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Background Dengue dynamics result from the complex interactions between the virus, the host and the vector, all being under the influence of the environment. Several studies explored the link between weather and dengue dynamics and some investigated the impact of climate change on these dynamics. Most attempted to predict incidence rate at a country scale or assess the environmental suitability at a global or regional scale. Here, we propose a new approach which consists in modeling the risk of dengue outbreak at a local scale according to climate conditions and study the evolution of this risk taking climate change into account. We apply this approach in New Caledonia, where high quality data are available. Methods We used a statistical estimation of the effective reproduction number (Rt) based on case counts to create a categorical target variable : epidemic week/non-epidemic week. A machine learning classifier has been trained using relevant climate indicators in order to estimate the probability for a week to be epidemic under current climate data and this probability was then estimated under climate change scenarios. Results Weekly probability of dengue outbreak was best predicted with the number of days when maximal temperature exceeded 30.8°C and the mean of daily precipitation over 80 and 60 days prior to the predicted week respectively. According to scenario RCP8.5, climate will allow dengue outbreak every year in New Caledonia if the epidemiological and entomological contexts remain the same. Conclusion We identified locally relevant climatic factor driving dengue outbreaks in New Caledonia and assessed the inter-annual and seasonal risk of dengue outbreak under different climate change scenarios up to the year 2100. We introduced a new modeling approach to estimate the risk of dengue outbreak depending on climate conditions. This approach is easily reproducible in other countries provided that reliable epidemiological and climate data are available.

Background Hemotropic mycoplasmas, previously classified in the genus Eperythrozoon, have been reported as causing human infections in Brazil, China, Japan, and Spain. Methods In 2017, we detected DNA from Candidatus Mycoplasma haemohominis in the blood of a Melanesian patient from New Caledonia presenting with febrile splenomegaly, weight loss, life-threatening autoimmune hemolytic anemia, and hemophagocytosis. The full genome of the bacterium was sequenced from a blood isolate. Subsequently, we retrospectively (2011–2017) and prospectively (2018–2019) tested patients who had been hospitalized with a similar clinico-biological picture. In addition, as these patients had been in contact with frugivorous bats (authorized under conditions for hunting and eating in New Caledonia), we investigated the role of these animals and their biting flies by testing them for hemotropic mycoplasmas. Results There were 15 patients found to be infected by this hemotropic mycoplasma. Among them, 4 (27%) died following splenectomy performed either for spontaneous spleen rupture or to cure refractory autoimmune hemolytic anemia. The bacterium was cultivated from the patient’s blood. The full genome of the Neocaledonian Candidatus M. haemohominis strain differed from that of a recently identified Japanese strain. Of 40 tested Pteropus bats, 40% were positive; 100% of collected bat flies Cyclopodia horsfieldi (Nycteribiidae, Diptera) were positive. Human, bat, and dipteran strains were highly similar. Conclusions The bacterium being widely distributed in bats, Candidatus M. haemohominis, should be regarded as a potential cause of severe infections in humans.

International audience; ObjectiveCarbapenemase-producing Enterobacteriaceae (CRE) and Enterococcus faecium resistant to vancomycin (VRE) constitute major threats to public health worldwide. The Pacific area is concerned and has implemented strategies to control antimicrobial resistance (AMR). However, accurate epidemiological data are rarely reported. Our study aimed to present the strategies applied to prevent and control the spread of highly resistant bacteria in the Pacific territory of New Caledonia.Patients and methodsCohort prospective study of all cases of highly resistant bacteria (HRB) isolated in New Caledonia from September 2004 to December 2020. Evaluation of the impact of the infection control measures implemented in healthcare settings: screening strategy, cohorting unit, IT tools and control of antibiotic prescriptions.ResultsA total of 346 patients with HRB were identified. Most of them (63.0%) were infected or colonized by VRE (n = 218) and 128 by CRE. While the number of CREs significantly increased from 2013 to 2020 (P < 0.0001), control procedures have limited their dissemination. Most patients were colonized by IMP-4-CRE (n = 124/128). The incidence density of VRE significantly decreased from 38.52 for 100,000 hospitalisation-days in 2015 to 4.19 for 100,000 hospitalisation-days in 2019 due to systematic screening of patients before sanitary repatriation from Australia and cohorting implementation. The risk of VRE diffusion is now well under control.ConclusionsOur study confirms that it is possible to control the spread of AMR in a circumscribed territory by means of a global control strategy involving screening, cohorting unit, IT tools and antibiotic prescription controls.

