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Volume 15, Number 1—January 2009


Selection Tool for Foodborne Norovirus Outbreaks

Linda VerhoefComments to Author , Annelies Kroneman, Yvonne van Duynhoven, Hendriek Boshuizen, Wilfrid van Pelt, Marion Koopmans, and on behalf of the Foodborne Viruses in Europe Network
Author affiliations: National Institute for Public Health and the Environment, Bilthoven, the Netherlands

Main Article

Table 1

Consensus list of parameters for optimal reporting of foodborne (viral) outbreaks as defined by expert opinion, and completeness for data collected in the FBVE surveillance database*

Parameters for outbreak data Variable Foodborne outbreak data (% missing ), n = 224 Other mode outbreak data (% missing), n = 654
EFSA (confirmed/probable)†
Type of outbreak: general or household Yes 224 (0) 654 (0)
No. human cases‡ Yes 217 (3) 651 (0)
No. hospitalizations‡ Yes 78 (65) 295 (55)
No. deaths‡ Yes 66 (70) 195 (70)
Foodstuff implicated Yes 93 (58) NA‡
Causative agent§ Yes 224 (0) 654 (0)
Setting Yes 224 (0) 654 (0)
Contributory factors Yes 202 (10) 482 (26)
Origin of foodstuff No NA NA
Strength of evidence food Yes 224 (0) NA
EFSA (thoroughly investigated)†
Reason reporting No NA NA
Laboratory results food Yes 202 (10) NA
Place food produced No NA NA
Place food consumed/purchased Descriptive 106 (52) NA
Age-affected persons Categorical 11 (95) 73 (89)
Gender-affected persons Yes 27 (88) 106 (84)
Additional information on agent Yes 224 (0) 653 (0)
Additional parameters in literature
Attack rate† Yes 121 (46) 226 (59)
Seasonality Yes 149 (33) 484 (26)
Duration of the outbreak† Yes 90 (60) 265 (59)
Epidemic curve/point source No 202 (10) 496 (24)
Sequence or variant Yes 224 (0) 654 (0)
Link with other outbreaks Yes 22 (90) 15 (98)
Additional parameters VWA experts
Incubation period Yes 51 (77) 65 (90)
Illness in food handlers and their family Partially 202 (10) NA
Presence of ill persons in setting No NA NA

*FBVE, Foodborne Viruses in Europe network; EFSA, European Food Safety Authority; NA, not applicable; VWA, Food and Consumer Products Safety Authority. Parameters listed in italics could not be included in univariate analyses.
†Not restricted to viral.
‡ A systematic retrospective check of Dutch data showed that variables for no. cases involved were reported to the national institute by regional health services when the outbreak was ongoing, and that these numbers were not updated when the outbreak had finished. The same situation was reported for other countries during the telephone survey.
§Inclusion criterion.

Main Article

1Persons contributing and countries represented: H. Vennema, E. Duizer (the Netherlands); D. Brown, B. Adak, J. Gray, J. Harris, M. Iturriza (United Kingdom); K.-H. von Bonsdorff, L. Maunula, M. Kuusi (Finland); B. Böttiger, K. Mølbak, G. Falkenhorst, C. Johnsen (Denmark); K.-O. Hedlund, Y. Andersson, M. Thorhagen, M. Lysén, M. Hjertqvist (Sweden); P. Pothier, E. Kohli, K. Balay, J. Kaplon, G. Belliot, S. Le Guyader (France); A. Bosch, A. Dominguez, J. Buesa, A. Sanchez Fauquier, G. Hernández-Pezzi (Spain); G. Szücs, G. Reuter, K. Krisztalovics (Hungary); M. Poljsak-Prijatelj, D. Barlic-Maganja, A. Hocevar Grom (Slovenia); F. Ruggeri, I. Di Bartolo (Italy); E. Schreier, K. Stark, J. Koch, M. Höhne (Germany); M. Lynch, B. Foley, P. McKeown, S. Coughlan (Ireland); K. Vainio, T. Bruun (Norway).