chap-8 (1)

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Chapter 8

SUMMARIZING THEINVESTIGATION

1) The Report

2) Purpose of The Report

3) Outbrea Report !or"at

#) E$a"p%es of Reports

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&HAPTER '

SUMMARIZING THEINVESTIGATION

I(trou*t+o(When an investigation is complete, the final responsibility is to providewritten documentation of events. This is necessary not only for largeoutbreaks involving many people but also for single complaints of possiblefoodborne illness. This chapter explains the importance of the report and its possible uses. Also included is a detailed explanation of a workable formatfor writing a report, what should be included in the report and who should

receive it. Finally, samples of outbreak reports of differing complexity areincluded as a guide.

While this chapter focuses on a report written for a more complexoutbreak, even single complaints should be documented as completely as possible. The single complaint must always be regarded as the possible firstindication of a larger problem.

1) The Report

The report documents what happened in a foodborne illness investigation. It is publicrecord and must be obective, accurate, clear, and timely.

!etail in the document should reflect the complexity of the incident under investigation. Asingle complaint might result in a "complaint form# $e.g., the Foodborne IllnessComplaint Worksheet) being completed with a list of action steps and any follow%up. $&ee'hapter (, &ection (%A for more information on the Foodborne Illness ComplaintWorksheet .)

A more complicated occurrence $i.e., a large outbreak) might involve people outside yourlocal urisdiction and re*uire a more comprehensive report. It may be necessary to enlist

all involved parties when writing a final report. It is the responsibility of the local board ofhealth $+-), however, to recruit state agency personnel or others to assist incompletion of the report.

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SUMMARIZING THE INVESTIGATION

2) Purpose of the Report

Whether the report is being written in response to an outbreak or a single complaint,complete documentation is important for the following reasons/

A document for action.In some cases, control and prevention measures will only be instituted in response to awritten report. 0ntil an outbreak is documented and summari1ed in a formal "outbreakreport,# it is easy for the implicated establishment operator to shift responsibility. Thedocument contains the "official# findings. It should be used in refuting rumors andspeculation.

A record of performance. A well%written report documents the magnitude of health problems and ustifies programactivities. A report clearly states events that occurred and the process that was followed. Itshould include all steps undertaken by everyone involved. The person writing the report

will need to gather that information. The comprehensiveness of the outbreak report shouldreflect the complexity of the investigation. This accurately documents events and alsoclearly illustrates staffing resources re*uired to undertake the investigations.

A document for potential legal issues. An investigative report written by health professionals must be written obectively,honestly and fairly. Information in these investigations is fre*uently used in legal actions.Thus, it is very important that a record exists that accurately documents events in a timelymanner to aid in any legal investigations that might ensue.

An enhancement of the quality of the investigation.

The process of writing a report and viewing the data in written form may result in newinsights. It could precipitate new *uestions to be answered before a conclusion is reached.The more investigations and outbreaks one writes up, the better the understanding of process and results.

An instrument to present control and preventive measures.The primary reason to undertake an investigation is to control and prevent disease. Thewritten report is an official medium to present control and preventive measures, and perform needs assessments. -ne may identify new trends, introduce new regulations or policies, identify training needs and reinforce existing regulations. When the report is presented to the owners and managers, encourage them to use it as a catalyst for change.

This document is an educational tool and may help to prevent the same problems fromreoccurring. $For example, operators who have been educated about the availability andsafety of a pasteuri1ed egg product will probably choose that over pooled whole, shelleggs.)

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&HAPTER '

3) Outbrea Report !or"at

There are a variety of ways to compile the information obtained during an investigationinto a professional, understandable and usable document. elow is the standard outlineused by the 2assachusetts !epartment of 3ublic ealth $2!3) to write an outbreak

report. The 2!3 staff usually follow this format because it logically describes the eventsthat occur during an investigation.

NOTE/ This format can be modified to reflect the complexity of the outbreak.

NOTE/ Three outbreak report examples $4.5, 4.6, and 4.7) are provided at the end of thischapter. 3lease note the varying complexity of each report.

