Swine Flu, Bird Flu, Wolf Flu

After their initial hysterics, the media seem to be quietening down over the Mexican/North American swine flu. Which maybe makes this a good time to consider how worried we should be.

A few years ago, SARS was in all the newspapers, as they panicked over the possibility of a global pandemic. Fortunately, although SARS is fairly deadly, it didn't seem to spread that well between humans. That outbreak worked as an important wakeup call to the authorities, but led to 774 confirmed deaths.

H5N1 bird flu has been in the news a lot over the past few years, as it spread around the world, but so far hasn't achieved significant person-to-person transmission.

H1N1 swine flu is very good at spreading between people, just like ordinary seasonal flu, but doesn't seem particularly aggressive when it is caught. So maybe it too is a wakeup call - a trial run to show that even after SARS there are still problems in global measures to contain virulent infections. Or maybe not.

One worry is that we don't yet know where it came from. La Gloria in Mexico is the favoured source, because they are the first people thought to have been badly hit by the infection. But nobody has checked. AP reports that a group is finally heading out there soon to check. The trouble is that this group reportedly has a vested interest in not seeking the full truth, as they are scientists from the biotech industry. This swine flu almost certainly evolved in the great pork factory farms favoured by US agribusiness, such as the giant pig farms surrounding La Gloria. Yet these scientists are only going to investigate the small household pig rearers in the village itself. Grist also reports, quoting the Wall Street Journal (but with a broken link), that it is likely that the main reason this H1N1 swine flu hasn't been found in the US's pig herds is that nobody has seriously looked. There is evidence that the novel flu strain is descended from a strain detected on an industrial pig farm in North Carolina in 1998. It doesn't inspire confidence that the US government appears to be more interested in protecting the commercial interests of its agribusinesses than in informing its consumers. The World Health Organisation is clear that it is dangerous to eat meat from flu-infected pigs, yet, as I understand it, that message is carefully not being passed on in the US. That said, I intend to continue eating pork - as long as it's free range, not factory farmed. 

The next worry is that flu viruses mutate rapidly. This current H1N1 strain seems relatively mild - roughly the same death rate as seasonal flu - but it has probably now become unstoppably established in both human and pig populations across the world. So next winter, when the Northern Hemisphere has its flu season, there is a good chance that an awful lot of us will get it, since we don't have much resistance to it. The 1918 flu pandemic, which is estimated to have killed 50-100 million people worldwide, is a major reason that scientists are worried. That pandemic began with a relatively mild outbreak, but was followed by a far more serious outbreak later in the year:-

The second wave of the 1918 pandemic was much deadlier than the first. During the first wave, which began in early March, the epidemic resembled typical flu epidemics. Those at the most risk were the sick and elderly, and younger, healthier people recovered easily. But in August, when the second wave began in France, Sierra Leone and the United States, the virus had mutated to a much more deadly form. 

Of course, there is no way of knowing whether a similar pandemic in 2009 would be more or less severe - the world was a very different place in 1918.

The final worry is that fearful people are going to be dosing themselves up with Tamiflu, and other antivirals, unnecessarily and ineffectively. This will establish resistance to these drugs in the general flu population, whence it is likely to spread to this swine flu. That stuffs up our front-line defence.

There have been a number of accusations that the authorities have been 'crying wolf' over the SARS, bird flu and swine flu episodes. From a scientific viewpoint, I believe that there is reason to worry, but not reason to panic. The current swine flu could mutate into a deadly pandemic, killing hundreds of millions over the next couple of years ... or it could just give a few of us a nasty dose of flu this winter. If it is the latter, that is something to be grateful for. Not least because it will have been a useful wakeup call to the world to get it right next time.

tags: sars  bird flu  swine flu  agribusiness  health  

links: technorati