Background: Computerized morbidity registration networks might serve as early warning systems in a time where
natural epidemics such as the H1N1 flu can easily spread from one region to another.
Methods: In this contribution we examine whether general practice based broad-spectrum computerized
morbidity registration networks have the potential to act as a valid surveillance instrument of frequently occurring
diseases. We compare general practice based computerized data assessing the frequency of influenza-like illness
(ILI) and acute respiratory infections (ARI) with data from a well established case-specific sentinel network, the
European Influenza Surveillance Scheme (EISS). The overall frequency and trends of weekly ILI and ARI data are
compared using both networks.
Results: Detection of influenza-like illness and acute respiratory illness occurs equally fast in EISS and the
computerized network. The overall frequency data for ARI are the same for both networks, the overall trends are
similar, but the increases and decreases in frequency do not occur in exactly the same weeks. For ILI, the overall
rate was slightly higher for the computerized network population, especially before the increase of ILI, the overall
trend was almost identical and the increases and decreases occur in the same weeks for both networks.
Conclusions: Computerized morbidity registration networks are a valid tool for monitoring frequent occurring
respiratory diseases and the detection of sudden outbreaks.