8ven if you do not get the opportunity to compile a complex "outbreak report,# you might be the recipient of one if a large outbreak occurs in your urisdiction. It would be helpfulfor you to be familiar with the following format and understand what information iscontained in each section. It will then be easier for you to adopt any or all of the sectionsfor use when responding to and documenting smaller scale incidents.

A foodborne illness outbreak report should include the following sections/

I. SummaryII. IntroductionIII. BackgroundI. !ethods A" Epidemiologic B" Environmental

#" $a%oratory and #linical. &esults A" Epidemiologic

B" Environmental #" $a%oratory and #linicalI. 'iscussionII. &ecommendationsIII. Ackno(ledgmentsI). Supporting 'ocumentation

I. Summary

The summary should consist of a paragraph or two that provide the reader with anoverview of the investigation $i.e., the W-, WAT, W898 and W8: of theoutbreak). It should describe what caused the outbreak or the causal hypothesis based onthe evidence.

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II. IntroductionInclude the specific events that led to the investigation. Include/5) how the outbreak was first reported,6) steps undertaken to confirm its existence, and7) all who assisted in the investigation.

III. Backgroundackground information is important. This section identifies the type of establishmentinvolved in the outbreak $e.g., take%out restaurant, ban*uet facility, caterer, fast foodestablishment, retail store). Also include whether the establishment is part of a nationalchain, a commissary, a dormitory or a buffet where attendees are likely to eat multiplefoods. In this section discuss the capacity of the food service operation, which may help todetermine the possible extent of the outbreak.

I. !ethods

A. Epidemiologic

8xplain how cases were defined. For example, even if you are investigating an outbreak of salmonella you are probably not confining yourself to only laboratory confirmedcases. !oes a case have to experience diarrhea or is abdominal cramping sufficient; Theissues should be determined and explained in detail. Also describe how cases becameknown, *uestions you asked, and how asked. Include descriptions of interviewtechni*ues and copies of *uestionnaires or surveys if used.

B. Environmental'learly outline the number and kinds of environmental investigations that occurred andwho conducted them. Was a A''3 risk assessment conducted of suspect foods aswell as physical facility inspections; Were there any tracebacks of food products;

#. $a%oratory and #linical!iscuss any analyses performed. It is important to note what kinds of and how manyspecimens were submitted for laboratory analysis. Was food available for testing; !idcases submit stool specimens or other clinical specimens for analysis; Were foodhandlers re*uired to submit stool samples for testing; :ote where the specimens weresent, what kinds of analyses were performed and who completed the testing. This couldinvolve private, state or federal laboratories.

. &esultsIn the previous section you outlined what steps you took to investigate the outbreak. Thissection is where you tell your readers what you discovered. These results can be presentedin tables, graphic figures and

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&HAPTER '

• symptoms experienced by cases

• duration of symptoms

• incubation period

• food or meal%specific attack rates

• statistical significance of foods eaten

• epidemic curve of the outbreak

• relationships among cases $if any)

B. Environmental

• results of any A''3 risk assessments conducted

• the results of the physical facilities inspection $e.g., violations noted)

• the results of any food tracebacks

#. $a%oratory and #linical

• culture or other laboratory results on food handlers, patrons, or other individualsconnected to the outbreak

• results on foods tested

I. 'iscussionThis section is where all aspects of the investigation are brought together and a conclusionis drawn.

NOTE* Not all out%reaks have a resolution. In fact+ it is rare (hen everythingcomes together and a cause can %e definitively determined. 'o not %e discouraged.

In most cases+ there (ill %e enough evidence to present a plausi%le hypothesis ,see#hapter -+ Section ". Be clear and present a detailed e/planation on (hat has

contri%uted to the conclusion.

II. &ecommendationsThis is the opportunity to educate. e detailed because these recommendations hopefullywill be read by many people in the establishment that was investigated. The establishmenthas a vested interest in following the suggestions. If the outbreak has been large anddisruptive, the establishment will not want it to reoccur. In addition to listing generalrecommendations on good food handling procedures, include specific recommendations

that address what might have been overlooked in the particular outbreak $e.g., attemptingto transport food long distances at inade*uate temperatures).

