[yummyfajitas]

Epidemic prevention certainly is, in the same way fire protection is - both a fire and an epidemic can rage out of control and kill lots of people. They are public goods because they have large positive externalities.

Both are also dirt cheap (i.e., single-digit percentages of government spending) and very few people oppose their public provision. So why bring them up?

[prodigal_erik]

It's hard to reconcile with the idealized version of the http://en.wikipedia.org/wiki/Night-watchman_state that does nothing more than enforce the non-aggression principle. I suppose one could consider arson (not accidents) as a form of aggression they must be prepared for, but I find this an obvious public good the night-watchman state doesn't account for very well.