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Objective: Hepatitis E virus (HEV) has been scarcely investigated in the Indian Ocean. Following a nationwide serosurvey among blood donors, we conducted a population-based serosurvey to assess the magnitude of HEV exposure on Reunion Island. Methods: Four hundred and sixty-six archived frozen human sera from the 2009 CoPanFlu-RUN cohort were analysed using the Wantai HEV IgG enzyme immunoassay. HEV seropositivity was defined as an IgG titre ≥5 UI/ml. Raw and weighted seroprevalences were assessed to account for the discrepancy between the CoPanFlu-RUN subset and the general community. Prevalence proportion ratios (PPR) were measured using log-binomial models. Results: The raw and the weighted seroprevalences of HEV were 9.01% (95% CI 6.41–11.61) and 6.73% (95% CI 4.47–8.98), respectively. The presence of HEV IgG antibodies was associated with increasing age (P

After the documentation of sporadic cases of Q fever endocarditis, we conducted a serosurvey to assess Coxiella burnetii exposure on Reunion Island. Two hundred forty-one stored frozen human sera were analyzed using an immunofluorescence assay. The weighted seroprevalence of Q fever was of 6.81% (95% confidence interval, 4.02%–9.59%). Despite the absence of infection in youths

International audience; Since 1953, leptospirosis has been recognized as a public health problem on Reunion Island. In 2004, was implemented a specific surveillance system that included systematic reporting and the realization of environmental investigations around hospitalized cases. Here, we present the synthesis of historical data and the assessment of 9 years of leptospirosis surveillance. From 2004 to 2012, 414 hospitalized cases were reported. Cases of leptospirosis occurred mostly during the rainy season from December to May. Approximately 41% of infections occurred at home, 12% of infections occurred during aquatic leisure and 5% of cases were linked to professional activities. Furthermore, for 41% of cases, the place of infection could not be determined due to the accumulation of residential and non-residential exposure. Most of the cases of leptospirosis were linked to rural areas or traditional, rural occupations. We did not observe a shift to recreational leptospirosis as described in some developed countries. According to the new surveillance system, the number of reported cases has regularly increased since 2004. This situation is in part due to the improvement of the system in the first years but also to a real increase in the number of detected cases due to the introduction of molecular methods and to increased biological investigation into the Dengue-like syndrome by medical practitioners on the island since the Chikungunya crisis in 2006. This increase is probably due to surveillance and diagnosis biases but need to be carefully monitored. Nevertheless, the possibility of an outbreak is always present due to climatic events, such as after the "hyacinth" hurricane in 1980.

On August 5, 2015, the world of virology lost one of its great unsung heroes, when Alain Michault, a top-class researcher on Chikungunya virus (CHIKV), died at age 64 years of cancer. Alain's friends: Florence Naze, Gerard Bertil, Sandrine Picot, Catherine Simac, Julien Jaubert, Caroline Lemonnier, Noor Hamdani, Francoise Belon, Frederik Staikowsky, Therese Couderc, Marc Lecuit, Philippe Despres, Patrick Mavingui, Jean-Louis Solet, Laurent Filleul, Herve Pascalis, Eric Cardinale, Amelie Desvars, Vincent Porphyre, and Olivier Pruvost. The authors thank Francine Michault and Diana Breysse for proofreading the article.

SUMMARYWe report herein the investigation of a leptospirosis outbreak occurring in triathlon competitors on Réunion Island, Indian Ocean. All participants were contacted by phone or email and answered a questionnaire. Detection and molecular characterization of pathogenicLeptospirawas conducted in inpatients and in rodents trapped at the vicinity of the event. Of the 160 athletes competing, 101 (63·1%) agreed to participate in the study. Leptospirosis was biologically confirmed for 9/10 suspected cases either by real-time PCR or serological tests (MAT or ELISA). The total attack rate, children's attack rate, swimmers’ attack rate, and the attack rate in adult swimmers were respectively estimated at 8·1% [95% confidence interval (CI) 4·3–14·7], 0%, 12·7% (95% CI 6·8–22·4) and 23·1% (95% CI 12·6–33·8). Leptospirosis cases reported significantly more wounds [risk ratio (RR) 4·5, 95% CI 1·6–13], wore complete neoprene suits less often (RR 4·3, 95% CI 1·3–14·5) and were most frequently unlicensed (RR 6·6, 95% CI 2·9–14·8). The epidemiological investigation supported that some measures such as the use of neoprene suits proved efficient in protecting swimmers against infection. PCR detection in rats revealed highLeptospirainfection rates. Partial sequencing of the 16S gene and serology on both human and animal samples strongly suggests that rats were the main contaminators and were likely at the origin of the infection in humans.

