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We missed H1N1 when it was still just swine flu because we weren't looking for it. There's only scattered surveillance for pig diseases in the U.S. and Canada; in Mexico, there's even less. According to the American Association of Swine Veterinarians (AASV), there were few reports of unusual sickness in the months leading up to the H1N1 outbreaks--not that vets would have necessarily noticed, since flu in swine is common and rarely serious. "We haven't seen anything that would have tipped us off," says Dr. Tom Burkgren, AASV's executive director.
Why should we spend scarce medical resources swabbing the inside of pigs' nostrils, looking for viruses? Because new pathogens--including H5N1 bird flu, SARS, even HIV--incubated in animal populations before eventually crossing over to human beings. In the ecology of influenza, pigs are particularly key. They can be infected with avian, swine and human flu viruses, making them virological blenders. While it's still not clear exactly where the H1N1 virus originated or when it first infected humans, if we had half as clear a picture of the flu viruses circulating in pigs and other animals as we do of human flu viruses, we might have seen H1N1 coming. (When it comes to sniffing out new pathogens, says one epidemiologist, "we're like a drunk looking for his keys.") Faster genetic sequencing and the Internet give us the technological means to create an early-warning system. But we need to spend more on animal health and get doctors talking to their veterinarian counterparts. "For too long, the animal side of public health has been neglected," says Dr. William Karesh, vice president of the Wildlife Conservation Society's global-health program.
H1N1 has already jumped out of animals and established itself in people, so it's too late to contain it, but there are new viruses brewing all the time in the animal world. That includes H5N1 bird flu, which is simmering in Asia and Africa and could still mutate and trigger a pandemic. Globalization has made us especially vulnerable to new diseases--the right pathogen in the right place could spread around the world in 24 hours--but it also gives us the tools to form an effective defense. "The fact that the world is one continuous village now means viruses that would have gone extinct before have the potential to take hold much more rapidly," says Nathan Wolfe, director of the Global Viral Forecasting Initiative (GVFI). "But it also means we can create a planetary immune system."
Wolfe's brainchild is a model of what that immune system might look like. With funding from the likes of Google, GVFI has teams on the ground in Africa and Asia surveilling wild animals and the people who live in proximity to them for new pathogens. These "sentinel populations" will provide early warning when a new virus emerges; if a dangerous disease is discovered as soon as it crosses from animals to people, quick action can contain it--but only if we're looking. "Tens of millions for surveillance could save us the hundreds of billions it would cost to deal with a pandemic," says Peter Daszak, president of the Wildlife Trust. "An ounce of prevention really is worth a pound of cure."
When a Pandemic Comes