Avian influenza (bird flu)

Avian influenza, also called bird flu, is an infection in birds caused by several strains of influenza A virus. Avian influenza is found in bird populations worldwide and some of these strains have spread from wild birds to domestic poultry. Some specific viruses (e.g. H5, H7 and H9 strains) have also spread from infected birds to humans, although this is usually rare.

In recent years, human cases have been reported in a limited number of countries, with most previous cases reported from China, Southeast Asia and Egypt, usually following exposure to avian species. However, human cases associated with international travel are very unusual. Check our Country Information pages for recent destination specific news and outbreaks.

In humans, avian influenza symptoms vary, depending on the virus strain. Symptoms range from a mild flu like illness, sometimes with conjunctivitis (red, sore, discharging eyes), diarrhoea and abdominal pain, to a severe respiratory illness with breathing difficulties and pneumonia. Human infections may be fatal.


Human infections are mainly associated with direct contact with infected birds or through indirect contact (contact with body fluids, including blood or bird droppings) in places where infected birds have been kept (e.g. poultry farms, bird markets). Transmission from human to human is very infrequent.

Close, prolonged contact with an infected bird is usually needed for bird flu to spread to humans, so all travellers should:

  • Avoid visiting live bird and animal markets and poultry farms and do not touch wild or domestic birds (alive or dead).
  • Avoid any contact with bird droppings, feathers and nests.
  • Do not eat or handle undercooked or raw poultry, egg or duck dishes.
  • Wash hands regularly with soap and water or use alcohol-based hand rubs when washing facilities are not available.

Seek prompt medical advice if you become ill with severe breathing difficulties within 10 days of travel to any country affected by avian influenza outbreaks.

The seasonal flu vaccine available in the UK from September/October each year will not prevent infection with avian influenza viruses.

Antiviral medications may be used, after specialist advice, to treat cases or suspected cases of avian influenza.

See UK Health Security Agency website for more information on avian influenza.


First published : 22 November 2018 Last updated : 09 July 2024

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Recent Avian influenza (bird flu) Outbreaks

06 June 2024

Influenza A(H5N2) in Mexico

As of 5 June 2024, a fatal human case of avian influenza A(H5N2) has been reported in Mexico. This is the first laboratory-confirmed human case of influenza A(H5N2) virus reported globally and the first human avian H5 virus infection reported in Mexico.

Take usual precautions

08 April 2024

Influenza A(H9N2) in Vietnam

As of 7 April 2024, the Vietnam Department of Information and Communications reported a confirmed human case of avian influenza A(H9N2) infection. This is the first confirmed human case of avian influenza A(H9N2) reported in Vietnam. To date, no further cases have been detected among close contacts.

Take usual precautions

26 February 2024

Highly Pathogenic Avian Influenza in Antarctica

On 25 February 2024, the presence of Highly Pathogenic Avian Influenza virus was confirmed for the first time in mainland Antarctica. The virus was detected in samples from dead skuas (predatory seabirds) found near the Argentine Antarctic base. Samples returned positive for HPAI A(H5) on 24 February 2024.

Take usual precautions

12 January 2024

Influenza A(H5N1) in South Georgia

As of the 11 January 2024, avian Influenza (H5N1) has been confirmed for the first time in mammals in sub-Antarctica. The disease was detected in elephant and fur seals on the island of South Georgia.

Take usual precautions