What is avian influenza (bird flu)?

How does bird flu spread?

Avian influenza is highly contagious among birds. Susceptible birds (and occasionally other animals such as cats and pigs) become infected with avian influenza through contact with an infected bird's saliva, nasal secretions or droppings. These can contaminate food, soil and drinking water, and spread on surfaces such as cages, food, shoes and clothing. Migratory waterfowl (e.g. wild ducks and swans) may carry avian influenza viruses great distances and spread the disease to domestic poultry flocks as they travel around the world.

The humans who have caught H5N1 have mainly picked up the virus through close direct contact with infected poultry, or surfaces and objects contaminated by their faeces. The first cases occurred following close contact with diseased birds on farms and in live poultry markets. All human cases have coincided with outbreaks of highly pathogenic H5N1 in poultry. High-risk activities include;

• slaughtering, plucking and butchering infected poultry
• preparing infected poultry for consumption
• children playing in areas contaminated with the faeces of free-range poultry and possibly, swimming in water contaminated by infected birds.

So far, there are no confirmed cases of the H5N1 virus spreading from one person to another. Although, some instances have been reported, these have been rare, have not continued beyond one person, and the route of infection has not been confirmed.

Should I be worried about catching bird flu?

Although H5N1, H7N3, H7N7 and H9N2 strains of bird flu can infect humans, only the H5N1 strain appears to cause severe illness, and this does not easily transfer to humans. People who have become infected with H5N1 have generally had close contact with sick or dead poultry (mostly during slaughtering, plucking, butchering and preparing poultry for consumption). The risk of contracting H5N1 is low, even if you have contact with infected birds. However, if you are travelling to areas with bird flu outbreaks, you should protect yourself by following the Department of Health's recommendations.

Click here to check the latest government advice before you travel.

What precautions should I take in an area affected by bird flu?

Travellers to affected areas are not at increased risk of infection unless direct and unprotected exposure to infected birds (including their feathers, faeces, raw or undercooked meat and egg products) occurs. If you are visiting an area with an outbreak of H5N1 among poultry, the Department of Health recommends that you:

• Do not visit bird or poultry farms or markets.
• Avoid close contact with live or dead poultry.
• Do not eat raw or poorly cooked poultry or poultry products (e.g. eggs).
• Wash your hands frequently with soap and water.
• Do not attempt to bring any live birds or poultry products back to the UK.

If you are exposed to poultry in an affected area, and develop flu-like symptoms (e.g. fever, cough, shortness of breath, headache, sore throat, sore eyes, muscle aches) you should seek medical attention. Antiviral drugs may reduce the length of the illness and improve the prospects of survival, if taken within 48 hours of symptoms starting.

Click here to check the latest government advice before travelling to an affected area.

Is it safe to eat poultry and poultry products in areas with outbreaks of bird flu?

Thorough cooking kills avian influenza viruses, so provided you follow the normal precautions of cooking these items thoroughly and handling them hygienically during food preparation there should be no risk of infection.

The main risk of catching H5N1 comes from being in close contact with live birds that have the disease - not from eating cooked poultry or eggs. However, for areas that are experiencing outbreaks of H5N1 in poultry, the World Health Organisation offers the following food safety advice:

• Do not allow any birds from diseased flocks to enter the food chain.
• Do not eat raw or poorly cooked poultry or poultry products (e.g. eggs) from areas with outbreaks of avian influenza.
• Take care when handling eggs. Wash them in soapy water and wash your hands afterwards.
• Always keep raw meat and eggs away from cooked and ready-to-eat foods.
• Use a separate chopping board and knife to prepare raw meat.
• Wash your hands immediately after handling raw meat or eggs.
• Clean and disinfect surfaces and utensils immediately after contact with raw meat or eggs.
• Cook poultry and eggs thoroughly - make sure all parts of the meat reach 70 ºC and that the meat is not pink in any part. Egg yolks should not be runny or liquid.
• Do not use raw or soft-boiled eggs in foods that will not be cooked.

The Food Standards Agency advises that avian influenza does not currently pose a food safety risk in the UK. The control measures that the government has in place, means that it is unlikely that infected poultry or eggs will enter the food chain. However, good food hygiene helps to prevent a wide range of infections, so it is important that all food is always prepared hygienically.

Click here for the latest advice from the Food Standards Agency about the safe preparation of poultry and poultry products.

Click here for general advice from the Food Standards Agency on food hygiene and keeping food safe.

Which countries have had infected birds?

Between late 2003 and early 2004, outbreaks of H5N1 occurred among poultry in eight countries in Asia (Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand and Vietnam). More than 100 million birds in the affected countries either died from the disease, or were killed in order to control the outbreak. By March 2004, the disease was thought to be under control. Since then, however, many countries around the world, including the UK, have reported outbreaks of H5N1 among domestic poultry. Infections in wild birds and pigs have also occurred.

Click here for maps published by the World Health Organisation showing which countries are experiencing H5N1 outbreaks in poultry and wild birds.

Click here for the World Organisation on Animal Health's latest update on outbreaks in birds and other animals.

Do birds in the UK have bird flu?

There have been reports of highly pathogenic avian influenza (HPAI) in small numbers of wild birds and poultry flocks in the UK. However, the important point to remember is that there have been no cases of avian influenza in humans and the risk to humans in the UK remains low.

