Bird flu, or avian flu, is an infectious type of influenza that spreads among birds. In rare cases but it can affect humans. Some avian influenza viruses have caused rare, sporadic infections in people, resulting in human illness ranging from mild to severe. These viruses are of public health concern because of their ability to cause human illness and also because of their potential to cause a pandemic.

There are many different strains of bird flu virus. Most of them don't infect humans. There are 4 strains that have caused concern in recent years:

H5N1 (since 1997)

H7N9 (since 2013)

H5N6 (since 2014)

H5N8 (since 2016)

Although there are several types of bird flu, H5N1 was the first avian influenza virus to infect humans. The first infection occurred in Hong Kong in 1997. The outbreak was linked to handling infected poultry. H5N1 occurs naturally in wild waterfowl, but it can spread easily to domestic poultry.

The disease is transmitted to humans through contact with infected bird feces, nasal secretions, or secretions from the mouth or eyes. 

Consuming properly cooked poultry or eggs from infected birds doesn’t transmit the bird flu, but eggs should never be served runny. Meat is considered safe if it has been cooked to an internal temperature of 165ºF (73.9ºC).

Symptoms of Bird Flu

The main symptoms of bird flu can appear very quickly and include:

High temperature or feeling hot or shivery

Aching muscles

Headache

Cough

Other early symptoms may include:

Diarrhea

Sickness

Stomach pain

Chest pain

Bleeding from the nose and gums

Conjunctivitis

It usually takes 3 to 5 days for the first symptoms to appear after getting infected. Within days of symptoms appearing, it's possible to develop more severe complications such as pneumonia and acute respiratory distress syndrome. Getting treatment quickly, using antiviral medicine, may prevent complications and reduce the risk of developing severe illness.

How to prevent to bird flu infecting you

Wash your hands often with warm water and soap, especially before and after handling food, in particular raw poultry

Use different utensils for cooked and raw meat

Make sure meat is cooked until steaming hot

Avoid contact with live birds and poultry

If it's thought you might have symptoms of bird flu you'll be advised to stay at home, or you'll be cared for in hospital in isolation from other patients. You may be given an antiviral medicine such as oseltamivir (Tamiflu) or zanamivir (Relenza). Antiviral medicines help reduce the severity of the condition, prevent complications and improve the chances of survival.

They are also sometimes given to people who have been in close contact with infected birds, or those who have had contact with infected people, for example family or healthcare staff.