Background Biological control programs involving Wolbachia-infected Aedes aegypti are currently deployed in different epidemiological settings. New Caledonia (NC) is an ideal location for the implementation and evaluation of such a strategy as the only proven vector for dengue virus (DENV) is Ae. aegypti and dengue outbreaks frequency and severity are increasing. We report the generation of a NC Wolbachia-infected Ae. aegypti strain and the results of experiments to assess the vector competence and fitness of this strain for future implementation as a disease control strategy in Noumea, NC. Methods/principal findings The NC Wolbachia strain (NC-wMel) was obtained by backcrossing Australian AUS-wMel females with New Caledonian Wild-Type (NC-WT) males. Blocking of DENV, chikungunya (CHIKV), and Zika (ZIKV) viruses were evaluated via mosquito oral feeding experiments and intrathoracic DENV challenge. Significant reduction in infection rates were observed for NC-wMel Ae. aegypti compared to WT Ae. aegypti. No transmission was observed for NC-wMel Ae. aegypti. Maternal transmission, cytoplasmic incompatibility, fertility, fecundity, wing length, and insecticide resistance were also assessed in laboratory experiments. Ae. aegypti NC-wMel showed complete cytoplasmic incompatibility and a strong maternal transmission. Ae. aegypti NC-wMel fitness seemed to be reduced compared to NC-WT Ae. aegypti and AUS-wMel Ae. aegypti regarding fertility and fecundity. However further experiments are required to assess it accurately. Conclusions/significance Our results demonstrated that the NC-wMel Ae. aegypti strain is a strong inhibitor of DENV, CHIKV, and ZIKV infection and prevents transmission of infectious viral particles in mosquito saliva. Furthermore, our NC-wMel Ae. aegypti strain induces reproductive cytoplasmic incompatibility with minimal apparent fitness costs and high maternal transmission, supporting field-releases in Noumea, NC., Author summary Dengue represents a risk for almost half of the world’s population, especially throughout the tropics. In New Caledonia, dengue outbreaks have become more frequent in the past decade along with the recent circulation of chikungunya and Zika viruses. The opportunity to use the biocontrol method involving the release of Wolbachia-infected Ae. aegypti mosquitoes has been investigated as an alternative solution to the traditional control methods, like elimination of larval habitats and pyrethroid insecticide application to kill adults, which are becoming insufficient. A local strain of Ae. aegypti carrying Wolbachia (NC-wMel) has been generated and tested to evaluate its pathogen blocking capacity for the four dengue virus serotypes as well as chikungunya and Zika viruses. The fitness of NC-wMel strain has also been assessed to estimate its ability to compete with the wild-type strain in the field. Noumea city, where a third of the population of New Caledonia resides, has been chosen as the first site to implement the method in New Caledonia. As Ae. aegypti is the only proven vector in New Caledonia, we expect a significant impact on dengue outbreaks occurring in Noumea as soon as a high frequency of NC-wMel is established in the population.

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New-Caledonia (NC) is a French community of the Asia-Pacific region where leprosy is still present. The epidemiological study of reported cases from 1983 to 2017 accounts for 342 cases. Since 1988 the overall annual prevalence is less than 1/10,000 inhabitants, the endemicity threshold set by the World Health Organization. Nevertheless, the study reveals an area of overendemia on the island of Bélep (location of the first leprosarium) where the 2007-2017 annual mean detection rate is 126.5/100,000 inhabitants. Over the last 10 years the predomi nance of multibacillary forms and the discovery of new cases of pediatrics leprosy show the persistence of a transmission in NC. Following this study, public health measures and in-depth studies were implemented., La Nouvelle-Calédonie (NC) est une collectivité française de la région Asie-Pacifique où la lèpre est toujours présente. La surveillance épidémiologique des cas notifiés de 1983 à 2017 comptabilise 342 cas. Depuis 1988, la prévalence globale annuelle est inférieure à 1/10 000 habitants, seuil d'endémicité fixé par l'Organisation mondiale de la Santé. Néanmoins, l'étude révèle une zone de surendémie sur l'île de Bélep (lieu d'implantation de la première léproserie) où le taux de détection moyen annuel 2007-2017 est de 126,5/100 000 habitants. Sur les 10 dernières années, la prédominance de formes multibacillaires et la découverte de nouveaux cas de lèpre pédiatriques démontrent la persistance d'une transmission en NC. Suite à cette étude, des mesures de santé publique et des études approfondies ont été mises en place.

International audience; New-Caledonia (NC) is a French community of the Asia-Pacific region where leprosy is still present. The epidemiological study of reported cases from 1983 to 2017 accounts for 342 cases. Since 1988 the overall annual prevalence is less than 1/10,000 inhabitants, the endemicity threshold set by the World Health Organization. Nevertheless, the study reveals an area of overendemia on the island of Bélep (location of the first leprosarium) where the 2007-2017 annual mean detection rate is 126.5/100,000 inhabitants. Over the last 10 years the predomi nance of multibacillary forms and the discovery of new cases of pediatrics leprosy show the persistence of a transmission in NC. Following this study, public health measures and in-depth studies were implemented.; La Nouvelle-Calédonie (NC) est une collectivité française de la région Asie-Pacifique où la lèpre est toujours présente. La surveillance épidémiologique des cas notifiés de 1983 à 2017 comptabilise 342 cas. Depuis 1988, la prévalence globale annuelle est inférieure à 1/10 000 habitants, seuil d'endémicité fixé par l'Organisation mondiale de la Santé. Néanmoins, l'étude révèle une zone de surendémie sur l'île de Bélep (lieu d'implantation de la première léproserie) où le taux de détection moyen annuel 2007-2017 est de 126,5/100 000 habitants. Sur les 10 dernières années, la prédominance de formes multibacillaires et la découverte de nouveaux cas de lèpre pédiatriques démontrent la persistance d'une transmission en NC. Suite à cette étude, des mesures de santé publique et des études approfondies ont été mises en place.

International audience; PurposeInvasive Meningococcal Disease (IMD) is three fold more common in New Caledonia (NC) than in metropolitan France and many IMD cases (35.7 %) are due to Y and W135 serogroups. The purpose of our study was to identify IMD risk factors in NC.MethodsA retrospective study of all IMD cases that occurred in NC between 2005 and 2011 was conducted. Socio-environmental, clinical and biological data were collected. A search for immune deficiency was proposed to all cases. IMD presentation and outcome were compared according to meningoccal serogroups and the complement deficiency status (C-deficiency).ResultsSixty-six sporadic IMD cases (29 B serogroup, 20 Y or W135, 6 C, 1 A, 10 unknown) occurred in 64 patients often