flu

Some war? Yeah, I've heard rumors to that effect.

Several reasons:

By the time it killed 99%, population density would be so low that propagation gain would fall below unity. All you need is Adam and Eve left.

Humans are genetically diverse enough that most people (like, 60% of the population) didn't get it.

It "only" killed a few per cent of the people who did get it.

Any viral family dumb enough to kill 100% of its host population would be eliminated with it.

Some isolated islands had zero infections.

And different susceptibilities.

John

They didn't; the foot soldiers of the Roman army weren't Romans.

Nonsense. The most famous use of decimation was after the Roman rout at the battle of Cannae. From "Cannae" by Gregory Daly:

"Cowardice in battle was unacceptable in the Roman army, individuals who threw away their arms being punished by being beaten to death by their fellows (Polybius 6.37.13). Furthermore, if entire maniples deserted their posts under pressure they would be subejct to 'decimation', where approximately 10 percent of the offenders would be chosen by lot to be beaten to death, the remaining troops being given barley instead of wheat as rations and having to camp in an exposed spot outside the main camp (Polybius 6.38). It is significant that these punishments were inflicted by the army as a whole, as the offenders' cowardice had endangered other soldiers; crimes against the unit were punished by the unit."

Cheers

Phil Hobbs

As near as anyone can figure, the virus survived just fine, but people developed an immunity to it (at least to that particular strain). Part of the reason that infectious disease folks get all het up about swine flu is because the 1918 virus apparently mutated itself into pigs and stayed there ever since.

The worry isn't that the 1918 flu will come back; the worry is that some _other_ strain, to which we are equally unprepared, will come raging through.

This is a kinda-good book on the subject (the first half is really good, but the middle gets kinda boring):

They talk about the swine flu 'epidemic' in the late '70s and bird flu, and why it causes consternation over at CDC.

Why not? There are few people alive who survived it. I don't suppose acquired immunity is heritable, is it?

the worry is that some

Got it, read it years ago. Time to read it again. Good book.

The press will no doubt praise Obama for reacting to this outbreak, just as they savaged Ford for his proactive concern for public health.

John

Swine flu.

The Muslim fanatics must think that this is a sign from God.

Sure! It's the third horseman of the pork lips - Death has been around since forever; famine has been rampant around the world for centuries; now all we need is some pestilence and we're pretty much done! ;-D

BTW, when they say, "the end of the World", I personally believe that it will be the end of the World the way the butterfly is the end of the caterpillar. ;-)

Cheers! Rich

Isn't that just two different ways of saying essentially the same thing?

Thanks, Rich

Er, what in that quote is supposed to be relevant?

Because the Roman soldiers executed each other. No "us and them" as you maintained.

Cheers

Phil Hobbs

I took you're "nonsense" as disputing that the soldiers weren't Romans.

The executions may have been carried out by the soldiers, but the decision would have been made by the (Roman) commanders. If a unit didn't carry out the order, they would all have been killed.

By whom? Either by adopting the same strategy at one level up (ordering the remaining units to kill the non-compliant ones), or failing that by another legion of another race.

The whole essence of the way that a small nation (Rome) could control a vast empire lay in their ability to use one subject people against another.

My dad took a fellowship in infectious disease.

Immunity's partly a numbers-game, Dad said. There's a race between the pathogen's ability to multiply and attack you, and your immune system's ability to manufacture antibodies to it.

If you get hit with a few virus particles and your immune system responds quickly, you'll get ahead in the race, beat it quickly, and have a minor case. If someone coughs a load of virus in your face, you're cooked.

Cheers, James Arthur

I've always wondered why exposure to a single critter doesn't always result in exponential growth and ultimate death. For bacteria at least, some threshold number of critters are usually needed to cause an infection; they clump and help one another out or something. Or maybe each one has a low probability of starting a successful attack.

Or maybe, as you say, the body can quickly recognize a very few invaders and start a large-scale immune response before they multiply enough to kill the immune system itself. That sounds mathematically tricky to me.

John

If you can make and deliver antibodies faster than the invader can multiply (or damage critical tissues), you live. Otherwise, you die.

There are several starting scenarios: - the invader gets in and immediately bumps into an immune cell, which recognizes & kills it. - the invader invades a cell, which expresses a flag on its membrane that alerts your immune system to destroy the infected cell. - the invader hijacks a cell, procreates, then disseminates copies, which then attack more cells. Game on.

If you're pre-primed by previous exposure then you've got zillions of factories ready for activation, pre-tooled for the exact proteins needed to beat the invaders. That saves time.

Mathematically it comes to how quickly you can recognize the invader, how many factories you can mobilize, and how quickly.

One of my speculations is that gentle exercise early on improves your odds--immune cells work by contact, and circulating them greatly increases the chance for favorable collisions.

Most pathogens don't target immune cells--that's AIDs' awful secret.

Cheers, James Arthur

Read Darwin's Black Box. AIRC, It describes enough of the immune system to give an idea of what happens, without requiring you to be a biochemist.

Ed

Just heard an interesting statistic... 19 people die _daily_ in the US from _ordinary_ flu.

So this "pandemic" is just another of Obama's distractions.

...Jim Thompson

Well, > 1 million die yearly due to Malaria worldwide, no news about it since the rich countries are not affected.

In America 13.000-17,000 people die from aspirin yearly (numbers vary depending on source, google it up).

So these few flu cases are so far miniscule, but the potential is big, I guess.

I have it; great book, must-read for anyone interested in molecular biochemistry and evolution. But I don't recall him getting into the dynamics of infection.

He make a tough case that many cellular machanisms couldn't have evolved incrementally. That they maybe couldn't have evolved at all.

John

That's the basic concern:

- It's an A/H1N1 strain, somewhat related to the one which caused the 1918 "Spanish Flue" three-wave pandemic (which also "started small", as do all pandemics), and

- It's novel: its coat protein structure is different enough from flu viruses to which people have previously been exposed, that it's unlikely that very many people have substantial immunity to it, and

- There is currently no vaccine effective against it, and

- It has shown itself capable of reasonably efficient human-to- human transmission. The good news is that so far, this particular strain's lethality isn't particularly high (except perhaps at its original focus in Mexico), and it does seem to be sensitive to two of the most common antivirals. I saw a report this morning which indicated that this strain seems to lack the specific mutation present in the 1918 strain which caused it to be as lethal as it was (triggering an immune overreaction which damaged the lungs of many of its previously-robust-and-healthy adult victims).

The bad news is that previous pandemics (e.g. 1918, and 1957 and 1958 if I recall correctly) also started out with a relatively mild first wave... followed by a second wave a few months later which had a much higher lethality rate among its victims... presumably due to a mutation in the virus population.

We can *hope* that this H1N1 strain doesn't mutate into a more dangerous form over the next year or so. If that's what happens, this incident may not turn out to be all that much worse than a typical bad year for a (non-novel) seasonal flu. It might blow itself out, as the SARS epidemic did a few years ago... that one never achieved pandemic status IIRC.

However, if it *does* mutate into a more dangerous form, as has occurred in several past pandemics, things could get very nasty... not just because it's more dangerous to patients, but because its genetic novelty means that most people will be susceptible to infection.

Given the strain's novelty, and its (albeit fairly distant) genetic relationship to the 1918 A/H1N1 strain, I don't think that the caution and concern being expressed by WHO and CDC is excessive, and I don't think it qualifies as a "distraction" on anyone's part. The

Here's hoping it does not!