Swine Flu and the Mexico Mystery Why does the swine flu seem to
be more deadly in Mexico? Click here to read more from Slate on
the swine flu. Two weeks ago, no one had heard of this strain of
swine flu. Now it's on every front page and almost every
continent. Is this the deadly global pandemic we've been
worrying about? Certainly there's cause for sober concern, if
not alarm. For of the two qualities vital to a nasty pandemic—to
spread readily and to be deadly—this flu, a brand-new strain of
swine flu, or H1N1, seems to possess the first: Evidence is
strong that it spreads readily among humans. In that sense, it's
an inversion of the bird flu. Bird flu terrifies infectious
disease experts because it kills about half the humans who get
it—but it has so far failed to develop the ability to jump
easily from person to person. This swine flu, meanwhile, does
seem to spread easily by airborne transmission. But how deadly
is it? Despite the 100-plus deaths in Mexico, we don't really
know. And that's why epidemiolog