Food Protection Trends - July/August 2017 - 242
infectious agent; its possible transmission routes; and
features such as incubation period, duration, and magnitude
of disease (18). An epidemic curve was created using
Microsoft Excel, and a transmission web of the outbreak
was created using a basic two-column Microsoft Excel
spreadsheet (one column for people infecting others and one
column for those they infected) imported into Cytoscape 3,
an open source software program for visualizing networks
(Cytoscape Consortium, San Diego, CA).
Infectious diseases can also be characterized by their
R0, which is simply the average number of people a single
infected person is expected to infect, assuming everyone
in the population is susceptible to the disease (10, 15).
The R0 represents the transmission potential of an infectious
agent; the higher the R0 relative to a benchmark of 1.0,
the more extensive the expected spread of disease (10,
15). Weighted averages of the number of returned buttons
(corresponding to 'confirmed' cases of norovirus) were
used to calculate R0 values.
RESULTS
Response rate
All 100 bags containing five buttons each were distributed
from the exhibit booth. Overall, 248 of the 500 people
potentially infected during the experiment visited the
NoroCORE exhibit booth (49.6% response rate), becoming
"confirmed" cases of norovirus, and 198 of these people
explained where and when they were infected (79.8%).
The 252 other individuals who may have been infected but
did not visit the booth were "suspected" cases of norovirus.
Ultimately, 88 individuals were responsible for spreading the
virus. However, because of unexpected enthusiasm for the
experiment on the first evening of the conference and the
number of buttons, restrictions had to be placed thereafter
on when infected individuals could receive buttons from the
exhibit booth.
Reproduction number
Excluding Patient Zero's initial ten infections (since these
were automatically recorded at the start of the outbreak),
the number of confirmed secondary cases arising from a
single infected individual varied from 8 to 0. As 77 of the 88
participants spreading the virus could distribute only five
buttons instead of ten, an adjusted weighted average of the
number of buttons that returned to the booth for each bag of
five buttons (Fig. 1) was used to estimate an R0 of 2.48.
Location of infection
Although the vast majority (n = 166, 84%) of infections
occurred in the exhibit hall, several (n = 16, 8%) occurred
in the conference oral presentation rooms (Fig. 2). The
"Reception" area represents the ten initial infections caused
by Patient Zero at the opening session reception (5%).
The five "Other" (2.5%) responses were specifically "City
242
Food Protection Trends July/August
Downtown" (n = 2), "Poster," "Lunch," and "Lobby"; some
of these may have been referencing the exhibit hall, but this
cannot be assumed.
Time of infection
Because the participants assigned their time of infection
to one of 12 four-hour time slots, an epidemiologic curve for
the mock outbreak was easily produced (Fig. 3). Unexpected
infection times (e.g., 12:00 a.m. - 4:00 a.m.) were confirmed
with the participant when they visited the booth. Because of
the high demand and limited supply, buttons were available
from the booth from 7:30 p.m. to 9:30 p.m. on Saturday, July
25th, 2015, and from 10:00 a.m. to 12:00 p.m. and from 5:00
p.m. to 5:20 p.m. on Sunday, July 26th. Recording of new
cases ended at 1:00 p.m. on Monday, July 27th, the last full
day on which the exhibit hall was open.
Web of infection
The node-link tree displays the entirety of the outbreak and
the connections between the individual participants (Fig. 4).
Blue dots signify infected individuals who had their button
number recorded at the booth ('confirmed' cases), while gray
dots represent buttons that may have been distributed but did
not come back to the booth ('suspected' cases). The longest
chain of confirmed cases reached eight degrees of separation
from Patient Zero, and distinct branches of transmission
arose from nine of the ten individuals initially infected at the
opening reception.
DISCUSSION
Public reception
Anecdotal feedback volunteered by the participants was
overwhelmingly positive; the attendees were perceived to be
enthusiastic and curious about participating, which generated
discussion about norovirus and similarly-transmitted agents.
People of all ages and genders participated and were a
representative cross section of IAFP membership, including
individuals from academia, industry, regulatory agencies, and
public health groups. Conference staff and other exhibitors
were also seen wearing the buttons. When the option to
infect other people was available, the majority of participants
did elect to distribute buttons. However, this enthusiasm
made it necessary to set restrictions on button distribution
periods. During distribution times, around 100 buttons
were leaving the booth per hour. This unforeseen outcome
undoubtedly affected the course of the exercise, although
because of the exponential nature of the outbreak, doubling
or even tripling the number of available buttons may have led
to a similar result.
Translating the interactive to real-world epidemiology
The exercise demonstrated the expansive nature of a norovirus outbreak and physical transmission of a pathogen.
