Article

Outbreak of norovirus in Västra Götaland associated with recreational activities at two lakes during August 2004.

European Programme for Intervention Epidemiology Training (EPIET), Solna, Sweden.
Scandinavian Journal of Infectious Diseases (impact factor: 1.72). 02/2007; 39(4):323-31. DOI:10.1080/00365540601053006
Source: PubMed

ABSTRACT A large community outbreak of norovirus (NV) gastrointestinal infection occurred in Västra Götaland County, Sweden in August 2004, following attendance at recreational lakes. A frequency age-matched case control study was undertaken of persons who had attended these lakes to identify risk factors. 163 cases and 329 controls were included. Analysis indicates that having water in the mouth while swimming (OR=4.7; 95% CI 1.1-20.2), attendance at the main swimming area at Delsjön Lake (OR=25.5; 95% CI 2.5-263.8), taking water home from a fresh water spring near Delsjön lake (OR=17.3; 95% CI 2.7-110.7) and swimming less than 20 m from shore (OR=13.4; 95% CI 2.0-90.2) were significant risk factors. The probable vehicle was local contamination of the lake water (especially at the main swimming area). The source of contamination could not be determined.

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Keywords

contamination
 
Delsjön lake
 
frequency age-matched case control study
 
fresh water spring
 
lake water
 
lakes
 
large community outbreak
 
main swimming area
 
norovirus
 
probable vehicle
 
recreational lakes
 
Sweden
 
Västra Götaland County