Gastroenteritis outbreaks in elderly homes in the east of France during winter 2009/10: aetiology research for a series of 37 outbreaks.

Although acute gastroenteritis is a common cause of morbi-mortality in care homes, there is no national surveillance system in France except for food-borne gastroenteritis. Since 2008, a specific surveillance system has been operating in nursing homes in Alsace, a region in eastern French. In the winter season 2009/10 we had the opportunity to study 37 outbreaks, collecting data on attack rate, duration and aetiology as well as epidemic management in nursing homes. We noticed the responsiveness of the institutions, with a mean period of 1.6 days between the onset of first symptoms and the implementation of management measures (95% confidence interval (CI): 1.0­2.2). One or several stool samples were taken in 27 of the 37 described outbreaks. The only pathogen detected was norovirus, and the positive samples were from outbreaks with a very typical pattern: vomiting in 36 of the outbreaks, a high average attack rate of 36.8% (95% CI: 31.5­42.2) and a short average duration of 8.9 days (95% CI: 5.8­7.0). No severe cases, hospitalisations or deaths were reported. The high frequency of norovirus isolation indicated that systematic bacteriological analysis in local laboratories is not cost-effective. Consequently, Cire Est recommends to test for bacteria and viruses only in cases presenting with fever or atypical symptoms. Nevertheless, Cire Est also recommends to continue sending stool samples to the French National Centre for enteric viruses, more for the benefit of the virological surveillance programme than for diagnostic purposes.

[Epidemic of influenza A(H1N1) 2009 in Reunion Island: epidemiological data]. / L'épidémie de grippe à virus A(H1N1) 2009 à la Réunion: données épidémiologiques.

In Reunion Island, a French subtropical island located in the southern hemisphere, the monitoring of the epidemiological dynamics of the epidemic linked to the emergence of pandemic virus A(H1N1) 2009 was achieved through the regular influenza surveillance system which has been reinforced on that occasion. It was mainly based on a network of sentinel physicians, combined with virologic monitoring, and on surveillance of severe cases and deaths. The data were analyzed and retroinformation was distributed according to a weekly frequency. The first imported case was confirmed on July 5, 2009 in a traveler arriving from Australia, whereas the first autochthonous cases were reported on July 23. The epidemic peak was reached in five weeks and the duration of the whole epidemic episode was 9 weeks. Pandemic virus has quickly supplanted seasonal viruses that had begun to circulate. The estimated attack rate for symptomatic cases of infection with virus influenza A(H1N1) 2009 was 12.85%. The hospitalization rate was 32 per 10,000 estimated cases, and 24 people had a serious form requiring care in ICU. Among death certificates received at the regional office for health and social affairs, 14 mentioned the influenza, including 7 in whom the pandemic virus has been laboratory confirmed. These deaths occurred in patients significantly younger than usually observed in Reunion Island during the seasonal influenza epidemics. Overall, the epidemic intensity and severity have been similar to those of seasonal influenza in Reunion Island.

A review of the dynamics and severity of the pandemic A(H1N1) influenza virus on Réunion island, 2009.

On Reunion Island, in response to the threat of emergence of the pandemic influenza A(H1N1)2009 virus, we implemented enhanced influenza surveillance from May 2009 onwards in order to detect the introduction of pandemic H1N1 influenza and to monitor its spread and impact on public health. The first 2009 pandemic influenza A(H1N1) virus was identified in Réunion on July 5, 2009, in a traveller returning from Australia; seasonal influenza B virus activity had already been detected. By the end of July, a sustained community pandemic virus transmission had been established. Pandemic H1N1 influenza activity peaked during week 35 (24-30 August 2009), 4 weeks after the beginning of the epidemic. The epidemic ended on week 38 and had lasted 9 weeks. During these 9 weeks, an estimated 66 915 persons who consulted a physician could have been infected by the influenza A(H1N1)2009 virus, giving a cumulative attack rate for consultants of 8.26%. Taking into account the people who did not consult, the total number of infected persons reached 104 067, giving a cumulative attack rate for symptomatics of 12.85%. The crude fatality rate (CFR) for influenza A(H1N1)2009 and the CFR for acute respiratory infection was 0.7/10 000 cases. Our data show that influenza pandemic did not have a health impact on overall mortality on Réunion Island. These findings demonstrate the value of an integrated epidemiological, virological and hospital surveillance programme to monitor the scope of an epidemic, identify circulating strains and provide some guidance to public health control measures.

Preliminary analysis of the pandemic H1N1 influenza on Reunion Island (Indian Ocean): surveillance trends (July to mid-September 2009).

First infections with the 2009 pandemic H1N1 influenza virus were identified on Reunion Island in July 2009. By the end of July, sustained community transmission of the virus was established. Pandemic H1N1 influenza activity peaked during week 35 (24 to 30 August), five weeks after the beginning of the epidemic and has been declining since week 36. We report preliminary epidemiological characteristics of the pandemic on Reunion Island in 2009 until week 37 ending September 13.