The fact that this was not a real disease outbreak and that
Table of Contents for the Digital Edition of Food Protection Trends - July/August 2017
Contents
Food Protection Trends - July/August 2017 - Cover1
Food Protection Trends - July/August 2017 - Cover2
Food Protection Trends - July/August 2017 - Contents
Food Protection Trends - July/August 2017 - 234
Food Protection Trends - July/August 2017 - 235
Food Protection Trends - July/August 2017 - 236
Food Protection Trends - July/August 2017 - 237
Food Protection Trends - July/August 2017 - 238
Food Protection Trends - July/August 2017 - 239
Food Protection Trends - July/August 2017 - 240
Food Protection Trends - July/August 2017 - 241
Food Protection Trends - July/August 2017 - 242
Food Protection Trends - July/August 2017 - 243
Food Protection Trends - July/August 2017 - 244
Food Protection Trends - July/August 2017 - 245
Food Protection Trends - July/August 2017 - 246
Food Protection Trends - July/August 2017 - 247
Food Protection Trends - July/August 2017 - 248
Food Protection Trends - July/August 2017 - 249
Food Protection Trends - July/August 2017 - 250
Food Protection Trends - July/August 2017 - 251
Food Protection Trends - July/August 2017 - 252
Food Protection Trends - July/August 2017 - 253
Food Protection Trends - July/August 2017 - 254
Food Protection Trends - July/August 2017 - 255
Food Protection Trends - July/August 2017 - 256
Food Protection Trends - July/August 2017 - 257
Food Protection Trends - July/August 2017 - 258
Food Protection Trends - July/August 2017 - 259
Food Protection Trends - July/August 2017 - 260
Food Protection Trends - July/August 2017 - 261
Food Protection Trends - July/August 2017 - 262
Food Protection Trends - July/August 2017 - 263
Food Protection Trends - July/August 2017 - 264
Food Protection Trends - July/August 2017 - 265
Food Protection Trends - July/August 2017 - 266
Food Protection Trends - July/August 2017 - 267
Food Protection Trends - July/August 2017 - 268
Food Protection Trends - July/August 2017 - 269
Food Protection Trends - July/August 2017 - 270
Food Protection Trends - July/August 2017 - 271
Food Protection Trends - July/August 2017 - 272
Food Protection Trends - July/August 2017 - 273
Food Protection Trends - July/August 2017 - 274
Food Protection Trends - July/August 2017 - 275
Food Protection Trends - July/August 2017 - 276
Food Protection Trends - July/August 2017 - 277
Food Protection Trends - July/August 2017 - 278
Food Protection Trends - July/August 2017 - 279
Food Protection Trends - July/August 2017 - 280
Food Protection Trends - July/August 2017 - 281
Food Protection Trends - July/August 2017 - 282
Food Protection Trends - July/August 2017 - 283
Food Protection Trends - July/August 2017 - 284
Food Protection Trends - July/August 2017 - 285
Food Protection Trends - July/August 2017 - 286
Food Protection Trends - July/August 2017 - 287
Food Protection Trends - July/August 2017 - 288
Food Protection Trends - July/August 2017 - 289
Food Protection Trends - July/August 2017 - 290
Food Protection Trends - July/August 2017 - 291
Food Protection Trends - July/August 2017 - 292
Food Protection Trends - July/August 2017 - 293
Food Protection Trends - July/August 2017 - 294
Food Protection Trends - July/August 2017 - 295
Food Protection Trends - July/August 2017 - 296
Food Protection Trends - July/August 2017 - 297
Food Protection Trends - July/August 2017 - 298
Food Protection Trends - July/August 2017 - 299
Food Protection Trends - July/August 2017 - 300
Food Protection Trends - July/August 2017 - 301
Food Protection Trends - July/August 2017 - 302
Food Protection Trends - July/August 2017 - 303
Food Protection Trends - July/August 2017 - 304
Food Protection Trends - July/August 2017 - 305
Food Protection Trends - July/August 2017 - 306
Food Protection Trends - July/August 2017 - 307
Food Protection Trends - July/August 2017 - 308
Food Protection Trends - July/August 2017 - Cover3
Food Protection Trends - July/August 2017 - Cover4
https://www.nxtbook.com/nxtbooks/trilix/fpt_20240910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20240708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20240506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20240304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20240102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20231112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20230910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20230708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20230506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20230304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20230102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20221112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20220910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20220708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20220506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20220304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20220102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20211112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20210910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20210708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20210506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20210304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20210102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20201112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20200910