Question: how many types of invasive viruses are there

  1. That’s actually a surprisingly difficult question to answer, partly because it’s hard to know if we’ve properly identified all of the viruses, and partly because it’s a little hard to define what makes one virus different from another. There’s actually an organisation that does nothing but put viruses into categories or groups (taxonomy), called the International Committee on Taxonomy of Viruses. They released their most recent report last year, and as you can see from their front page, they identify 2480 species of virus in 395 genera, 95 families, and 6 orders. (Don’t know what genera, families, or orders are? Check out this Wikipedia entry on biological classification). So in this regard, there’s nearly 2500 species of viruses. Keep in mind, though, that new viruses are being discovered all the time, especially in plants and insects (if you look at the ICTV page, you’ll notice that each new version of the report has more viruses in it). Also, because viruses are so small and replicate so fast, they evolve really quickly, meaning that new types of viruses can pop up a lot faster than new kinds of larger animals (mammals, etc). It’s still not that common, especially in the viruses of larger animals, but it can happen.