Influence of temperature on mortality in the French overseas regions: a pledge for adaptation to heat in tropical marine climates.

CONTEXT: Tropical areas and small islands are identified as highly vulnerable to climate change, and already experiencing shifts in their temperature distribution. However, the knowledge on the health impacts of temperatures under tropical marine climate is limited. We explored the influence of temperature on mortality in four French overseas regions located in French Guiana, French West Indies, and in the Indian Ocean, between 2000 and 2015. METHOD: Distributed lag non-linear generalized models linking temperature and mortality were developed in each area, and relative risks were combined through a meta-analysis. Models were used to estimate the fraction of mortality attributable to non-optimal temperatures. The role of humidity was also investigated. RESULTS: An increased risk of mortality was observed when the temperature deviated from median. Results were not modified when introducing humidity. Between 2000 and 2015, 979 deaths [confidence interval (CI) 95% 531:1359] were attributable to temperatures higher than the 90th percentile of the temperature distribution, and 442 [CI 95% 178:667] to temperature lower than the 10th percentile. DISCUSSION: Heat already has a large impact on mortality in the French overseas regions. Results suggest that adaptation to heat is relevant under tropical marine climate.

From the threat to the large outbreak: dengue on Reunion Island, 2015 to 2018.

BackgroundWith more than 300 million infections estimated annually worldwide, dengue is the most prevalent arboviral infection. On Reunion Island, after a large outbreak in 1977-78, only limited episodes of viral circulation or sporadic cases were reported till 2015.AimOur objective was to document and report on the circulation of dengue virus after the occurrence of a small outbreak during austral summer 2015/16 and until the large outbreak of 2018.MethodsBeside the mandatory notification of biologically confirmed dengue cases, additional systems of surveillance were set up: estimation of dengue-like syndrome in people seeking care by their family doctor, surveillance of emergency department visits related to dengue, surveillance of hospitalised dengue patients and deaths classifications.ResultsAfter a moderate outbreak during summer 2015/16 with 231 cases, 2017 was characterised by limited viral circulation (97 cases) which, however, persisted during the austral winter. By February 2018, the number of cases had increased and led to a peak at the beginning of May 2018. More than 6,000 cases were reported this year (dengue virus type 2 only). In addition, six deaths of dengue patients were notified.ConclusionIn 2017, the persistence of transmission during winter created favourable conditions for the emergence of an epidemic during summer 2018. After this moderate epidemic wave, the viral circulation persisted during winter 2018 for the second year, opening the door for the second wave in 2019 and for potential endemisation of the disease on Reunion Island in the near future.

Health monitoring during water scarcity in Mayotte, France, 2017.

BACKGROUND: During the 2016-2017 austral summer, unprecedented water scarcity was observed in the south of Mayotte, French island in the Indian Ocean. Therefore, authorities introduced restrictive measures to save the water of this part of the island. The rationing system affected over 65,000 people, for four months. In order to detect a possible deterioration of the health situation, a strengthened epidemiological surveillance system was set up. METHODS: Surveillance focused on intestinal and skin diseases, which are often associated with a lack of hygiene or poor-quality drinking and bathing water. Three pathologies were monitored: acute diarrhoea, acute gastroenteritis and skin diseases and also, proportion of antidiarrhoeal and rehydration solutions sales in pharmacies. Cases of leptospirosis were also under surveillance. The analyses consisted of comparing the collected data according to the areas that were either affected or not affected by the water restrictions. Comparisons with historical data were also made. RESULTS: Although none of the surveillance systems were able to demonstrate any impact on skin diseases, they revealed a very sharp increase in the proportion of consultations for acute diarrhoea and gastro-enteritis in the southern area. This was corroborated by a high increase in the sales of antidiarrhoeals and oral rehydration solutions via the sentinel pharmacists in the south of the island compared with those of the north. Comparison with historical data highlighted the occurrence of an unusual situation. CONCLUSION: These water restrictions caused a real deterioration in the health status of the inhabitants who were deprived of water.

Seroprevalence and risk factors of chikungunya virus infection in Mayotte, Indian Ocean, 2005-2006: a population-based survey.

