The influenza virus is incredibly small, but has caused the death of millions of people around the world.

Symptoms of influenza

The symptoms of flu include:
•  a high fever, feeling hot and cold in turns with sweating and shivering.
• aching muscles and painful joints.
• severe headaches
• sore throat and swollen glands
• breathlessness - this is because influenza attacks the deeper respiratory tubes of your lungs.
• exhaustion

Treatment of influenza

Just like a cold, ‘flu is caused by a virus and so there is no cure. There are some antiviral medicines which help the body to recover more quickly, but none of them has any big effect on the virus. The symptoms can be relieved to some extent with medicine which act as pain killers, bring down the fever, decongestants etc.

Most people need to be in bed for a time from several days to a couple of weeks. It is very important to keep taking fluids, because as you sweat a lot with the fever you tend to dehydrate and this makes the headache even worse.  You are unlikely to feel like eating. It can take several weeks to fully recover from a severe bout of flu.

The flu virus attacks and kills the ciliated epithelium cells lining the respiratory tubes  in the lungs, so it leaves the lungs very open to other infections. Many of the deaths linked to ‘flu are in fact deaths from secondary bacterial infections such as pneumonia and bronchitis. Anyone with asthma or heart disease is also very vulnerable to the flu virus.

How is influenza spread?

The flu virus mutates rapidly. Usually the changes are very small so the flu virus is similar, although not the same, from year to year. But sometimes these mutations mean a very different strain of the flu virus appears. These are particularly dangerous because non-one is already immune to them. They can spread across a whole country (an epidemic), several countries or even across the world (a pandemic).

Over the last few centuries there has been a major outbreak of flu approximately every 30 years. As people travel more and more freely from country to country, the risks of a flu outbreak becoming a pandemic are always increasing.

One of the best ways to deal with flu is to prevent the spread in the first place.
• Wash your hands every time you sneeze or cough into your hand, to wash away the droplets that carry the virus
• throw out damp, germ-laden, used tissues immediately
• stay away from school or work while feeling ill
• you can be immunised against the flu but you need to be given a different vaccine each year. This is because of the rapid mutation of the flu virus. Flu vaccines are mainly recommended for older people, people with ongoing illnesses and people taking medication that weakens their immune system.