January 30, 2012 2:30:00 PM
We can easily predict when hurricanes are going to hit by looking at satellite photos, and we can prepare, but we can't do anything to stop a storm. What if we could predict when a new virus outbreak might be coming and take action to quash it? It might mean that our justified fears about such illnesses as swine flu, AIDS, and Ebola could be reduced as we take action against them. To make such predictions, we'd have to know details of viral history, the roles viruses have played as humans evolved, the mechanisms they use to infect us and spread themselves, and human behavior that causes their spread, and we would have to have a sophisticated reporting system. Getting such details has been the goal of biologist Nathan Wolfe, who directs an organization called Global Viral Forecasting. "The main objective of my work," he says, "is to hunt down these events - the first moments at the birth of a new pandemic - and then work to understand and stop them before they reach a global stage." It's a prospect for disease control we have never had before, and in The Viral Storm: The Dawn of a New Pandemic Age (Times Books), Wolfe has given an exciting, even optimistic account about how these scary illnesses have affected us in the past and how new ones might be less scary in the future.
Most of the book is about viruses, although diseases caused by cellular parasites (like malaria) and prions (like Creutzfeldt-Jakob disease) are covered here, too. A virus is a complicated, tiny structure of encapsulated DNA (or the associated molecule RNA), which injects its genome into a cell and hijacks the cell's reproductive system to make more copies of itself. Many viruses don't do much of anything besides spread themselves, and we don't even know it; some cause minor problems like colds, and others are deadly. They multiply quickly, they have high mutation rates, and if two viruses infect the same animal, they can swap genetic information to make a mosaic virus with new properties. That sort of novelty is what makes for virus outbreaks.
We share lots of viruses with other animals. This makes special sense in our sharing them with chimps and bonobos, from whom the human lineage split around four million years ago. We were swapping viruses back and forth then, and we continue to do so. The bonobos aren't so important as a source of viruses, but chimps are because humans continue to deal with them; humans hunt chimps and chimps hunt humans (mostly infants). Ancestors of humans and chimps didn't cook meat, and killing and butchering in those days were good ways for viruses to swap around. When the branch that became humans went through a near extinction event we lost lots of the viruses that had grown along with us, and we also decreased their transmission into us by learning to cook our meat. That sounds like a good thing, but we also lost our bodily defenses against them. The viruses continued to grow and change within the population of our ape cousins, and this is why they are a threat now. Also, we domesticated animals, and this not only allowed us to swap viruses with them (while they continued to swap them with wild populations), it was one factor in our settling down in communities with populations of humans that could easily transmit viruses to each other. Much of the viral upsurge Wolfe studies is due to the harvesting of "bushmeat" in Africa, but our factory farms have their own role to play in the easy spread of disease. The pattern is simply that new diseases result from microbes jumping into us from animals.
Viruses are tiny structures that are amoral, though we think of them as enemies. Wolfe urges a larger view; viruses are part of the biological evolutionary landscape, and may be our friends in ways we don't even know. After all, he reminds us that if you were to tote up all your cells from you head to your toes, only ten percent would be "your" cells with your DNA, the rest being cells riding on and in you, and there are probably even more viruses along for the ride. We do know that viruses are our friends when mild ones help us to combat deadly ones, as deliberate cowpox infections reduced the toll from smallpox starting in the eighteenth century. We may be entering an age of virotherapy. The Seneca Valley virus seems to specifically afflict tumor cells. It probably came from pig or cow sources, showing that cross-species jumps are not always deleterious. Studies are underway to see about using this virus, and others, to combat cancer.
Our current world of viruses is an inviting one for them. We are crowded together in cities, and into many of them we inject "wet markets" where live animals of diverse species are gathered together in close proximity to themselves and to ourselves. We transplant organs and give blood, and we share needles. We continue to push into wild areas, and hunters continue to pursue bushmeat to keep their families going. We can transport a person with a deadly virus to a new continent in a few hours, giving the virus a new realm in which to prosper. We have labs that handle viruses all the time, and while there are safeguards, there are always errors. There is always the prospect that someone might deliberately tinker with a virus just for the sake of making it more deadly.
That's all bad news. The good news is that along with those changes we have made in the way we live, there are technological changes as well. We have new ways of diagnosing and identifying microbes, and of doing it quickly. Most important, in Wolfe's view, is that we have new tools for microbe forecasting. With Google, texting, and social media, it is possible to watch what people are talking and thinking about. Monitoring Google searches for influenza, for instance, provided an accurate picture of trends of the disease faster than the Centers for Disease Control could gather data and report it. Early data on a disease emergence could mean early steps to keep it from spreading. Wolfe works in this specific field, and you'd expect him to be optimistic about advances to come, but his book shows there are at least some reasons for the optimism.
Wolfe is a likeable writer, putting in many anecdotes like the time he himself got malaria. He is gracious in his acknowledgement of colleagues, which he does repeatedly. If he seems to rub shoulders with colleagues who are respectively "possibly the world's greatest expert," "a quiet but incredibly productive physician and scientist," "devoted," "world renowned," and more, let us hope he is not bragging or being effusive, but really is traveling in the best-informed circles as he does his work. Sometimes his pop-talk does him a disservice; he really ought not to refer with admiration to "an incredible study published in the top medical journal..." His book, however, will be smooth reading for anyone of any science background who wants to keep up with the newest ideas in how viral detection and containment may soon be done.