public health aspects of cumbria foot and mouth disease outbreak

Dr Nigel Calvert Consultant in Communicable Disease Control

Public Health Aspects of the Foot and Mouth Epidemic

Topics

Topics: 1 Background

• Background –Foot and mouth disease –The 1967 outbreak –The 2001 outbreak

• How does it compare to 1967? • Veterinary policies on dealing with the

epidemic – Slaughter v Vaccination

• Agencies involved

Topics: 2 Public Health

• Public Health Aspects –Health Care Issues –Environmental Health Issues

• Rendering • Burning • Burying

–Human Infection

Topics: 3 The Future

• Ongoing Issues & The Future –Surveillance

• CueDoc • Routine notifications

– Lessons for the future –Conclusions

1. Background



• Veterinary policies on dealing with the epidemic

– Slaughter v Vaccination


Background: Foot and Mouth Disease

• Highly infectious viral animal illness • Cloven hoofed animals • Usually not fatal

–Can be fatal in young & old –Decreased meat / milk production

• Vaccine preventable


• PicoRNA Virus • diameter 24nm • pH sensitive -

inactivated at pH5

• sensitive to Ultraviolet radiation


• Picornaviridae • 7 serotypes:

–O; A; C; SAT1; SAT2; SAT3; Asia1


• The current outbreak in the United Kingdom –highly virulent pan-Asiatic serotype O –endemic in many parts of the world

• Asia • South America • Africa • Much of Europe


• Spread in three ways: – Directly, from an infected animal to another

animal, by contact, or through the air. – Indirectly, from infected animals by people

who have handled them. – Indirectly from infected material such as

dung, urine, and saliva picked up by people, vehicles, equipment, dogs, scavenging animals and vermin.


• Presentation in animals: –acute fever, followed by the

development of blisters chiefly in the mouth and on the feet.

– Infected animals secrete numerous virus particles before clinical signs appear

Background: The 1967 Outbreak


• 2,364 outbreaks were detected – Cheshire – Shropshire – Wales

• 442,000 animals slaughtered • Costs:

– £150 million in slaughter costs and lost sales in 1967 and 1968.

– £27 million compensation was paid out to farmers


• “Every day we would hear the latest reports of villages where there had been new outbreaks.

• “In our area there were 27 reported cases within five or 10 miles so you can imagine how worried we were. Our hearts were in our mouths for more than eight weeks.”


• How does it compare with 1967? –Time had elapsed before the infection

at the probable source farm was disclosed. • Suspicious lesions found on pigs at

Heddon-on-the-Wall on 22 February – May have been incubating the disease for at

least two and possibly up to three weeks.


• How does it compare with 1967? – Infection confirmed on 23 February,

• infected animals had already spread through markets and dealers:

– Cumbria – Dumfries and Galloway – Devon – Cheshire – Herefordshire – Northamptonshire.


• How does it compare with 1967? –Larger scale of animal movements

nowadays • Much improved network of roads and

motorways • Supermarkets buy animals nationally and

transport to a small number of abattoirs


• Total number of confirmed foot-and-mouth cases in the UK 1,538 (2,364 in 1967)

• 2,382,000 animals have been slaughtered (442,000 in 1967)

• 118,000 animals awaiting slaughter


• Infection spread quickly to sheep, and then among sheep –harder to diagnose –dispersed flocks on the fells

Background: Veterinary Policies

• MAFF Policy –Restrictions on movements –Slaughter

• Infected flocks, herds etc • Neighbouring animals


• Slaughter Policy –Plus Points

• Proven to work

–Negative Aspects • Welfare • Environmental and health consequences • Economic consequences


• Alternatives to Slaughter: the case for and against Vaccination –Vaccine controllable disease –85% efficacy –Protective antibodies after 4 days


• Vaccinated animals to be slaughtered later • Avoid backlog of carcasses


• Arguments against Vaccination –Office International des Epizooities – List of “FMD free countries where

vaccination is not practised” • Record of regular and prompt animal

disease reporting • Documented evidence of an effective

system of surveillance.


• Also not allowed to import animals vaccinated against foot and mouth disease

– Serological testing cannot differentiate between infected and vaccinated animals.

• “Foot and mouth free zone” may be established in a country in which parts are infected, separated from the rest by a buffer zone


• "These are not simply economic concerns, as some have suggested.

• "There is a real possibility that the use of vaccination could actually prolong this outbreak, resulting in the culling of more cattle rather than less.

Ben Gill NFU President


• "Once we go down this road there will be no going back. And it is farmers throughout the UK - not just in vaccinated areas and not only cattle farmers - who will have to bear the consequences for a very long time to come."

