Key factors in successful outbreak management

Lessons learned in theUnited Kingdom

Alastair TomlinsonIFEH World Congress, Las Vegas

10th July 2014

Overview• Two major outbreaks of Escherichia

coli O157 in the UK have been subject to independent review in recent years

• What factors influenced the successful management (or otherwise) of these outbreaks?

• How can we be ‘fully prepared’ for major outbreak situations?

Escherichia coli O157• Highly infectious – only a few organisms can cause infection• Effect on some people can be mild but on others can be

very serious and sometimes fatal. Some people suffer permanent kidney or brain damage.

• Young children (<5) and the elderly (75+) particularly vulnerable – more likely to develop unpreventable and untreatable complications

• Main source is intestines of cattle and sheep, shed via their faeces

• Can also be transmitted between people, good personal hygiene practice vital to prevent spread

• Organism killed by cooking so action to prevent cross-contamination of ready-to-eat foods is an essential food safety measure

Case study 1• Outbreak of E. Coli O157 in South

Wales• September-November 2005

• Public Inquiry chaired by Professor Hugh Pennington published report in March 2009

• http://wales.gov.uk/ecoliinquiry/

South East Wales, UK

Organisations involved• Local authority environmental health departments

– Responsible for the control of food poisoning and notifiable infectious diseases in their areas, including food safety enforcement• Rhondda Cynon Taff (RCT)• Caerphilly• Merthyr Tydfil• Bridgend

• Local Health Boards– Responsible for health of people in their areas and commissioning

of health services• National Public Health Service for Wales

– Provide public health services, support and expertise to help local authorities and LHBs to fulfil their statutory duties

• Food Standards Agency– Advises local authorities and others on food safety matters

Timeline of events (2005)Wednesday 14th SeptemberThree children admitted to Prince Charles Hospital, Merthyr Tydfil, with watery, blood-stained diarrhoea.Thursday 15th SeptemberTwo more children admitted to Prince Charles Hospital. 3 other children with bloody diarrhoea seen in assessment unit and discharged home.Friday 16th SeptemberNPHS contacted by Paediatric Senior House Officer, to advise of the cases admitted and seen by Prince Charles Hospital over previous couple of days.Later the same morningMicrobiologist reports that E.coli O157 identified in two samples. Outbreak is declared and Outbreak Control Team formed, meeting the same afternoon.

Initial OCT meeting• Outbreak declared, source not identifiable on

basis of available information• RCT & Merthyr EHOs asked to contact probable

and confirmed cases to interview using standardised E.coli protocol questionnaire

• Working case definitions agreed and case finding process established

• Out-of-hours service arrangements established with NPHS and local authorities. Some difficulty in contacting LHB officers on call.

Second OCT meetingAfternoon of Saturday 17th September• Results of initial interviews available• Only common factor between all cases was

consumption of school meals, but precise source not yet identified

• Advice given to hospitals on control measures, and all schools with cases to be thoroughly cleaned before Monday 19th September

• Letters to parents in affected schools• Advice to GPs to raise awareness

Third OCT meetingMorning of Sunday 18th September• Source of outbreak discussed, attention focussing

on school meals.• Decision made to investigate chains of distribution

and supply, in particular those common to the schools with E.coli O157 cases, and to investigate school menus for relevant period

• Rapid Case Control Study undertaken that day– Comparing those with illness (cases) to an otherwise

similar group free from illness (controls)– Examines whether cases exposed to a common factor

that is not shared by ‘controls’

Fourth OCT meeting• 5.00pm, Sunday 18th September• Initial case-control study findings suggest likely

cause an element of school dinners, but source could not be confirmed based on information available.

• School menus included several items that could potentially be sources: milk, water, fruit, cold cooked and sliced meat

• Common supplier of cold cooked and sliced meats – John Tudor & Son, catering butcher business based in Bridgend

What would you do now?• You’re a member of the OCT. Based on the information

available to you, which of the following courses of action would you recommend:– Close all schools with affected children– Halt provision of all school meals across affected area– Investigate supplier of cold and cooked meats– Wait for results of further epidemiological investigation to

confirm vehicle of infection– Withdraw cooked & sliced meat products from schools across

affected area– Something else?

