From a link in the paper, one can read at The News and Observer site
"This virus was found in pigs here in the United States," Rabadan said in an interview. "They were getting sick in 1998. It became a swine virus."Then from the Gazette article itself you can read
And therefore you’ve got a lot of hosts available to exchange a pathogen, which is one of the processes by which viruses and bacteria evolve and acquire mutations. And then the way in which these operations are run – and I want to stress that this is a worldwide issue, it is not peculiar or restricted to Mexico.
People have also isolated influenza virus from the legs and feet of flies in the vicinity of these operations. This was noted in some outbreaks of avian influenzas, for example, in Japan.This new disease is neither new nor inevitable. We can start to change this global health issue ourselves by changing the way that we choose the food we eat. Eat locally grown food from farmers who use sustainable, humane methods.