The North American Swine flu H3N2 was first identified in North Carolina, in 1998. "A decade which saw the state’s hog production rise from two million to 10 million, even as the number of farms dropped. H3N2 originated in a relatively benign swine flu strain first identified in 1918, but had absorbed new genes from bird and human flu's."
At the genetic level, the years that followed remain a mystery — hog flus are poorly monitored, compared to human influenza. But eventually an H3N2 spawn merged with a strain of Eurasian pig flu, producing the swine flu variant that’s now infecting humans.
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. (Source: Wired.com)
Swine Flu from Pigs Only - Not Humans or Birds
At the genetic level, the years that followed remain a mystery — hog flus are poorly monitored, compared to human influenza. But eventually an H3N2 spawn merged with a strain of Eurasian pig flu, producing the swine flu variant that’s now infecting humans.
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. (Source: Wired.com)
Swine Flu from Pigs Only - Not Humans or Birds
