The symptoms of bird flu (avian flu) in humans are similar to those of other types of flu.

Symptoms include:

- a sudden high temperature (fever) of 38C (100.4F) or above

- a dry, chesty cough

- headache

- tiredness

- chills

- aching muscles

- limb or joint pain

- diarrhoea or stomach upset

- sore throat

- runny or blocked nose

- sneezing

- loss of appetite

- difficulty sleeping (insomnia)

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.

Complications

In many cases, bird flu can cause rapid deterioration, pneumonia (inflammation of the tissue of one or both lungs), acute respiratory distress syndrome (where the lungs cannot provide enough oxygen for the rest of the body) and multiple organ failure, all of which can be fatal.

Prompt treatment with antiviral medication may help prevent complications and reduce the risk of death.

When to seek medical advice

As the symptoms of bird flu are similar to more common types of flu, any flu-like symptoms you experience are unlikely to be signs of bird flu unless you have been in close contact with birds in an area where an outbreak has been reported.