Publicatie datum

Mapping influenza-activity in Europe.

Meuwissen, L.E., Wienand, I., Kistemann, T.H., Paget, W.J., Uphoff, H. Mapping influenza-activity in Europe. European Journal of Public Health: 2006, 16(Suppl. 1) 69-70. Abstract. 14 th Eupha conference "Politics, Policies and /or the Public's Health", Montreux, 16-18 November 2006.
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Issue: Twenty-nine European countries report influenza-activity on a weekly basis to the European Influenza Surveillance Scheme (EISS). Data are collected through a network of sentinel physicians in each country, who register the number of people who consult for influenza-like-illness or acute respiratory infection. Because of differences in health care usage, health care organization, and surveillance systems, national data on influenza activity have a limited comparability. Furthermore, national aggregation of data as currently used obscure geographical diffusion of influenza, and influenza may circulate for considerable time before it is visible. In a situation of unusual, possibly pandemic influenza virus activity, more detailed and cross-border information is necessary. Description: A pilot project, financed by DG SANCO through EISS, is currently being undertaken in nine European countries and aims to visualize and analyse influenza activity patterns and to develop an early warning system. Weekly information on influenza activity from each data collection point is converted into a harmonized estimation, an index. The index is based on historical reference values and indicates whether the observed influenza activity can be categorized as low, moderate, usual, high, or very high. Countries are supported to map these indexes using spatial interpolation techniques of Geographical Information Systems. The aim is to produce additionally weekly cross-border influenza maps that are easily understandable (like a weather map). The process has stimulated renewed interest to study and address regional and individual differences between data collection points. Lessons: Mapping is an interesting strategy to give feedback to the participating physicians, the backbone of the surveillance system. Participating European public health institutes have been very interested in this innovative way of presenting their data. Conclusions: The project can improve the quality of the surveillance system. Mapping contributes to early warning by timely information on unusual patterns of spread. Weekly European influenza maps are a novel tool to communicate and study influenza-activity across borders, and the approach could be useful for other contagious diseases too. (aut. ref.)