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How viruses work?

Viruses are some of the smallest microbes there are, way smaller than bacteria.  You cannot see them with an ordinary microscope like bacteria; you need to use a very special microscope to see viruses properly.  Viruses are so basic that they are not even cells, just genetic material (genes) wrapped up inside a strong ‘coat’ made of protein.  They cannot survive by themselves, viruses have to use a host to grow and multiply which makes them a type of parasite.    

Some viruses are very clever.  They don’t die off if they don’t have a host, they just hibernate (they become dormant) and wait for the right conditions to come along so they can make copies of themselves.  Viruses can spread very easily from one person to the next just by touch or by sneezing or coughing when they fly out into the air in tiny water droplets.  If a person doesn’t cover their mouth and nose when they sneeze or cough, you could breathe in their virus!  Other viruses are spread when people are lazy about personal hygiene and they don’t wash their hands very often, especially when they have been to the toilet.  Viruses also wait in areas you wouldn’t expect them to like door-handles or telephones so you should make sure to clean up after you and that you wash your hands regularly!

There are several thousand different types of viruses which use plants animals or even you as a host!  Once a virus gets inside its host, it uses the hosts own cells to grow and make copies of itself.  When a virus gets into your body and sees a cell it likes, it latches on and either injects its genes into your cell or your cell swallows it up.  The virus then takes over the parts that make your cell work so it can make more copies of itself.  These copies are identical to the first virus and usually, so many are made that your cell bursts!  The new viruses spread to the cells next door and then the cells next to these, infecting your body bit by bit.  Just one virus in your body can make thousands of copies of itself and make you very sick! 

Viruses do lots of damage to their host and they damage normal healthy cells, causing disease.  Some viruses cause diseases you will have heard of like measles, chickenpox and, of course, the flu!  The flu (influenza) is one of the most famous viral diseases in the world.  It affects your respiratory system and gives you cough, sore throat, runny nose, headache, fever, fatigue and pain.  The flu is much more severe that a cold (which is also caused by a virus) although sometimes people do call a cold the flu!  If the flu isn’t treated, it can lead to respiratory (breathing) difficulties, like bronchitis or pneumonia which is very dangerous in the very young, older people or people who are sick with something else already. 


Scientists now know much more about how viruses like the flu work and viruses really are very clever.  They can change themselves (mutate) very quickly so as soon as a new vaccine is made, a new type of flu appears that is just a little different from the last one!  When a virus makes you sick, your immune system makes antibodies to help to fight the invaders.  If the virus changes, even if it changes just a little, the antibodies made by your body don’t recognise it so you don’t have any defences to protect you.  Viruses are different to bacteria which can be treated with antibiotics so there is no point taking antibiotics if you have a virus because they don’t work!  The best defence against viruses is to be vaccinated before the virus gets a chance to get inside your body!

Viruses have different shapes but they are usually seen as large rods, spheres, or small, many-sided spheres.  There are even viruses shaped like a spaceship!  These are called bacteriophages and they infect and bacteria.  Researchers and scientist are trying to find ways of using these viruses to fight bacterial infections that can be used instead of antibiotics. 

Did you know…?

Not only are the parasitic viruses not animals or plants, they are not really even living organisms!  Living organisms can survive without a host, whereas the parasitic virus cannot!

The word ‘virus’ comes from the Latin word for ‘poison’

People who study viruses are called virologists and the study of viruses is called virology.


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