Individual and contextual risk factors for chikungunya virus infection: the SEROCHIK cross-sectional population-based study.

The purpose of the study was to weigh the community burden of chikungunya determinants on Reunion island. Risk factors were investigated within a subset of 2101 adult persons from a population-based cross-sectional serosurvey, using Poisson regression models for dichotomous outcomes. Design-based risk ratios and population attributable fractions (PAF) were generated distinguishing individual and contextual (i.e. that affect individuals collectively) determinants. The disease burden attributable to contextual determinants was twice that of individual determinants (overall PAF value 89.5% vs. 44.1%). In a model regrouping both categories of determinants, the independent risk factors were by decreasing PAF values: an interaction term between the reporting of a chikungunya history in the neighbourhood and individual house (PAF 45.9%), a maximal temperature of the month preceding the infection higher than 28.5 °C (PAF 25.7%), a socio-economically disadvantaged neighbourhood (PAF 19.0%), altitude of dwelling (PAF 13.1%), cumulated rainfalls of the month preceding the infection higher than 65 mm (PAF 12.6%), occupational inactivity (PAF 11.6%), poor knowledge on chikungunya transmission (PAF 7.3%) and obesity/overweight (PAF 5.2%). Taken together, these covariates and their underlying causative factors uncovered 80.8% of chikungunya at population level. Our findings lend support to a major role of contextual risk factors in chikungunya virus outbreaks.

[Chikungunya outbreak on Reunion Island in 2005/2006: role of hospital physicians in raising alert]. / L'epidémie de chikungunya de la Réunion 2005-2006; place du médecin hospitalier dans l'alerte et la gestion de l'epidémie.

The epidemic of chikungunya (CHIK) that swept through Reunion Island from late 2005 to mid 2006 affected 38.2% of the population, i.e., 300000 people. Although this outbreak took place in a French overseas department with high public health standards, failure to anticipate a large-scale epidemic associated with unprecedented severity and unexpectedly high mortality led to a major public health crisis. The purpose of this report is to provide a complete account of the experience of hospital intensive care physicians in addressing problems ranging from discovery of severe forms to management of a major health crisis. This report underlines the role of the head hospital physician and the necessity of mutual trust and collaboration with supervisory authorities.

An interdisciplinary approach to controlling chikungunya outbreaks on French islands in the south-west Indian ocean.

The outbreak of chikungunya that occurred on French Island territories in the southwest Indian Ocean in 2005 and 2006 caused severe morbidity and mortality. In the aftermath, French authorities set up a scientific task force including experts in epidemiology, public health, entomology, virology, immunology, sociology, animal health, community and hospital medicine. The mission of the task force was to conceive and propose research programs needed to increase understanding of the disease and epidemic and to help public health officials in improving epidemic response measures. The purpose of this article is to describe the findings of the task force at the end of its two-year existence and initial outcomes in the the areas studied. Discussion emphasizes topics requiring further study.

[Acute respiratory distress due to Influenza A (H1N1) S-OIV and extracorporeal oxygenation: the benefit of a multidisciplinary care network]. / Affection pulmonaire maligne à grippe A (H1N1) S-OIV et oxygénation extracorporelle: de l'intérêt d'un réseau de soins.

Between August and September 2009, on Reunion Island, our Intensive Care Unit (ICU) treated several severe Influenza A (H1N1) S-OIV cases. We report the following case: a 23-year-old female patient with no prior medical history presented a severe respiratory distress that required high frequency oscillation ventilation and finally Extracorporeal Membrane Oxygenation (ECMO). She was hospitalized in the ICU for 41 days. Recovery was complete. It is important to note the stead of each technique in those types of respiratory distresses and describe the practical details of the ECMO's set up by a non-trained medical crew. We want to underline, within the current context of severe respiratory distresses due to Influenza A pandemic, the necessity to develop a multidisciplinary care network, or to reinforce the existing channels between well-trained medical crews familiar with ECMO's technics and the ICU that are not.

[Outbreak of influenza A(H1N1)/2009: description of cases and crisis management in a ICU in Reunion Island]. / Épidémie de grippe A(H1N1/)2009 : description des cas et expérience de gestion de crise dans un service de réanimation réunionnais.

OBJECTIVES: to describe the characteristics, treatment and outcome of critically ill patients with influenza A(H1N1) infection at St Pierre Hospital in Reunion Island during the 2009 outbreak, as well as the measures of care reorganization implemented to face them. PATIENTS AND METHODS: prospective observational study of probable and confirmed cases of influenza A (H1N1)/2009 infection concerning hospitalized patients in a polyvalent intensive care unit (ICU). RESULTS: thirteen patients have been included between August and September 2009. Three (23 %) didn't have any medical history. The median age was 42 [22-69]. Eleven have required pulmonary ventilation for 10.3 days (± 8). Three (23 %) have developed an ARDS. Three patients (23 %) died. To cope with the influx of cases and considering our situation of geographic isolation, it has been needed to totally rework the organization of care: set-up of a specific welcoming channel, division into sectors of the department, opening of additional beds, new on-duty assignment, inter and intra hospital cooperation. CONCLUSION: reunion Island has been an experimental lab of crisis management during the H1N1/2009 epidemic, several months ahead of the mother country. To anticipate the reorganization of care in intensive care units during an outbreak period, particularly in small units or units isolated like ours, looks to us a must so to quietly face a sharp influx of patients.

Misspecified regression model for the subdistribution hazard of a competing risk.

We consider a competing risks setting, when evaluating the prognostic influence of an exposure on a specific cause of failure. Two main regression models are used in such analyses, the Cox cause-specific proportional hazards model and the subdistribution proportional hazards model. They are exemplified in a real data example focusing on relapse-free interval in acute leukaemia patients. We examine the properties of the estimator based on the latter model when the true model is the former. An explicit relationship between subdistribution hazards ratio and cause-specific hazards ratio is derived, assuming a flexible parametric distribution for latent failure times.