Ben Gill NFU President

Background: Agencies involved

• MAFF • Army • Environment Agency • National Farmers’ Union • Local Authorities • Health Authorities • Central Office of Information

2. Public Health




–Human Infection

Public Health: Health Care Issues

• Farmers and their families • Wider community • Knock-on Effects on the Community

–Tourism –Local Businesses – Increased workload for NHS, Social

Services, Voluntary Sector


• Physical Health and Somatisation –Review by Ng and Stevenson (1) – Link between exposure to disasters/

economic hardship and subsequent use of health and social care services

– (1) Ng V, Norwood A. Psychological trauma, physical health and somatisation. Annals of the Academy of Medicine, Singapore. 29(5):658-64, 2000 Sep.


• Unemployment and Ill Health –Unemployment associated with

increased consultation rates in General Practice

• Carr-Hill RA, Rice N, Roland M. Socioeconomic determinants of rates of consultation in general practice based on fourth national morbidity survey of general practices. BMJ. 312(7037):1008-12, 1996 Apr 20

• Yuen P. Balarajan R. Unemployment and patterns of consultation with the general practitioner. BMJ. 298(6682):1212-4, 1989 May 6


• Two nurse practitioners will be recruited to work in the community with people affected by FMD.

• An intensive training package is being developed with St Martin’s College for community and practice nursing staff.


• The Health Authority will assist with locum fees for General Practitioners who cannot practice normally because of restrictions on their movement.


• Additional Nursing time for practices most affected

• PCTs/HA




–Human Infection

Public Health: Environmental Health Issues


• Hazards from Decaying Carcasses – Bacterial Infection

• E. coli • Salmonella • Campylobacter etc.

– Vermin – Contamination of Water Supplies

• Public Supplies • Private Supplies


• Hazards from Burying Carcasses – Bacterial Infection

• E. coli • Salmonella • Campylobacter etc.

– Contamination of Water Supplies • Public Supplies • Private Supplies


• Hazards from Burning Carcasses – Airborne Pollution

• Smoke & Particulates • Chemicals - dioxins; PAHs; SO2 etc.

– Contamination of Water Supplies • Public Supplies • Private Supplies

– Prions – Airborne spread of Foot & Mouth

virus?


• Preferred Options –Rendering – Landfill –Burial not in Landfill –Burning

• Small pyres v large pyres


• Involvement in Decision Making • Particular Considerations

–Prions –Dioxins –Particulates & Sulphur Dioxide


• Involvement in Decision Making –Minimal at the start

• 1st Cumbrian Case 1st March 2001 • Health Authority and Environmental

Health Departments first involved early April 2001


• Attempts to get Involved in Decision Making –Phone calls – Legal advice – Letter to Chief Medical Officer


• During March 2001 –Great Orton Burial Site – Large number of pyres lit

• Longtown


• Department of Health Guidance on Pyres –Too late for North Cumbria


• Prions – not allowed to bury

cows more than 5 years old

– risk of contaminating water courses


• Prions – also theoretical risk of

transmission by burning

– DoH risk assessment • 1 in a million risk from

burning 100 cows • many assumptions


• Dioxins – natural product of

combustion – can cause DNA damage

• cancers • congenital anomalies

– most of our exposure is in the food chain


• Particulates & Sulphur Dioxide –Can exacerbate existing chest disease

• asthma • chronic obstructive airways disease etc.

–Advice • minimise exposure • inhalers


• Air Quality Monitoring Results – Hazelsprings near Caldbeck

• Dioxins low • Particulates and SO2 high in several samples

• Consultation Rates – Monitoring of asthma out of hours

consultation rates with CueDoc • No increase in March or April 2001 compared with

March and April 2000




–Human Infection


10th March 2001

Public Health: Human Infection

–Extremely uncommon –37 cases described in the world –Apart from physical signs, diagnosis was

based on: • virus isolation alone (6 cases) • virus isolation together with a rise in antibody

titres (5 cases) • virus isolation and demonstration of antibody

in convalescent serum (9 cases) • demonstration of antibody alone (9 cases).


–Most of these cases had been involved in occupations working with animals, or the manufacture of foot and mouth disease vaccine.


• The incubation period 1 to 10 days –usually between 2 and 7 days


• Initial symptoms – fever & sore throat –headache & general malaise – later, vesicles appear on the hands,

feet and in the mouth. • Person to person spread never

recorded


• Case Definition –People who have

• (a) had direct physical contact with farm animals (cattle, sheep, pigs) on infected farms and

• (b) have oral blistering lesions

–blistering lesions


• Case Investigation –Specimens will include

• throat swab • blood sample for serology • vesicular fluid if possible • stool sample to exclude enterovirus


• Most likely to be: –Hand Foot & Mouth Disease

(Coxsackie virus) –Herpes –Orf –Mechanical trauma (eg biting tongue)




–Human Infection

3. The Future


• Surveillance –CueDoc

• Asthma

–Routine notifications • Gastrointestinal infections

–United Utilities • Water Quality


• Lessons for the Future –Public enquiry likely

• Periodic outbreaks of foot & mouth are expected

– Why weren’t the agencies ready?

• Local consultation poor – Public – Agencies

• Local relationships


• Lessons for the Future




–Human Infection

public health aspects of cumbria foot and mouth disease outbreak

Health & Medicine