Eli5-If a virus isn’t technically alive, I would assume it doesn’t have instinct. Where does it get its instructions/drive to know to infect host cells and multiply?
In: 7067
Imagine you had an IKEA instruction manual. It tells you to get some paper, some ink, and 2 staples and make a copy of the manual. It also tells you to stick it in a box and leave the copy on your neighbor’s porch.
Is there a purpose to doing this? No. But there are now two version of it anyway. Does it have guiding instincts? Still no, but it didn’t need them. It got in your home somehow and used you to make a second copy which is about to infect your neighbor. Similarly, viruses give instructions to your cells to make copies. There are some safeguards against this, but in general, you just churn out new versions that infect others, repeating the process.
Why we have different effects of viruses very simply boils down to (1) how they get into your house (cell), (2) how they tell you to make copies, and (3) how they stop the cops from busting your illegal IKEA instruction manual production ring.
1. Viruses are dumb, but they can recognize certain things. Covid, for instance, has patterns on it that match up to something called the ACE-2 receptor. This is a pretty common receptor, but there is a lot of it in the nose and lungs (where are most of your symptoms?). This starts a series of steps that results in the replication material getting inside.
2. Once it is inside, the virus has to get your body to make copies. Some viruses (ie: Herpes/HIV) are long term because part of their instruction manual told the previous host to make some machinery that busts open your DNA and inserts the virus. Others are more short-term and simply tell your cells to make a bunch of copies really quickly.
3. One of the most important parts of viruses is how they stop your immune system. Your cells tend to occasionally display what they are currently working on, analogous to a window into the house. Your immune system has a black-list of certain compounds and will straight up burn the house down if you aren’t working on something it approves of. Certain viruses, like influenza, are able to mutate though. While your immune system is looking for the red IKEA catalog, the flu has 1000’s of variations of the catalog. While you are immune to any red IKEA catalog versions, you have to learn that the blue I-KEA catalog is just as bad.
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The Immune Deficiency Foundation: https://primaryimmune.org/waystogive
The Institute for Effective Education: https://www.tiee.org/about/
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