Left Behinds

The anti-andrewsullivan.com. Or, the Robin Hood (Maid Marian?) of bright pink Blogger blogs.

Wednesday, May 10, 2006

So Should I Stock Up on Tuna or What?

Arguments for and against avian flu panic both seem reasonable to me, and I am just not qualified to discern which is the most compelling science. Plus there's always the risk of panics being used to distract from other problems.
A month or two ago, Antid Oto argued that the avian flu threat has been grossly underestimated. "Flu pandemics happen roughly every 30–40 years," he writes (though how reliable is this stat? might the incidence change because of changing public health conditions?), and this could be a particularly bad pandemic because, like the Spanish flu pandemic, this flu "mainly seems to kill people with healthy immune systems," because it hyperactivates "cytokine storms," whatever those are.

In the other corner, Slate argues that it's very unlikely that the virus will mutate to allow human-to-human transmission (because it "has a different molecular structure than the 1918 bug," especially in the structure of its hemagglutinins, whatever those are). What's more, flu strains have become less lethal over the past century as public health has improved. "Whether a person exposed to a pathogen contracts the disease is tremendously influenced by the state of the person's health," says Slate. This, of course, ignores AO's point that the avian flu mainly affects healthy people.

A ridiculous TV bird flu disaster movie aired tonight (though, as Republic of T points out, it ignores the scariest character who would emerge in a flu pandemic, some incompetent Bush hack named Stuart Simonson).

Panic is never a pleasant smell. Take this example from Wonkette. Some guy wrote her (and I'm skipping the first five points of his conspiracy theory) about the real reason Goss resigned from leading the CIA;

5) Face it — when the [avian flu] pandemic hits, interstate transport shuts down and you guys in Washington are feeding on each other like cannibals —literally, not just politically — Goss will be setting on his front porch eating goat cheese, sipping homemade Cabernet and enjoying the rural sunset. Laughing his ass off as he tells his wife about how Donald Rumsfeld talked Dick Cheney into buying an estate on the Chesapeake Bay —an area which receives the largest dump of migratory goose droppings in the country.

How could we not have seen? Of course! It makes perfect sense that Porter Goss unexpectedly resigned because HE KNOWS ABOUT THE COMING BIRD FLU HOLOCAUST. Thanks for the email, but shouldn’t you be on your way to Rochester, Representative Kennedy?

Anyhow, notwithstanding the truly paranoid, which is it? Stock up on bottled water and tuna fish, or focus on a genuine risk, like rotavirus and global warming?

>Tags: news and politics, bird flu, avian flu, risk


  • At 2:26 AM, Blogger Antid Oto said…

    I wouldn't panic, but I would take it seriously. First, a cytokine storm works like this (from the Wikipedia description of the H1N1 Spanish Flu of 1918:

    The virus infected lung cells, leading to overstimulation of the immune system via release of cytokine bursts into the lung tissue. This lead to extensive leukocyte migration towards the lungs, causing destruction of lung tissue and secretion of liquid into the lung, and making it difficult for the patient to breathe. Due to the nature of the infection, people with a normal healthy immune system were more susceptible to the disease, such as young adults compared to young children and the elderly.

    Why is this relevant? Because Marc Siegel is being a bit optimistic when he says this:

    That disease incubated in the World War I trenches before it spread across the world, infecting soldiers who were exhausted, packed together in trenches, and lacked access to hygiene. These conditions were an essential breeding ground for the virus. Today, there is no way a huge number of people would be packed together in WWI-like conditions. Also, technology allows doctors to diagnose and isolate flu patients far more effectively.

    Keep in mind that this virus, if it arises in humans, is very likely to come from Asia, where population densities can be quite high. And doctors can only diagnose more effectively once they have a diagnostic profile, something that is so far lacking. The projections I have seen indicate that in order to contain an outbreak, a country has to move from diagnosis to laboratory confirmation to countermeasures within about three weeks of the initial human-to-human transmission event, or else the virus will have already grown exponentially beyond control. That requires disease surveillance beyond what most countries in Southeast and East Asia currently have in place, from what I understand.