BACKGROUND: Since 2006, Chikungunya virus (CHIKV) has re-emerged as an important pathogen of global concern. However, individual and household factors associated with the acquisition and the magnitude of clinically silent CHIKV infections remain poorly understood. In this present study, we aimed to investigate the seroprevalence, estimate the proportion of symptomatic illness and identify the risk factors for CHIKV infection in the primo-exposed population of Mayotte. METHODS/ PRINCIPAL FINDINGS: We conducted a household-based cross sectional serosurvey in Mayotte in November and December 2006 using complex multistage cluster sampling. To produce the results representative of the island population aged 2 years or older, sample data were adjusted with sample weights. Explanatory and multiple logistic regression analyses were performed to investigate associations between CHIKV infection seropositivity (presence of IgM and/or IgG to CHIKV by enzyme-linked immunoabsorbent assay) and risk factors. A total of 1154 individuals were analyzed. The overall seroprevalence of CHIKV infection was 37.2% (95% CI = 33.9-40.5), 318 (72.3%) of the seropositive participants reported symptoms consistent with a CHIKV infection during the epidemic period. Risk factors for CHIKV seropositivity among adults (aged 15 years and older) were male gender, low socioeconomic index, schooling < or = 6 years and living in makeshift housing. CONCLUSIONS: Our findings indicate that roughly one out of four CHIKV infections is asymptomatic. Conditions associated with poverty may be considered as critical in CHIKV acquisition. Thus, these conditions should be taken into account in the development of future prevention strategies of CHIKV disease.

[Electronic transmission of epidemiologic data and monitoring of the chikungunya virus epidemic in Reunion Island, 2006]. / Transmission télématique de données épidémiologiques et surveillance de l'épidémie de chikungunya à la Réunion en 2006.

INTRODUCTION: When the first cases of the 2005-2006 chikungunya epidemic struck Reunion Island, local health authorities set up an island-wide operational epidemiologic surveillance system for these infections. This system relied on vector control teams, which conducted active case-finding around the reported cases, and on a sentinel physician network. In addition, in March 2006, the Sephira and Reunion-Telecom companies, in partnership with the Reunion-Mayotte interregional epidemiology bureau (CIRE), developed an innovative system of epidemiologic monitoring by electronic data transmission. METHODS: This system relied on the participation of volunteer physicians who transmitted epidemiologic data through the data terminals used for the transmission of electronic treatment forms to the health insurance funds. Using the patient's insurance identification card, each physician provided information about consultations related to chikungunya. This information was transmitted, via the Sephira server in France to Reunion-Telecom, which processed, aggregated and transmitted these data weekly to the CIRE. This network was separate from and independent of the sentinel physician network, RESULTS: In all, 44 physicians, accounting for 6% of the general practitioners in Reunion, participated in this system, which went into operation during week 14 of 2006. The data collected allowed an assessment of the trends in the epidemic incidence rate by calculating the percentage of consultations related to chikungunya among all consultations (office visits and house calls). For weeks 14-26 of 2006, when the epidemic transmission had spread across the entire island, the Reunion-Telecom health network data proved to be closely correlated with the results of the sentinel physician network surveillance system used to monitor the epidemic trends (correlation coefficient=0.97). CONCLUSION: The system provided very encouraging results in monitoring disease time trends in a period of massive epidemic. Its simplicity of use and the speed of data transmission are undeniable assets for its future development. Because it offers the possibility of monitoring other diseases with epidemic potential, such as dengue and influenza, it opens new prospects for infectious disease surveillance.

A major epidemic of chikungunya virus infection on Reunion Island, France, 2005-2006.

In January 2005, an epidemic of chikungunya fever broke out in the Comoro Islands and lasted until May 2005. In April, cases were also reported in Mayotte and Mauritius. On Réunion Island, the first cases were reported at the end of April. Surveillance of this epidemic required an adaptive system, which at first was based on active and retrospective case detection around the cases reported, then relied on a sentinel network when the incidence increased. Emerging and severe forms of infection were investigated. Death certificates were monitored. By April 2006, the surveillance estimate was 244,000 cases of chikungunya virus infection, including 123 severe cases and 41 of maternoneonatal transmission, with an overall attack rate of 35%. Chikungunya infection was mentioned on 203 death certificates and significant mortality was observed. This epidemic highlighted the need for a mutual strategy of providing information on arboviral diseases and their prevention and control between countries in the southwestern Indian Ocean.