The federal government has declared what DHS Secretary Napolitano urges Americans to view as a "declaration of emergency preparedness", which allows the government to move doses of the anti-viral drug Tamiflu to parts of the country with potential swine flu outbreaks, release monies and take other preparedness steps.

A continuing mystery is why the apparent swine flu infections in the US appear to be much less virulent than the one in Mexico.

Late Update: Let me take a moment to reemphasize the 'appear' and 'apparent' in the sentence above. There are various hypotheses as to why there might be such a difference, as this Times article explains. But it's important to note that whatever spread there is of swine flu in the US seems much earlier along than in Mexico. And the sample size of cases in the US is exceedingly small. So we simply do not have enough data yet to judge what the difference in the virulence in the two countries is or whether there's any difference at all. I strongly recommend reading the Times article linked above.