Birds with, or exposed to, the disease will be slaughtered
With Britain still on bird flu alert after the deadly H5N1 strain was detected in the country for the first time, we look at preparations for a major outbreak.
The H5N1 strain of the virus has killed at least 90 people in Asia and in Turkey and so far seems able to be passed to people by birds but not easily from one human to another.
But if, as experts fear, it mutates into an easily transmittable human form, there are predictions of a massive flu pandemic, which could kill hundreds of thousands across the world.
So what is the UK doing to protect its population?
STOPPING BIRD FLU COMING FROM ABROAD
The UK has banned imports of live chickens from Croatia, Turkey, Romania, Russia, Kazakhstan, Thailand, Cambodia, China, Hong Kong, Laos, Indonesia, Vietnam, Pakistan, Malaysia, South Africa, and North Korea, where bird flu outbreaks have occurred.
The EU temporarily banned imports of captive birds from outside the union and all imports of poultry products and eggs from Thailand.
The importation of various birds and bird products from South Africa has also been banned.
DETECTING BIRD FLU IN WILD BIRDS
Wild birds are known carriers of various strains of bird flu - also known as avian flu - and could possibly bring the most dangerous H5N1 strain to Britain.
Tests have been carried out on more than 3,000 wild birds across the country to see what strains of bird flu are being carried by the wild bird population and the results processed by government experts.
The deadly H5N1 strain was detected in Britain for the first time in a wild swan found dead on a beach in Fife in April.
SHIELDING DOMESTIC BIRDS
Keepers have been advised to keep their birds away from wild birds and to feed and water them indoors.
Keepers such as free-range farmers whose flocks normally live outdoors have been advised to make preparations to bring them under cover if necessary to protect them from infection.
Such measures were put in place in eastern Scotland in the immediate aftermath of the discovery of the infected swan.
COMBATING BIRD FLU
Report unusual bird deaths
Report sick or dead cats
Keep cats away from birds or indoors
Avoid stray cats
Keep dogs on leads outdoors
Use gloves to put dead birds in bags
Wash hands frequently
Clean litter trays and feeding dishes regularly
Under a newly adopted EU directive, anyone with 50 or more birds has been obliged to add them to a national register.
Smaller flocks can also be added on a voluntary basis.
Poultry keepers have been informed about the disease and urged to look out for symptoms.
Bird flu is a "notifiable" disease, which means farmers are obliged by law to report infected birds.
Thousands of birds have been culled on a farm in Norfolk after an outbreak of a suspected H7 strain of bird flu killed several chickens.
Although H7 strains can be highly pathogenic in birds, they usually cause only mild flu symptoms and conjunctivitis in humans and are not considered a major threat to public health.
WHAT HAPPENS IF BRITISH POULTRY ARE INFECTED WITH H5N1?
Movement of animals, litter and vehicles from infected farm or premises would be prohibited and the premises and its vehicles cleaned and disinfected.
Birds that are diseased, suspected of being diseased or which have been exposed to infection would be slaughtered.
Eggs would also be destroyed.
A 3km bio secure "protection zone" would be set up around the infected premises for at least 21 days.
Any people or vehicles going in or out of poultry farms within the zone would have to be disinfected first.
A wider 10km "surveillance zone" would also be set up, within which vets could visit those keeping birds and search for signs of bird flu.
This zone would remain for at least 30 days.
Within it, movement of eggs and birds would be restricted. Poultry would have to be kept within their living quarters and markets, fairs and shows banned.
WILL FARMERS BE COMPENSATED?
Farmers are entitled to compensation for slaughtered birds found not to have been infected.
Free-range farmers forced to bring their birds undercover to protect them from infection are allowed to keep their free-range status for 12 weeks.
WHAT IS BEING DONE TO PREPARE FOR A HUMAN BIRD FLU?
If the virus mutates into a form easily transmitted between humans, drug companies will set to work developing a vaccine.
The government says it will buy 120 million doses of it - enough to treat the whole UK population.
But a vaccine will only be able to be formulated once the pandemic has begun and will take up to six months to prepare.
Drug manufacturers have been invited to tender for the contract in advance.
A stockpile of 14.6 million courses of the antiviral drug Tamiflu is also being built up. This would not be a cure or offer immunity from the disease but could alleviate symptoms and slow its progress.
It would be enough to treat a quarter of the UK population.
The government has also purchased a limited supply of vaccines against one Asian bird flu strain - A/H5N1. It is not known how effective this would be against a mutated strain being transmitted between humans but it might offer some protection.
And leaflets have been sent to health professionals to advise them about what to expect in case of a flu pandemic.
