Bird Flu in England
"werl, not really a problem for me izzit? I mean this bird flu stuff. Why? Cos I'm a bloke, of course."
Watching the TV as I sweated away on an exercise cycle in the gym this morning, it struck me how dumbed down the news in the UK really is. And how patronising are the various "experts" called on to explain that there really is no danger. I guess they're forgetting the last epidemic, five short years ago, when a variety of similar experts and boneheaded bureaucrats laid waste to vast areas of the country and burned much of the national herd trying to combat the spread of another virus amongst animals.
The influenza virus is a sneaky little bugger. It has a protein coat with spikes on - two kinds of spike actually. The one kind, haemagglutinin (abbreviated to H) has 16 variants of which three have been seen in cases of human infection so far (H1, H2 and H3) and the rest have been implicated in animal infections.
The other protein, neuraminidase (I suppose technically it's an enzyme, ending in -ase as it does) has 9 variants, of which two have thus far been seen in human infections (N1 and N2) and the rest in animal infections.
So there are hundreds of different possible variations in the "spike pattern" on the virus coat. If it's a H1N1 pattern then there is a fair chance it can infect a human, and so on. In fact there is a relatively high level of residual immunity in the world population to some of these variants, due to repeated infections.
Each time a virus infects a cell, it essentially commandeers that cell's assembly line for making useful proteins and converts it over to making more viruses. These are eventually released (often by rupturing the cell) and bumble off to infect other cells. As with any rush production line, the replicating process can, over time, cause some slight changes in the nature of the spikes even though broadly they still remain the same kinds of H and N as they were. Some people believe this is due to the malign nature of the virus, ascribing a level of cunning to it, while others look at it as typical of any knock-off factory in Asia with a high tolerance for defects in its mass production.
This slight alteration in the pattern on the protein coat of the virus (called antigenic drift, which is the slow change in the spikes which make them become slightly different "strains" of 'flu and allow them to sneak past the very literal-minded antibodies guarding our systems, kind of like Peter Sellers disguising himself with a false nose in the "Pink Panther" movies) is why we sometimes have only partial immunity to a strain of the disease.
A more fundamental change in the spikes (antigenic shift) can also happen. This is when, with a snap and a crackle (like a hedgehog rolling into a ball) a new set of spikes appear, new H and N proteins that the human body does not recognise at all and consequently is not immune to. Sometimes this is associated with interspecies transmission of the virus - and that's what we're worrying about here.
The birds dying of Avian Flu at the moment are contracting an H5N1 strain of the virus. Traditionally this is not a concern for humans, unless of course you are a poultry farmer and see your livelihood expiring in small sneezing lumps of feathers around you, but for some strange reason it seems that humans are occasionally able to contract this strain of H5N1 from birds, although mercifully as yet the virus expires with the patient and is not transmitted onwards to another human.
If, however, the H5N1 virus undergoes an antigenic shift as a result of its travels from bird to human, and then becomes a different strain that can cause infection from human to human, why then dear readers we are in deep doo-doo. Because already if a human catches H5N1 avian 'flu, they often die. And all that is saving us right now is that the little bugger of a virus has not yet worked out how to reconfigure its spikes so as to pass from person to person.
So no real point in rushing off to your doctor for a 'flu vaccination (unless you're in the traditional "at risk" category of elderly or infirm and want to avoiud catching normal 'flu). Why? Well, the H5N1 variant that is transmissible from human to human does not yet exist, and so it is not yet possible to get some in a syringe and inject it into chicken eggs (strangely enough that is how we make vaccines, and I am sure I'd be laughed at if I pointed out a correlation between this method of growing viruses to be later killed and made into vaccines and the rise of bird to human transmision of viruses).
So then, all you ever wanted to know about flu. Not complicated. But sadly enough, too many big words for Sky News and so all we get is more and more impossibly-coiffed presenters asking dumb questions of nerdy scientists. And a blanket reassurance that we have more chance of winning the lottery than of catching bird flu. Tell you what, though, someone does win the lottery quite often. And if that winning ability was able to be spread from human to human, why we'd be millionaires quite soon in this overcrowded little island.
See ya.
Watching the TV as I sweated away on an exercise cycle in the gym this morning, it struck me how dumbed down the news in the UK really is. And how patronising are the various "experts" called on to explain that there really is no danger. I guess they're forgetting the last epidemic, five short years ago, when a variety of similar experts and boneheaded bureaucrats laid waste to vast areas of the country and burned much of the national herd trying to combat the spread of another virus amongst animals.
