Hong Kong Confirms First Human Case of Bird Flu

There was also a BBC documentary called "Pandemic" which was pretty good, with more relatable characters than Contagion had in my opinion.

Pandemic strains of influenza are noted for, among other things, their tendency to utterly ignore the routine seasonal patterns of flu. See: The 2009 pandemic, which kicked off in late spring, when the major wave of seasonal influenza is on the way out, if not over entirely.

Is it time for the media to go pant shitting crazy about epidemics again? Seriously?

Has anyone else noticed a pattern here?

>2. So far it doesn't seems to have crossed the threshold to be able to spread quickly from person to person. Doing that will imply a few more mutations that will likely make it less aggressive and deadly (it's hard to spread if you kill your host too quickly).

I've done some epidemiology, but I'm not a biologist. I don't understand your line of reasoning there. I suspect it stems from a logical mix-up, but its not detailed enough to say for sure.

I understand that if a disease kills its host, before it can infect more people, then it will 'burn itself out' and fail to spread. Therefore, all other things being equal, a disease that kills more slowly, or kills less, will spread more.

However, that does not mean that a disease must become less aggressive and deadly to spread quickly from person to person - or even has pressure to.

We can use the terminology of compartmental epidemiology modelling to make this clearer:

- The rate which describes how contagious the disease is, between an infected person, and a non-infected person: 'B' (beta).

- The rate a which someone infected becomes non-infective (recovered or dead): 'v'.

- Lets also talk about the mortality rate, the % of infected people who become dead, rather than recovered.

You say:

>(it's hard to spread if you kill your host too quickly).

I interpret that as a statement about 'v': you are saying that if the disease kills too quickly, it won't spread too fast.

That's true - if 'v' is much shorter than a normal flu - let's say its minutes, as an illustrative unrealistic extreme - then clearly even a very contagious disease (high Beta) will burn itself out.

However:

> So far it doesn't seems to have crossed the threshold to be able to spread quickly from person to person.

That is a statement about 'B'.

You imply that it is necessary, or likely, that 'v' changes as 'B' increases.

But what reason do you have to think that?

There's no reason to think that a disease couldn't have a normal 'v' (couple of weeks; but even a couple of days would probably still be incredibly dangerous), but a really high 'B' and a really high mortality rate, if we are very unlucky.

The mutation of the disease isn't guided, or intelligent; it doesn't care if it reaches equilibrium with its host population, or kills us all.

The evolutionary pressure on the disease to become less lethal is a populations-of-diseases level pressure (i.e. the specific disease will die, if it kills all humans); whereas the evolutionary pressure to spread more applies at the level of individual members of this specific disease (which is normally how we think about evolutionary pressures).

Why think there's a casual link from the former to the latter? I believe your argument mixes the two up, leading to a faulty conclusion, and an unwarranted assumption of an extra safety factor.

I've seen a number of people working in the area of epidemiology make what I think is this mistake, and I'd like to know whether I'm missing something or they are.

Your comment adds nothing to the discussion and is severely exaggerating what's likely to happen.

That said, I'm imagining the small possibility that people of the future look back on this comment going like "this guy knew and everyone ignored him."