Viruses, small infectious agents that replicate only inside the living cells of other organisms, have been around for billions of years. They can infect all types of life forms, from microorganisms, plants and animals to humans. It has been estimated that there are 10 to the power of 31 viruses on Earth, but humans don’t just live in a viral world, we are also part virus ourselves. Viruses actually comprise up to the 8% of the human genome and these so called endogenous retroviruses (ERVs) represent ancient viral infections that became integrated into the human genome. Read more