Bird flu outbreak: signs and symptoms of Avian influenza, what is the H5N1 strain and how many UK human cases

UK officials have confirmed that a person living in the south-west of England has caught bird flu.

But which strain has been found and what are the signs and symptoms of bird flu in humans?

Here’s what you need to know.

What is bird flu?

Bird flu, also known as avian flu, is a type of influenza that spreads among birds.

The UK has recently seen a large number of outbreaks and incidents of the H5N1 strain of avian influenza in birds across the country, but human to human transmission of bird flu is very rare.

Some strains of bird flu can pass from birds to people, but this is also very rare and requires close, prolonged contact.

Officials have said that the person in question got the infection from "very close, regular contact with a large number of infected birds, which they kept in and around their home over a prolonged period of time".

The virus they caught is the H5 type that is found in birds, but it is not yet clear whether it is the same H5N1 strain that has been causing recent outbreaks in poultry.

Although this is the first human case of this strain in the UK, there have been cases elsewhere globally.

There are lots of different strains of bird flu virus. Most of them don’t infect humans, but there are 4 strains that have caused concern in recent years:

• H5N1 (since 1997)
• H7N9 (since 2013)
• H5N6 (since 2014)
• H5N8 (since 2016)

Although H5N1, H7N9 and H5N6 don’t infect people easily and aren’t usually spread from human to human, several people have been infected around the world, leading to a number of deaths.

In February 2021 H5N8 was found to have infected a small number of people for the first time, in Russia.

Bird flu is a notifiable disease so the World Health Organization has therefore been informed about the case in the UK.

However, experts said there is no evidence of onward spread and all close contacts of the person are being monitored.

The individual is currently well and self-isolating, and the risk to the public is very low.

What are the symptoms of bird flu?

According to the NHS, the main symptoms of bird flu can appear very quickly and include:

• a very high temperature or feeling hot or shivery
• aching muscles
• headache
• a cough or shortness of breath

Other early symptoms may include:

• diarrhoea
• sickness
• stomach pain
• chest pain
• bleeding from the nose and gums
• Conjunctivitis

It usually takes three to five days for the first symptoms to appear after you’ve been infected.

Within days of symptoms appearing, it’s possible to develop more severe complications such as pneumonia and acute respiratory distress syndrome.

However, getting treatment quickly and using antiviral medicine may prevent complications and reduce the risk of developing severe illness.