MercoPress. South Atlantic News Agency

Dallas in state of disaster; aerial spraying of mosquitoes to combat West Nile virus

At least ten people have died of the disease in Dallas County

The city of Dallas in Texas is joining other municipalities declaring a state of disaster during what has become the worst outbreak of West Nile virus in the United States in 2012.

Dallas Mayor Mike Rawlings signed an emergency proclamation Wednesday morning that authorizes him to call for aerial spraying of mosquitoes over the course of the next week. Beyond the next seven days, City Council members would have to authorize an extension of the emergency proclamation.

“I believe this is the right decision,” Rawlings said during an emergency briefing of council members and the public at City Hall on Wednesday. “I cannot have any more deaths on my conscience because we did not take this action at this point.”

As of Wednesday morning, 10 people in Dallas County with West Nile virus have died. Five of them were Dallas residents. Throughout North Texas, more than 500 people have been sickened by the virus, including 111 in the city of Dallas.

According to state officials who spoke during the briefing, it is equal to the number of West Nile virus deaths in Dallas in the past nine years.

Rawlings said he would recommend the entire city be sprayed by airplanes, not just the areas north of Interstate 30 that are most affected by the virus. Spraying was set to begin Thursday night, weather permitting, Dallas County Judge Clay Jenkins said.

Specially-outfitted prop planes will dispense less than 2 tablespoons of Duet pesticide per acre from about 200 feet above ground.

West Nile virus was first identified in 1937 in Uganda in eastern Africa and it was first discovered in the United States in the summer of 1999 in New York. Since then, the virus has spread throughout the United States.

The West Nile virus is a type of virus known as a flavivirus. Researchers believe West Nile virus is spread when a mosquito bites an infected bird and then bites a person.

Mosquitoes carry the highest amounts of virus in the early fall, which is why the rate of the disease increases in late August to early September. The risk of disease decreases as the weather becomes colder and mosquitoes die off.

Although many people are bitten by mosquitoes that carry West Nile virus, most do not know they've been exposed. Few people develop severe disease or even notice any symptoms at all.

Thus far in 2012, 43 states in the US have reported West Nile virus infections in people, birds, or mosquitoes. A total of 693 cases of West Nile virus disease in people, including 26 deaths, have been reported to CDC (Centres for Disease Control and prevention). Of these, 406 (59%) were classified as neuro-invasive disease (such as meningitis or encephalitis) and 287 (41%) were classified as non-neuro-invasive disease.

The 693 cases reported thus far in 2012 is the highest number of West Nile virus disease cases reported to CDC through the second week in August since West Nile virus was first detected in the United States in 1999. Over 80% of the cases have been reported from six states (Texas, Mississippi, Louisiana, Oklahoma, South Dakota, and California) and almost half of all cases have been reported from Texas.