H1N1 Appears To Be Transmittable From Human To Pig 132
mpetch writes "In an interesting twist, it appears that H1N1 influenza can be transmitted from humans to swine. Apparently a Canadian pig farmer vacationed in Mexico, returned to Canada and infected about 10% of the swine on an Alberta farm. The swine subsequently developed flu symptoms."
Re:is this how it started? (Score:4, Informative)
Influenza viruses go back and forth between humans, pigs, and birds, and they also mutate regularly. So, this didn't really "start" anywhere, it's a normal part of how the influenza virus lives.
propagation of influenza (Score:3, Informative)
As to how it jumps species in the first place, one way is to drink raw avian blood as in Tit Canh [ehow.com]. Then infect some tourist who gets on a plane and who coughs infected droplets into air that is recycled for a number of hours.
Re:Obligatory (Score:4, Informative)
From WHO: "There is no indication of virus adaptation through transfer from human to pigs at this time."
http://www.who.int/csr/don/2009_05_03a/en/index.html [who.int]
US exports $5 billion+ pork each year. Mexico imports most of its pork from US/Canada. Other countries such as China know that the swine flu was much more likely to have incubated in the massive pig farms of US and Canada before transferring to humans, rather than the other way round as so called "news" like this try to make us believe.
"China was also selective, banning only pork from Texas, California and Kansas, while the Philippines, South Korea, Thailand, Kazakhstan, Serbia, Ukraine, United Arab Emirates and Ecuador said theyâ(TM)re stopping all U.S. pork imports, according to Nefeterius Akeli McPherson of the U.S. trade representativeâ(TM)s office."
China ban US pork [google.com]
Re:Surprised? (Score:5, Informative)
Current reports indicate that this strain of H1N1 influenza contains genetic material from swine, avian, and human forms of the disease. That's probably why it can spread easily from humans to pigs; normally, a virus does not cross species unless there is frequent or prolonged close contact between the two, because making the leap depends on genetic mutation. In this case, the virus is already adapted to both hosts.
To further clarify, the name "H1N1" refers only to a particular configuration of two proteins on the surface of the virus (H is hemagglutinin and N is neuraminidase). The configuration of these proteins determines how the immune system will react to a given strain of influenza (i.e. which antibodies will be able to recognize and attack it), which is the most useful information to have when it comes to treating the disease, but there are other factors that determine a given strain's properties.
So the news here is not that H1N1 flu can jump from humans to pigs -- it can't, not necessarily -- the news is that this variety appears to be able to. And it's not that we didn't know this could be possible -- we've seen this kind of thing countless times, and in fact it's believed that all forms of influenza ultimately come from birds -- it's just that calling it "H1N1 flu" doesn't give us enough information to make those kinds of predictions about its virulence.
G'dang our VP is a moron. (Score:3, Informative)
As to how it jumps species in the first place, one way is to drink raw avian blood as in Tit Canh [ehow.com]. Then infect some tourist who gets on a plane and who coughs infected droplets into air that is recycled for a number of hours.
Ok, we need to put a stop to this myth like thirty years ago.
THE AIR ON PLANES ISN'T RECYCLED.
Bottled oxygen and CO2 scrubbers are heavy and expensive, and completely unnecessary.* The plane is surrounded by a breathing medium that is perfectly adequate in every way except temperature and density. A problem which is solved by the same step: Compressed air is diverted from the engines before the fuel is mixed in. The compression is mostly adiabatic, so that raises the temperature, too.
*A small amount of bottled oxygen is carried. But nowhere near enough for a whole trip. Just enough to descend to a breathable altitude and maybe land.
The air cycles out pretty quickly, too. Since there are a lot of fat people on board, you need to handle more than one cubic foot per person per minute.
And it leaks out through all the seams, not just the control valves. There's a good chance most of the air you exhale exits the plane mere inches from your face.
And the air from the overhead blower is directly off the engine tap. It's 100% fresh outside air. If you're worried about mixing, just turn that sucker on and point it at your nose. (but wear a wet rag over your nose so you don't dry out.)
Re:Recycled Aircraft Air (Score:4, Informative)
When people speak of "recycled air" on an airplane they seem to think that aircraft are like submarines, completely airtight, and the only air is that which you had when you took off from the runway. This simply isn't the case -- it's all going to get cycled out and continuously refreshed. Of course a certain amount is getting recirculated, just as in a closed car, but sooner or later it's all fresh air. You're not landing with the same air molecules you had when you took off.
In commercial aircraft (I don't know about small craft like Cessnas), there are one or more apertures, usually near the rear of the plane, which can open and close to variable diameters, and that's part of how cabin pressure is regulated. You pump more air into the cabin than you let out through the aperture, and the result is a higher air pressure than what's outside -- and that air is indeed being pumped in from the outside, through the engines (which are basically doing nothing but forcing air around at high velocity anyway).
Incidentally this is also why shooting a gun in an aircraft and blowing a hole through the hull isn't the huge deal everyone thinks it is, resulting in decompression and a big crisis. If such a thing occured, the apertures would simply close a bit more to compensate for the drop in pressure, and all would be well -- at least as far as cabin pressure is concerned.