Another bird flu to watch for... H7N9 in China
Another bird flu to watch for... H7N9 in China
http://www.dailykos.com/story/2013/04/28/1205208/-Another-bird-flu-to-watch-for-H7N9-in-China
Birds have different respiratory receptors than we do. For those who need a quick reminder, any article that mentions Hs and Ns, the spiky proteins on the outer membrane of the flu virus, is talking about influenza A (influenza A causes both seasonal flu and worldwide pandemics whereas influenza B only causes seasonal flu but does not cause pandemics.)
The H stands for hemagglutinin; it binds to a receptor while infecting a host. We have one kind of receptor, birds have another, and some animals like swine have both. The much more limited (in spread, not in illness to humans) influenza B hits humans and seals. Don't ask me why, I don't know, but its limited host range may help keep it from causing worldwide pandemics. The N stands for neuraminidase and helps the virus get released from cells to move on in its infective cycle.
There are 17 different Hs and 9 different Ns in every combo you can come up with, and birds get them all. Humans typically only get the first three, so the swine flu pandemic of 2009 was an H1N1, and the seasonal flu circulating this year is an H3N2, as well as influenza B.
Since even within a category flu viruses mutate rapidly, there's a new flu virus made each year. ....
