Avian influenza: guidance, data and analysis

The symptoms, diagnosis, management and epidemiology of avian influenza (bird flu).

Avian influenza is an infectious disease of birds caused by the influenza A virus. Birds are the hosts for most avian influenza viruses and a variety of influenza subtypes can be found in birds, particularly in water fowl and shore birds. Domestic poultry are especially vulnerable and the virus can rapidly cause epidemics in flocks.

Human infections with avian influenza are rare. However, some viruses, such as H5N1 or H7N9, have been associated with human disease.

The symptoms of avian influenza in humans vary considerably depending on the strain or subtype of the virus involved. Most infections take the form of a flu-like illness (fever, cough, body or muscle pain, sore throat, runny nose). Other symptoms can include conjunctivitis (red, sore and discharging eyes).

Information on the different strains of influenza virus can be found on our health protection archive website.

The Defra website has information and guidance on:

  • the latest avian flu situation
  • how to spot avian flu, including what to do if you suspect it
  • measures to prevent it

Further information on avian influenza in humans is available on the WHO website.

The UN World Organisation for Animal Health (OIE) provides regular updates on avian influenza in animals.

For advice on working with avian influenza virus in laboratory or birds, see the Health and Safety Executive (HSE) website.

Communications to health professionals

Diagnosis and management

Advice for travellers and useful information for clinicians is available on the National Travel and Health Network Centre (NaTHNaC) website and the Foreign and Commonwealth Office website.

Epidemiology and risk assessments

Laboratory diagnostics and guidance

Promotional material

Updates to this page

Published 30 August 2014
Last updated 29 June 2023 + show all updates
  1. Added document 'Asymptomatic Avian Influenza Surveillance Study protocol'.

  2. Added 'HAIRS risk assessment: avian influenza A(H5N1)'.

  3. Updated 'Epidemiology and risk assessments' section.

  4. Risk Assessment of Avian Influenza A(H9N2) added to the Epidemiology section.

  5. Added a link to a new risk assessment under the heading 'Epidemiology': 'Avian influenza A(H7N4): risk assessment'

  6. Promotional material related to Avian Influenza added.

  7. Added Avian Influenza A(H7) and influenza A(H5) documents.

  8. Risk assessment of avian influenza A(H5N6) published.

  9. Avian influenza A(H5N2) and A(H5N8): risk assessment added.

  10. Risk assessment of avian influenza A(H5N1) added.

  11. The avian influenza A(H5N8): risk assessment has been added.

  12. First published.