This swine flu is unusual because it combines virus segments from 3 different animals - birds, pigs and humans - and also from 3 different continents - Europe, Asia and North America.
As the Wall Street Journal puts it:
In addition to genetic material associated with North American swine flu, the strain has gene segments associated with European and Asian swine flu, North American avian flu and human flu.
(confirmed here).
If not, we need to know that immediately.