Nearly half of the confirmed cases of West Nile virus in the county have been diagnosed in Texas, and more than half of the virus’s fatalities have happened there.

Dallas, where there has been a concentration of cases, has now declared an emergency to pave the way for aerial spraying for mosquitos, the insect known to transmit the virus. It’s hoped that by spraying, the city and county will be able to depress the mosquito population and protect residents from further infection.

Aerial spraying to combat the virus is already used in New York City and in Sacramento.

West Nile was first discovered in the U.S. in 1999. For Texas, they set a record with the number of cases in 2003. So far, 2012 has tripled that previous mark.

From Fox News:

The mayor of Dallas declared a state of emergency in the ninth largest U.S. city Wednesday to combat the spread of West Nile virus infections, which have been more prevalent than usual in Texas and other states this year.

There have been more cases of West Nile virus reported so far this year than any year since the disease was first detected in the United States in 1999, the Centers for Disease Control said on its website.

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