    The "H5" portion of "H5N1" refers to the hemagglutinin protein in the protective coat of the virus. It is indeed different from the "H1" protein in H1N1, the Spanish Flu virus, and it is the key protein governing whether the virus can infect humans. But scientists differ on how likely it is for H5 to mutate in a way that would allow human-to-human transmission. Marc Siegel obviously believes it is unlikely. Here's what Wikipedia says:

    Influenza viruses have a relatively high mutation rate that is characteristic of RNA viruses. The H5N1 virus has mutated into a variety of types with differing pathogenic profiles; some pathogenic to one species but not others, some pathogenic to multiple species. [18] The ability of various influenza strains to show species-selectivity is largely due to variation in the hemagglutinin genes. Genetic mutations in the hemagglutinin gene that cause single amino acid substitutions can significantly alter the ability of viral hemagglutinin proteins to bind to receptors on the surface of host cells. Such mutations in avian H5N1 viruses can change virus strains from being inefficient at infecting human cells to being as efficient in causing human infections as more common human influenza virus types. [19] This doesn't mean one amino acid substitution can cause a pandemic but it does mean one amino acid substitution can cause an avian flu virus that is not pathogenic in humans to become pathogenic in humans.

    In July 2004, researchers led by H. Deng of the Harbin Veterinary Research Institute, Harbin, China and Professor Robert Webster of the St Jude Children's Research Hospital, Memphis, Tennessee, reported results of experiments in which mice had been exposed to 21 isolates of confirmed H5N1 strains obtained from ducks in China between 1999 and 2002. They found "a clear temporal pattern of progressively increasing pathogenicity". [20] Results reported by Dr. Webster in July 2005 reveal further progression toward pathogenicity in mice and longer virus shedding by ducks.

    Keep in mind that the greater the global reservoir of virus, the greater the likelihood that a human-to-human-transmissible virus could eventually arise. It is certainly possible that the pandemic will run its course among birds before that happens, but we have a way to go on that yet. The most likely way for this mutation to occur is not directly among humans but in some other domestic mammal--very likely pigs. For a good explanation see here.

    I'll grant that a pandemic on a scale comparable to the 1918 flu is less likely to happen than not. But in assessing risk I wouldn't only look at how likely a thing is but construct a kind of rough equation combining the probability with the badness, something like this:

    X% likelihood * Y # of people dead = risk

    Obviously you can't do this with any kind of precision, but the number of epidemiologists who have voiced serious concerns makes me believe that X is a big enough fraction to pay attention to, and the 1918 flu indicates that the worst-case scenario for Y is pretty bad. I don't think we should get hysterical, but I do think this is a far more serious and real threat than anthrax or smallpox, with which Siegel dismissively links it.

  • At 2:50 AM, Blogger Solomon Grundy said…

    I knew you were the man to ask.

    You've convinced me that the threat is real (especially with that bit about how the mutation of one single amino acid could dramatically alter what species the virus infects). The Slate guy seems to not be aware of the cytokine storm thing, because much of his argument rests on improved overall public health compared to 1918, and you're saying that if anything that makes everything worse.

  • At 1:43 PM, Blogger Antid Oto said…

    I don't think it makes it worse--there's a difference between public health (by which I assume he means public-health systems) and how healthy individuals are. Improved public-health systems should improve our ability to diagnose and isolate an outbreak. But public-health systems in all places where the disease could arise (Nigeria, for example) are not necessarily in the best shape, and we don't yet have a consistent diagnosis for the disease in humans.

    I'd be very surprised if Siegel doesn't know about the cytokine storm effect--he is after all a professor at NYU Med School, a bit more of an expert than lil' ol' me.

  • At 11:46 PM, Blogger Solomon Grundy said…

    I think his point was that both public health systems and general health and nutrition are much improved since 100 years ago, including in developing countries.

    But if cytokine storms particularly affect healthy people, those improvements would seem to augur more doom and gloom, not less.


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