Outbreaks of viral gastroenteritis in the Netherlands since 1994

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Outbreaks of viral gastroenteritis in the
Netherlands since 1994

• Sanela Svraka, PhD student
• National Institute for Public Health and the
  Environment (RIVM), Bilthoven, the Netherlands
• ErasmusMC, Rotterdam, the Netherlands

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Contents of presentation

• EVENT, FBVE and project explanation
• Viral outbreak investigation
• Criteria of viral gastroenteritis
• Diagnostic assays performed on viral
  gastroenteritis samples
• Results
• Discussion and conclusion

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Project acronym Enteric Virus Emergence, New
Tools (EVENT) FBVE network Foodborne Viruses
in Europe 29 institutes in 14 countries http//w
ww.eufoodborneviruses.co.uk fbve_at_rivm.nl

• Project objective
• Providing tools to prevent emergence of enteric
  viruses
• Understanding unexplained viral gastroenteritis
  and hepatitis

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The basic dataset Outbreak surveillance,
The Netherlands

• Viral gastroenteritis diagnosis since 1994
• Reported by regional health services or food
  inspection services
• Minimum dataset requested
• Viral outbreak definition
• Kaplan for a part, but some viral outbreaks are
  missed
• At least two cases linked in time and space with
  two or more episodes of vomiting and/or diarrhea
  in period of 12 hours
• Common bacterial and parasitical causes excluded
• Vomiting and diarrhea
• Fecal outbreak samples stored at 4ºC
• Diagnostics of viral gastroenteritis outbreaks
  performed at RIVM Norovirus, Rotavirus,
  Sapovirus, Adenovirus, Astrovirus

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Diagnostic assays

• 1994-2005 1025 gastroenteritis outbreaks reported
  and tested
• September 2005 - June 2006
• Retesting of unexplained outbreaks with
  state-of-the-art protocols
• Aichivirus

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Results
Bacteria Salmonella, Shigella, Clostridium
perfingers, Campylobacter Sapovirus and Aichi
virus not found in outbreaks from 1994 to 2005
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Diagnostic yield of GE viruses other than
Norovirus and additionally found NoV outbreaks
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Conclusions

• Number of reported outbreaks increased over the
  years
• Number and fraction of unexplained outbreaks
  increasing
• 71.8 of outbreaks caused by Norovirus
• 11.2 of outbreaks remained unexplained
• Diagnostic assays improving continuously
• Random priming and multiplex PCR assays with
  internal controls
• New techniques micro arrays
• Classical virology
• Electron Microscopy
• Culture

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Acknowledgements

• Marion Koopmans
• Erwin Duizer
• Harry Vennema
• Joukje Siebenga
• Annelies Kroneman
• Bas van der Veer
• Erwin de Bruin