Monday, October 31, 2005

Safety Last

I am as pessismistic as they come, but somehow I failed to get on the "Bird Flu is coming! The Bird Flu is coming!" bandwagon.

It's come to Canada. According to CTV.ca, the H5 flu virus (aka Bird Flu, Avian Flu, Asian Bird Flu) has shown up in Quebec and Manitoba. Quebec immediately notified the H5 virus that if they don't speak French they can hit the bricks.

But, you exclaim, H5 is not the lethal H5N1 subtype! Aha, WHO officials reply, there there are 15 known subtypes to infect birds. To date, outbreaks of the pathogenic form have been caused by influenza A virus subtypes H5 and H7.
Oh.

WHO officials can fill in some answers here, too. Type A influenza viruses are genetically labile. They also lack mechanisms for the "proofreading" and repair of errors that occur during replication - as a result of these uncorrected errors, the viruses' genetic composition changes as they replicate. These constant permanent (usually small) changes are known as "antigenic drift."

The WHO officials add another caveat: influenza A viruses, and this includes subtypes from different species, can swap genetic materials and merge. This is known as "antigenic shift." Rather poetic naming conventions. What this means to us is that a new subtype is created, different from the parent parent viruses, and the host populations (that would be us) will not have immunity and there would be no vaccines for protection. And that's why antigenic shift is responsible for lethal pandemics.

On the other hand, the infected birds are still alive. Hmm.

The same CTV article reports that 121 people have been infected in Asia and caused more than 60 deaths in Thailand, Vietnam, Indonesia, and Cambodia. We've been getting warned (run for your lives!) about the imminence of a pandemic bird flu for months, but that fatality number is stubbornly hanging on at 60. What a terrible showing for a pandemic.

As I have noted in an earlier blog, we have more to fear from ATVs (particularly if you're in Kentucky).

When that big bad flu comes raging through, I think we will have very little warning. And our medical system will be unable to handle the crushing load of infected patients and those who think they may be infected. We should focus on staying healthy and keeping the immune systems in tip-top shape. Don't see much of that advice in those scare articles.

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