Avian Influenza H5N1 Questions & Answers

This is general information about avian influenza. For specific advice about the current situation in the UK, see HPA website.

What is Avian Flu?

Avian influenza, or 'bird flu', is an infectious disease caused by viruses that normally infect only birds. Whilst all bird species are thought to be susceptible to infection, domestic poultry are especially vulnerable to infection and the virus can rapidly cause epidemics in flocks resulting in large numbers of deaths.

Wild waterfowl, on the other hand, may experience little or no disease. Once infection is suspected in a domestic flock, the remaining birds are culled to prevent further spread of the infection.

There are a number of strains of avian flu, each with slightly different symptoms; these are commonly called ‘fowl pest’.

Can humans be infected by H5N1?

Yes, there have been over 300 cases of human infection with H5N1 since 2003; over 200 have been fatal. Most of these have been in south east Asia, and have been associated with close contact with diseased birds. Close contact means handling or being within one metre of the birds or their secretions. Birds shed influenza virus in their faeces so close contact with their faeces or their immediate living environment, rather than directly handling the birds, may also be a possible transmission route.

For this reason, the HPA is identifying people associated with the infected premises who may have been exposed to the virus before the disease was confirmed; they are being offered antivirals. Antivirals are also being offered to those involved in culling the birds before the workers enter the farm.

More information on the number of human cases of H5N1 is available from WHO.

Can H5N1 be transmitted from person to person?

There have been a limited number of well documented cases in which there is evidence to suggest human-to-human transmission but to date there is no evidence that the highly pathogenic avian influenza virus has adapted to spread easily in humans.

What are the signs and symptoms?

The symptoms of avian influenza in humans vary considerably depending on the strain or subtype of the virus involved. The symptoms of highly pathogenic H5N1 infection are sudden onset of fever (temperature of 38°C or more) and cough or shortness of breath. Other symptoms may include: body/muscle pain/aches, sore throat, runny nose, or red, sore and discharging eyes.

How long does it take for humans to develop symptoms?

The usual time from exposure to infection to onset of symptoms is believed to be 3 – 5 days, up to a maximum of seven days.

I have been in contact with someone who is now ill (or has had a flu-like illness) – am I at risk of getting bird flu?

There are many much more common causes of coughs and colds and flu-like illnesses, particularly at this time of the year. If you have been in contact with someone with a cough or flu-like illness it is highly likely that it is due to one of these more common causes. There is no evidence that the highly pathogenic avian influenza virus has adapted to spread easily in humans.

I've been experiencing flu-like symptoms. Could this be avian flu?

Unless you have been in contact with infected birds or someone with confirmed or suspected avian flu then it is very likely that you have some other infection which can lead to a cough, a cold, or similar infection. You should take the actions you would normally take, such as taking plenty of fluids, rest and appropriate medication such as paracetemol and contact your GP or NHS Direct if you feel especially poorly.

Despite this occurrence the current level of risk to humans from avian flu is extremely low. Most human H5N1 infections so far have occurred through direct and prolonged contact with live or dead infected poultry.

Does the seasonal flu jab protect against avian flu?

No. The seasonal flu jab does not protect against avian flu. It is given as a precautionary measure to individuals associated with the incident, to prevent the avian and a human flu virus potentially mixing, and creating a virus that is more capable of infecting humans.

How do I protect myself from becoming infected?

Generally, infection requires close, prolonged contact with live or dead infected birds. Unless you are a poultry worker or work with animal health services associated with this latest incident, you are unlikely to have been in contact with the avian influenza virus.

If you keep poultry, advice is available from the Defra website or via the Defra helpline on 08459 33 55 77.

If there is avian flu in your area you should avoid contact with the infected areas and respect any exclusion zones.

Is there any vaccination available to prevent me becoming ill / infected?

No. There is not a vaccination available that will prevent you from becoming ill from avian flu. Current ’flu jabs’ which protect against human flu are offered as a precautionary measure to prevent the avian and a human flu virus potentially mixing, and creating a virus that is more capable of infecting humans. Poultry workers and cullers, who may be exposed to AI viruses, are offered the flu jab for this reason.

How do I protect myself from becoming infected?

For specific advice on the current situation in the UK, see HPA website and Defra's website.

If you have any other enquiries about avian flu, please contact the 24-hour health information service NHS Direct 0845 4647.

Last reviewed: 13 August 2008