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20200708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20200506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20200304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20200102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20191112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20190910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20190708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20190506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20190304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20190102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20181112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20180910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20180708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20180506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20180304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20180102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20171112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20170910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20170708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20170506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20170304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20170102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20161112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20160910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20160708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20160506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20160304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20160102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20151112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20150910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20150708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20150506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20150304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20150102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20141112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20140910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20140708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20140506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20140304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20140102
https://www.nxtbook.com/nxtbooks/trilix/fpt_20131112
https://www.nxtbook.com/nxtbooks/trilix/fpt_20130910
https://www.nxtbook.com/nxtbooks/trilix/fpt_20130708
https://www.nxtbook.com/nxtbooks/trilix/fpt_20130506
https://www.nxtbook.com/nxtbooks/trilix/fpt_20130304
https://www.nxtbook.com/nxtbooks/trilix/fpt_20130102
https://www.nxtbook.com/nxtbooks/trilix/fpt_201212
https://www.nxtbook.com/nxtbooks/trilix/fpt_201211
https://www.nxtbook.com/nxtbooks/trilix/fpt_201210
https://www.nxtbook.com/nxtbooks/trilix/fpt_201209
https://www.nxtbook.com/nxtbooks/trilix/fpt_201208
https://www.nxtbook.com/nxtbooks/trilix/fpt_201207
https://www.nxtbook.com/nxtbooks/trilix/fpt_201206
https://www.nxtbook.com/nxtbooks/trilix/fpt_201205
https://www.nxtbook.com/nxtbooks/trilix/fpt_201204
https://www.nxtbook.com/nxtbooks/trilix/fpt_201203
https://www.nxtbook.com/nxtbooks/trilix/fpt_201202
https://www.nxtbook.com/nxtbooks/trilix/fpt_201201
https://www.nxtbook.com/nxtbooks/trilix/fpt_201112
https://www.nxtbook.com/nxtbooks/trilix/fpt_201111
https://www.nxtbook.com/nxtbooks/trilix/fpt_201110
https://www.nxtbook.com/nxtbooks/trilix/fpt_201109
https://www.nxtbook.com/nxtbooks/trilix/fpt_201108
https://www.nxtbook.com/nxtbooks/trilix/fpt_201107
https://www.nxtbook.com/nxtbooks/trilix/fpt_201106
https://www.nxtbook.com/nxtbooks/trilix/fpt_201105
https://www.nxtbook.com/nxtbooks/trilix/fpt_201104
https://www.nxtbook.com/nxtbooks/trilix/fpt_201103
https://www.nxtbook.com/nxtbooks/trilix/fpt_201102
https://www.nxtbook.com/nxtbooks/trilix/fpt_201101
https://www.nxtbook.com/nxtbooks/trilix/fpt_201012
https://www.nxtbook.com/nxtbooks/trilix/fpt_201011
https://www.nxtbook.com/nxtbooks/trilix/fpt_201010
https://www.nxtbook.com/nxtbooks/trilix/fpt_201009
https://www.nxtbook.com/nxtbooks/trilix/fpt_201008
https://www.nxtbook.com/nxtbooks/trilix/fpt_201007
https://www.nxtbook.com/nxtbooks/trilix/fpt_201006
https://www.nxtbook.com/nxtbooks/trilix/fpt_201005
https://www.nxtbook.com/nxtbooks/trilix/fpt_201004
https://www.nxtbook.com/nxtbooks/trilix/fpt_201003
https://www.nxtbook.com/nxtbooks/trilix/fpt_201002
https://www.nxtbook.com/nxtbooks/trilix/fpt_201001
https://www.nxtbook.com/nxtbooks/trilix/fpt_200912
https://www.nxtbook.com/nxtbooks/trilix/fpt_200911
https://www.nxtbook.com/nxtbooks/trilix/fpt_200910
https://www.nxtbook.com/nxtbooks/trilix/fpt_200909
https://www.nxtbook.com/nxtbooks/trilix/fpt_200908
https://www.nxtbook.com/nxtbooks/trilix/fpt_200907
https://www.nxtbook.com/nxtbooks/trilix/fpt_200906
https://www.nxtbook.com/nxtbooks/trilix/fpt_200905
https://www.nxtbook.com/nxtbooks/trilix/fpt_200904
https://www.nxtbook.com/nxtbooks/trilix/fpt_200903
https://www.nxtbook.com/nxtbooks/trilix/fpt_200902
https://www.nxtbook.com/nxtbooks/trilix/fpt_200901
https://www.nxtbook.com/nxtbooks/trilix/fpt_200812
https://www.nxtbook.com/nxtbooks/trilix/fpt_200811
https://www.nxtbook.com/nxtbooks/trilix/fpt_200810
https://www.nxtbook.com/nxtbooks/trilix/fpt_200809
https://www.nxtbook.com/nxtbooks/trilix/fpt_200808
https://www.nxtbook.com/nxtbooks/trilix/fpt_200807
https://www.nxtbookmedia.com