The U.S. Centers for Disease Control and Prevention reported two independent cases of swine influenza A in a 10-year-old boy and a 9-year-old girl, both from Southern California in the April 21, 2009, Morbidity and Mortality Weekly Report (MMWR). Both kids have since recovered fully. Here’s the interesting part: Neither child reported exposure to pigs, although the little girl did go to an agricultural fair.

Swine flu, as you no doubt guessed from the name, comes from pigs and primarily stays within pigs, although occasionally humans fall ill from it, but they tend to have more contact with pigs than you or I might. I’m guessing that not too many pig farmers read this blog, although slaughterhouses and agricultural fairs could pose other routes of transmission. Even though swine flu occurs regularly among pigs, it doesn’t tend to kill them.

So if it hasn’t killed anybody and we only have two confirmed cases, what’s the big deal? Well, aside from the fact that it’s a new strain and that the virus demonstrated resistance to two of the antibiotics used to treat influenza (and resistance is never really a good thing), public health officials will want to make sure that no more new cases are occurring. Ideally, they’re not.

You can pretty much bet that CDC folks are boarding California-bound planes right now to make sure that we don’t have the start of a pandemic on our hands. But according to David Brown’s Washington Post article, that probability is low.

Read more about influenza at HowStuffWorks.com:
How the Flu Works
How Bird Flu Works
Why are British scientists creating a human-pig hybrid?
10 Worst Epidemics
10 Scariest Bioweapons