# 3117
Pig and humans share a remarkably similar physiology.
And if you find that concept disconcerting . . . imagine how the pig feels. Like humans (and some other mammals and birds), pigs are susceptible to the influenza virus.
So much so that scientists fear that they could serve as a `mixing vessel’ – allowing two or more influenza viruses to swap genetic material (reassortment) – and produce new strains of influenza.
The 1918 pandemic virus (also an H1N1 – but quite a bit different from today’s virus) apparently infected pigs, although the exact sequence of which species carried the virus first (birds, humans, or pigs) is still a matter of discussion in some scientific circles.
It is generally assumed, however, that the virus in 1918 jumped first from birds to humans, and then from humans to pigs.
NIAID illustration of potential influenza antigenic shift
Crof over at Crofsblog has a report this afternoon from the Canadian Press, indicating that authorities have discovered this newly emerging A/H1N1 strain in pigs in Alberta.
Alberta pigs believed to be infected with swine flu: source
28 minutes ago
OTTAWA — The Canadian Press has learned federal officials are set to announce the swine flu virus is believed to have infected pigs in Alberta.
A government source says the animals were thought to be infected by a farm worker who had recently been to Mexico and fell ill upon his return.
This may be the first time this particular swine flu virus has been found in pigs.
The H1N1 virus, which is made up of swine flu genes, is believed to have jumped to humans sometime back and has been passing person to person.
The World Health Organization has insisted there is no evidence that pigs are passing the virus to humans, or that eating pork products poses an infection risk.
Genetic testing shows the pigs in Alberta were infected with the same virus responsible for cases in California, Mexico and other countries around the world.
Official confirmation of the pigs' infection is expected at a news conference scheduled for Saturday afternoon in Ottawa.
Assuming this report is verified, the next question is: What does this mean, and does it really matter?
I’m sure we’ll get far more authoritative answers than I can provide to those questions over the next couple of days, but for now I can think of a couple of potential issues.
This complicates matters, I should think, particularly since health authorities have maintained for more than a week that this strain has not been found in pigs.
If nothing else, this could become another major public relations headache for a hog industry already reeling from the public’s concern over `swine flu’.
Obviously more surveillance is now needed to see just how widespread this virus becomes in pigs. This adds another layer of complexity to this outbreak, and will be a particular challenge in those countries where veterinary surveillance is limited.
And of course, I have to imagine that this increases concerns that the pig `mixing vessel’ theory will come into play with this new virus.
It certainly doesn’t guarantee that the virus will reassort with another influenza virus, of course.
But if a large number of pigs should become infected (and that is not a given), it would give the virus more opportunities to do so.
Reassortment can occur in a human, as well, if they are co-infected by two different flu viruses.
Another facet to this rapidly developing story, and one that I expect we’ll be hearing a lot about over the next few days and weeks.
