Jennifer Gardy notes the seeming disparity between the apparent mortality rates in Mexico and the U.S. / Canada. Since she posted this, a comparative analysis of the genomes indicates that the strains in Mexico and Canada are identical. So why the Mexican deaths?
I would also speculate that the number of deaths in Mexico could be the numerator over a very large denominator. That is, the number of low level swine flu infections could be quite large among the Mexican population, but underreported due to poor access to health care and other confounding issues like the prevalence of other infectious diseases, with similar symptoms, among the poor. In populations wracked with chronic respiratory and gastrointestinal infection, would low to moderate swine flu infections be distinguishable? In that context, the actual mortality rate might be much lower than media reports.
Other good stuff in her post about tracking the outbreak by following money, and the sequencing efforts.