The influenza virus is a sneaky little bugger. It has a protein coat with spikes on - two kinds of spike actually. The one kind, haemagglutinin (abbreviated to H) has 16 variants of which three have been seen in cases of human infection so far (H1, H2 and H3) and the rest have been implicated in animal infections.
The other protein, neuraminidase (I suppose technically it's an enzyme, ending in -ase as it does) has 9 variants, of which two have thus far been seen in human infections (N1 and N2) and the rest in animal infections.
So there are hundreds of different possible variations in the "spike pattern" on the virus coat. If it's a H1N1 pattern then there is a fair chance it can infect a human, and so on. In fact there is a relatively high level of residual immunity in the world population to some of these variants, due to repeated infections.
Each time a virus infects a cell, it essentially commandeers that cell's assembly line for making useful proteins and converts it over to making more viruses. These are eventually released (often by rupturing the cell) and bumble off to infect other cells. As with any rush production line, the replicating process can, over time, cause some slight changes in the nature of the spikes even though broadly they still remain the same kinds of H and N as they were. Some people believe this is due to the malign nature of the virus, ascribing a level of cunning to it, while others look at it as typical of any knock-off factory in Asia with a high tolerance for defects in its mass production.
This slight alteration in the pattern on the protein coat of the virus (called antigenic drift, which is the slow change in the spikes which make them become slightly different "strains" of 'flu and allow them to sneak past the very literal-minded antibodies guarding our systems, kind of like Peter Sellers disguising himself with a false nose in the "Pink Panther" movies) is why we sometimes have only partial immunity to a strain of the disease.
A more fundamental change in the spikes (antigenic shift) can also happen. This is when, with a snap and a crackle (like a hedgehog rolling into a ball) a new set of spikes appear, new H and N proteins that the human body does not recognise at all and consequently is not immune to. Sometimes this is associated with interspecies transmission of the virus - and that's what we're worrying about here.
The birds dying of Avian Flu at the moment are contracting an H5N1 strain of the virus. Traditionally this is not a concern for humans, unless of course you are a poultry farmer and see your livelihood expiring in small sneezing lumps of feathers around you, but for some strange reason it seems that humans are occasionally able to contract this strain of H5N1 from birds, although mercifully as yet the virus expires with the patient and is not transmitted onwards to another human.
If, however, the H5N1 virus undergoes an antigenic shift as a result of its travels from bird to human, and then becomes a different strain that can cause infection from human to human, why then dear readers we are in deep doo-doo. Because already if a human catches H5N1 avian 'flu, they often die. And all that is saving us right now is that the little bugger of a virus has not yet worked out how to reconfigure its spikes so as to pass from person to person.
So no real point in rushing off to your doctor for a 'flu vaccination (unless you're in the traditional "at risk" category of elderly or infirm and want to avoiud catching normal 'flu). Why? Well, the H5N1 variant that is transmissible from human to human does not yet exist, and so it is not yet possible to get some in a syringe and inject it into chicken eggs (strangely enough that is how we make vaccines, and I am sure I'd be laughed at if I pointed out a correlation between this method of growing viruses to be later killed and made into vaccines and the rise of bird to human transmision of viruses).
So then, all you ever wanted to know about flu. Not complicated. But sadly enough, too many big words for Sky News and so all we get is more and more impossibly-coiffed presenters asking dumb questions of nerdy scientists. And a blanket reassurance that we have more chance of winning the lottery than of catching bird flu. Tell you what, though, someone does win the lottery quite often. And if that winning ability was able to be spread from human to human, why we'd be millionaires quite soon in this overcrowded little island.
See ya.
posted by Shane Hodgson at 8:14 am
2 Comments:
Seriously. Fascinating. Love the Peter Sellers analogy.
I'm off to buy a Lotto ticket ~ it's the big one tonight, you know.
Interesting. I knew a bit about viruses and spikes. Can you clarify, if you know it, how the spikes enable they virus to lock unto a cell? Blocking that locking-on mechanism is on of the major avenues of research into the creation of an HIV vaccine (it's been successful in creating similar vaccines for strains of viral melangitis etc).
(Nice to see you're still alive, btw, up there in God's Urinal [aka England ;)] ).
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