I for one welcome the Zombie Apocalypse that draws near

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[DOD]Asprilla;14407093 said:
I'm as worried about swine flu as I am about 'normal' flu. Both are very contagious and capable of killing you
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Swine flu is about 100x more contagious than normal flu since nobody at the present has any immunity to it. That's the problem.
 
I need swine flu so I can stay in and just hammer the 360! Fallout 3 and Mass effect to play requires so serious gamer time!
 
I'm ready.
bringiton.jpg
 
No bother as I am Fully Trained & Equipped for the Apocalypse, Whether it be a Mad Max style carnage or a Swarm of Flesh eating Zombies, I for one am ready.
Where do I sign up. :D
 
Nitefly said:
Swine flu is about 100x more contagious than normal flu since nobody at the present has any immunity to it. That's the problem.
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If you can get immunity to flu then who do so many people catch it each year? My brother used to get flu on a regular basis when we were kids, but I've never had it. Surely he would have built up some immunity?
 
[DOD]Asprilla;14407376 said:
If you can get immunity to flu then who do so many people catch it each year? My brother used to get flu on a regular basis when we were kids, but I've never had it. Surely he would have built up some immunity?
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You get immunity to the strain. Antigenic drift means we will never gain immunity to influenza A, unless someone comes up with something incredibly clever...
 
Nitefly said:
You get immunity to the strain. Antigenic drift means we will never gain immunity to influenza A, unless someone comes up with something incredibly clever...
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But you just said that Swine Flu was 100x more contagious because no-one had immunity. Now you are saying that we will never have immunity to Imfluenza A?

I'm confused.
 
My Landy carrys 7 including me but I'll take 4 if you have shottys & we can use the spare seats for the ammo. :D
 
[DOD]Asprilla;14407399 said:
But you just said that Swine Flu was 100x more contagious because no-one had immunity. Now you are saying that we will never have immunity to Imfluenza A?

I'm confused.
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There are two proteins around the outside of the virus that the human immune system detects (Haemagglutinin and Neuraminidase). These can have different structures due to slight variations in the genetic code for these genes.

An influenza subtype has a code based on which versions of these proteins the virus had. For example, if the virus has Haemagglutinin type 5 and Neuraminidase type 1, the virus will be called H5N1.

When we encounter a virus, or bacteria, or anything foreign, our body creates 'antibodies' which recognise the foreign invader to our bodies allowing them to be subsequently destroyed. Thus if we encounter H5, our body will eventually create corresponding antibodies to H5, giving us immunity to this 'type' (but more accurately 'strain') of virus. However, this immunity is limited.

The structure of each version of either H or N changes over time randomly due to mutation. It gets to a point where a H5 now looks different enough from other H5s that some individuals' antibodies cannot recognise the new type of H - thus we are at risk from the new strain of virus. This is antigenic drift, and is how we get 'seasonal flu'.

Now, the real danger comes from antigenic shift. Influenza A exists in many types of animal groups, including birds and pigs. The subtypes in these animals have evolved over a long period of time without infecting humans, therefore no human immune system has a clue what those avian and swine viruses look like.

Let us assume that there is the virus H8N8 is common in humans. Now, the virus H16N16 in birds crosses over with H8N8 in a human which has both viruses. The result could be hypothetically any combination of genes between the two viruses - including one which has all the nasty genes from H8N8, but the appearance to the human immune system of H16N16. The new virus would spread like wildfire and would be extremely serious - this is what happened in the Spanish flu of 1918:

http://en.wikipedia.org/wiki/1918_flu_pandemic

This is very similar to what could potentially happen with swine flu, hence the scientific concern.
 
3 deahts already :(

only another 17 and it will be up equal on the uk killer list with the notorious electric blankets deaths per year!
 
Nitefly said:
Valuable and detailed explanation
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Thanks for that, very useful.

However, what are the chances of such a mutation taking place, given that interaction between viruses must take place on an almost constant basis all over the globe.

There is lots of talk of 'if' but I've not seen any statistical analysis of the likelyhood in the mainstream media (now there's a surprise).
 
[DOD]Asprilla;14407591 said:
Thanks for that, very useful.

However, what are the chances of such a mutation taking place, given that interaction between viruses must take place on an almost constant basis all over the globe.

There is lots of talk of 'if' but I've not seen any statistical analysis of the likelyhood in the mainstream media (now there's a surprise).
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You are most welcome :)

When you are infected with Influenza A (or any virus), there are millions of viral particles (potentially well into the trillions) in your body in certain areas. When a virus replicates, the virus unfolds from its simple structure, replicates, then the genes come together to make new virus particles.

In Influenza A, there are only 8 genes! H and N are coded by one gene each.

If a human has the aforementioned H8N8 and H16N16, both will be potentially replicating in that persons body. Of all the trillions and trillions of particles and 8 times as many viral genes floating around, it will take just one H or N gene from H16N16 to be boxed up with H8N8 and you will have your new, deadly virus, which will subsequently replicate into millions in that one person.

So, the chance of a nasty version of swine flu appearing depend on two factors:

1) The chance that an individual will house swine flu and a human flu at the same time. Considering the contagious nature of swine flu, this is almost inevitable.

2) The chance of the gene swapping as above. As you can probably guess, the chances of this occuring are far from small...
 
If the chances of it happening are far from small then why doesn't it happen more frequently across more viruses, not just flu?

Also, would it be that all of the possible mutations are leathal and highly contagious, or would it be a small number, or possibly even none of them?
 
[DOD]Asprilla;14407754 said:
If the chances of it happening are far from small then why doesn't it happen more frequently across more viruses, not jsut flu?
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I can't really speak for any other viruses since I haven't studied many of them in depth. However, they do not all have the same life cycle (in terms of transmission) and they certainly do not all have animal reservoirs like Influenza A (remember, the pandemics come from the antigenic shift which occurs when the virus infects humans from an animal population).

Influenza A can be beaten by the immune system and is highly contagious, hence the evolution of its virulence is going to be greatly accelerated compared to something like HIV, which has almost no selective pressure to evolve.

In terms of new strains of viruses, think how many times you have had a common cold. Each time will have been a new strain.
 
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