Epidemics follow patterns because diseases follow patterns. Viruses spread; they reproduce; they die.

Epidemiologists study patterns in order to combat infection. Stories about epidemics follow patterns, too. Stories aren't often deadly, but they can be virulent: spreading fast, weakening resistance, wreaking havoc.

Taxes are what we pay for civilized society, for modernity, and for prosperity. The wealthy pay more because they have benefitted more.

The epidemic of avian flu can now spread on a global scale.

There has been a level of complacency that has helped the epidemic spread.

Folklore used to be passed by word of mouth, from one generation to the next; that's what makes it folklore, as opposed to, say, history, which is written down and stored in an archive.