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BackgroundDengue dynamics result from the complex interaction between the virus, the host and the vector, all being under the influence of the environment. Several studies have explored the link between climate and dengue outbreaks in New Caledonia. None of them have explored the evolution of the dengue outbreak risk facing climate change.Methodology/Principal FindingsIn this study we chose the threshold time dependent reproduction number (Rt) as the modeling target to focus on time frames suitable for outbreak growths. A weekly statistical model of dengue outbreak risk (i.e. dengue outbreak probability) based on climate variables was developed using support vector machines (SVM) and then used in combination with CMIP5 projections of rainfall and temperature to estimate the future evolution of seasonal weekly risk and the inter-annual yearly risk of dengue outbreak up to the year 2100. The weekly risk of dengue outbreak is estimated using the number of days with maximal temperature exceeding 30.8°C during 80 days preceding the predicted week and the mean of precipitation during 60 days preceding the predicted week. According to the SVM model and to the worst greenhouse gas emission scenario projection (RCP8.5), the time frame suitable for epidemic growth will gain one month starting in November instead of December and the yearly risk of dengue outbreak occurrence increases regularly up to 2100 and reach a probability of 1 around 2080, making the dynamic of dengue fever endemic in New Caledonia.Conclusions/SignificanceA complete method to assess seasonal and inter annual variability of the risk of dengue outbreaks with respect to climate change is proposed. We conclude that climate change is likely to increase the risk of dengue in New-Caledonia (the other non climatic parameters remaining constant) in terms of both frequency of outbreak and temporal spread of the outbreak.Author summaryDengue virus is transmitted to human through the bite of an Aedes mosquito vector. Dengue fever is a worldwide public health concern, especially on tropical and subtropical countries. Over the last decade, the toll of dengue fever has increased in New Caledonia, raising questions about the future of the disease in this French island territory located in the South Pacific. Climate has a strong influence on dengue through its influence on the ecology of the vector and the viral cycle. Several studies have explored the link between climate and dengue in New Caledonia, with the aim of explaining and predicting dengue outbreaks. None of these studies have explored the possible outcome climate change will have on the risk of dengue fever in New Caledonia. This is the goal of this study, through projections of rainfall and temperature and the selection of an appropriate prediction target for our statistical model, we assess the climate-induced risk of dengue outbreaks up to the 2100 horizon. We prove that the inter-annual risk of dengue outbreaks in New Caledonia will raise, according to all the greenhouse gas emission scenarios and according to the high emission scenario, dengue fever will become an endemic disease in New Caledonia.

Background In 2017, New Caledonia experienced an outbreak of severe dengue causing high hospital burden (4379 cases, 416 hospital admissions, 15 deaths). We decided to build a local operational model predictive of dengue severity, which was needed to ease the healthcare circuit. Methods We retrospectively analyzed clinical and biological parameters associated with severe dengue in the cohort of patients hospitalized at the Territorial Hospital between January and July 2017 with confirmed dengue, in order to elaborate a comprehensive patient’s score. Patients were compared in univariate and multivariate analyses. Predictive models for severity were built using a descending step-wise method. Results Out of 383 included patients, 130 (34%) developed severe dengue and 13 (3.4%) died. Major risk factors identified in univariate analysis were: age, comorbidities, presence of at least one alert sign, platelets count 9/L, prothrombin time 10 N, and previous dengue infection. Severity was not influenced by the infecting dengue serotype nor by previous Zika infection. Two models to predict dengue severity were built according to sex. Best models for females and males had respectively a median Area Under the Curve = 0.80 and 0.88, a sensitivity = 84.5 and 84.5%, a specificity = 78.6 and 95.5%, a positive predictive value = 63.3 and 92.9%, a negative predictive value = 92.8 and 91.3%. Models were secondarily validated on 130 patients hospitalized for dengue in 2018. Conclusion We built robust and efficient models to calculate a bedside score able to predict dengue severity in our setting. We propose the spreadsheet for dengue severity score calculations to health practitioners facing dengue outbreaks of enhanced severity in order to improve patients’ medical management and hospitalization flow.

International audience; Arboviruses are viruses transmitted to humans by the bite of infected mosquito vectors. Over the last decade, arbovirus circulation has increasingly been detected in New Caledonia (NC), a French island territory located in the subtropical Pacific region. Reliable epidemiological, entomological, virological and climate data have been collected in NC over the last decade. Here, we describe these data and how they inform arboviruses' epidemiological profile. We pinpoint areas which remain to be investigated to fully understand the peculiar epidemiological profile of arbovirus circulation in NC. Further, we discuss the advantages of conducting studies on arboviruses dynamics in NC. Overall, we show that conclusions drawn from observations conducted in NC may inform epidemiological risk assessments elsewhere and may be vital to guide surveillance and response, both in New Caledonia and beyond.

International audience; Zika virus (ZIKV) infection has been associated with neurologic disorders including Guillain-Barré syndrome (GBS). In New Caledonia during the ZIKV outbreak (2014-2015), case-control and retrospective studies have been performed to assess the link between ZIKV and GBS. Among the 15 cases included, 33% had evidence of a recent ZIKV infection compared to only 3.3% in the 30 controls involved. All patients were Melanesian, had facial diplegia and similar neurophysiological pattern consistent with acute inflammatory demyelinating polyneuropathy, and recovered well. Furthermore, during the peak of ZIKV transmission, we observed a number of GBS cases higher than the calculated upper limit, emphasizing the fact that ZIKV is now a major trigger of GBS.

