Epidemiology and estimated costs of a large waterborne outbreak of norovirus infection in Sweden

Epidemiol Infect. 2014 Mar;142(3):592-600. doi: 10.1017/S0950268813001209. Epub 2013 May 29.

Abstract

A large outbreak of norovirus (NoV) gastroenteritis caused by contaminated municipal drinking water occurred in Lilla Edet, Sweden, 2008. Epidemiological investigations performed using a questionnaire survey showed an association between consumption of municipal drinking water and illness (odds ratio 4·73, 95% confidence interval 3·53-6·32), and a strong correlation between the risk of being sick and the number of glasses of municipal water consumed. Diverse NoV strains were detected in stool samples from patients, NoV genotype I strains predominating. Although NoVs were not detected in water samples, coliphages were identified as a marker of viral contamination. About 2400 (18·5%) of the 13,000 inhabitants in Lilla Edet became ill. Costs associated with the outbreak were collected via a questionnaire survey given to organizations and municipalities involved in or affected by the outbreak. Total costs including sick leave, were estimated to be ∼8,700,000 Swedish kronor (∼€0·87 million).

MeSH terms

  • Caliciviridae Infections / epidemiology*
  • Caliciviridae Infections / virology
  • Disease Outbreaks*
  • Feces / virology
  • Gastroenteritis / epidemiology*
  • Gastroenteritis / virology
  • Humans
  • Norovirus / isolation & purification
  • Surveys and Questionnaires / economics
  • Sweden / epidemiology
  • Water Microbiology*
  • Water Supply