International audience; This paper reports on an entomological survey performed over the period 2009-2011 in endemic focus of pen-urban TOSV in South of France located from 24 km east of Marseille. Sand flies were captured using CDC light traps set in sand fly resting places overnight, and temperature, relative humidity and wind were recorded to establish possible relations between meteorological factors and vector densities. The most common species, of 5,432 specimens collected and identified, was Phlebotomus perniciosus (74%), followed by Sergentomyia minuta (6%) and Phlebotomus ariasi (1%). Male flies were highly predominant for all Larroussius species instead of S. minuta which counted (85%) of females. The results shed light on the wide population's dynamic of P. perniciosus in France showing a diphasic seasonal trend with two abundance peaks at the beginning of July and late August, when a mean temperature is from 23.3 to 25.7 degrees C. Interestingly, these two peaks are corresponding to the peaks of occurrence of human TOSV cases. Among the 1724 females collected, 549 (32%) were blood-fed. Based on the results of blood meal analyses, P. perniciosus fed on large animal's diversity (man, chicken, rabbit, others mammalians, etc.), including bats that are the only species found naturally infected by TOSV. Results indicate that host choice was probably related to its availability than specific attractiveness. Data presented confirm that sand flies easily adapted to the periurban sites like, P. pemiciosus may represent a public health concern for pathogen transmission in similar Mediterranean environments. (C) 2015 Elsevier B.V. All rights reserved.

International audience; The 2014 seasonal influenza in Réunion, a French overseas territory in the southern hemisphere, was dominated by influenza B. Resulting morbidity impacted public health. Relative to the total number of all-cause consultations over the whole season, the rate of acute respiratory infection (ARI) consultations was 6.5%. Severe disease occurred in 32 laboratory-confirmed influenza cases (31.7 per 100,000 ARI consultations), 16 with influenza B. The observed disease dynamics could present a potential scenario for the next European influenza season.

International audience; Retrospective studies and surveillance on humans and animals revealed that Rift Valley Fever virus (RVFV) has been circulating on Mayotte for at least several years. A study was conducted in 2011 to estimate the seroprevalence of RVF in humans and in animals and to identify associated risk factors. Using a multistage cluster sampling method, 1420 individuals were enrolled in the human study, including 337 children aged 5 to 14 years. For the animal study, 198 seronegative ruminants from 33 randomly selected sentinel ruminant herds were followed up for more than one year. In both studies, information on environment and risk factors was collected through a standardized questionnaire. The overall weighted seroprevalence of RVFV antibodies in the general population aged ≥5 years was 3.5% (95% CI 2.6-4.8). The overall seroprevalence of RVFV antibodies in the ruminant population was 25.3% (95% CI 19.8-32.2). Age (≥15), gender (men), place of birth on the Comoros, living in Mayotte since less than 5 years, low educational level, farming and living close to a water source were significantly associated with RVFV seropositivity in humans. Major risk factors for RFV infection in animals were the proximity of the farm to a water point, previous two-month rainfall and absence of abortions disposal. Although resulting in few clinical cases in humans and in animals, RVFV has been circulating actively on the island of Mayotte, in a context of regular import of the virus from nearby countries through illegal animal movements, the presence of susceptible animals and a favorable environment for mosquito vectors to maintain virus transmission locally. Humans and animals share the same ways of RVFV transmission, with mosquitoes playing an important role. The studies emphasize the need for a one health approach in which humans and animals within their ecosystems are included.

International audience; In Reunion Island, the risk of emerging infectious diseases lies mainly in several viral zoonoses: West Nile fever, Sindbis virus, Nipah virus, Wesselsbron virus, Rift Valley fever and Japanese encephalitis. There morbidity and consequences are more or less important but they all have a non-negligible epidemic potential, so they have to be monitored. Indeed, the struggle against these emerging infectious diseases requires an early detection of the cases, thus a surveillance system capable of detecting them as early as possible, thanks to a real international network of information, warning and prevention.; A La Réunion, le risque d’émergence de maladies virales est constitué par plusieurs zoonoses virales qu’il convient de surveiller: infections à virus Sindbis, virus de l’encéphalite japonaise, virus Wesselsbron, virus Nipah, virus Zika, virus West Nile, virus de la fièvre de la vallée du Rift. La lutte contre ces maladies virales émergentes (MVE) passe par une détection précoce des cas et donc un système de surveillance doté d’un véritable réseau d’information, d’alerte et de prévention international.

