28 December 2001

F&Mvaccination:Yes or No?

This year has seen the livestock industry in a quandary over

many issues, such as the need for contiguous culling and

merchants supplying medicines to producers. Over the next

few pages, FW reporters review some of these debates,

kicking off with perhaps the most hotly debated issue –

whether or not to vaccinate against foot-and-mouth

VACCINATION against foot-and-mouth has had its supporters and critics in the past 10 months. In this outbreak it remained firmly on the shelf, but future use remains a hot topic.

Despite initially stating that vaccination would not be used, in late March farmers weekly discovered the government had requested and received permission from EU vets to start vaccinating dairy cattle in Devon and Cumbria.

A UK government source in Brussels said the aim was to target housed cattle to allow turnout on to pastures previously occupied by sheep. Plans included treating about 180,000 cattle in the two counties.

No decision was taken on whether or not cattle would be slaughtered. But without slaughter, it was believed that exports of milk or meat would be banned for 12 months after vaccination or the last F&M case.

The need for slaughter post-vaccination was debated throughout April. Vaccinated animals would have to be slaughtered at a later date, insisted Chris Bostock, head of the Institute of Animal Health. "Internationally agreed standards for the resumption of trade require infected and vaccinated animals to be culled."

Keith Sumption, an animal disease expert at Edinburgh University, argued that slaughter of vaccinated animals was only necessary if they are shown to be infected with F&M.

However, the differentiation between F&M infected and vaccinated animals depended on using a genetically modified marker vaccine, according to Mac Johnston, of the Royal Vet College. "None of these marker vaccines have undergone trials or been licensed for use."

Such vaccines have been administered in Holland, but they were only used to allow the authorities to catch up with slaughter, said Prof Johnston.

However, many believed vaccinated animals need not be slaughtered, so support for a vaccination policy grew. A coalition of organisations, such as Elm Farm Research Centre and the National Trust, took up the cause, while support from individuals was co-ordinated by the Soil Association.

In the Vet Record, Joe Brownlie, of the Royal Vet College, also pledged support for strategic vaccination of endangered breeds or for farms downwind of large pig units. But he believed ring vaccination around infected farms would have had little influence on virus spread by sheep movements.

Prof Brownlie also pointed out that it can take two to three weeks for animals to gain immunity following vaccination, during which time they may remain susceptible to infection.

He was supported by Prof Johnston, who was concerned that vaccination could mask what was really going on. "When the disease dies down, we wont have a clue what we are dealing with. If ewes are vaccinated, they may show no signs of disease for up to two years and then suddenly under stress, say at lambing, there could be a flare up."

The NFU also remained opposed to vaccination. President Ben Gill refused to support emergency vaccination of cattle in Devon and Cumbria after the government failed to answer more than 50 questions he submitted on the subject. "Farmers are effectively being asked to take a leap of faith."

Mr Gills stance was supported by local union members in Devon and Cumbria. Many Cumbrian farmers were turned off the idea of vaccination when they realised the trade implications, said NFU county chairman Gordon Capstick.

John Duncan, chairman of the Federation of Milk Groups, also expressed concern. "We are aware of processors that say they will not accept milk from vaccinated animals."

The supermarkets also said they would not sell meat products from vaccinated stock, as MAFF planned to override the opposition from farming unions to force of a firebreak vaccination programme in mid-April.

Despite frequent criticism, the NFU was supported by many producers. In a farmers weekly survey of 100 producers who had stock culled, conducted in late April, only 16% of respondents said vaccination should have been introduced compared with 64% against.

It also became apparent that MAFF officials didnt have the legal power to force farmers to vaccinate livestock, so the NFU effectively won the early battle.

But as the crisis extended into June, producers, tourism industry representatives and the public formed the National Foot-and-Mouth Group to press for vaccination. "We want government to consider whether limited vaccination would deliver disease-free status in the most sensible timescale," said spokeswoman Janet Bayley.

One campaigner for vaccine use was Ruth Watkins, a former consultant virologist who farms 102 ewes in Carmarthenshire. She believed producers were never told the true facts about vaccination. "As the number of slaughtered animals grew, politicians and union leaders could not bring themselves to admit they were wrong about the need to slaughter vaccinated animals and about the impact on meat sales and exports."

Farmers For Action continued the campaign in August with a meeting of campaign groups to agree a plan to persuade the government to stop culling, start vaccination and guarantee to hold a full public inquiry.

But the NFU maintained its opposition despite increasing farmer support for the policy.

The government, however, was making provisional plans to vaccinate livestock around Thirsk, North Yorks, to protect the heart of the UK pig herd. This received backing from the National Pig Association when producer group chairman Stewart Houston said the NPA would back firebreak vaccination around Thirsk as a last resort.

DEFRA – MAFF no longer existed by this time – continued to say vaccination had not been ruled out, although its true intentions are easily questioned.

In September, chief government scientist David King told the Press that there has never been a case for vaccination and nor was there now.

He said vaccination does not stop disease developing in infected animals and as it produced antibodies in animals, it would hamper the national blood testing programme.

But many of those against vaccination during the current F&M outbreak agreed that it is likely to be included in the control policy for any future outbreak.

In June, DEFRA minister Margaret Beckett gave the first hint that the government would not automatically opt for a slaughter policy to deal with any future F&M epidemic, during a Press briefing in Lancs.

And speaking at the British Vet Association Congress in October, Archie Robertson, of the Environment Agency, suggested that vaccination should be included in future contingency plans. "Landfill and burial are the least popular way of disposing of carcasses. Top of our list is reducing the number of carcasses in the first place."

As the inquiry into F&M by the Royal Society of Edinburgh began, president William Stewart said a key question was why vaccination had not been used. "It has been said there are too many F&M strains to allow vaccination to be effective, but there are no more strains than of flu. I am not saying we should have used vaccination in this outbreak. But I dislike people who rule out any role it may play in future."

However, it is likely that vaccination would only form part of a future F&M eradication plan. Vaccination tends to prolong disease eradication and no country has managed to eradicate F&M using vaccination alone, explained Devon vet Dick Sibley.

The Dutch eradicated F&M by recognising the limitations of vaccination. All those animals are now dead, together with the virus, he added. Vaccinating may also hide infected animals carrying the disease because there is not currently an accurate blood test to distinguish vaccinated animals.

Although the issue of slaughtering following vaccination has never been resolved, progress has recently been made on a test to differentiate between vaccinated and infected stock. Intervet announced in November that it had developed such a test and was applying for registration (Livestock, Nov 9). &#42

Many Cumbrian producers were put off vaccination against foot-and-mouth by possible trade implications, says Gordon Capstick.

Ben Gill refused to support emergency vaccination of cattle.

&#8226 Slaughter of vaccinated stock?

&#8226 Strategic or ring?

&#8226 Differentiating test?

&#8226 Future outbreak policy?

No country has eradicated F&Musing vaccination alone,

explains Devon vet Dick Sibley.