• Vote now! (select up to 3 that you think might be applicable)– http://poll.fm/4uvje

Poll resultshttps://polldaddy.com/polls/8159018/results/What they did:• Concluded outbreak could not be due to failures in hygiene

at school kitchens because of pattern of cases• Serious concern that the source might be cold cooked and

sliced meat supplied to schools, which was not re-heated before being served

• Withdrew all such meat from school kitchens in RCT & Merthyr, on a precautionary basis

• Agreed that schools could remain open, but withdrew cooking and plasticine, sand and water play activities

• Established helpline and series of press releases urging those with severe or bloody diarrhoea to seek medical attention

Further development of outbreak (1)Monday 19th September

All remaining cold cooked and sliced meats withdrawn from school kitchens in RCT and Merthyr Tydfil. Bridgend & RCT EHOs inspect John Tudor & Sons premises in Bridgend. Emergency Prohibition Notice (EPN) served prohibiting use of the vacuum packing process on the basis of “the serious risk of cross-contamination from the use of it for both raw and cooked foods”.

Tuesday 20th September

Same steps taken in Caerphilly & Bridgend to withdraw meats supplied by Tudors from the schools food chain. Further inspection of John Tudor & Sons. Another EPN served closing the premises entirely due to “unsanitary condition of premises due toinadequate disinfection procedures”. Tudor provides details of customers he supplies.OCT meets again at 4pm. 48 cases now identified. FSA and LAs agree to withdraw from the food chain cooked meat products that had been vacuum-packed at Tudors. Food Alert for Action issued by the FSA. General guidance on hygiene issued to all schools, not just those affected by outbreak.

Thursday 22nd September

It becomes clear that customer list provided is substantially incomplete. Food Alert updated accordingly. FSA begin task of analysing 10000+ invoices to establish comprehensive list of suppliers and customers. LAs to contact all small/medium-sized businesses likely to sell/use cooked meats in order to remove meat supplied by Tudors.

Friday 23rd September

OCT meeting – 75 cases compatible with E.coli O157 infection identified. LAs reinforcing handwashing message, but helpline receiving some complaints about inadequate handwashing facilities in schools.

Further development of outbreak (2)

Tuesday 27th September

Next OCT meeting. 122 cases meet case definition. OCT agree that swimming pools can remain open provided they are properly maintained and chlorinated. Appears that cases arising now are ‘secondary’ i.e. as a result of contact with a ‘primary’ case. Media inquiries decreasing but helpline remains open.

Thursday 29th September

OCT meets again. 155 cases that meet case definition, 81 microbiologically confirmed as E.coli O157. FSA reports to OCT that they are reasonably satisfied that the source of the Outbreak was not as a result of infected meat that had been supplied to Tudors in the first place. Helpline to be closed on 30th September and replaced with answerphone message directing calls to NHS Direct (national tele-health service).

Monday 3rd October

OCT considers that message concerning hand washing in the home had drifted. It was agreed that those homes where there were cases would be visited by a Health Visitor to re-emphasise the point. Microbiological and epidemiological investigations continue.

Tuesday 4th October

In the early hours of the morning, Mason Jones, a 5-year old from Deri in Caerphilly Borough, died of Haemolytic Uraemic Syndrome arising from E.coli O157 infection. He had originally fallen ill on 21st September and had been admitted to hospital on 25th September.OCT continued to meet during October, and less frequently in November andDecember 2005. The Outbreak was declared over on 20 December 2005.

