Signs and symptoms

Although the exact incubation period for bird flu in humans is not clear, illness seems to develop within one to five days of exposure to the virus. Sometimes the only indication of the disease is a relatively mild eye infection (conjunctivitis). But more often, signs and symptoms of bird flu resemble those of conventional influenza, including:

• Cough
• Fever
• Sore throat
• Muscle aches
• Headache
• Lethargy
• Conjunctivitis (eye infections)
• Breathing problems
• Chest pains

People with the most virulent type of bird flu virus – H5N1 – may develop life-threatening complications, particularly viral pneumonia and acute respiratory distress, the most common cause of bird flu-related deaths.

Complications of bird flu
Bird flu in humans can cause a range of serious and potentially fatal complications, including:

• Eye infection
• Pneumonia, including viral pneumonia
• Acute respiratory distress
• Inflammation of the brain and heart

Diagnosis
In the UK or US there have been no reports of human exposure to bird flu. It is extremely unlikely unless you have been exposed to infected poultry or wild birds in countries that have outbreaks of bird flu. If you have been in contact with infected poultry or birds, and are concerned about bird flu, you should visit your GP.

Your doctor will examine you and ask you about your symptoms. He or she will need to know which countries or regions you have recently visited and if you have been exposed to dead or unwell birds.

Your doctor may take a swab from your nose and throat. These samples will be sent to a laboratory to be examined.

Treatment
It is possible that antiviral drugs used to treat other types of flu may be effective in treating bird flu in humans. It is hoped that if administered early (within two days) these drugs will improve the chances of people who get bird flu.