International audience; It is increasingly suspected that the health impact of air pollution may be greateramong socioeconomically disadvantaged populations than among those who are betteroff. However, health impact assessments of air pollution generally do not takesocioeconomic status into account. In this paper, we propose an approach to thequantitative estimation of the short-term impacts of environmental risk factors such as airpollution among socioeconomically contrasted populations. We do so through anillustrative case study of ambient air pollution and emergency calls for asthma attacks inStrasbourg (France). Next, we discuss the potential advantages of this approach as well asits current limitations, and then look at the research needs that must be addressed toimprove its applicability. Among these, the most urgent appear to be the needs forimproved exposure estimates and for large-scale epidemiological studies that useharmonized methods to investigate the modification by socioeconomic status and otherfactors of the effects of air pollution. Case-crossover designs offer promisingperspectives for that purpose, especially as more accurate and individualized estimatesof air pollution exposure become available for epidemiological studies; On suspecte de plus en plus que l’ampleur des impacts sanitaires de la pollution atmosphérique augmente à mesure que le niveau socio-économique des populations décroît. Cependant, à ce jour, les évaluations d’impacts sanitaires de la pollution atmosphérique n’intègrent en général pas la dimension socio-économique. Dans cet article, une approche est proposée pour estimer quantitativement les effets à court terme de la pollution atmosphérique au sein de populations présentant des niveaux socio-économiques contrastés. Cette approche est illustrée par une application aux appels d’urgence pour crises d’asthme dans la communauté urbaine de Strasbourg. Les avantages de l’approche proposée y sont discutés, ainsi que les limites actuelles à son application. Des axes de recherche à développer pour améliorer son applicabilité sont identifiés. Parmi ceux-ci, l’amélioration de l’estimation des expositions à la pollution atmosphérique ainsi que la réalisation d’études multicentriques de grande ampleur, employant des méthodologies harmonisées afin d’étudier simultanément les interactions par le niveau socio-économique et par d’autres facteurs apparaissent de première importance. Le schéma d’étude cas-croisés offre des perspectives prometteuses pour répondre à cet objectif. Il permettra en particulier de prendre en compte à l’échelle individuelle des indicateurs d’exposition de plus en plus fins, au fur et à mesure que ceux-ci deviendront disponibles pour des études épidémiologiques.

To the Editor: Chikungunya virus (CHIKV) first emerged in Indian Ocean islands off the eastern coast of Africa in 2005 and was responsible for large-scale epidemics on the islands of Reunion, Comoros, Mayotte, Mauritius, Madagascar, and Seychelles (1–4). On Reunion Island, a French overseas territory of 810,000 inhabitants, herd immunity reached 38% in October 2006 (5). Molecular epidemiology of the strain responsible for these outbreaks indicated that it had originated in Kenya (6). The epidemic on Reunion Island was associated with a mutation in the envelope protein gene (E1-A226V) that improves replication and transmission efficiency in Aedes albopictus mosquitoes (7). Since 2006, the Regional Office of the French Institute for Public Health Surveillance in the Indian Ocean has conducted epidemiologic and biological surveillance for CHIKV infection. Case definitions have been described (8). During December 2006–July 2009, no confirmed case was detected on Reunion Island and Mayotte, but new outbreaks were reported in Madagascar (9). In August 2009, a cluster of cases was identified on the western coast of Reunion Island (8). We report an outbreak of CHIKV infection that occurred on Reunion Island in 2010. The first case was detected on March 17, 2010. As of July 6, a total of 100 confirmed and 32 probable cases had been identified (Figure A1). Median age of case-patients was 39 years (range 6 months–80 years), and the ratio of male to female case-patients was 0.81:1. In addition to fever (95%), case-patients had arthralgia (95%), headache (78%), and myalgia (75%). Seven (5%) were admitted to hospitals. No severe illness or death was reported. The outbreak remained largely restricted to residents of Saint Paul (75%) on the western coast. Sporadic cases in other cities also were detected. Sequence comparison based on partial envelope gene or complete genome showed a high level (>99.6%) of nucleotide and amino acid identity of 2010 isolates from Reunion Island with the strains of the 2009 sporadic cases on Reunion Island, as well as with the Malagasy strains circulating since 2006. All isolates sequenced bore the A226V substitution within the E1 protein. Altogether, these results support the hypothesis of a continuous circulation of A226V strains in the southwestern Indian Ocean since 2006 and the possible reintroduction of CHIKV on Reunion Island, most probably from Madagascar. Once again, human travel may have contributed to the rapid spread of the virus between islands because imported and autochthonous cases on Reunion Island occurred after a holiday period for residents on Reunion Island who often traveled to Madagascar. Migration and birth rate on Reunion Island might have contributed to a decrease in the immunity of the population. Furthermore, seroprevalence in 2007 was not homogenous throughout the territory. A hypothesis would be that a lower immunity of the population in the Saint Paul area and environmental and vectorial characteristics contributed to the emergence of this CHIKV disease cluster. On Reunion Island, Ae. albopictus mosquitoes have been described as the main vector responsible for transmitting CHIKV (10). The austral winter may contribute to moderate vector activity and transmission. We cannot exclude a continuous transmission until next austral summer, followed by an increase of cases and an extension to the whole island, as occurred in 2005 (1). Epidemiologic and entomologic surveillance has been reorganized to prevent this risk. Medical staff, the general population, and travelers have been informed about the situation through the news media and meetings organized by health authorities, and recommendations have been issued about destroying mosquito breeding sites and preventing mosquito bites. In recent years, the area of circulation and the epidemic potential of CHIKV have increased, and CHIKV has emerged as a major public health problem. This outbreak could be a new warning to Reunion Island health authorities about the need for preparation not only for CHIKV but also for dengue virus (DENV). With the extent of human travel to and from areas with active CHIKV and DENV circulation, viremic returning travelers constitute an ongoing risk for introduction of such viruses on Reunion Island. In May 2010, two locally acquired DENV-3 cases were also detected, illustrating this threat. These cases occurred during an outbreak of DENV-3 in Comoros Island. Public health efforts to control Ae. albopictus mosquitoes have not been completely effective. This outbreak of CHIKV infection, the detection of autochthonous cases of DENV infection, and the influenza season on Reunion Island emphasize the difficulty of making the appropriate clinical diagnosis. Clinicians and biologists should be aware of the cocirculation of CHIKV, DENV, and influenza viruses. The reemergence of CHIKV on Reunion Island illustrates the permanent threat of circulation of exotic pathogens in the Indian Ocean and the need for strong epidemiologic and laboratory surveillance. Human travel and the geographic expansion of Ae. albopictus mosquitoes raise concern for the spread of CHIKV in Europe and North America.