Introduction Lors de l’epidemie de Zika virus (ZikV) en Nouvelle Caledonie (NC) en 2014 (1500 cas), une augmentation de l’incidence du syndrome de Guillain Barre (SGB) a ete notee. Objectifs Nous avons voulu savoir si cette augmentation d’incidence du SGB etait significative et si la seropositivite au ZikV etait significativement plus importante chez les SGB par rapport a la population generale. Patients et methodes Les SGB remplissant les criteres diagnostiques de Brighton survenus entre 2011 et 2015 ont ete inclus de maniere retrospective. En parallele, une etude cas temoin a ete realisee comparant la seropositivite au ZikV des SGB de 2014 par rapport a 2 temoins apparies par âge, genre et origine geographique. Enfin nous avons collecte les donnees cliniques et neurophysiologiques des SGB ZikV + et compare aux donnees de la litterature. Resultats Entre 2011 et 2015, 43 cas de SGB ont ete rapportes en NC. L’incidence annuelle augmentait de maniere non significative de 2,29 cas pour 100 000 habitants en 2011 a 5,01 en 2014 ( p = 0,06). En 2014, 15 SGB ont ete rapportes dont 5 etaient seropositifs au ZikV comparativement a 1 temoin sur 30 ( p = 0,011). Ces SGB ZikV+ presentaient tous une diplegie faciale, des latences distales motrices tres allongees et une diminution des amplitudes motrices. Discussion Le doublement de l’incidence des SGB en 2014 n’est pas significatif, possiblement en rapport avec un faible nombre de SGB. Par contre il existe significativement plus d’infection a ZikV chez les SGB en faveur d’un lien entre ces 2 pathologies. Comme decrit dans la litterature, ces cas de SGB post ZikV auraient un profil clinique et neurophysiologique specifique. Conclusion Notre travail est en accord avec les precedentes etudes, mettant en evidence des liens epidemiologique, clinique et neurophysiologique entre le SGB et l’infection par le ZikV.

In ecotoxicology, critical effect concentrations are the most common indicators to quantitatively assess risks for species exposed to contaminants. Three types of critical effect concentrations are classically used: lowest/ no observed effect concentration (LOEC/NOEC), LC x (x% lethal concentration) and NEC (no effect concentration). In this article, for each of these three types of critical effect concentration, we compared methods or models used for their estimation and proposed one as the most appropriate. We then compared these critical effect concentrations to each other. For that, we used nine survival data sets corresponding to D. magna exposition to nine different contaminants, for which the time-course of the response was monitored. Our results showed that: (i) LOEC/NOEC values at day 21 were method-dependent, and that the Cochran–Armitage test with a step-down procedure appeared to be the most protective for the environment; (ii) all tested concentration–response models we compared gave close values of LC50 at day 21, nevertheless the Weibull model had the lowest global mean deviance; (iii) a simple threshold NEC-model both concentration and time dependent more completely described whole data (i.e. all timepoints) and enabled a precise estimation of the NEC. We then compared the three critical effect concentrations and argued that the use of the NEC might be a good option for environmental risk assessment.

International audience; The purpose of this study was to compare Daphnia magna responses to cadmium between two toxicity experiments performed in static and flow-through conditions. As a consequence of how water was renewed, the two experiments were characterised by two different exposure time patterns for daphnids, time-varying and constant, respectively. Basing on survival, growth and reproduction, we addressed the questions of organism development and sensitivity to cadmium. Classical analysis methods are not designed to deal with the time dimension and therefore not suitable to compare effects of different exposure time patterns. We used instead a dynamic modelling framework taking all timepoints and the time course of exposure into account, making comparable the results obtained from our two experiments. This modelling framework enabled us to detect an improvement of organism development in flow-through conditions compared to static ones and infer similar sensitivity to cadmium for both exposure time patterns. (C) 2011 Elsevier Inc. All rights reserved.

The no-observed-effect concentration (NOEC) is known to be based on a wrong usage of hypothesis tests, and the use of confidence intervals is preferred. The purpose of the present study is to provide an easy and proper way to interpret ecotoxicological tests based on simultaneous confidence intervals associated with the commonly used Dunnett procedure, and to show how these intervals may allow one to infer ECx values (effective concentrations). Environ. Toxicol. Chem. 2011;30:2888–2891. © 2011 SETAC

The main route of human Q fever infections is inhalation of infectious aerosols. The bacterial agent, Coxiella burnetii, is frequently found throughout domestic ruminants. Females constitute potential shedders of C. burnetii through vaginal mucus, faeces and milk. Q fever is also a common cause of abortion, especially in goats. Massive load of bacteria is associated with placentas and aborted foetuses. In experimental conditions, the Coxevac inactivated phase 1 vaccine (CEVA Sante Animale, Libourne, France) was efficient, and dramatically reduced abortion and excretion of bacteria [1]. The aim of the present study was to evaluate the Coxevac vaccination impact on bacterial shedding in goats affected by Q fever in natural conditions.