Health staff are being trained in how to deal with a pandemic and NHS bodies are formulating contingency plans which could be brought into play.
WHAT MEASURES WOULD BE USED TO COPE WITH A PANDEMIC?
In the time it takes to develop and procure the new vaccine, the following measures would be used to try to buy time and stop the virus spreading:
- Travel between the UK and infected countries restricted and health screening begun at ports
- Infected people asked to go into voluntary isolation and those who had been in contact with them into voluntary quarantine
- Public gatherings such as football matches and concerts restricted, along with movement of people within local areas
- Schools closed
- Infected people, those who had been in contact with them and possibly the general public told to wear face masks.
In addition, government television, radio and newspaper advertisements would give simple advice on hygiene and how to avoid infection.
Once a vaccine was available, it would be administered according to the following priorities:
1. Health workers occupationally most at risk
2. Key service workers
3. Group(s) most vulnerable to illness (this will depend on the strain and will not necessarily include the elderly)
4. Enclosed communities, such as residential care homes
5. People most likely to transmit the virus, such as children
6. General population.
The World Health Organization predicts that one in four of the UK population could be infected in a bird flu pandemic, resulting in a possible 50,000
THE IMPACT ON THE UK POPULATION
Government plans are based on a quarter of the human population being infected at some point during a pandemic. This could rise to 50% in a worst case scenario.
The virus may hit in several waves coming either weeks or months apart.
All age groups will be at risk, though children and otherwise fit adults may be most vulnerable.
Older people might turn out to have some residual immunity due to having been exposed to a similar flu strain earlier in their lives.
The illness is likely to hit sufferers harder than "normal" influenza, with more people developing severe prostration, viral pneumonia and complications or dying.
The likely fatality rate is not yet known, but the government is using a possible overall figure of 48,400 deaths for planning purposes.
The total number of deaths in the UK per week is expected to rise to at least double the normal level of 12,000 at the peak of a pandemic.
At least a third of flu deaths could be in the under-65s, compared with the normal rate of less than 5%.
IMPACT ON HEALTH SERVICES
The government warns the "intense, sustained and nationwide" impact of a pandemic could quickly overwhelm health and social services.
Demand on health services will increase as more people become sick and at the same time the workforce itself is likely to be depleted by sickness, caring responsibilities and deaths.
GPs are likely to see as many as 14 million more patients during a pandemic than normal.
Hospitals will see a rise of at least 50% in admissions for acute respiratory conditions, with at least 20,000 new patients per week needing hospitalization at the peak.
IMPACT ON BUSINESS AND DAILY LIFE
Transport systems, supply networks and utilities are likely to be disrupted by staff sickness and movement restrictions.
This, plus staff sickness, will have a knock-on effect for all workplaces in the UK.
This includes all the emergency services, the military and essential services such as fuel supply, food production and distribution and transport, as well as prisons, education and businesses.
Employers are advised to base their contingency plans on a total of 25% of workers having to take between five and eight days off over a period of three to four months due to sickness and caring responsibilities.
But the virus may spread faster in workplaces, hitting them harder over a shorter period of time.
In the worst case scenario, staff absenteeism is expected to peak at a maximum of 15% at any one time.
However, some employers may be hit harder than others.
The virus is also expected to spread rapidly in schools, where infection rates of 90% are envisaged.
Other institutions such as prisons and care homes will be similarly hit.
Closing schools would have serious implications for the wider society, as parents were forced to stay home from work to care for children.
In addition to maintaining the continuity of their work, businesses are advised to consider how they would protect the security of their premises if they were badly affected by sickness.
They are advised to make plans to run their operations with minimum staffing, and consider redeploying staff to areas they might not normally work in or taking on additional staff or volunteers where necessary.
Employers should also consider providing accommodation, such as bunks in temporary buildings, where staff can rest in between shifts if transport disruption or movement restrictions mean they cannot get home.
HOW VULNERABLE IS THE UK?
According to a study by business risk consultancy Maplecroft, the UK is at "extreme risk" from the spread of a flu pandemic, along with much of Western Europe, the US and Canada.
The firm ranks the UK at number 25 on its list of countries most vulnerable to the overall effects of a pandemic - the highest ranking Western state.
It is ranked ninth in the world on a list of countries where a human version of bird flu is most likely to emerge.
On a list of countries to and within which the virus is most likely to spread, the UK comes top.
Maplecroft says this is because of the openness of the UK economy, its high population density and high numbers of tourists, immigrants and visitors from abroad.
However, on a list of countries which would struggle most to contain the virus, the UK is ranked 148th, indicating a low risk.