III. Ackno(ledgmentsIn the spirit of cooperation, it is proper to thank those who assisted in the investigation.This might include health care personnel, the food handlers and

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I). Supporting 'ocumentationWhen compiling the report, attach copies of all items that are relevant. These wouldinclude the following/

• inspection reports

• blank samples of the surveys or *uestionnaires

• letters to management• menus

• copies of posted notices

• food testing results

• foodborne illness worksheet$s) $without names or other personal identifiers)

When compiling material, be aware of confidentiality issues $see 'hapter (, &ection =).Information that can lead to the identification of individual cases ,e.g.+ test resultsthat include personal identifiers"+ should not %e included in the out%reak report. Thename of the establishment under *uestion is part of the public record and can be disclosed.!ata that cannot be used to identify individuals can be presented. 3eople cooperate ininvestigations on the basis of protected confidentiality, and this should be respected.

'istri%uting the &eport'opies of the report should be made available to all parties involved in the investigation.This would include, but not be limited to, the owner and

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&HAPTER '

in homes as well as food%service establishments. It is important to encourage participationin investigations of home outbreaks and document events that took place.

E/ample 0. % This sample is a report summari1ing the investigation of a large point%source outbreak of an unidentified gastrointestinal illness that occurred at a wedding. Thisinvestigation included the use of *uestionnaires and data analysis to identify a suspect fooditem. In an outbreak of this magnitude, it is important to be as complete as possible because years later one could be asked to provide information on the investigation.

Foodborne Illness Complaint Worksheet . Another type of report would be a completed Foodborne Illness Complaint Worksheet. In some situations, a follow%up investigation of acomplaint may not be warranted or minimal follow%up may be sufficient $e.g., complaintsinvolving one person or for complaints where it is obvious that the symptoms or diagnosisare clearly unrelated to the food which the complainant believes to be causal and no otherinformation is available). !ocumentation can consist of a completed Foodborne IllnessComplaint Worksheet with an inspection report attached, if applicable. This formcomprises the entire "report.# If no violations were noted during the environmental

inspection and no other complaints about the establishment were received, close theinvestigation. $2ore information on the Foodborne Illness Complaint Worksheet can befound in 'hapter (, &ection (%A.)

Refere(*es

ryan, F. Guide for Investigating Foodborne Disease utbreaks and Surveillance Data!0.&. !epartment of ealth and uman &ervices, '!'. Atlanta, >eorgia, 5?45.

olland, W. et al. "ford #e"tbook of $ublic %ealth, -xford 0niversity 3ress, 5?4=@ 7/64(%64?.

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E,AMP-E '.1OUT/REA0 REPORT

!E!O&AN'4!

To/ The File

From/ Writer of the 9eportB

!ate/ Canuary 6, 5??D

9e/ -utbreak of Salmonella tyvar&copenhagen andatypical Salmonella enteritidis among patrons of

9estaurant E during the month of &eptember, 5??=.

I. Summary

-n :ovember 5D, 5??=, the !ivision of 8pidemiology of the 2assachusetts !epartmentof 3ublic ealth $2!3) was notified by a resident of Town who had been confirmedwith Salmonella tyvar copenhagen that she and a friend had eaten at 9estaurant E on&eptember ?, 5??= and had become sick on &eptember 5Gth and 55th respectively. 0ponfurther investigation of Salmonella tyvar copenhagen cases reported to the bacteriologylab of the &tate +ab Institute $&+I) during &eptember and -ctober, 5??=, nine other caseswere reported in the vicinity of Town , including four from a nearby town of only 7,GGG

people. 8ight of these cases were eventually contacted, and all reported eating at9estaurant E previous to their illness with six reporting eating there in the two to threedays before their illness. An additional case was identified from a complaint received froma resident of a distant town who had eaten at the restaurant in &eptember and was laterdiagnosed with S. tyvar&copenhagen. Illness onset dates ranged from &eptember D to&eptember 6=. A secondary case had an onset date of -ctober =. The cases ate a varietyof food items including chicken, French toast, soup, salad, and a cheese steak sandwich.&eventeen food handlers submitted stool samples during !ecember. All tested negative, but it was almost three months after the outbreak. There were, however, anecdotalreports of two food handlers being ill during the month of &eptember.

