[Epidemiological situation of human norovirus infections in Poland during 2004-2008].

This paper described epidemiological situation of human norovirus infections in Poland. Our analysis were based on data from routine surveillance system on foodborne and waterborne outbreaks in Poland. A total number of 154 norovirus outbreaks were registered from 2004 to 2008. The outbreaks showed seasonal peak in winter months. Those outbreaks mainly occurred in hospitals and residential-care facilities (53.8%). The period of the outbreaks ranged from 1 to 50 days. The size of the outbreaks fluctuate between 2 and 140 people (median - 14) and mostly involved school-aged children and adults. Common clinical symptoms were diarrhea (78%), vomiting (51.6%), abdominal pain (44.3%) and nausea (33.7%). Number of norovirus outbreaks in łódzkie voivodeship in 2006 were estimated based on 25 outbreaks classified as caused by agent of unknown etiology or one of bacteria of natural gut flora. Specimens were available from 10 of 25 outbreaks and tested by commercial ELISA tests. As a result of laboratory tests 9 (90%) of 10 analyzed outbreaks were reclassified as caused by norovirus.