Friday, February 24, 2006

Here's the basic information I think anyone who wants to avoid catching the disease, or failing that to survive it needs to know.

First the basics. H5N1 is a strain of influenza which normally affects migratory birds. Recent mutations in the virus have made it capable of surviving for several days or even weeks in ducks. The reason the virus is mutating is that like all viruses, the genetic composition of H5N1 is liable to have irregularities as it multiplies. Some of these mutations are "unsuccessful": they die out and the "mainstream" carries on. The problem for people is that there is a possibility that one such mutation will be spreadable from person to person (peer-to-peer of a kind not even filesharers would like). Already, H5N1 strains exist that are especially comfortable in a human host, and the death rate is not getting better at this time.

I've been tracking bird flu for nearly two months now. Every morning I check the World Health Organization's alerts for the latest developments, I know where all the human cases have been, I also know what the indicators are that market traders and scientists alike are waiting for.

Since I started, the death toll has increased by about 20%, which isn't too bad: fewer than 100 people are confirmed dead from bird flu across the world since 2003. The bad news is that the mortality rate is deteriorating, from exactly 50% when I first looked in early January, to 54.1% now. Also, some countries (like India) have governments which belatedly think there may be people who died of bird flu and it wasn't realised at the time.

The only really good news so far is that although H5N1 will quite possibly kill you, if you are unfortunate enough to catch it, you can only catch it from a bird, and so far chickens (overwhelmingly the major source of human infection) don't catch the virus easily from migratory birds. So the death rate would go up if either chickens caught the disease easier, or if the disease mutated into a human-transmissible killer, or both. Since November 2005, the WHO has considered the the avian flu outbreak to be in a "category 3" status (out of 6). The reason for this is that large nmbers of people have not been confirmed as having caught the disease from other people. Even the first few confirmed human-to-human casualties would not necessarily justify raising the alert level, but you can expect share prices to crash if "category 4 " is reached, the problem being that there is presently no reason to supposed that categories 5 and 6 would not rapidly follow.

The big unknown for industrialised countries is whether the death rate will be lower in better nourished populations where people are quicker to get medical help. We don't really know if taking vitamin C doses will reduce the chances of contracting H5N1. We know that some treatments exist for the existing strand of H5N1, but we don't really know if these would work on the mutated form, or how well.

Chickens and eggs are the two most likely sources of human infection. If both are cooked before you come near them there is no reason to worry (at least I'm pretty sure, and I would trust that myself). However, if like me you like to buy free range eggs by opening the box and checking the contents for cracks then I reckon that's going to be suicidal if local chickens are infected and somehow the eggs got into the stores. For environmental sceptics there is the joy of knowing that battery hens are safe in their crowded and inhumane pens, their eggs will be the last to be infected. Better still, for party-poopers, the only "organic chickens" left in the UK will probably be pumped full of vaccines and antibiotics to keep them from catching H5N1 from a passing protected wildfowl.

1 Comments:

Anonymous Anonymous said...

Good luck with what is an excellent idea. I gave up reading about health stories in the MSM some time ago, the combination of sensationalism and scientific illiteracy was simply too much to bear.

On the subject of self protection, I have read some journal papers which suggest supplementary zinc can reduce cytokine production during infection. As there is a theory it is the cytokine cascade which makes H5N1 so deadly, I thought it worthwhile spending £1.50 on some zinc tablets....

7:13 PM  

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