Until yesterday, we could only speculate about the origins of the current H1N1 virus killing human beings – but now we know more. The Centre for Computational Biology at Columbia University has studied the virus and now believes that it is not a new emergence of a triple human-swine-bird flu virus. It is a slight variant on a virus we have seen before. We can see its family tree – and its daddy was a virus that evolved in the artificial breeding ground of a vast factory farm in North Carolina.
Did this strain evolve, too, in the same circumstances? Already, the evidence is suggestive, although far from conclusive. We know that the city where this swine flu first emerged – Perote, Mexico – contains a massive industrial pig farm, and houses 950,000 pigs. Dr Silbergeld adds: "Factory farms are not biosecure at all. People are going in and out all the time. If you stand a few miles down-wind from a factory farm, you can pick up the pathogens easily. And manure from these farms isn't always disposed of."
It's no coincidence that we have seen a sudden surge of new viruses in the past decade at precisely the moment when factory farming has intensified so dramatically. For example, between 1994 and 2001, the number of American pigs that live and die in vast industrial farms in the US spiked from 10 per cent to 72 per cent. Swine flu had been stable since 1918 – and then suddenly, in this period, went super-charged.
How much harm will we do to ourselves in the name of cheap meat? We know that bird flu developed in the world's vast poultry farms. And we know that pumping animal feed full of antibiotics in factory farms has given us a new strain of MRSA. It's a simple, horrible process. The only way to keep animals alive in such conditions is to pump their feed full of antibiotics. But this has triggered an arms race with bacteria, which start evolving to beat the antibiotics – and emerge as in the end as pumped-up, super-charged bacteria invulnerable to our medical weapons. This system gave birth to a new kind of MRSA that now makes up 20 per cent of all human infections with the virus. Sir Liam Donaldson, the British government's Chief Medical Officer, warns: "Every inappropriate use in animals or agriculture [of antibiotics] is potentially a death warrant for a future patient."
Of course, agribusinesses is desperate to deny all this is happening: their bottom line depends on keeping this model on its shaky trotters. But once you factor in the cost of all these diseases and pandemics, cheap meat suddenly looks like an illusion.
We always knew that factory farms were a scar on humanity's conscience – but now we fear they are a scar on our health. If we carry on like this, bird flu and swine flu will be just the beginning of a century of viral outbreaks. As we witness a global pandemic washing across the world, we need to shut down these virus factories – before they shut down even more human lives.