Eurosurveillance - Volume 15, Issue 6, 11 February 2010

At least 11 linked outbreaks of gastroenteritis with a total of 260 cases have occurred in Denmark in mid January 2010. Investigations showed that the outbreaks were caused by norovirus of several genotypes and by enterotoxigenic Escherichia coli. Lettuce of the lollo bionda type grown in France was found to be the vehicle.

This short report based on clinical surveillance and laboratory data describes the circulation of rhinoviruses, influenza viruses and respiratory syncytial viruses (RSV) in France during the 2009-10 season compared with the previous winter season. The delayed circulation of RSV observed in 2009-10 compared with 2008-09 suggests that the early circulation of the 2009 pandemic influenza A(H1N1) viruses had an impact on the RSV epidemic.

A questionnaire survey on the attitude of healthcare workers towards pandemic influenza vaccination showed low acceptance (17%) of the pandemic vaccine. Factors associated with vaccine uptake were acceptance of seasonal influenza vaccination, medical profession and age. The main reason for refusal of vaccination was fear of side effects, which was stronger in those who received information on the safety of the vaccine mainly from mass media.

During the influenza season 2007-8, the proportion of seasonal influenza A(H1N1) viruses resistant to the neuraminidase inhibitor oseltamivir increased worldwide. We conducted an investigation to compare patients infected with oseltamivir-resistant (ose-R) and oseltamivir- susceptible (ose-S) influenza A(H1N1) viruses regarding risk factors for resistance and the capability to transmit in the household setting. Within a cohort of 396 laboratory confirmed influenza patients from sentinel physicians we conducted a nested case-control study among patients infected with A(H1N1). Thirty patients in the cohort were infected with influenza B, none with influenza A(H3N2) and 366 with A(H1N1). Of the 366 A(H1N1) viruses 52 (14%) were ose-R. Demographic characteristics, oseltamivir exposure, travel history and outcome were not significantly different between ose-S and ose-R patients. Among 133 households in the nested case-control study, secondary household attack rates in households with ose-R cases and households with ose-S cases were similar (23 versus 26%; p-value=0.54). Ose-R household status and occurrence of secondary cases were associated with an odds ratio of 0.85 (95% confidence interval 0.38-1.88). We conclude that seasonal ose-R influenza A(H1N1) viruses have transmitted well in the household setting.

In Belgium, the majority of cases of listeriosis are sporadic cases. In this study we present evidence for an episode of listeriosis: a time-linked cluster of cases that occurred in 2006 and 2007, and the identification of identical strains. The episode involved 11 patients, infected with Listeria monocytogenes of serovar 4b. The source of infection was not detected.