International audience; BACKGROUND: To date, there is little information that reflects the true extent of spread of the pH1N1/2009v influenza pandemic at the community level as infection often results in mild or no clinical symptoms. This study aimed at assessing through a prospective study, the attack rate of pH1N1/2009 virus in Reunion Island and risk factors of infection, during the 2009 season. METHODOLOGY/PRINCIPAL FINDINGS: A serosurvey was conducted during the 2009 austral winter, in the frame of a prospective population study. Pairs of sera were collected from 1687 individuals belonging to 772 households, during and after passage of the pandemic wave. Antibodies to pH1N1/2009v were titered using the hemagglutination inhibition assay (HIA) with titers ≥ 1/40 being considered positive. Seroprevalence during the first two weeks of detection of pH1N1/2009v in Reunion Island was 29.8% in people under 20 years of age, 35.6% in adults (20-59 years) and 73.3% in the elderly (≥ 60 years) (P

International audience; The socio-economic status (SES) of populations has an influence on the incidence or mortality rates of numerous health outcomes, among which respiratory diseases (Prescott et al., 2003; Ellison-Loschmann et al., 2007). Considering asthma, the possible contribution of SES to overall prevalence –regardless of asthma severity-, remains controversial in industrialized countries. Several studies indicate that allergic asthma is more prevalent in more well-off populations whereas the non-allergic forms of asthma are more common in the deprived ones (Cesaroni et al., 2003; Blanc et al., 2006). On the other hand, severe asthma whatever its etiology appears to be more frequent in the latter populations, as compared to the more affluent (Basagana et al., 2004). Risk factors for exacerbations (e.g., passive smoking (Wright Subramanian, 2007), psychosocial stress (Gold & Wright, 2005), cockroach allergens (Kitch et al., 2000), and suboptimal compliance with anti-inflammatory medication (Gottlieb et al., 1995)) are generally more common among people with asthma and low SES than their better-off counterparts. These observations support the hypothesis that some factors more present in deprived populations contribute to asthma exacerbation (Mielck et al., 1996).

International audience; We report results of the prospective surveillance system established in the largest intensive care unit (ICU) of Reunion Island (25 beds). This system covers 500,000 residents (62% of the total population) and monitors the daily status of patients >17 years of age who had a positive reverse transcription–PCR (RT-PCR) for pandemic (H1N1) 2009 virus. Reunion Island is a French overseas territory in the Southern Hemisphere, with health care facilities similar to those of mainland France. Patients were followed up until discharge from the ICU or death. Data were collected during July 15–September 30, 2009.