Avian virus cross-species jumpimg

[TillEulenspiegel]

This seems like a major concern in health specialists' view. There have been many examples of cross species infection (AIDS is one ), but this particular virus seems to bring an unusual and worrysome outlook by the WHO,CDC .et al.

Anyone have a real handle on this?

[Rolfe]

This behaviour isn't really all that out of the ordinary. Flu virus goes to ground in birds in the far east every year, rearranges its antigens so as to fool the vaccines, and comes back fighting for another go. This is why you need a new vaccine every year, you need to figure what's going to come out of the melting pot.

But they're always worried about the strain called "Spanish flu" which killed millions in 1919. Nobody's really sure what it was, or even if it was flu at all. It could even have been SARS. But I think the reason they're worried about this one is they think it might be similar to whatever Spanish flu was.

I think. Share office with guy who is expert on this, will ask tomorrow.

Rolfe.

[pupdog]

And the scientists who have been studying this have been talking about evolution --not how an intelligently-designed virus was re-designed to hop species!

[Rolfe]

Colleague says he thinks that there is an element of human flu viruses and avian flu viruses exchanging antigens, which is a worry. And that they expect an antigenic shift about every seven years, at which point clinical disease becomes worse because the human population doesn't have any residual immunity. Looks like one of these is about due. And this strain does seem to have a high mortality rate.

Also, apparently they have succeeded in isolating virus DNA from the body of a Spanish flu victim, and it was indeed flu, not SARS or anything exotic. If it could do it once it can do it again (kill millions, I mean).

Don't know whether you'd call what the flu virus does "evolution" or not. It's just part of its life cycle, to change its antigenic makeup to avoid antibodies built up to past infections. I'd say this is something it has evolved to do, rather than that it is actually evolving before our eyes.

The point is that the association between flu virus and birds has always been a known part of the biology of that virus, it's not a new cross-species infection. AIDS, on the other hand, was exactly that.

Rolfe.

[mummymonkey]

There is a bit about the 1918 outbreak here:

A VICTIM of the world’s worst flu epidemic is to be exhumed to help scientists trying to avert the spread of bird flu, it was revealed yesterday.

Scientists plan to remove lung samples from the body of 20-year-old Phyllis Burn, who was buried 85 years ago.

http://news.scotsman.com/scitech.cfm?id=115862004

[TillEulenspiegel]

Rolfe,
Evedently your Colleague is right on the mark the 1/23/04 issue of science has two papers on the subject. One about the mechinism of species jumping and the other shows the minutest difference of the avian flu and the 1918 pandemic............scary.

edit to add :
I don't provide a link as the magizine is for subscribers only, but a google search shows a direct reference and many other quotes.

[Hand Bent Spoon]

Call me an optimist, but I don't believe a flu virus can inflict that sort of damage nowadays (or at the very least, it is highly unlikely). Why?

1. Survivors of that variety of flu passed on their survivability traits to many of the people living today. The H1 variety virus looks dangerous in a historical context, but given this passing down of survivability, any impact from an H1 would be mitigated by this.

2. Medical science has come a very long way since 1918. A flu strain would be hard pressed to replicate the mortality of 80+ years ago. We have better treatments, and vaccinations for those most vulnerable, both of a quality and on a scale unheard of in those days.

Can a new deadly flu come along and cuase such a pandemic? Theoretically, yes. But it won't be the H1 the article mentions. The scariest scenario would be the virus doing something 'new' and unexpected. But now you're talking about what, a 1 in a billion chance?

[Rolfe]

Originally posted by Hand Bent Spoon
Call me an optimist, but I don't believe a flu virus can inflict that sort of damage nowadays (or at the very least, it is highly unlikely). Why? ....Well, I hope you're right.

I'm a bit more cautious, though. First, I don't think one epidemic is enough to make a huge amount of difference to the gene pool in terms of resistance to that disease. It's usually reckoned that a species has to live with an infectious organism on an endemic (enzootic) basis for a good few generations before any real disease resistance becomes evident.

Second, flu is a virus, and the only things you can do are better nursing, and antibiotic treatment of secondary infections (such as bronchitis). Would these be enough to save large numbers of people who would have died in 1919? I'm not sure, to be honest.

And I sort of half heard a TV discussion last night about developing a vaccine for this type of flu, and the message was that it wasn't so easy and it could take at least 5 years to get a GM-based product through development, testing and licensing.

I think preventive measures might be the most important thing here, and our better grasp of how to do that might be largely offset by the much greater mobility of the population these days.

I'm still a bit concerned.

Rolfe.

[Prester John]

Maybe in 1st world countries we will be better, but i wouldn't be too sure. The 1918 flu pandemic killed more people than died in WW1, maybe as many as 55 million people. One of the scary aspects is that many of the victims were young healthy people. It didn't just kill the elderly and very young as is the case in flu epidemics at the moment.

The problem is caused in the genetics of influenza. What virologists are scared of is an antigenic shift in influenza. This would mean a strain of flu that our immune systems has not encountered before, not very similar to other flu strains that we have encountered. This shift, together possibly with other factors would increase the lethality of the virus. Yes it is scary. Some virologists i have known say When not If. This is why there is such a big panic whenever these new strains occur. The potential death toll is millions.

The usual yearly strains are genetic drift variations. These are much smaller variations, so that they are similar enough to previous strains to give the immune system a head start.

I think that influenza doesn't actually kill itslef, but leaves it victims vulnerable to secondary infections. Anyone who has had real influenza will tell you its a real nasty virus. What most people call the flu is not, its just a cold. Influenza will put you in bed for a fortnight, and i mean in bed, not i feel a bit ill but can go down stairs and watch TV ill :)

[sickstan]

The trouble with influenza is that it regularly jumps species from avian to mammalian amongst animal reservoirs. I read somewhere that Arctic terns with their polar migration patterns may be responsible for the incredible reach of avian flu strains. I believe that human flu can also infect our animal pets and livestock as well. Hand bent spoon said:
The scariest scenario would be the virus doing something 'new' and unexpected. But now you're talking about what, a 1 in a billion chance?

But isn't that precisely what might happen given the hundreds of millions of infected humans and countless billions of avian and mammalian cases of influenza? The fact that the conditions that favor viral survival in the environment (cold, dry) cause concurrent seasonal peaks in human and animal reservoirs makes the exchange that much more close and frightening, especially in areas where cultures allow pervasive animal and human contact.

Anybody that doesn't fear the flu should keep in mind that flu/flu-related illness is the single most deadly infectious disease in this country far out ahead of monkeypox, cyclospora, flesh-eating "virus", and all the other phony epidemics the media has chosen to include on their "the world is ending" placards they've been waving in front of us. If a completely new strain arrives and is not promptly contained, it will dwarf AIDS, malaria, diarrheal diseases, and tuberculosis as a cause of mortality in the world.