A Planet of Viruses - Carl Zimmer [8]
Once scientists sequenced the genes of the new Human/Swine 2009 H1N1, they realized that it was the product of two different flu viruses: the triple reassortant and a Eurasian bird-to-pig strain. By comparing the new mutations that had arisen from the viruses infecting different patients, researchers have estimated that this new virus first evolved in the fall of 2008. It circulated quietly before coming to light in the spring of 2009.
Because Human/Swine 2009 H1N1 was such a new virus, public health authorities swung quickly into action. The Mexican government essentially shut down the entire country for a time, hoping to prevent the virus from finding new hosts. As Human/Swine 2009 H1N1 turned up in other countries, their governments took actions of their own. By May 2009, it was clear that while the new virus was unusually swift, it was not significantly more dangerous than typical seasonal flu.
As I write in 2010, no one can say if the new strain will fade away, outcompeted by other flu strains, or if it will mutate into a more dangerous form, or experience even more reassortment and pick up new genes. But we are not helpless as we wait to see what evolution has in store for us. We can do things to slow the spread of the flu, such as washing our hands. And scientists are learning how to make more effective vaccines by tracking the evolution of the flu virus so they can do a better job of predicting which strains will be most dangerous in flu seasons to come. We may not have the upper hand over the flu yet, but at least we no longer have to look to the stars to defend ourselves.
Rabbits with Horns
Human Papillomavirus
The stories about rabbits with horns circulated for centuries. Eventually they crystallized into the myth of the jackalope. If you go to Wyoming and twirl a rack of postcards, chances are you’ll find a picture of a jackalope bounding across the prairie. It looks like a rabbit sprouting a pair of antlers. You may even see jackalopes in the flesh—or at least the head of one mounted on a diner wall.
On one level, it’s all bunk. Most jackalopes are nothing but taxidermic trickery—rabbits with pieces of antelope antler glued to their heads. But like many myths, the tale of the jackalope has a grain of truth buried at its core. Some real rabbits do indeed sprout horn-shaped growths from their heads.
In the early 1930s, Richard Shope, a scientist at Rockefeller University, heard about horned rabbits while on a hunting trip. He had a friend catch one and send him some of the tissue so that he could figure out what it was made of. Shope’s colleague, Francis Rous, had done experiments with chickens that suggested viruses could cause tumors. Many scientists at the time were skeptical, but Shope wondered if rabbit “horns” were also tumors, somehow triggered by an unknown virus. To test his hypothesis, Shope ground up the horns, mixed them in a solution, and then filtered the liquid through porcelain. The fine pores of the porcelain would only let viruses through. Shope then rubbed the filtered solution onto the heads of healthy rabbits. They grew horns as well.
Shope’s experiment did more than show that the horns contained viruses. He also demonstrated that the viruses created the horns, crafting them out of infected cells. After this discovery, Shope passed on his rabbit tissue collection to Rous, who continued to work on it for decades. Rous injected virus-loaded liquid deep inside rabbits and found that