I was curious to see what swine had in PB2/627. This is the location of a "switch" that controls at what temperature a virus will best replicate. The higher (bird) setting is an "E", while the lower (mammalian) is a "K".
What I found was very interesting.
Back in the 1930s and up through 1980, all swine samples showed a "K" - for mammalian body temperatures.
However, starting in 1981 in Europe (but not North America), there were several changes, including position 627 - it was now showing some instances of "E" - for bird body temperatures. That change stayed in only European samples until 2000 in Thailand, then in Canada for the first time in 2002. The first "E" sample in the US was in 2004 - Ohio/75004. All samples since have been "E".
While the PB2 in H1N1/2009 originates largely from birds, it appears that the bird-temp "E" is comfortable in at least 3 mammals at present - pigs, humans, and pikas.
So is influenza repeating in humans what it did in swine? If so, why?
.
What I found was very interesting.
Back in the 1930s and up through 1980, all swine samples showed a "K" - for mammalian body temperatures.
However, starting in 1981 in Europe (but not North America), there were several changes, including position 627 - it was now showing some instances of "E" - for bird body temperatures. That change stayed in only European samples until 2000 in Thailand, then in Canada for the first time in 2002. The first "E" sample in the US was in 2004 - Ohio/75004. All samples since have been "E".
While the PB2 in H1N1/2009 originates largely from birds, it appears that the bird-temp "E" is comfortable in at least 3 mammals at present - pigs, humans, and pikas.
So is influenza repeating in humans what it did in swine? If so, why?
.
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