The first case of H5N1 was detected in October 2005, in an imported parrot in a quarantine unit in Essex. The second case of H5N1 was confirmed on 6 April 2006, when a dead whooper swan was found in Fife, Scotland.

On 3rd February 2007, an outbreak of H5N1 in a poultry flock resulted in the death of 2,500 turkeys on a farm at Holton, Suffolk. The Department for the Environment, Food and Rural Affairs (DEFRA) contained the outbreak by culling the remaining birds, imposing controls on the movement of birds within the vicinity of the farm, and setting up a protection zone around the centre of the outbreak.

On 13 November 2007, a further outbreak of H5N1 was reported on two linked turkey farms near Diss in Norfolk. Again, DEFRA contained the outbreak by culling the entire flocks and placing a protection zone around the premises.

During 27 December 2007 to 27 March 2008, ten wild mute swans died from H5N1 in a wild bird reserve near Abbotsbury on the Dorset coast. Another infected swan was found at Redipole Lake in Weymouth.

On 22 May 2008, an outbreak of HPAI caused by H7N7 began in a flock of laying hens at a farm near Banbury in Oxfordshire. Of the 25,000 hens at the premises, 10,000 died of the disease and the remaining 15,000 were culled to contain the outbreak.

On 20 November 2008, the UK was officially declared free from avian influenza.

Click here for the latest news from DEFRA on outbreaks of HPAI in the UK.

What symptoms do infected birds show?

Birds infected with HPAI may die suddenly or show a range of clinical signs including respiratory symptoms, swollen heads, cyanosis (blue discolouration) of the combs and wattles, dullness, loss of appetite, diarrhoea and a drop in egg production. Some birds, especially waterfowl, can be infected without showing any signs of disease.

In domestic poultry, infection with HPAI is often dramatic. The virus can spread rapidly through poultry flocks, causes disease affecting multiple internal organs, and can kill up to 100 % of the infected birds, often within 48 hours.

Should I take any special precautions when handling birds?

Yes. The DEFRA website provides advice to bird owners, those who work with poultry or game birds, and those who find any dead birds. Click here for the latest advice from DEFRA.

If you are a poultry worker, ask your GP whether you need a seasonal flu immunisation (flu jab). As a precautionary measure, the NHS offers free flu jabs to those who work in close contact with poultry because of the slight risk of picking up the bird flu virus when in close contact with infected birds. If the bird flu and human flu viruses were to mix, a new flu virus could form. Having a flu jab protects against human flu and helps to reduce the risk of the viruses mixing.

Click here for the latest advice about immunisations from the NHS.

Are cats and dogs at risk of catching bird flu?

Although there have been a few reports of the disease in these species, it is rare for cats and dogs to be infected with avian influenza. The few animals that have become infected probably picked up the disease through direct contact with infected dead birds. To reduce the risk of infection in areas affected by bird flu, it is sensible to;

• avoid contact between pets and birds
• walk dogs on a lead
• keep cats inside
• not let pets eat raw poultry or wild birds.

Click here for the latest advice from DEFRA.

Which countries have had human cases of avian influenza (H5N1)?

As of 11 August 2009, 438 human cases of avian influenza (H5N1) have been confirmed in Azerbaijan, Bangladesh, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Lao, Myanmar, Nigeria, Pakistan, Thailand, Turkey and Vietnam. Of these cases, 262 have been fatal. So far, no human cases of H5N1 have occurred in the UK.

Click here for the latest update from the World Health Organisation.

What are the symptoms of avian influenza (H5N1) in humans?

When humans have acquired avian influenza viruses from birds, the symptoms have ranged from typical flu-like symptoms (e.g. fever, cough, shortness of breath, sore throat and muscle aches) and eye infections (conjunctivitis), to viral pneumonia, acute respiratory distress and other severe and life-threatening complications. Some people have also had diarrhoea, vomiting, abdominal pain, chest pain and bleeding from the nose and gums in the early stages of infection.

Unlike seasonal influenza, which usually only causes mild respiratory symptoms in most people, avian influenza (H5N1) infection can cause rapid deterioration (within 1 to 3 days) and high fatality. Viral pneumonia and multi-organ failure have been common among people who have become ill with avian influenza (H5N1). Children and young adults seem to be most susceptible. However, globally the incidence of avian influenza (H5N1) in humans remains low.

Is there a vaccine to protect people from avian influenza (H5N1)?

Yes - a human vaccine specific to the H5N1 virus is available. The government has stockpiled over 3.3 million doses of this vaccine and health officials will advise on its use if the H5N1 virus gains the ability to spread between people.

What is the real threat from avian influenza?

The real threat from avian influenza comes from the ability of influenza viruses to mutate. If the H5N1 virus acquires the ability to spread easily from one person to another, because this virus would be new to humans, there would be little or no immunity to it in the human population and a flu pandemic (a worldwide outbreak of disease) would be likely to occur. It is important to remember that this has not happened yet. However, governments and health agencies around the world are monitoring the situation and will alert us if the risk of a flu pandemic increases.

Click here for news about avian influenza outbreaks in the UK and the latest advice from the Department of Health.