I and !ethods and &esults

A. Epidemiologic

Attempts were made to contact all S. tyvar&copenhagen cases reported to the 2!3during &eptember and -ctober 5??=. 8leven cases were reported in the vicinity of

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&HAPTER '

Town , two of which had been the original complainants. 8ight of the remaining ninecases had reported eating at 9estaurant E previous to their illness. They had eaten avariety of foods on different days. The ninth case was unable to be contacted but anadditional case was identified from a complaint received from a resident of ageographically distant town who was later diagnosed with S. tyvar&copenhagen. TheTown health agent reported that there had been another separate complaint againstthe restaurant in &eptember which involved a father and daughter, both of whom wereill, although only the daughter was confirmed with atypical Salmonella enteritidis.There were no other atypical Salmonella enteritidis cases reported to the &+I in thearea of Town involving 9estaurant E.

B. Environmental

The Food 3rotection 3rogram $F33) inspected the restaurant on :ovember 6G, 5??=.The following deficiencies were noted/ no hand washing sink with soap and papertowels in the kitchen, poor lighting in walk%ins, chowder cooling in four gallon pails,and no light shields in side preparation area. F33 reviewed various aspects of food

temperatures, handling, storage, preparation, hygiene, and saniti1ing. F33 did notobserve any food preparation since the inspection occurred between meal times $&eeAttachment 5).

#. $a%oratory

:o food items were available for testing. &eventeen food handlers submitted negativestool samples during !ecember.

I 'iscussion

There appeared to be eleven cases of S. tyvar&copenhagen associated with 9estaurant Eduring the month of &eptember, 5??=. These cases did not eat a common food item anddid not eat on a common day. This supports the theory that contamination occurred in therestaurant. This contamination could have occurred as a result of poor food handlingamong Salmonella%infected food handlers or contamination of environmental surfaces bySalmonella&infected food items. The inspection report mentions no hand washing sink inthe kitchen. The food handlers who submitted stool specimens tested negative, but thiswas two to three months after the outbreak, ample time for the Salmonella bacteria to becompletely cleared from the stool of a previously infected person.

II. &ecommendations

5) To prevent outbreaks, efforts should be directed at optimi1ing conditions for sanitation, preventing contamination of foods or water, and cleaning environmental surfaces that may be at risk for contamination.

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6) Any food handler who experiences any type of gastrointestinal illness must report it toa supervisor and must refrain from participating in foodhandling activities. Food handlersshould be aware of the importance of good hygiene in preventing the spread of foodborneillness. andwashing should be done fre*uently, especially after toilet use.

7) All foods to be served to the public should be stored and prepared in a facilityspecifically for that purpose.

() 3otentially ha1ardous foods which contain poultry and

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&HAPTER '


MEMORANDUM

To: The File

From: [Writer of the Report]

Date: February 6, 1996

Re: Outbreak of atypical Salmonella Enteritidis at a Privateome i! """"", #$ o! De%ember &', 199()

*!tro+u%tio!:

O! De%ember &6, 199(, the Diviio! of -pi+emiolo.y /a!oti0e+ by the """"" oar+ of ealth that 11 out of &( people /hoatte!+e+ a private family holi+ay +i!!er i! To/! " +uri!. the lateafter!oo! of De%ember &' ha+ be%ome ill /ith !auea, +iarrhea,ab+omi!al %ramp, a!+ fever the !e2t +ay) $ll of the ill people /erereporte+ to have eate! laa.!a at the +i!!er party) Other foo+ itemat the +i!!er i!%lu+e+ e..pla!t parmea!, %hi%ke!, a!+ a!tipato) The laa.!a ha+ bee! prepare+ at home by a rei+e!t of To/! 3 /hoi!itially %o!ta%te+ the boar+ of health)