Summary of the outbreak• 157 cases, 127 aged ≤18. 31 admitted to hospital, 9 children & 2 adults

requiring specialist care• The Outbreak was caused by cooked meats that had been contaminated

with E.coli O157. Extensive microbiological testing and typing revealed that the strains of E.coli O157 in people who were infected were indistinguishable from those found on cooked meats recovered from schools, in a sample of raw meat recovered from the premises of John Tudor & Son, a catering butcher business, and in samples of cattle faeces taken from a farm.

• The Outbreak occurred because of food hygiene failures at the premises of John Tudor and Son. The responsibility for it falls squarely on the shoulders of William Tudor, the Proprietor.

• William Tudor pleaded guilty to seven food hygiene offences. He was sentenced to twelve months imprisonment and banned from participation in managing any food business. He misled and lied to EHOs on the use of the vacuum packing machine.

• Inspections by EHOs from Bridgend did not assess or monitor food safety management at the business as well as they should have done. They failed systematically to assess accuracy and effectiveness of HACCP documentation. Inconsistencies and problems were not picked up and clues were missed.

Pennington: findings on outbreak management

• Outbreak was handled well: identified common link at a very early stage, and took action to remove cooked meats from food chain

• Considerable time and effort taken, including overtime and out-of-hours working

• Good communication between members of the OCT• Improvements needed in relation to communication

directly with the public, and with health professionals

• Without quality of investigation, analysis & control measures taken by OCT, outbreak would have been more severe & prolonged

Case study 2• A Major Outbreak of E. Coli O157 in Surrey• August/September 2009

• Independent Investigation Committee established by the Health Protection Agency, chaired by Professor George Griffin

• Published report in June 2010• http://is.gd/GriffinReport

Godstone Farm, Surrey• Located in the village of Godstone in Surrey,

approximately 20 miles south of Central London

• Open Farm used exclusively as a visitor attraction, in operation for more than 25 years

• Open to members of the public and also hosts pre-arranged visits from groups e.g. nurseries and primary schools

• Popular venue for birthday parties

Godstone Farm: Location

Godstone Farm: Visitor numbers• 200,000 visitors

per year• 1500-2000 per

day in summer• Nearly half are

under 12• Similar

business operated 12 miles away at Horton Park near Epsom, Surrey

Layout & attractions

Site information• Display & handling area for rabbits & small

mammals• 2 animal petting barns: all animals can be touched

– Main: sheep, goats, pigs, a calf & a Shetland foal– Top: goats, calves & piglets– Children encouraged to climb into the pens and play

with the lambs in the main barn• Tearoom & ice cream outlets, picnic areas• Indoor play area, outdoor adventure playground,

sandpits• History: August 2000, 8 confirmed cases of E.coli

O157: source of infection probably goats

Organisations involved• Surrey & Sussex Health Protection Unit (HPU)

– Part of the Health Protection Agency. Responsible for surveillance of communicable disease including outbreak recognition, co-ordination of joint policy on outbreak control, and convening and chairing of Outbreak Control Teams.

• Tandridge District Council Environmental Health Department (EHD)– Responsible for delivery of environmental health service including

enforcement of food safety and health & safety legislation at Godstone Farm.

• Health & Safety Executive (HSE)– Responsible for health & safety enforcement at agricultural premises (but

not tourist attractions such as open farms)• Evelina Children’s Hospital• Animal Health

– Government agency with role to safeguard animal health and welfare through research, surveillance and inspection

Timeline of eventsThursday 20th August 2009

HPU informed of child with presumptive E.coli O157. EH Department also advised of this case plus sibling. Both had visited Godstone Farm.

Wednesday 26th AugustHPU & EHD advised of another case who had visited Godstone Farm on 15th August, and who had also recently returned from holiday in Spain.

Thursday 27th August

HPU advised of another presumptive case who had become unwell on 24th August.

Friday 28th AugustHPU pass details of this case to EHD. EHD find out that this case visited Godstone Farm on 21st August, no other apparent risk factors.

