When West Nile Virus came to the U.S.

West Nile virus is in 47 states as of Thursday afternoon. A mere 13 years ago, there had never been a case of the virus in the United States!

On this day in 1999, the first cases of an encephalitis outbreak were reported in New York City. Seven people died. At the same time, there was an unusual number of dead crows throughout the city.{} Birds were found dead at the Bronx Zoo as well.

The Centers for Disease Control and Prevention came to investigate. They discovered the birds had contracted West Nile. Mosquitos were passing it on to humans.

Prior to this time, West Nile virus was found only in Uganda and the Middle East.