Swine Flu Ancestor Born on U.S. Factory Farms

At an environmental level, the conditions which shaped H3N2 and H1N2 evolution, and increased the variants’ chances of taking a human-contagious form, are well understood. High-density animal production facilities came to dominate the U.S. pork industry during the late 20th century, and have been adopted around the world. Inside them, pigs are packed so tightly that they cannot turn, and literally stand in their own waste.
Diseases travel rapidly through such immunologically stressed populations, and travel with the animals as they are shuttled throughout the United States between birth and slaughter. That provides ample opportunity for strains to mingle and recombine. An ever-escalating array of industry-developed vaccines confer short-term protection, but at the expense of provoking flu to evolve in unpredictable ways.

The Pew commission concluded that this system created an “increased chance for a strain to emerge that can infect and spread in humans.” Scientists and public health experts have said the same thing for years, in even starker terms.
In 2003, the American Public Health Association called for a ban on contained animal feeding operations. One year later, St. Jude’s Children’s Hospital virologist Richard Webby, one of the original chroniclers of H3N2’s emergence, called the U.S. swine population “an increasingly important reservoir of viruses with human pandemic potential.” United States Department of Agriculture researcher Amy Vincent reportedly said that vaccine-driven evolution