S. Larrieu

Short-term associations between fine and coarse particles and hospital admissions for cardiorespiratory diseases in six French cities

Objectives: Little is known about the potential health effects of the coarse fraction of ambient particles. The aim of this study is to estimate the links between fine (PM2.5) and coarse particle (PM2.5−10) levels and cardiorespiratory hospitalisations in six French cities during 2000–2003. Methods: Data on the daily numbers of hospitalisations for respiratory, cardiovascular, cardiac and ischaemic heart diseases were collected. Associations between exposure indicators and hospitalisations were estimated in each city using a Poisson regression model, controlling for confounding factors (seasons, days of the week, holidays, influenza epidemics, pollen counts, temperature) and temporal trends. City-specific findings were combined to obtain excess relative risks (ERRs) associated with a 10 μg/m3 increase in PM2.5 and PM2.5−10 levels. Results: We found positive associations between indicators of particulate pollution and hospitalisations for respiratory infection, with an ERR of 4.4% (95% CI 0.9 to 8.0) for PM2.5−10 and 2.5% (95% CI 0.1 to 4.8) for PM2.5. Concerning respiratory diseases, no association was observed with PM2.5, whereas positive trends were found with PM2.5−10, with a significant association for the 0–14-year-old age group (ERR 6.2%, 95% CI 0.4 to 12.3). Concerning cardiovascular diseases, positive associations were observed between PM2.5 levels and each indicator, although some did not reach significance; trends with PM2.5−10 were weaker and non-significant except for ischaemic heart disease in the elderly (ERR 6.4%, 95% CI 1.6 to 11.4). Conclusions: In accordance with other studies, our results indicate that the coarse fraction may have a stronger effect than the fine fraction on some morbidity endpoints, especially respiratory diseases.

Sentinel physician's network in Reunion Island: A tool for infectious diseases surveillance

UNLABELLED The surveillance of infectious diseases in Reunion Island is based on a sentinel network of family physicians (FPs) coordinated by the Indian Ocean regional institute for public health surveillance (French acronym OI Cire). The objectives are to identify and monitor outbreaks of influenza, gastroenteritis, and chicken pox, and to characterize circulating influenza viruses. The network can monitor other potentially epidemic diseases. METHOD The Réunion sentinel network ensures a continuous and permanent surveillance. Physicians send their weekly activity data to the Cire that collects, processes, and interprets it; they also collect samples for biological surveillance of influenza. Statistical thresholds, based on historical data and the estimated numbers of incident cases, are calculated to follow the trend, detect outbreaks, and quantify their impact. RESULTS The network currently includes 56 FPs and pediatricians, accounting for 6.5% of FPs on the island. The network has clarified the seasonality of influenza during the austral winter and identified the seasonality of acute diarrhea with an epidemic peak when school starts in August. The sentinel FPss reports allowed monitoring the epidemic trend and estimating the number of cases during the 2005 and 2006 chikungunya outbreaks and 2009 influenza A (H1N1) outbreaks. CONCLUSION The network has proven its contribution, responsiveness, and reliability for epidemiological surveillance during outbreak. It is an essential tool for infectious diseases surveillance in Reunion Island.

Dengue outbreaks: a constant risk for Reunion Island. Results from a seroprevalence study among blood donors.

BACKGROUND Immunity against dengue virus (DENV) on Reunion Island could play an important role in the risk of dengue outbreaks but is rather unknown. A study was performed to estimate seroprevalence of antibodies against DENV among blood donors. METHODS An age- and sex-stratified sample of 1825 sera was randomly selected. RESULTS Overall seroprevalence was 3.1% (95% CI: 2.2-3.9%); seroprevalence increased with age and was much higher in women than in men. CONCLUSION The low level of herd immunity is consistent with the absence of an endemic circulation of DENV, and makes it probable that Reunion Island will face future outbreaks.

Hospitalized cases of influenza A(H1N1)pdm09 in the French territories of the Americas, July 2009-March 2010

OBJECTIVE To describe the methodology used for implementing a surveillance system specifically for influenza A(H1N1)pdm09 in the French West Indies and French Guiana during an outbreak of this new virus in 2009-2010, and to report its main results. METHODS This was an observational descriptive study of confirmed and probable cases of influenza A(H1N1)pdm09 hospitalized for at least 24 hours in 23 July 2009-3 March 2010. Reverse transcription polymerase chain reaction was performed on nasopharyngeal swab samples according to the Centers for Disease Control and Prevention protocol. A probable case was defined as fever > 38ºC or aches or asthenia with respiratory symptoms (cough or dyspnea). All confirmed and probable hospitalized cases were reported, along with patients age, sex, clinical condition at admission, place and length of hospitalization, antiviral treatment, underlying conditions, complications, and clinical evolution. A case was classified as severe if respiratory assistance or intensive care was required or if death resulted. RESULTS A total of 331 confirmed and 16 probable cases were hospitalized, with a hospitalization rate ranging from 4.3 per 1 000 clinical cases in Saint Martin to 10.3 in French Guiana. Of these, 36 were severe, and subsequently, 10 were fatal. The median length of stay was 4 days for non-severe cases and 9 days for severe (P < 0.05). The mean patient age was 21 years, and severe cases were significantly older than non-severe (mean: 38 years versus 19 years, P < 0.05). Underlying conditions associated with a higher risk of severity were 65 years of age or more (RR = 7.5, 95%CI = 4.2-13.3), diabetes (RR = 3.7, 95%CI = 1.5-9.4), cardiac insufficiency (RR = 8.4, 95%CI = 5.2-13.6), and morbid obesity (RR = 4.4, 95%CI = 1.8-10.4). Patients who received antiviral treatment within 2 days of symptom onset had shorter hospital stays (mean: 4 days versus 6.5 days, P < 0.05), and the illness tended to become less severe (11.1% versus 19.0%, P = 0.13). CONCLUSIONS Active research of hospitalized cases enabled almost exhaustive surveillance. The pandemics hospitalization rates and lethality were more moderate than expected. Some previously known underlying conditions of severity were confirmed during this outbreak. Furthermore, these results show the validity of early antiviral treatment.