Foo+ Preparatio!:

The Foo+ Prote%tio! Pro.ram 4FPP5 revie/e+ the preparatio!pro%e 4$P rik aeme!t5 for the laa.!a /ith the rei+e!t)-i.ht helle+ e.. /ere mi2e+ /ith ri%otta %heee +uri!. thepreparatio! pro%e) The laa.!a /a refri.erate+ over!i.ht at therei+e!t7 houe) *t /a tra!porte+ to To/! " i! a! u!refri.erate+ %arfor &8 mi!ute a!+ the! left out o! a por%h, u!refri.erate+, forappro2imately t/o hour) The laa.!a /a the! put i! a preheate+ove! at (88F for appro2imately 8 mi!ute) Fi!ally, the %ooke+

laa.!a /a left out o! a table at room temperature for more tha! t/ohour) Pleae refer to atta%hme!t 1 for more +etail)

aboratory Reult:

-leve! ill .uet of the holi+ay +i!!er ubmitte+ tool pe%ime!/hi%h tete+ poitive for atypical Salmonella enteritidis) The .uet of the

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party /ere !ever ;uerie+ a to their foo+ hitory at the party, buta!e%+otal report i!+i%ate+ that all the ill people ate the laa.!a) $ample of the laa.!a a!+ %hi%ke! from the party /ere tra!porte+ tothe

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&HAPTER '


!E!O&AN'4!

To/ The File

From/ 9eport WriterB

!ate/ Canuary 6J, 5??D

9e/ -utbreak of >astrointestinal illness at a wedding reception at 9estaurantE, Town , 2A on -ctober 5(, 5??=.

I. Summary

An outbreak of gastrointestinal illness began -ctober 5=, 5??= among attendees of awedding reception held at 9estaurant E in Town , 2A. Approximately 5(G peopleattended the reception. -f JD attendees who responded to a *uestionnaire, (5 $=(K) fitthe case definition. 8pidemiologic analysis of the *uestionnaires indicated that illness was primarily associated with the consumption of gravy and stuffed turkey. An evaluation of procedures used to prepare reception foods identified improper cooling, storage, andreheating techni*ues which could have resulted in time%temperature abuse of both gravyand stuffing, and cross%contamination of turkey. :either food nor clinical specimens wereavailable for testing. 'linical, epidemiologic, and environmental evidence suggests that thisoutbreak occurred as a result of consumption of gravy and

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III. Background

9estaurant E, located in Town , 2A, is a large restaurant including a ban*uet andconference room. 0p to 66= patrons can be accommodated in a ban*uet setting.

I. !ethods

A. Epidemiologic

A case was preliminarily defined as any person who attended the weddingreception on -ctober 5( $or ate leftovers from the reception) and who had onsetof abdominal cramps, diarrhea, nausea, or vomiting during the next seven days.This definition was subse*uently narrowed to only include those who had onset ofsymptoms within three days of the reception.

-ne hundred thirty%eight *uestionnaires regarding symptomatology, medical care,

and food item consumption history were sent to a list of reception attendeesobtained from the Town - $Attachment 5). 'ompleted *uestionnaires wereentered into a database analysis system $83I I:F-, Lersion D.G6). !escriptive casestatistics were calculated and a retrospective cohort analysis was performed.

B. Environmental

An on%site investigation was conducted by the Town - at 9estaurant E on :ovember 6, 5??=, in which procedures used in the preparation of foods served atthe function were reviewed. The groom was interviewed by the Food 3rotection3rogram regarding procedures he used to manufacture hard cider served at the

reception.

. &esults

A. Epidemiologic

-f 574 *uestionnaires sent out, J4 $=JK) were received. &eventy%six of the J4were completed and used in data analysis. Forty%one of the JD respondents fit thecase definition.

