Q&A: Bird flu in the UK

Find out how outbreaks of bird flu are dealt with in the UK Enlarge Image

A person working on a Norfolk farm has conjunctivitis after coming into contact with chickens infected with the H7 strain of bird flu.

It is a completely different form of bird flu to the deadly H5N1 strain which has killed over 100 people, mainly in South Asia.

Earlier this month, restrictions imposed after a wild whooper swan with the H5N1 strain was discovered on the Fife coast were lifted.

What is the virus - and what are the risks for birds and humans?

What is bird flu?

Like humans and other species, birds are susceptible to flu.

There are many different types, which each have different "postcodes" based on differences in the hemagglutinin and neuraminidase proteins on the surface of the virus.

But the one concerning experts at the moment is the "highly pathogenic" H5N1 strain - this means that it is highly likely to cause disease.

What is the H7 strain?

H7 versions of bird flu are highly infections to chickens, but are less threatening to humans than the H5N1 strain.

The strain found in dead chickens on Witford Lodge Farm at Hockering, Norfolk was H7N3.

Is it worrying that a worker was infected?

Occasional infections do occur in people in very close contact with birds.

As in this case, most people with an H7 form of bird flu, develop conjunctivitis, but no other symptoms.

However, in 2003, an outbreak of the H7N7 strain of the disease in the Netherlands led to the death of a vet, while 89 poultry workers contracted the virus.

Why was there concern after one swan died?

It was because the swan had the deadly H5N1 virus.

The worry was that wild birds - such as the swan - could spread the virus to domestic poultry flocks.

It spreads easily among them, and could devastate the industry if it took hold.

What measures were put in place?

A "wild bird risk area" was set up covering 2,500 square kilometres around the area where the swan was found.

Poultry owners were directed to keep their flocks indoors where possible, or find other measures of separating them from wild birds.

A three-kilometre exclusion zone around where the swan was found, where movement of birds was restricted and a surveillance zone of 10 kilometres was set up.

Why are the restrictions being lifted?

A programme of veterinary inspections of all premises with poultry in a surveillance zone have all returned negative results.

Twelve swans and two birds of other species were also checked by Scottish authorities - but none were found to be H5N1 positive.

GLOSSARY Pathogenic - disease causing Outbreak - a sudden increase in occurrence of a disease, often worldwide Epidemic - affecting many people in a population at once Pandemic - an outbreak which crosses international boundaries

So should chickens in the UK be vaccinated - as in other European countries?

The measure has not been ruled out, but there are concerns that vaccination - as has happened in France and the Netherlands - could mask the virus' presence in flocks.

What should I do if I see a dead bird?

Do not touch it. Government advice is that if you find one or more dead swans, ducks or geese, more than three dead birds of the same species or more than five dead birds of different species, in the same place, you should contact the Defra helpline on 08459 33 55 77.

Is it possible to stop bird flu coming into a country?

No. Wild birds do not recognise natural boundaries. But measures such as the exclusion zones and bringing poultry indoors are designed to stop the virus taking hold.

What is the risk to human health if a bird does have H5N1?

It is extremely low. One expert described it as "virtually zero".

People have only contracted the virus from being in very close contact with infected birds.

Someone would need to be close enough to touch a bird's beak, pluck its feathers or come into contact with its droppings to be at risk.

How deadly is the virus?

So far, there have been 191 cases of H5N1 - mainly in people living in South East Asia. The virus has killed around half of those affected.

But it does not spread easily between people.

If that is the case, why are experts concerned about flu spreading in people?

The concern is that the virus could mix with a human flu virus and mutate into a version which can spread easily between people.

The world is overdue a flu pandemic - and experts believe a mutated H5N1 virus is the most likely candidate - so plans are in place if that happens.

The UK government has stockpiled 14.6m course of the anti-viral drug Tamiflu.

There is no vaccine for a pandemic - because no-one knows what the flu strain would be which causes it.

But the government has said it will buy a limited supply of a vaccine against current strain H5N1 which could be given to groups such as health-workers.

Can the virus be passed on through eating poultry or eggs?

No. The virus is easily destroyed by cooking, so even if it was present it would be destroyed.

Should I keep my chickens, or my dogs and cats indoors?

Bird keepers around Fife were told to keep their flocks inside.

People do not need to bring their pets inside - but experts say it is always sensible to stop pets eating dead birds because they could have other infections.