Free-Floating Hostility

Monday, January 30, 2006

Epi Shack: Avian Flu in Iraq

Raise your hand if you're tired of reading about Influenza. Now put your hand down and sit on it. I'm going to be working this semester on adapting UC Berkeley's SARS Preparedness plan into a plan for pandemic Influenza. The consequence of which, for you, is that I'm going to be thinking about flu all the time, and will share a small fraction of my thoughts with you.

Here is a link to a Times story about a confirmed case of Avian flu in a human in Iraq. There is one more case whose remains are being tested. Michael shared with me while food shopping that that is how he believes Avian flu will come to the States, via military personnel. That showed me that my job as Epi Educator was not yet done, and here's why:

Avian flu is one particular strain of Influenza. As I've mentioned before, the difference between one strain and another has to do with our immune system's ability to recognize the virus. Viruses are mutating all the time, but if two mutants have the same two types of protein on their surfaces than from the point of view of our immune system, they are the same. We indentify them the same way, and we handle them the same way. [Aside: Those two surface proteins are called, respectively, a hemaglutanin and a neuraminidase, and it is for them that strains are systematically named. Avian flu is technically called H5N1, because its type of hemoglutanin was the fifth to be discovered, while its neuraminidase was the first (the same type of neuraminidase on the strain that caused the 1918 pandemic).]

Avian flu isn't the only strain with the potential to cause a pandemic, but it's dangerous for several reasons. First, almost the entire human population is naive to it, meaning we don't have any immunity either individually or at the population level. Second, it is virulent, which is to say its symptoms are no picnic and it has a high mortality rate. Third, we know it has the ability to infect humans. The good news is that as yet there has never been a case of H5N1 being passed from one person to another person, which is why Michael's theory about Gulf War veterans spreading the flu isn't likely unless they have intense contact with birds. The hundreds of people (which, considering, is still a low number) who have contracted Avian Flu since it first appeared in humans about a decade ago all got it directly from animals. Thus prevention focuses on vaccinating birds, not people, despite the fact that a human vaccine is available (more good news). In order to start a pandemic, the H5N1 strain would have to mutate into a form that made it transmissable from person to person. So far, so not-the-worst, unless you happen to be one of the people who has died from this strain, like 15-year-old Shengeen Abdul Qadr.

The farther the strain spreads in birds, the more people can potentially be exposed. As I have mentioned, near-perfect international cooperation is required to contain an outbreak. The people at greatest risk are those who work or live with poultry, and those people are typically from poor countries. It happens to be in the interest of rich countries to help in this situation, but that's not always smooth sailing, especially in a war zone. Mass vaccination and culling of sick birds is in order in Iraq. But what about the rest of the world? So far we haven't succeded in containing Avian flu in the countries where it first originated. That means it may pop up somewhere else soon. Disease surveillance in this case means keeping good data on how many birds have the strain and where they are before any people in that area get infected, and that, too requires international cooperation.

So the agricultural poor in unstable countries are the most vulnerable right now. The rest of the world is only as vulnerable as they are.

1 Comment(s):

  •   Posted by Blogger BrooklynDodger at February 01, 2006 4:32 AM | Permanent Link to this Comment
  • Michael's fear about gulf war veterans spreading flu is not completely ahistorical. The 1918 flu is widely thought to have been spread by soldiers not yet domobed from WW I. Whatever population is at ground zero when or if the virus mutates for human to human transmission will be the vector. There's no special reason to fear the middle east, which is only now getting the virus in birds, and bird to people.

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