Naked Science Forum
Life Sciences => Cells, Microbes & Viruses => Topic started by: thedoc on 11/02/2014 13:00:58
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A new fatal strain of flu has been identified in a patient in
China...
Read the whole story on our website by clicking here (http://www.thenakedscientists.com/HTML/news/news/1000435/)
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The analysis also showed that the coat proteins of the virus, comprising the H and N molecules, were from two different bird flu viruses, while the internal genes, which control how the virus grows and replicates itself, were from an H7N9 virus similar to the one found circulating in China in 2013.
One of the concerns, of course, is that if the bird flu viruses can recombine from several different viruses, that eventually they'll infect someone with a co-infection of the human type flu, and recombine to form a new form of bird flu - human flu hybrid capable of propagating quicker.
I wonder if one of the problems in China is that chickens are often sold as live meat. In the USA, the end consumer almost never gets the live chickens. The farmers and butchers may already have an immunity to the bird flu strains, but the general public would not.
Would selling packaged meat reduce the likelihood of the bird flu jumping to humans in the near future?
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Maybe, but not necessarily, because the reassortment event that produces the fatal strain can occur in birds and then only limited contact with humans is needed for the infection to jump into us, assuming it's got the power to spread.
In China there are a lot of people and a lot of migratory aquatic birds, which are the natural hosts of flu and the perfect mixing pot for these reassortants to establish and evolve.
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What are the symptoms of the flu in a bird?
Hacking cough?
Runny nose?
Getting nasal mucosa on one's hands and touching everything in sight?
It is quite possible that chickens are different enough from humans that a highly infectious strain capable of jumping to humans and passing from human to human could not be incubated solely in birds. Of course the birds might be able to catch the human version of influenza, or there is the risk is that if the virus could slowly pass from human to human, in a few generations it could increase its infectious rate.
Other mammals such as pigs, cattle, goats, dogs, or cats may be more likely to generate a strain of the flu that is highly infectious to humans.
The risk, though, is that if the avian flu rarely passes to humans, then we could be significantly lacking in immunity.
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I think so far the cases have been bird to human transmission. Avian flu binds to a receptor that is uncommon in the human upper repository tract but is present deeper in the lungs, which is why infection has mainly been in poultry workers.
Epithelial cells of the pig trachea carry both the human and avian type receptor molecules, so pigs can be infected with both avian and human influenza virus strains and thus serve as a ‘mixing vessel’ for the emergence of types of influenza through reassortment.