!escriptive analyses of the cases revealed that 65 $=5K) were female and that agesranged from 6G to JJ with a median age of (5 years. The incubation period between food consumption and illness ranged from two to fifty%eight hours with amedian time of 56 hours $Table 5). 2aor case symptoms included diarrhea $?7K),abdominal cramping $J7K), nausea $7JK), and fatigue $6(K). Fever and vomitingwere very infre*uent and no bloody stools were reported by the cases

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&HAPTER '

$Table 6). 2edical care was sought by one case. The reported duration of illnessranged from 6 hours to 5G days, with a median of 6( hours and most fre*uentlyreported duration of (4 hours $6(K) $Table 5).

The epidemic curve shown in Figure 5 suggests that this outbreak occurred after

the reception attendees were exposed to a common source. A retrospective cohortanalysis of completed *uestionnaires indicates that the consumption of each of fiveitems, including turkey, stuffing, gravy, corn, and ranch dressing, was statisticallyassociated with illness $Table 7). All cases consumed turkey $estimated risk ratio99B M 5G.47, ?=K confidence'IB M 0ndefined, p%value M G.GG5), stuffing $99BM 4.54, 'IB M 0ndefined, p%value M G.GGJ), and gravy $99B M 5G.47, 'IB M0ndefined, p%value M G.GG5). The observed association with illness for both cornand ranch dressing consumption is likely confounded by stuffed turkey or gravyconsumption. !ue to low cell counts, however, stratification did not reveal furthermeaningful statistics.

Food and beverage consumption dose data was obtained for most items listed onthe *uestionnaire. 9esults from a chi s*uare analysis for trend indicated that thereported *uantity of turkey, stuffing, and gravy consumed was linearly associatedwith illness $Table ().

B. Environmental

The following high risk factors were revealed during the environmentalinvestigation of 9estaurant E by the Town - combined with subse*uentfollow%up by the Food 3rotection 3rogram/ 5) &tuffing made with sautNed onions,celery, butter, bread crumbs, and seasoning may have been prepared the day beforeservice. ot stuffing prepared ahead of time was placed in five%gallon plastic

containers, covered with saran wrap, and placed in the walk%in refrigeratorovernight. This may have resulted in improper cooling@ 6) &even gallons of gravyconsisting of chicken stock, flour, and butter was prepared at noon the day beforeservice, covered, and stored overnight in two five gallon plastic buckets, possiblydelaying cooling and allowing the growth of vegetative bacterial cells. The gravywas then reheated in a double boiler prior to service. +ower cooking temperaturesand

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cider was fermented with carbon dioxide and aged for approximately two and one%half years.

I. 'iscussion

The gastrointestinal illness observed in this outbreak was characteri1ed primarily bydiarrhea, abdominal cramps, and nausea, with very little vomiting or fever reported. Themedian incubation and duration periods were calculated as 56 and 6( hours respectively.These clinical features closely resemble those of both Clostridium perfringens and longincubation 'acillus cereus infections, although a viral or other bacterial etiology remains possible.

8pidemiologic analysis of food consumption histories obtained from *uestionnairessuggests that the consumption of gravy and

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&HAPTER '

thermometers to monitor temperatures while cooling.

7. 9eheat foods to 5D=GF within one hour. 0se a thermometer to measuretemperature after reheating.

III. Ackno(ledgments

The 2!3 Working >roup on Foodborne Illness 'ontrol thanks the Town oard ofealth for their participation and assistance in this investigation. In addition, 9estaurant Eand the wedding reception organi1ers are thanked for their cooperation.

TAB$E 1.I:'0ATI-: 389I-! A:! !09ATI-: -F I++:8&&

>I -utbreak, Town , 2A % -ctober 5??=

IN#4BATION 5E&IO' ,6O4&S"n 7 81

9A:>8 6%=4

28A: 56.?

