Key factors in successful outbreak management Lessons learned in the United Kingdom Alastair Tomlinson IFEH 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/
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
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 agreedand 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 meeting Afternoon 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 meeting Morning 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 results https://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
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.coliO157. 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.
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 Pennington: findings on outbreak management
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
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, Surrey
Godstone Farm: Visitor numbers 200,000 visitorsper year 1500-2000 perday in summer Nearly half areunder 12 Similar business operated 12 miles away at Horton Park near Epsom, Surrey
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 Site information
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
What would you do now? • You are the senior officer investigating the matter for TandridgeDC. 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 results https://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.
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?)
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 Griffin: Recommendations
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