“Coughs and sneezes spread diseases…” Who hasn’t heard that or something similar throughout their childhood? Often accompanied by the thrust of a tissue or handkerchief in the direction of that same cough or sneeze.
Far from being the brain child of some paper product manufacturer to boost his business, this action has plenty of science behind it. Not least because your cough or sneeze has plenty of power to infect others.
Hi, I’m Alina. Me and my friends and cousins make the instructions for your body. We also make them for every other living thing out there. We call ourselves the Dinky Amigos, but you might know us as DNA.
Today we are inside the Influenza A virus. This is the virus most likely to give you a dose of the flu. It is tiny so we have had to make a few changes to fit in*.
Viruses have one goal only – to make copies of themselves. Because there are so few of us, we can’t make all the instructions we need to do this. We have to rely on help from your body as well.
Sadly for us, though, your body isn’t really that keen on helping us out. We have to get really quite stroppy! After our copies are made, we end up storming off. To leave we must burst open the cells in your body. This makes you ill. All the stuffy nose and sore throat, the achy body and chills – that’s us breaking open your cells and having a massive argument with your immune system.
Even though your body is not happy, we love living there. You are lovely and warm and we particularly like hanging out in your lungs. It is really cosy and just the right place for us to spend the winter.
We normally get to stay in your body for about a week during which time you might be quite poorly. Then we are rather rudely (if I might say so) ejected by your body and you get better. But we don’t want to leave and prefer it if your immune system doesn’t find us.
Hiding
If you have never had flu before, your body doesn’t know what we look like, so we can hide for ages. This is when we do the most damage and can make you really ill. If you have had flu before, your body might think it knows what we look like. Sometimes it has a picture of us from a previous visit. If this happens it can find us really quickly.
You can also get a flu vaccination. An injection or nasal spray circulated a description of our virus to your immune system. That is then on the look-out for us which makes it harder to sneak in.
So we have become Masters of Disguise.
Every year or so we change what we look like so your body has to start looking all over again. It’s like playing hide and seek with a shape shifter! The longer your body takes to work out where we are, the more copies of our virus we can make. The more copies of our virus we can make, the more ill you will be. Sorry about that – but it’s you or us.
If you are healthy, we know that your body will eventually find us by itself and throw us out. We can’t wait for that to happen, so we need to find new homes in other people.
To stay warm we must move from person to person as quickly as possible.
3, 2, 1, Blast off!
You make that really easy for us. All we have to do is snuggle down into the droplets of mucus you have inside your mouth and nose.
And wait.
When you cough, about 3,000 droplets can shoot out at around 50 miles per hour. Anyone within a metre radius can breathe us in.
Sneezes are even better. Ten time as many droplets can explode out of your nose with the speed of a sports car at full throttle (that’s about 200 mph). Perfect for catapulting us to the next person.
People are more likely to stay indoors in winter, so our plan works really well – there are often loads of people in the same room. If there is no one about, we can hang around on the floor or door handles, rails or other hard surfaces for a day or so, waiting for someone to come along and help us out with our instructions. If someone does comes along and touches the spot we are loitering on, we can jump onto their warm hand. If they touch their face, especially their mouth, nose or eyes, we’re in!
Perfect Planning
The best time to eject from your body is a day before you actually become ill. Then no one knows to keep away from you and infecting someone else is much easier.
It gets a bit harder after you show symptoms. You may also cough or sneeze into a tissue. We can’t live on those very well. If you throw them in the bin, we have no chance. If you wash your hands with soap, we are in trouble too.
You will be infectious for about 5 days as we try our best to relocate from you to another person.
Our plan works really well. Every year we infect hundreds of thousands of people throughout the world using this technique.
If you want to stay healthy, stop your coughs and sneezes from spreading droplets. But don’t do it on our account – we love it!
*Because of these changes, scientists call us RNA instead