Wednesday, December 21, 2005

Don't Panic Pandemic

My neighbor asked me what I thought about the possibility of a Bird Flu pandemic. I talked for 10 minutes without stopping, so I guess I really did have something to say on the issue. I'm not sure what he thought of my answer, or whether he'll ever ask my opinion again, but since I think it's worth something, here goes.

This is not 1918! In that year, as others have pointed out, tens of thousands of soldiers, wounded and healthy, were being transported in trains and ships and lying in hospital beds, all packed together like cigarettes in a box. No space was wasted. When a single case of Influenza appeared in this kind of surrounding, it jumped easily from person to person through coughs, physical contact and shared objects, maybe even cigarettes.

Now in evolutionary terms, a virus has two ways to go. It can minimize its footprint on the health of the host, maintaining a semblance of life and mobility, in order to maximize the chances of further transmission. AIDS would fall into this class. Alternatively, it can reproduce as fast as possible, creating as many copies of itself as possible, without regard for the damage it does, in order, once again, to maximize the chances of further transmission. Ebola virus exemplifies this strategy. In fact, it spreads so quickly and destructively among humans that it actually burns itself out by using all the fuel too quickly.

Humans will eventually develop resistance to the first class of virus. Humans who survive longer with the disease are more likely to reproduce before they die. Humans who are less likely, no matter how small the advantage, to become infected, will preferentially pass their genes to the next generation. The contest between humans and the virus becomes who adapts faster. Humans have always won. A plethora of childhood diseases represents the residue of past battles.

With the second type of virus, humans don't necessarily have a chance to develop immunity, but it doesn't matter because they just have to be lucky. Such pathogens will flare up in rare outbursts quickly disappearing. This will continue until such time as they learn to be kinder to the host. If that occurs, the virus falls into the first class and after a few pandemics will become too gentle to fear much.

The Flu is not really like Ebola. It is for most people, more like the common cold. It is in the evolutionary transition phase of becoming like the common cold. The reason it didn't act like that in 1918 was because of the unusual crowded conditions. It spread so quickly through the trainloads of soldiers that it evolved into a new thing. Note that by the time it reached civilian populations in Europe and the US it had specialized for that particular ecological niche. Young men and women were the preferential targets. Very few old people and very few children died of Influenza in the 1918 pandemic.

The Avian Flu will not be bad this time around because, under evolutionary pressure, it has changed and so have we. Since the majority of the world was effected, most people alive today are the descendents of those who were challenged and survived. Myself as well. Most of my antecedants shrugged it off, but one grandmother contracted the disease and came close to dying. In subsequent years she had three children, twelve grandchildren, and many more great-grandchildren. Are they all immune? Maybe not, but it won't be as bad as it was.

This is not 1918 in other ways as well. When SARS struck cities in Asia, people wore surgical masks to inhibit transmission. If a pandemic strikes the US, we will be wearing custom-made designer versions of HEPA respirators. Antiviral medications will be used whereever an outbreak occurs, and researchers will be working to find better antivirals and new immunization procedures, with generally good chances of success. Doctors will develop new techniques for sustaining patients long enough for the gamma globulin injections to take effect, and the internet will allow all these new techniques to be widely shared. Remember, in 1918 the germ theory was still relatively new, no one knew about viruses and there wasn't a microscope on the planet that could capture the image of a virus.

There may be some situation analogous to the incubation opportunity of 1918, but I personally can't imagine what it is, and I've tried. Tell me if you think of one. But, even if such a thing exists, today is different. We will find a way to resist.

Really. Don't worry. Some people may die, but the Flu kills thousands every year anyway. The Avian Flu is not going to mark the coming of the Apocalypse.

12/21/2005 12:35 AM

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