So is this new swine flu outbreak the next great plague, or just a global spasm of paranoia?

Are we seeing a pandemic or a panic?

The pathogen that has seized the world's attention has an official name (swine-origin influenza A H1N1), an acronym (S-OIV), a nickname (swine flu) and an apparent birthplace (Mexico). But the essential nature of the pathogen, its personality, its virulence, remain matters of frenetic investigation. Like all influenza viruses, it is mutating capriciously and, thus, is not a static and predictable public health threat but an evolving one.

The bug has gone global, having shown up in Asia Friday with the first reported case in Hong Kong. It also popped up in Denmark, as well as in eight new U.S. states.

But there has been some flu-scare backlash, with some officials questioning whether schools are too quick to close their doors at the first hint of the virus.

The World Health Organization directly addressed the pandemic-versus-panic issue Friday by cautioning the public against leaping to any conclusions about the virulence of the virus. It has yet to show lethality outside Mexico (the one person to die in the United States was a toddler who traveled from Mexico to Texas), though that doesn't mean it will remain a mild pathogen in the weeks and months to come, said officials.