Avian influenza, commonly known as bird flu, refers to a disease in birds caused by infection with avian (bird) influenza (flu) Type A viruses, a flu virus closely related to human flu viruses. These viruses do not normally infect humans. However, sporadic human infections with bird flu viruses have occurred.

Expand All | Collapse All

Understanding Avian Influenza

Bird flu viruses occur naturally among wild birds and can infect domestic poultry such as chicken, ducks and turkeys. Human infections with the bird flu virus are rare but have been occurring sporadically over the years since its first detection in Hong Kong in 1997.

The avian influenza viruses are divided into several sub-types. The most frequently identified sub-types of avian influenza that have caused human infections are the H5N1 and the H7N9 viruses:

  • The H5N1 virus sub-type is highly contagious in birds and has been associated with severe disease and deaths in humans. Since its widespread re-emergence in 2003, this bird flu virus has spread from Asia to Europe and Africa, and has become endemic in poultry populations in some countries such as China and India. Most human infections have occurred after prolonged and close contact with infected poultry. Rare, limited and non-sustained person-to-person spread of this virus had been reported.
  • Human infections with H7N9 were first reported in China in March 2013. Most human infections had occurred after exposure to infected poultry or live bird markets. Similarly, rare instances of limited, non-sustained person-to-person spread have been reported in China.
  • Sporadic cases of human infections with other bird flu viruses, including H5N6 and H9N2 virus sub-types, have also been reported in China and other countries. Spread from birds to humans is infrequent and no person-to-person spread has been reported.

The signs and symptoms of human infection with the bird flu viruses range from mild to severe, and infection may be fatal. Human infection with H9N2 tends to result in mild disease while reports of severe illness and death had been reported in persons infected with H5N1, H5N6 and H7N9 viruses.

The World Health Organization (WHO) advises that further cases of human infection with the bird flu viruses can be expected globally as long as the virus continues to be detected in poultry populations.

How bird flu viruses are transmitted to human

Human infection with the bird flu virus is primarily acquired through:

  • direct or close contact with infected live or dead birds;

  • direct exposure to environments contaminated by secretions or excretions from infected birds.

Slaughtering, de-feathering, handling or preparing infected birds for consumption, especially at home, may increase the risks of contracting bird flu.

There is currently no evidence to suggest that the virus can be spread through the consumption of properly prepared poultry or eggs, although a few cases have been linked to consumption of dishes containing raw, contaminated poultry blood.

Spread from one person to another is rare.

Symptoms of human infection with the bird flu virus

The most common symptoms of human infection with the bird flu virus are similar to those of regular flu:

  • High fever (usually over 38 degrees Celsius)

  • Cough

  • Sore throat

  • Runny nose

  • Phlegm

  • Difficulty breathing

Other possible symptoms include:

  • Diarrhoea

  • Vomiting

  • Stomach pain

  • Chest pain

  • Bleeding from your nose or gums

Protecting against bird flu

If you plan to travel to countries with known cases of bird flu, minimise your risk by:

  • Avoiding visits to commercial or backyard poultry farms, and markets selling live birds and animals.
  • Avoiding contact with wild birds (alive or dead), live poultry (including backyard poultry), or other live birds (e.g. ornamental birds) sold at live bird or animal markets.
  • Avoiding handling or eating raw or undercooked poultry or foods containing uncooked poultry, including eggs.
  • Avoiding contact with animal waste or untreated bird feathers.
  • Avoiding crowded areas and maintaining good ventilation.
  • Washing hands thoroughly with soap and water after handling live or dead poultry and birds.
  • Observing good personal and environmental hygiene.

If you suspect that you may be infected with the bird flu virus, you should:

  • Consult your doctor as soon as possible if you have had contact with live or dead birds, had visited live bird and animal markets or poultry farms, or had recently travelled to a country with bird flu cases. Inform your doctor of the countries you had visited and your possible exposure.
  • Be socially responsible, please wear a surgical mask to the doctor and avoid taking public transport if possible.
  • Refrain from travelling, if you are overseas, until you are certified fit to travel.

Treatment for human infection with the bird flu virus

Treatment may vary, depending on your symptoms. If the disease is caught early, Tamiflu (Oseltamivir) is often the recommended treatment alongside symptomatic treatment. Tamiflu may also be offered to any family members who have been exposed to the virus as (prevention) prophylaxis.

More rarely, person with severe diseases may be hospitalised.

There is currently no bird flu vaccine available for humans, and the seasonal influenza vaccines do not protect against bird flu infection.