Rise of deadly disease is a cultural thing

[Kailassa]

October 17, 2005
Tony McMichael.

The main concern is whether the H5N1 strain will become transmissible from human to human. That concern has been reinforced by two scientific findings in the past few weeks.

First, the genome of the 1918-19 (Spanish flu) H1N1 virus, which killed 30-40 million people, has been reconstructed. It appears that this particular pandemic strain may have arisen directly, via spontaneous mutation, from an avian influenza virus.

Unlike the 1957 H2N2 and 1968 H3N2 strains, the H1N1 strain did not require recombination of genetic material from bird and human strains. Could H5N1 do likewise?

http://www.smh.com.au/news/opinion/rise-of-deadly-disease-is-a-cultural-thing/2005/10/16/1129401141539.html

No, I'm not telling anyone to panic. Collecting information empowers us, it does not mean we have to lose sleep and hand over more power to Buschco.

To explain the significance of this finding:

- Avian Influenza is not a big problem yet, as it cannot be easily transmitted person to person.

- Until now, it was believed that the only way this virus could gain the ability to transmit person to person was for a human or animal to be infected with Avian Influenza and Influenza type A simultaneosly, allowing the virus to recombine within the person's cells to form a highly contageous and mutagenic form of bird flu. This could spread through the world like wild-fire, killing up to 1/4 of those infected.

- Now we know it could be much easier for this virus to change to an easily contageous form than we realized, as the 1918 virus appears to have mutated on its own to do this, and not needed to recombine with the human virus at all.

[motocicleta]

1. I'm a bit of a dullard

Could you please explain what this means?
a) does this make it more likely H5N1 would spread human to human?
b) if it doesn't require recombination of genetic material from bird and human strains, does that alter its virility in any way? Or is the point just that H5N1 has a few different options for becoming a pandemic?
Thanks
Matt

[Kailassa]

2. Dullards don't ask for clarification, only smart people do ;-)

a) This, sadly, makes it more likely for H5N1 to gain the ability to spread easily between humans as it can gain the ability by itself.

b) Recombining with the human virus meant it might also pick up the decreased lethality the influenza viruses we are already living with, by incorporating a part we already have an immunity to. Changing on its own makes this unlikely.

[motocicleta]

3. Thanks.

I'm depressed. I don't mind taking my chances, I don't often get sick. But having a wife and daughter has really changed my feelings on mortality (my daughter is 2 1/2).

Ya pays yer money and ya takes yer chances, I guess.

[momster]

5. Parental Worry

My daughter's 12 and the worry doesn't change...it increases (G). If she's in pre-school, make sure she washes her hands the minute she walks in your door (you too!) Don't go nuts with the antimicrobial wipes and stuff, though. A few germs are helpful in staving off bigger illnesses. When and if the big flu hits, don't send her to pre-school anymore (recent studies prove what parents have always said -- pre-schools are germ factories). If she's a picky eater, make sure she takes a vitamin supplement of some kind. Get a pet, if she's not already asthmatic or allergic, because having an animal in the house builds up immunities to those kind of breathing difficulties and with flu, you want strong lungs. It also teaches compassion for living things that don't look just like you, but that's another story.

And relax a little. Relaxed parents are better parents.

[skooooo]

4. Good thing evolution is just a theory!!

Otherwise, viruses like this would be able to adapt and mutate to survive!!!

Oh...

:sarcasm:

[superconnected]

7. expeically 1918 ones, with a little help from a chem lab...

[mike_c]

6. actually, recombination and mutation are both possible routes...

...to an H5N1 strain with high human transmissibility and always have been. Recombination is still the statistically more likely event, since mutations occur randomly. The H1N1 Spanish flu genome suggests that direct mutation into a human transmissible form is possible, but we've always known that in principle-- the sequence data simply confirms that principle. But mutations accumulate relatively slowly and face rigorous selection tests, whereas a recombination occurs rarely, but rapidly. A recombinant virus is much more likely to receive genes that improve its fitness than a mutant virus, since the parent material for the recombinant has already "proven" itself in human hosts.

The bottom line is that influenza uses both mutation and recombination strategies for staying ahead of host immune systems. The H1N1 jump to human hosts was a relatively long jump by mutation, but the data suggest that it happened that way. But the recombination monster is still in the closet, and still the likeliest route to a human H5N1 strain.