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Wednesday, August 15, 2012 - Page updated at 05:00 p.m.

Texas West Nile outbreak kills 16

By Molly Hennessy-Fiske
Los Angeles Times

HOUSTON — Dallas County officials have declared a state of emergency after the West Nile virus infected at least 190 people, killing at least 10, as the nation's worst outbreak hit Texas.

An unusually warm winter and rainy spring in the Dallas-Fort Worth area and elsewhere in Texas provided ideal conditions for breeding mosquitoes, key West Nile carriers, officials said.

The emergency declaration in Dallas clears the way for state money and resources to fight the outbreak. In coming days the county will deploy small planes for aerial-insecticide spraying over hard-hit neighborhoods, in addition to ground spraying already being done.

Texans have contracted the highest number of West Nile infections and have suffered more West Nile deaths than any state, according to the Centers for Disease Control and Prevention (CDC).

Statewide, 16 deaths — including the 10 in Dallas County — have been reported this year, compared with two in 2011 and seven the year before, according to the Texas Department of State Health Services.

The virus is spreading at a faster pace this year across the state. As of Monday, 381 West Nile infections had been reported in more than 24 Texas counties, compared with 27 infections reported statewide last year in a handful of counties.

In Houston, about 95 percent of tested mosquitoes carried the virus.

According to the CDC, neighboring states also are reporting higher infection rates this year: Louisiana and Mississippi each reported 39 West Nile infections and one death. Oklahoma has had 22 infections, but no deaths.

Tarrant County, home to Fort Worth, has reported 171 West Nile infections and two deaths — compared with two cases last year and no deaths — in what county medical director Dr. Sandra Parker described as "an atypical year."

"Texas is on track to have the worst year ever for West Nile virus," said Christine Mann, a spokeswoman for the Texas Department of State Health Services.

The Lone Star state's worst West Nile year was 2003, one of the first years the virus was reported to have spread west from Northeastern states. That year, Texas saw 439 West Nile cases and 40 deaths, according to state figures.

Marc Fischer, a CDC medical epidemiologist based in Fort Collins, Colo., said tracing the roots of West Nile outbreaks is tough.

"It's a pretty complicated story," he said, a combination of the right warm, wet weather, mosquitoes, birds (another West Nile carrier) and human behavior.

"Each year we have seasonal outbreaks, and they tend to happen in different places because of those factors," Fischer said.

"People really should be aware of what they can do to prevent infections, primarily protect themselves from mosquito bites," he added.

Those infected with West Nile virus may develop West Nile fever, with symptoms such as headache, fatigue, body aches, a skin rash on the trunk of the body and swollen lymph glands. The illness can last a few days to several weeks, according to the CDC.

They may also develop the more serious West Nile encephalitis, meningitis or poliomyelitis, with some of the same symptoms but also neck stiffness, disorientation, tremors, convulsions and muscle weakness that can lead to neurological damage, coma, paralysis and death. The elderly and those with weakened immune systems are most at risk of becoming seriously ill once infected.

Kristy Murray, an infectious-diseases specialist at Baylor College of Medicine's National School of Tropical Medicine, has been studying Texans infected with West Nile since 2003, and found 90 percent said they had done nothing to protect themselves from mosquitoes carrying the virus.

"People just become complacent," she said.

Nationwide, 241 West Nile infections were reported to the CDC as of the end of July, the most cases reported during that period since 2004.

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