What would you do now?• You are the senior officer investigating the matter for

Tandridge DC. This weekend Sat 29th-Mon 31st August is the summer Bank Holiday, one of the busiest tourism and holiday weekends of the year. HPU staff have rung you to emphasise the importance of dealing with this before the Bank Holiday Weekend.

• What would you do?– Call a meeting of the outbreak control team– Telephone the site manager at Godstone Farm to advise on

extra signage– Visit the farm immediately to inspect the premises and assess

the risk of infection– Wait and see how the situation develops over the weekend– Something else?

• Vote now! http://poll.fm/4h93o (pick one only)

Poll resultshttps://polldaddy.com/polls/7523412/results/

What they did:• Tandridge EHD contacted Godstone Farm by telephone to

advise them of the cases and the need to alert parents about hand washing and hygiene measures. Arranged a visit to the farm for the following week.

• HPU did not declare an outbreak, convene an OCT or make any arrangements to review the circumstances over the Bank Holiday weekend.

• That weekend, there were nearly 5000 visitors to the Farm, including 2000 children.

Further development of outbreak (1)Tuesday 1st September

EHD advises HPU of a fourth case of E.coli O157 (sibling of first reported case). They suggest there may be an outbreak associated with Godstone Farm.

Wednesday 2nd September

HPU & EHD arrange to visit Godstone Farm the following day.

Thursday 3rd September

Joint team visits Godstone Farm and discuss options to reduce risk of infection – focussing on handwashing facilities and risk associated with feeding animals.By evening, total number of cases known to have visited farm rises to 8.

Friday 4th September

Following visit HPU send email to Godstone Farm suggesting extra signage and staff to emphasise handwashing, measures to prevent waste spilling on paths, and closure of sandpits. Suggests farm ‘may wish to consider voluntary closure’.Farm decides to restrict direct contact with animals by closing main petting barns and prohibiting feeding of animals. Also close sandpits.

Monday 7th September

Multi-agency Outbreak Control Team (OCT) meets via teleconference. All key agencies represented except Tandridge DC EHD, who do not attend. OCT agrees there appears to be no ongoing risk, no further measures required, Farm does not need to be closed – animal petting barns already closed (since 4th Sep) and none of the cases reported so far visited after 31st August. OCT agrees to meet again on 18th September.Veterinary Laboratories Agency visits Godstone Farm to take faecal samples from animals.

Further development of outbreak (2)

Tuesday 8th September

Nephrology Unit at Evelina Children’s Hospital calls HPU to express serious concern about cases of Haemolytic Uraemic Syndrome associated with Godstone Farm. They are advised that the matter ‘is in hand’.

Thursday 10th September

Preliminary farm sample results indicate majority of samples from ruminant animals (83%) are positive for E.coli O157. Information about the outbreak is sent to neighbouring HPUs, hospitals and primary care providers, and local education authority.3 new patients admitted to Evelina Nephrology Unit with HUS. Evelina concerned that Farm still open. Lead person from HPU does not return their call.

Friday 11th September

Farm sample results confirmed. 2 further patients admitted to Evelina Nephrology Unit with HUS. Local HPUs in London report a further 7 presumptive cases of E.coli O157. Two had visited Godstone Farm on 1st and 4th September respectively.HPUs hold teleconference and decide to request that farm closes. They telephone Tandridge EHD to request them to close the farm.

Saturday 12th September

Tandridge EHD visits farm before it opens at 10am. Farm agrees to immediate voluntary closure for indefinite period.2nd Oct meering. Now 36 confirmed or presumptive cases of E.coli O157, including 12 hospitalised with complications. HPUs plan to undertake an epidemiological study.

Sunday 13th September

3rd OCT meeting. Agreed that helpline should be managed through NHS Direct. Complaints from parents that farm should have been closed earlier are reported in the media.

Further development of outbreak (3)

Monday 14th September

Fourth meeting of the OCT. Intense local and national media interest.

Thursday 17th September

Health Protection Agency issues apology for delays in handling the outbreak.

