Friday, March 03, 2006

Wherein I disagree with Laurie Garrett

Laurie Garrett has paid her dues. She is properly highly regarded as a prophet of today's current concern for emerging or re-emerging epidemic diseases and when she speaks she rightly commands respect. So while according her the respect she's due, I would also like to politely disagree with her latest pronouncements, issued from her seat at the Council for Foreign Relations and published in the International Herald Tribune. It's about bird flu.

Her thesis is that we are on the verge of losing the battle against the virus for a lack of effective strategy. Taxpayer's money has been wasted ("spent inappropriately") and we cannot expect to win by frantically stockpiling Tamiflu. No argument so far. But then she posits something I don't think is true: that we know enough about this virus, the way it spreads and the way to contain it that if we had a coherent strategy we could stop it.
First, let's stop pretending nature is mysterious, and concentrate on what we know. H5N1, though deadlier and potentially far more devastating than any other influenza seen in nearly a century, has followed a fairly clear set of biological, predictable principles since it first surfaced in Hong Kong in 1997.


We should not be astonished to learn of H5N1 outbreaks in birds or people in the next few weeks in nations located along the East Africa flyway, which overlaps with the already contaminated Black Sea/Mediterranean one: Cameroon, Chad, Ethiopia, Sudan, Uganda, Rwanda, Burundi, Tanzania, Gabon, Angola, Namibia, South Africa, Madagascar, Mozambique, Malawi and the rest of the eastern African countries.

Because H5N1 has been confirmed in Nigeria, Egypt, Germany and Spain, which straddle the intersections of the Black Sea/Mediterranean and the East Atlantic flyways, over the next six weeks we should not be surprised to hear of H5N1 bird and even human cases in several northern European nations, including Britain and Iceland. (International Herald Tribune)
Thus Garrett takes it as a given the virus is spread via wild migratory birds. While there is some dispute about this (and the issues are not so clear cut as she would have us believe), I think it is highly plausible this is one way the virus can and probably does move in some instances. But most spread is local, not long distance, and that local spread is among poultry. Some poultry movements are also long distance. And it may also be true that poultry are giving the disease to migratory birds, not the other way around.

Garrett takes as the seminal moment an apparent change in the virus that allowed it to spread long distances, a change signaled by a large wild bird die-off in remote western China at Qinghai Lake. But the virus in southeast asia that has spread to Indonesia seems distinct from that one and may well not have been from wild bird spread. Although she claims we now know enough to act, she admits we don't know what happened at Qinghai. This is one of the many real surprises this virus has given us, not the hallmark of something that is entirely predictable. The problem has not been so much that we thing the virus is mysterious but that we thought it would follow the pattern of other avian viruses. It hasn't. In a real sense we know less about this virus than we did ten years ago.

But my main objection isn't really to her total reliance on migratory birds as the vector for geographic spread. That may turn out to be true as part of a small-world or scale-free network topology that allows sudden jumps and short linkage distances ("six degrees of separation"). There is a great deal about this kind of spread we have yet to learn.

But it is her main point I consider to be, well, pointless:
Instead of simply sitting back and watching nature take its course, the global community should be proactive. Being ahead of the virus is akin to being ahead of the migrating birds. Instead of waiting for dead birds, and even dying people, to turn up in new areas, political leaders should heed the warnings from science and act accordingly - as, apparently, Sweden and the Netherlands are doing. The Swedes and Dutch looked at their maps, plotted the movements of infected birds, and last week ordered farmers to bring their flocks indoors, out of harm's way. In poorer regions of the world, where indoor facilities for animals may be unaffordable, simple nets and fences can radically decrease contact between wild and domestic birds, and mass public education campaigns warning people to avoid contact with sick birds or carcasses may decrease the likelihood of avian-to-human transmission of H5N1.

One of the best untapped resources in this epic battle against influenza is bird-watchers, who are among the most fanatic hobbyists in the world. The major bird-watching organizations and safari clubs ought to work with the World Health Organization and OIE, the World Organization for Animal Health, to set up Web-based notification sites, where birders could report sightings of groups of dead birds, and the movements of key migrating species. (International Herald Tribune)
That's it. Getting out ahead of the virus means bending all our efforts to keeping wild birds from poultry and if they arrive via a long distance flyway detecting them early. But there is no evidence that any of these measures will work. Even if they were effective in some places, they are bound to fail in others. And then what?

Good surveillance is important but it is no longer going to save us. It is now much more important to plan for what to do if there is a pandemic. Use our resources to mobilize the community to provide better social service networks and public health infrastructure, to locate the critical points (ventilators, essential drugs in pharmacies, emergency supply chains for staples, continuity of operations plans for utilities and businesses, etc.) and to prepare people calmly and rationally for what might come.

No one knows if the biological pieces will be in place to allow the emergence of a pandemic strain or when it will happen. But standing guard for wild birds will only encourage irrational and harmful measures, like indiscriminate killing of wildlife and fruitless attempts to destroy their natural habitats. Once that damage is done we'd still have our pandemic. If it is going to happen it cannot be stopped at this point.

Those are the biological facts and they shouldn't be a surprise.