What is bird flu?
Although the name is similar, bird flu is different from the flu someone might get around winter time (seasonal influenza).
Bird flu (or ‘avian influenza’) is a contagious disease, caused by viruses that affect birds, and sometimes pigs. This means these animals can pass the virus on to each other. There are a number of different types, or ‘strains’, of the virus. In some of these strains, the virus can be passed on from infected birds to humans, though this is very rare.
The most common symptoms are problems with breathing, often getting worse as the illness progresses. Someone may also experience:
- vomiting (being sick)
- chest pain
- confusion and seizures, caused by inflammation of the brain
Sadly, around 6 in every 10 humans who have had bird flu have died. The chances of dying depend on a range of factors, including the strain of the virus and how long it takes to diagnose the virus.
How do humans get bird flu?
Bird flu getting passed on to humans is rare. From looking at the cases of humans who have had bird flu, it appears that certain circumstances can put you at risk. The biggest risk factor appears to be direct contact with, or very close exposure to, infected dead poultry. Eating an infected bird that hasn’t been cooked properly can also put you at risk.
Other things that put you at risk (but probably not as seriously) include visiting a poultry market in an affected country, or being in prolonged close contact with an infected human.
Only rare instances have been recorded of a human passing bird flu on to another human. There’s no evidence that any outbreak of bird flu has been caused by sustained human-to-human transmission.
Most cases of bird flu in humans have been a strain called H5N1. The first recorded cases of humans with this strain of bird flu were in Hong Kong in 1997. This appeared to have been suppressed, but more cases emerged – mainly across Asia and the Middle East – in 2003 and 2004. Further occasional cases have been reported since.
In 2013 there was an extensive outbreak of another strain (H7N9) in China. This lasted for a couple of years and affected over 600 people (with over 100 dying).
You may have seen bird flu in the news recently as one strain (H5N8) has been spreading through birds in Europe. This has mainly caused the death of wild birds, but there have also been outbreaks in domestic poultry, and a handful in captive birds.
It’s important to stress that there have been no H5N8 cases in the UK, and no human infections with H5N8 have ever been reported.
However, it is possible that the spread could continue to other countries, including the UK. The Department for Environment, Food and Rural Affairs currently classifies this risk as ‘medium’. Humans being infected with H5N8 can’t be entirely ruled out, but it’s thought to be extremely unlikely.
With regards to the recent spread of H5N8 across Europe, the World Health Organization recommends some simple steps to stay safe:
- Avoid contact with any birds (poultry or wild birds) or other animals that are sick or are found dead and report them to the relevant authorities.
- Wash your hands properly with soap or a suitable disinfectant.
- Follow good food safety and good food hygiene practices.
You also need to be careful if you’re travelling to countries where the H5N1 strain is still a problem. In 2014, the poultry in Bangladesh, China, Egypt, India, Indonesia and Vietnam were commonly found to have this strain. The problem isn’t serious enough that you should avoid these countries, but there are precautions you can take if you travel there:
- Avoid close contact with sick or dead poultry.
- Don’t go to live food markets.
- Ensure any poultry you eat is well cooked.
- Avoid any potentially contaminated surfaces.
A pandemic occurs when a virus evolves with the ability to transmit between humans, and the human population has no immunity against it. Some strains of bird flu seem to have been transmitted between humans in rare cases, but there has been no sustained transmission between humans. However, we can’t rule out the virus evolving to a stage where a pandemic is triggered. The good news is that researchers are keeping a very close eye on these viruses, to stay ahead of the game and ensure plans are in place for if this happens.