Bird flu is still flu and one expects an uptick of cases during “flu season” which usually gets underway in earnest in December. So from that perspective it isn’t a surprise that December has seen human fatalities from bird flu in six countries: Pakistan, China, Vietnam, Egypt, Burma and, of course, Indonesia. Once the Pakistani cases are officially confirmed and added to the December tally for this flu season it will make it the worst December yet, but we shouldn’t read too much into this. Flu seasons are notoriously variable and the numbers bounce around a lot from year to year. But . . .
For the same reason we shouldn’t make that much out of this December likely being the worst yet, we shouldn’t make that much out of the fact that the last bird flu season case total was less than two years ago, which so far was the worst on record. We don’t know enough about the annual dynamics of the disease or the many factors that influence reporting, diagnostic accuracy and surveillance accuracy in the affected areas. It seems very probable we will be seeing many more cases reported next month and the months thereafter with a downturn not until late spring. That’s if the usual pattern repeats itself.
The problem, of course, is that the usual pattern might not repeat itself. I can think of no biologically plausible reason a divergence from the pattern would take the form of a sudden disappearance of the disease in humans. Of course it’s possible. We don’t really know what this disease is going to do. But if the pattern is going to be broken the most likely scenario would be a sudden increase in human disease as the virus’s random search happens on a new recipe to make copies of itself in us. From the virus’s point of view, we are 6 billion pieces of meat, laid out before it in a most appetizing manner.
The only thing I feel confident about is that the virus is out there, infecting host cells whenever possible. The means (cells of which hosts) to make new copies of itself are not a matter of relevance for an individual virus particle but the overall success in terms of the sheer number of infected cells paints the epidemiological picture. How much a part of that picture will be made up of infected humans we don’t know at this point. There seems to be no obvious reason why it should confine itself primarily to bird cells, however. In terms of sheer mobility and the variety of ways for a virus to get around, humans must be towards the top of the list of other species likely to be a good host. That’s looking at it evolutionarily. There may be severe biological constraints for the virus.
But I wouldn’t bet on it. In fact if I were laying a wager, I’d put the money into building a better defense: sound public health and social service infrastructures and the many other ways that make up resilient and robust human settlements (aka “communities”). Done the right way it isn’t even a wager or more euphemistically, not even an insurance policy.
It’s an investment that will pay off with certainty in many other ways, whether a pandemic comes or not.