Hey there. Welcome to Life Noggin. Viruses are one of the earliest forms of life. As we know it, there are little strings of genetic material called RNA coded in a protein jacket. They’ve evolved to make people sick in very specific ways. They hijack cells and use the cells to produce more viruses. Once the virus is ready, it can force its hosts to share it with others. For example, the Varicella Zoster Virus (VZV) causes little red spots to appear all over the infected person. We call them chickenpox. They are very, very itchy. And the virus did that on purpose. It fills the box with more viruses, so when people scratch them, they let the virus out of their body, spreading it to people nearby. It’s actually pretty smart in an evil way. And this is how lots of viruses move through the population. They get inside a body and then after a few days, or sometimes years, they’ll try and hitch a ride to another body.
The time from when they get inside a person to when they try and spread it is called, the Incubation Period. During that time, the virus is invading cells and fighting the immune system. During the incubation period if you have a virus, you might not even notice. Chicken pox can take weeks before the first POX’s appear. The flue is another common virus and in less patients. It’s incubation period is only half of a day. It really wants to get out into the world again. The flu spreads so fast through your friends, because it can spread so fast in your body too. The influenza virus evolves to make you cough and sneeze so it can hitch a ride on the tiny droplets of water that come out when you do. So let’s say Ian has the flu and coughs, then Pat inhales a few droplets later, once inside his body, the influenza virus hopes to hit an epithelial cell.
Epithelial cells line the airway and are the perfect place for a new flu virus to set up shop. Once it finds the right cell, it has to get inside, but cells don’t just let anyone off the street inside their membranes. So to convince the cell to let it in, viruses have little bumps on the outside of their jacket called receptors, receptors are like keys and if the virus has the right key our cell will surround it, called endocytosis. This can happen less than 10 minutes after the flu droplet is inhaled. Once inside the cell, the influenza takes off its jacket it transforms, and from there the little bit of genetic RNA material heads to the nucleus of the cell, and it does something called cap snatching. It steals a cap from the host RNA molecules and puts it on itself. Once wearing the cap, the flu virus can trick the DNA in the nucleus to make more flu virus. Again and again and again! As more and more virus fills up the cytoplasm, the new guys steal bits of the cells outer membrane to put on a jacket and head out into the body.
Even though the influenza virus, invades human cells really quickly, it can take a day or two before you’ll feel sick. The immune system is on the prowl, looking for infected cells and any virus in your bloodstream. It’s a huge battle! If you have a fever or feel sore and achy, that’s a side effect of your immune system attacking an infection. Fevers change the body’s temperature to try and slow the virus down. The achiness comes from our own body trying to help the immune system cells fight the infection. After a few days, the immune system usually wins out. But chances are you’ve already spread the virus to someone else.
Sorry! In the end, viruses aren’t trying to hurt us, they’re just fighting to survive.
Just How Fast Does A Virus Spread?