Bird flu, or avian flu, is an infectious type of influenza that spreads among birds. In rare cases, it can affect humans.
There are many different strains of bird flu virus, most of which don't infect humans. However, two particular strains have caused serious concern in recent years:
- H5N1 (since 1997)
- H7N9 (since 2013)
Although these viruses don't infect people easily and aren't usually transmitted from human to human, several people have been infected around the world, leading to a number of deaths.
Other bird flu viruses – particularly H7N7 and H9N2, and more recently H6N1, H10N8 and H5N6 – have also infected people, but these have been very rare or only rarely caused severe illness.
Bird flu affects many species of birds, including chickens, ducks, turkeys and geese. It can be passed between commercial, wild and pet birds. Birds don't always get sick from infection, so seemingly healthy birds may still pose a risk to people who come into contact with them.
Bird flu in the UK
No humans have been infected with bird flu in the UK, although plans are in place to manage any suspected cases.
A few cases of bird flu were confirmed in poultry in the UK recently. In February 2015, a low-severity H7N7 strain of bird flu was confirmed at a farm in Hampshire, but restrictions around the premises were lifted 21 days later after cleaning and disinfection.
Before that, in November 2014, H5N8 bird flu was confirmed at a duck breeding farm in Yorkshire, but the Department for Environment, Food and Rural Affairs (Defra) said the risk to public health was very low. This is because H5N8 infection was not found in humans during the recent worldwide epidemic among birds.
The last reported case of H5N1 in the UK was in early 2008.
You can read reports on recent cases of bird flu in the UK on the GOV.UK website.
Signs and symptoms
Like other types of flu, bird flu symptoms often include:
- a high temperature (fever)
- aching muscles
- respiratory symptoms, such as a cough or runny nose
Diarrhoea, vomiting, abdominal (tummy) pain, chest pain, and bleeding from the nose and gums have also been reported as early symptoms in some people.
These symptoms can come on suddenly. The time from infection to the start of symptoms (incubation period) is usually three to five days, although in some cases it can be up to seven days.
Within days of symptoms appearing, potentially fatal complications such as pneumonia, acute respiratory distress syndrome and multiple organ failure may develop. Prompt treatment with antiviral medication may help prevent complications and reduce the risk of death.
Read more about treating bird flu in humans.
When to seek medical advice
You should contact your GP or call NHS 111 immediately if you experience these symptoms and you've visited an area affected by bird flu in the last two weeks.
Having flu-like symptoms is extremely unlikely to mean you have bird flu, unless you've been in recent close contact with birds in an area where outbreaks have been reported.
Read more about how bird flu is diagnosed.
You can also read about outbreaks of bird flu in the UK on the GOV.UK website.
How bird flu spreads to humans
Bird flu is spread through direct contact with infected birds (dead or alive), an infected bird's droppings, or secretions from their eyes or respiratory tract.
Close and prolonged contact with an infected bird is generally required for the infection to spread to humans. For example:
- touching infected birds that are dead or alive
- inhaling or being in contact with dried dust from the droppings or bedding of infected birds
- inhaling or being in contact with droplets sneezed by infected birds
- culling, slaughtering, butchering or preparing infected poultry for cooking
Another possible source of bird flu can be live markets, where birds are sold in crowded and sometimes unsanitary conditions. Avoid visiting these markets if you're travelling in countries that have had an outbreak of bird flu.
Bird flu isn't transmitted through cooked food. Poultry and eggs are safe to eat in areas that have experienced outbreaks of bird flu.
Preventing bird flu
There are a number of things you can do to reduce your risk when you visit areas where outbreaks have been reported, such as:
- avoid visiting live animal markets and poultry farms
- avoid contact with surfaces that are contaminated with bird droppings
- don't pick up or touch birds (dead or alive)
- don't eat or handle undercooked or raw poultry, egg or duck dishes
- don't bring any live poultry products back to the UK, including feathers
- always practise good personal hygiene, such as washing your hands regularly
There are no restrictions on travel to countries that have been or are currently affected by bird flu.
Read more about preventing bird flu.
Reporting suspected cases of bird flu
Bird flu is a notifiable disease in animals and you should report any suspected case to the Animal and Plant Health Agency (APHA), even if you're not sure.
Call the Department for Environment, Food and Rural Affairs (Defra) helpline on 08459 33 55 77 if you find five or more dead birds in the same place.
Read about notifiable diseases in animals on the GOV.UK website.
The World Health Organization (WHO) confirmed that by May 2015, 840 people had been infected with the H5N1 virus worldwide and 447 had died. Indonesia, Egypt and Vietnam experienced most cases and fatalities.
Since March 2013, there have been reports of people being infected with the H7N9 virus, mostly in the southeastern part of mainland China. By May 2015, there had been 665 confirmed cases and 229 deaths. Most cases were among middle-aged to elderly men. A small number of cases were reported in travellers from Hong Kong, Taiwan, Malaysia and Canada.
For both viruses, there have been some reports of limited human to human transmission, usually as a result of very close contact between family members.
People who have had bird flu generally developed the virus after coming into close and prolonged contact with infected birds. Millions of birds have been killed during outbreaks to prevent the disease spreading and being passed on to people.
Page last reviewed: 28/05/2015
Next review due: 28/05/2017