Epidemiology and Infection

Original Papers

Norovirus

Multiple outbreaks of a novel norovirus GII.4 linked to an infected post-symptomatic food handler

C. N. THORNLEYa1 c1, J. HEWITTa2, L. PERUMALa1, S. M. VAN GESSELa1, J. WONGa1, S. A. DAVIDa1, J. P. RAPANAa1, S. LIa1, J. C. MARSHALLa3 and G. E. GREENINGa2

a1 Auckland Regional Public Health Service, Auckland District Health Board, Auckland, New Zealand

a2 Institute of Environmental Science and Research Ltd, Porirua, New Zealand

a3 Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand

SUMMARY

Multiple norovirus outbreaks following catered events in Auckland, New Zealand, in September 2010 were linked to the same catering company and investigated. Retrospective cohort studies were undertaken with attendees of two events: 38 (24·1%) of 158 surveyed attendees developed norovirus-compatible illness. Attendees were at increased risk of illness if they had consumed food that had received manual preparation following cooking or that had been prepared within 45 h following end of symptoms in a food handler with prior gastroenteritis. All food handlers were tested for norovirus. A recombinant norovirus GII.e/GII.4 was detected in specimens from event attendees and the convalescent food handler. All catering company staff were tested; no asymptomatic norovirus carriers were detected. This investigation improved the characterization of norovirus risk from post-symptomatic food handlers by narrowing the potential source of transmission to one individual. Food handlers with gastroenteritis should be excluded from the workplace for 45 h following resolution of symptoms.

(Received May 29 2012)

(Revised December 16 2012)

(Accepted January 09 2013)

(Online publication February 07 2013)

Key words

  • Food safety;
  • foodborne infections;
  • hand hygiene;
  • norovirus;
  • outbreaks

Correspondence

c1 Author for correspondence: Dr C. N. Thornley, Ministry for Primary Industries, Pastoral House, 25 The Terrace, PO Box 2526, Wellington 6140, New Zealand. (Email: craig.thornley@mpi.govt.nz)

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