Almost anytime there is a panic over a worldwide epidemic that will wipe out humanity, the culprit is usually among the tiniest replicating organisms on Earth: viruses. We use the word "organism" loosely here because many argue about whether viruses are indeed living organisms, or whether they are all part of an Illuminati conspiracy. But, those are usually the same types of people who say that Ho-Ho's are bad for you. Dad ate Ho-Ho's everyday, and he lived to the ripe old age of 37.
It is amazing how frequently we talk about viruses. We are scared of virus epidemics like "bird flu," "swine flu," "Bieber Fever," or "SARS." We often refer to online videos going "viral," or we refer to an attack by a computer "virus," but what exactly does the term "virus" mean in all of these instances? What it means is that you should stop opening those emails your uncle sends you, no matter how cheap the deal on Viagra is.