28!IA: 56

&! 4.(

'4&ATION O9 I$$NESS ,6O4&S"n 781

9A:>8 6%6(G

28A: 7(.4

28!IA: 6(

2-!8 (4

&! 7?.J

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TAB$E 2.&23T-2& -F 'A&8& $n M (5)

>I -utbreak, Town , 2A % -ctober 5??=

&23T-2 :0289 $389'8:T)

!iarrhea 74 $?6.JK)

loody G $GK)

Abdominal 'ramps 7G $J7.6K)

:ausea 5= $7D.DK)

Fatigue 5G $6(.(K)

+oss of Appetite J $5J.5K)

eadache D $5(.DK)

2uscle Aches ( $?.4K)

Lomiting 7 $J.7K)

'hills 7 $J.7K)

!i11iness 6 $(.?K)

Fever 5 $6.(K)

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TAB$E .ATTA'O 9AT8 F--! '-:&028!

>I Illness, Town , 2A % -ctober 5??=

Attack &ates

E/posed 4ne/posed

9ood Item Total E/posed &isk &atio :;< #.I. p3value =

Turkey D4 DGK GK 5G.47 PPP 0ndef G.GG5 PP

&tuffing JG =?K GK 4.54 PPP 0ndef G.GGJ PP

>ravy D4 DGK GK 5G.47 PPP 0ndef G.GG5 PP

2ashed 3otatoes D? =JK 6?K 5.?4 G.DG, D.= G.674 PP

'orn D6 D5K 65K 6.4D 5.G7, J.?= G.G5D

'ranberry &auce (J =JK (4K 5.5? G.JD, 5.4J G.=44

9olls (J =JK (4K 5.5? G.JD, 5.4J G.=44

utter =7 =JK (4K 5.54 G.J7, 5.?7 G.D(?

&alad DG ==K =GK 5.5 G.D(, 5.4? G.?(5Italian !ressing 64 (7K DGK G.J5 G.((, 5.5= G.65(

9anch !ressing 76 D?K (7K 5.=? 5.G=, 6.(G G.G(4

'hicken Fingers 7 DJK =7K 5.6= G.==, 6.4D 5.GGG PP

acon &*uares 5( (7K =JK G.JD G.(G, 5.(( G.=76

!eviled 8ggs 5? D7K =5K 5.6( G.45, 5.?G G.=GD

&tuffed 'elery 6J ((K =?K G.J= G.(D, 5.66 G.765

'rackers (G ==K =7K 5.G( G.D?, 5.=4 G.?J5

'heese 7J =5K =DK G.?5 G.DG, 5.74 G.476

Water =6 =6K =4K G.4? G.=4, 5.7D G.J4(

Ice (D =(K =7K 5.G6 G.DD, 5.=D G.446

ard 'ider 6= DGK =5K 5.54 G.JJ, 5.J? G.D6

eer 6= (4K =JK G.4( G.=7, 5.7= G.D6?Wine 5( J5K =GK 5.(7 G.?(, 6.5D G.6(4

'offee (5 (DK D7K G.J( G.(?, 5.56 G.66J

'ake 74 D5K (JK 5.64 G.4(, 5.?= G.7=J

P ates 'orrected unless otherwise notedPP FisherQs 8xact $6%sided)PPP 9isk 9atio 8stimate $G.= added to each cell)

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TAB$E 8.'I &R0A98 A:A+&I& F-9 T98:!

$Turkey, &tuffing, and >ravy 'onsumption)>I -utbreak, Town , 2A % -ctober 5??=

Turkey #onsumption

Amount Attack p%value 'onsumed 9ate

:one GK

&ome 75.DK G.GGGGJ P

All J5.(K

Stuffing #onsumption


:one GK

&ome 7GK G.GGJ P

All JGK

>ravy #onsumption


:one GK

&ome 77.7K G.GGGGD P

All J6.7K

P2antel 8xtension

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&HAPTER '

9igure 1 3 Epidemic #urve

Onset of Illness %y ?uarter 'ay

@edding &eception+ To(n 3 April 1::;

11#

p"4

12a"

115

12a"4

a"

115

a"4

12p"

115

12p"4

p"

115

p"4

12a"

11

12a"4

a"

11

a"4

12p"

11

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