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Out of Africa, into the Bronx

作者:阙礞    发布时间:2019-03-07 04:14:10    

By Nell Boyce in Washington DC AN AFRICAN virus never before seen in the Western Hemisphere has cropped up in New York City. Surprised public health officials are now worried that migratory birds may spread the virus throughout the Americas. In late August, New York City health officials reported an outbreak of what looked like St Louis encephalitis, which can spread to people from birds via mosquitoes (New Scientist, 18 September, p 12). Now the story has taken an unexpected twist, with the discovery that the virus appears to be West Nile virus, which is normally found in Africa and Asia. It is also transmitted by mosquitoes. The first clues came from the Bronx Zoo, where pathologist Tracy McNamara had been investigating deaths among wild crows and captive birds. When the birds tested negative for common viruses she sent samples to the Centers for Disease Control and Prevention (CDC) in Atlanta, which diagnosed West Nile virus. Most lab tests can’t distinguish this from St Louis encephalitis. And when the samples from the human victims of the New York City outbreak were rechecked, the lab again diagnosed West Nile virus. How did the virus reach the Americas? “That’s probably a question we’ll never know the answer to,” says Tom Skinner,

 

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