The coming plague
All of which brings us back to Plague, the book. And when it comes to the story line, current events are certainly lending a hand. With the Northern Hemisphere flu season beginning, today’s pandemic of H1N1 swine flu has justifiably received a lot of coverage because the organism has spread around the globe in a matter of months. But no matter how impressive its human-to-human transmissibility, this strain simply cannot be the influenza A subspecies for our novel. It’s just not hold-on-to-your-hat virulent enough. Although this disease has killed a few people, even a few seemingly healthy people, for the most part it causes a relatively mild illness, perhaps even milder than the normal yearly flu, which also kills its share of people.
But that is not the case with another flu subspecies that originally appeared in 2006 and which is now slowly spreading from Southeast Asia, particularly in its normal reservoir of aquatic birds. This is the subspecies designated HPAI A(H5N1), standing for “highly pathogenic avian influenza A of subtype H5N1,” or avian flu for short. Luckily it has very low transmissibility — which it makes up for with knock-your-socks-off lethality. A truly scary percentage, about 60 percent, of those humans unlucky enough to have contracted the illness over the last three years have quickly died.
You don’t have to be a rocket scientist to see the problem. Is there a chance these two subspecies could hook up and help each other? The answer is definitely yes, and that is the worry because one of influenza A’s most disturbing characteristics is its ability to indulge in recombination of its 11 genes, which are arranged on its eight pieces of RNA. This produces what is called genetic shift — in other words, transfer of entire genes or gene combinations, and hence traits. It will become key to our plot.
The actual Plague story might start with a farmer in China’s Guangdong province — call him Wang Lung — who takes some produce to Hong Kong in early September 2009, where we know H1N1 is already having a field day (the city reported 514 new cases of the disease in one 24-hour period this September). Let’s have Wang indulge in some social activity after he is finished with his business. During this activity he inhales aerosolized H1N1 and contracts the illness. Back home, still mostly asymptomatic yet massively contagious, he hand-feeds his pet duck, which is already harboring H5N1. The duck adds the H1N1 to its gut, and then the bird is returned to its cage, which is suspended over Wang’s bevy of pigs. Such an arrangement is frequent in Asia not only to save space but also to wrest as much caloric value out of the duck’s feed as possible by making the bird’s poop mix with the pigs’ slop.
For the influenza A virus, things couldn’t be better; pigs are its favorite brewing cauldrons. The avian H5N1 and the human-adapted swine H1N1 can enter pig cells simultaneously by the availability of separate pig epithelial cell receptors. And of course, this is what happens in Plague, giving the two viruses the opportunity to recombine with each other. During the millions or billions of replications of the virus inside the pigs, either the H5N1 gives its virulence to H1N1, or H1N1 gives its transmissibility to H5N1. Either way, a genetically shifted subspecies emerges, and the entire world faces something similar to what Europe faced in 1346 when the first Y. pestis-infected rat jumped ship in Crimea.
The whole thing is worth a read. I have combating instincts here. On the one hand, people are always predicting doom and gloom and you can’t live life clutched in the grip of apocalyptic notions; on the other, sometimes these doom-and-gloomers are right. Cook’s conclusion is that we need to be able to concoct and distribute vaccine for this potential super flu in an incredibly efficient manner. We need to be able to make it and get it to people fast. Very fast. Is this such a terrible goal? Would it be so hard for a country like the United States to achieve? What about the third world?