://www.theses.fr/2012AGUY0565/document

Éditeur(s) : Elsevier
Résumé : The "Summer Syndrome", a septicemic vibriosis caused by Vibrio nigripulchritudo, is responsible for one of the two main seasonal mortalities which affect shrimp aquaculture in New Caledonia. It was identified for the first time in December 1997 in an intensive shrimp farm (called farm DF) and has been enzootic ever since. The "Summer syndrome" affects shrimp during warm-season growout. Although the geographic area concerned is limited, it is a potential threat for the industry in that the disease could spread. Analysis of grow out data from 1991 to 2002 in this farm was carried out in order to characterize the disease and the environmental conditions in relation to mortality. Results of farm DF were compared to data from farms not affected by the disease (called farms HC). The "Summer syndrome" occurs during the warm season which is characterized by an increase in water temperature and sunny duration. This disease is characterized by simultaneously highest densities and weakest drying duration between crops in the farms studied. Between 1991 and 2002, the increase of feed input and nitrogen rate in feed has led to a significant increase of the growth rate over the years in farm DF. At the same time, water management has not changed and has induced an increase in environmental waste production. In consequence, an early eutrophication of water is observed, which is concomitant with the beginning of the mortality outbreaks. This could play a role by inducing directly or indirectly a stress for shrimp and/or a growth and/or virulence factors of the pathogen.
Aquaculture (0044-8486) (Elsevier), 2006-08 , Vol. 261 , N. 3 , P. 1039-1047

Droits : 2006 Elsevier
http://archimer.ifremer.fr/doc/2006/publication-1868.pdf
DOI:10.1016/j.aquaculture.2006.08.036
http://archimer.ifremer.fr/doc/00000/1868/