There is a scientist at Columbia University who disputes the claim that it is a chimera and says that the virus involved in this epidemic consists only of swine flu.
(I can find a link to that if you need one.)
All of the sites Mexico where this began are towns adjacent to giant pig farming operations which have nasty lagoons of pig manure. The spread of this type of coporate factory farm to Mexico is a consequence of NAFTA.
The Mexican orgins of this disease may go back as early as February when there was an outbreak in the town of La Gloria that caused two thirds of the residents to fall ill. One of the people in that episode tested positive for H1N1.
The name swine flu may be entirely appropriate. The push to stop calling it swine flu is corporate public relations damage control.