Case registry systems for pandemic influenza A(H1N1)pdm09 in Europe: are there lessons for the future?

Countries across Europe developed a range of database systems to register pandemic influenza A(H1N1)pdm09 cases. Anecdotal reports indicate that some systems were not as useful as expected. This was a cross-sectional, semi-structured survey of health professionals who collected and reported pandemic influenza A(H1N1)pdm09 cases in 23 countries within the 27 European Union (EU) Member States plus Norway. We describe here the experiences of using pandemic case register systems developed before and during the pandemic, whether the systems were used as intended and, what problems, if any, were encountered. We conducted the survey to identify improvements that could be made to future pandemic case registers at national and EU level. Despite many inter-country differences, 17 respondents felt that a standardised case register template incorporating a limited number of simple standard variables specified in advance and agreed between the World Health Organization and the European Centre for Disease Prevention and Control could be useful. Intra- and inter-country working groups could facilitate information exchange, clearer system objectives and improved interoperability between systems.

Changes in prevention and outbreak management of Legionnaires disease in the Netherlands between two large outbreaks in 1999 and 2006.

We describe an outbreak of Legionnaires' disease in 2006 in Amsterdam, the Netherlands. Comparisons with the outbreak that took place in 1999 are made to evaluate changes in legionella prevention and outbreak management. The 2006 outbreak was caused by a wet cooling tower. Thirty-one patients were reported. The outbreak was detected two days after the first patient was admitted to hospital, and the source was eliminated five days later. The 1999 outbreak was caused by a whirlpool at a flower show, and 188 patients were reported. This outbreak was detected 14 days after the first patient was admitted to hospital, and two days later the source was traced. Since 1999, the awareness of legionellosis among physicians, the availability of a urinary antigen tests and more efficient early warning and communication systems improved the efficiency of legionellosis outbreak management. For prevention, extensive legislation with clear responsibilities has been put in place. For wet cooling towers, however, legislation regarding responsibility and supervision of maintenance needs to be improved.

Human-to-human transmission of avian influenza A/H7N7, The Netherlands, 2003.

An outbreak of highly pathogenic avian influenza A virus subtype H7N7 began in poultry farms in the Netherlands in 2003. Virus infection was detected by RT-PCR in 86 poultry workers and three household contacts of PCR-positive poultry workers, mainly associated with conjunctivitis. To determine the magnitude of and risk factors for human-to-human transmission of influenza A/H7N7 in the Netherlands, a retrospective cohort study among household members of infected poultry workers was undertaken. In total, 33 (58.9%) of 56 (among 62) participants who provided blood samples had positive H7 serology, using single convalescent serum samples obtained at least 3 weeks after onset of symptoms of the index case. Eight household members (12.9%) reported symptoms (conjunctivitis and/or ILI), of which four of five (80.0%) tested seropositive. On univariate analysis, significant risk factors for seropositivity included having at least two toilets, a pet bird, and using cloth handkerchiefs. It was not possible to obtain a stable model for binomial regression for the outcome of A/H7N7 infection. Further seroprevalence studies among contacts of asymptomatic H7 cases should be conducted.

Human-to-human transmission of avian influenza A/H7N7, The Netherlands, 2003.

An outbreak of highly pathogenic avian influenza A virus subtype H7N7 began in poultry farms in the Netherlands in 2003. Virus infection was detected by RT-PCR in 86 poultry workers and three household contacts of PCR-positive poultry workers, mainly associated with conjunctivitis. To determine the magnitude of and risk factors for human-to-human transmission of influenza A/H7N7 in the Netherlands, a retrospective cohort study among household members of infected poultry workers was undertaken. In total, 33 (58.9%) of 56 (among 62) participants who provided blood samples had positive H7 serology, using single convalescent serum samples obtained at least 3 weeks after onset of symptoms of the index case. Eight household members (12.9%) reported symptoms (conjunctivitis and/or ILI), of which four of five (80.0%) tested seropositive. On univariate analysis, significant risk factors for seropositivity included having at least two toilets, a pet bird, and using cloth handkerchiefs. It was not possible to obtain a stable model for binomial regression for the outcome of A/H7N7 infection. Further seroprevalence studies among contacts of asymptomatic H7 cases should be conducted.

The validity and reliability of signs of early infarction on CT in acute ischaemic stroke.

It has been suggested that subtle signs of early cerebral infarction on CT are important indicators of outcome and of the effect of thrombolytic treatment in acute ischaemic stroke. We studied these signs prospectively, in 260 patients with an anterior circulation stroke from a European-Australian randomised trial of lubeluzole in acute ischaemic stroke. Interobserver reliability was assessed by means of the chi statistic. The validity of the early signs was assessed by comparing the assessments of the first CT with another CT at 1 week after the onset of stroke, and with stroke outcome at 12 weeks. Each initial CT study was assessed by two of a group of five reviewers, who were blinded to each other's assessments and to the findings on the follow-up CT. The images were assessed twice, once without clinical information and again after disclosure of the side (left or right hemisphere) of the lesion. All reviewers were experienced clinicians with a special interest and training in vascular neurology and CT. The median time between stroke onset and the first CT was 3.2 h; 59% of the patients were imaged within 3 h and 77% within 6 h. More than half of the patients (52%) had a large middle cerebral artery territory (MCA) infarct on follow-up CT. Chance-adjusted interobserver agreement (chi) for any early infarct was 0.27 (95% confidence interval (CI): 0.15 to 0.39). Agreement (chi) on the extent of a middle cerebral artery (MCA) infarct and on the indication for treatment with recombinant tissue plasminogen activator (rt-PA) was fair: 0.37 and 0.35, respectively. Patients with early signs of an infarct of more than 1/3 of the MCA territory were more likely to have a large MCA infarct on follow-up CT (odds ratio 5.7, 95% confidence interval 2.8-11.5); the positive and negative predictive value of these signs was 81% and 57%, respectively. Chance-adjusted interobserver agreement on early, subtle signs of a large MCA territory infarct on CT by neurologists was thus no more than fair, and the accuracy of prediction of actual infarct size on the basis of these signs only moderate, under circumstances which resemble everyday clinical practice.