East Anglian poultry farmers have been urged to bolster their biosecurity measures and make contingency plans against an infectious strain of bird flu spreading throughout Europe.

Cases of highly-pathogenic avian influenza (AI) have been found in Austria , Croatia, Denmark, Germany, Hungary, the Netherlands, Poland and Switzerland.

A flock of 30,000 chickens was destroyed on Sunday and Monday in Germany to try to contain the H5N8 strain of the virus, which can easily spread among birds – but is not known to infect humans. Meanwhile Dutch poultry farmers have been ordered to keep all their birds indoors as a precaution.

Defra has defined the risk of incursion to British poultry farms at 'low – but heightened', although the risk of the incursion of a wild bird infected with H5N8 in the coming weeks 'has significantly increased to medium from low'.

In East Anglia, the National Farmers' Union said the new cases in Europe served as an important reminder for farmers to maintain high standards of hygiene and biosecurity, as well as taking steps to avoid contact with wild birds.

NFU Norfolk county adviser John Newton said: 'With the colder weather coming, some of these infected birds could be landing in East Anglia. So the risk has gone up a notch. It is still fairly low to be fair, but it is slightly more heightened than it was a couple of weeks ago.

'At this time of year the risk is always heightened because of migrating birds, and it is a reminder to people to keep their biosecurity up to scratch, because it is the only way to stop avian influenza getting into their flocks.'

The NFU has been running a series of AI roadshows to advise farmers on preventative measures, and also to talk about contingency planning to ensure the right access and documentation is available to officials should an outbreak be identified on a specific farm.

Following Monday's event in Diss, the next roadshow in East Anglia will be at the NFU regional office on Willie Snaith Road in Newmarket, on December 14.

'The purpose of these meetings is to remind people of the need for good biosecurity, but also the need to have contingency plans in place,' said Mr Newton. 'These are the steps farmers can take in 'peacetime' to ensure that, if there was an outbreak on their premises, they are ideally placed to deal with it.

'They should be doing these things already. It is not just about avian influenza, it is campylobacter and salmonella as well – they can all be reduced by keeping visitors to the farm to a minimum, using appropriate foot dips at various entry points, keeping a list of visitors and keeping wild birds out of farms.'

NFU chief poultry adviser Gary Ford said: 'It is important to stress that this is a disease in birds and that there is no risk to human health. The NFU has taken the lead in ensuring the poultry industry is knowledgeable on AI and how it can impact farm businesses.'

How to spot avian influenza

Avian influenza spreads from bird to bird by direct contact or through contaminated body fluids and faeces.

There are two types of the disease. Highly pathogenic avian influenza (HPAI) is the more serious type, and is often fatal in birds. The main clinical signs of HPAI in birds are:

• Swollen head.

• Blue discolouration of neck and throat.

• Loss of appetite.

• Respiratory distress such as gaping beak, coughing, sneezing, gurgling, rattling.

• Diarrhoea.

• Fewer eggs laid.

• Increased mortality.

Clinical signs can vary between species of bird and some species may show minimal clinical signs.

Low pathogenic avian influenza (LPAI) is usually less serious. It can cause mild breathing problems, but affected birds will not always show clear signs of infection.

Farmers have been urged to report any signs of avian influenza to their vet or the Animal and Plant Health Agency (APHA).

Biosecurity guidance

Anyone keeping poultry is advised to seek prompt advice from their vet if they have any concerns about avian influenza.

Biosecurity measures advised by the government to prevent an outbreak on farms include:

• Cleansing and disinfecting protective clothing, footwear, equipment and vehicles before and after contact with poultry; if practicable use disposable protective clothing.

• Minimising potential contamination from manure, slurry and other products that could carry disease, by reducing movements of people, vehicles or equipment into and from areas where poultry are kept.

• Thoroughly cleaning and disinfecting housing at the end of a cycle.

• Having disinfectant and cleaning material ready at farm entrances, so essential visitors can disinfect themselves before entering and leaving premises.

• Minimising contact between poultry and wild birds.