Monday 21st September

Joint inspection visit to Godstone Farm by Tandridge EHD and Health & Safety Executive (acting in advisory role at request of Tandridge DC). HSE subsequently invited to join the OCT.

Monday 28th September

Animal Health agency provides advice to Godstone Farm on cleansing and disinfection of the Farm, to be supervised by a veterinary officer from Animal Health.Case-control study begins. HPA staff conduct telephone interviews with parents/guardians of children who have visited Godstone Farm.

Thursday 15th October

Outbreak declared over.

Monday 26th October

Godstone Farm re-opens play areas.

Summary of the outbreak• Epidemiology

– 93 cases, 91 lab confirmed. Most aged <10. All from surrounding area.– 37 primary cases visited after Friday 28th August. No infection of

primary cases occurred after farm closed petting barns on Friday 4th September.

– Cases less likely to be regular visitors, more likely to have visited for prolonged period and visited main animal barn. Petting sheep increased risk further.

• Microbiology– Human isolates all phage type 21/28. All but one of animal isolates

also PT 21/28. 5 surface samples also positive for PT 21/28.• Farm management

– Deep litter system allowed accumulation of animal faeces in animal pens which children were permitted access to.

– Pen fronts and farm layout did not prevent contamination of visitor walkways.

– Over-reliant on hand washing as primary control measure. Possible to access play areas and catering facilities with limited opportunities for hand washing.

The Griffin investigation: key findings on outbreak management

• Unacceptable delays in:– Recognising outbreak: inadequate communication & out-of-

hours handover arrangements– Convening OCT: earlier OCT meeting would have enabled a

more timely assessment of risks and more effective control– Initiating control measures: many cases could have been

prevented if action taken before the Bank Holiday– Undertaking epidemiological investigations– Alerting GPs and hospital clinicians about the outbreak– Reaching a decision about reopening Godstone Farm– Publishing OCT report

• Lack of public health leadership by Health Protection Unit (and local authority environmental health?)

Griffin: Recommendations• 1993 circular on outbreak management to be updated• Every LA to identify senior post with responsibility for managing

outbreak control function• Review of HPZone (surveillance system)• Every case of E.coli O157 to be assessed for potential of: outbreak,

ongoing source of infection & risk of secondary spread• Robust handover arrangements in HPUs & LAs• OCT to be convened as soon as 2 presumptive cases of E.coli O157

with potential common link are identified• First meeting to specifically assess ongoing risk to public and

effective control measures, and agree communication strategy• Analytical epidemiological investigations for identifying source &

mechanism of infection to be conducted wherever possible as a matter of urgency

• Parents visiting open farms to have clear information about risk of E.coli O157

What are the key factors influencing successful outbreak

management?• Fast identification, investigation &

control measures• Clear understanding of roles &

responsibilities of all OCT members• Excellent communication: internal &

external• Willingness to take formal action to

instigate control measures if necessary

Who wants to be on an OCT?• Stakes are high to get

the answers right quickly• Very public arena• Phone a friend – reliance

on one individual opinion• Ask the audience –

collective wisdom• Consequences extend

considerablybeyond the time of the event

How can we be fully prepared?• Know our roles and responsibilities and those of other

key individuals and organisations• Maintain excellent communication at all times

– Routine surveillance success relies on effective communication

– Successful outbreak management communicates effectively internally (within the OCT) and externally (with the public, the media and relevant stakeholders)

• Act fast to identify and investigate the outbreak• Be prepared to take a precautionary approach to

instigation of control measures – act on basis of reasonable suspicion not incontrovertible proof– Prepare the ground by discussing the likely need for this

within, for example, outbreak control plans and in discussions with senior managers/politicians who have oversight

Contact detailsAlastair Tomlinson

Chartered Environmental Health PractitionerSenior Lecturer in Environmental & Public HealthProgramme Director, MSc Applied Public Health

Cardiff Metropolitan University +44 (0)29 2020 1528

agtomlinson@cardiffmet.ac.uk @agtomlinson