Tarrant County preparing ahead for West Nile season

Posted Tuesday, Mar. 26, 2013  comments  Print Reprints

Avoiding West Nile

The easiest way to avoid infection is to prevent mosquito bites. Here are four key steps to follow:

When you are outdoors, use insect repellents containing an EPA-registered product.

Mosquitoes are most active at dusk and dawn, so be sure to use repellent and wear long sleeves and pants if you are outdoors during those times.

Make sure you have good screens on windows and doors to keep mosquitoes out of your home.

Eliminate mosquito breeding sites by emptying standing water from flower pots, buckets and barrels or anywhere it accumulates. Change the water in pet dishes and replace the water in bird baths weekly.

Source: Centers for Disease Control and Prevention

Symptoms of West Nile virus

About one in 150 people infected with the virus will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

Up to 20 percent of people who become infected will display symptoms which can include fever, headaches, body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days but even healthy people can be sick for a few weeks.

About 80 percent of people who are infected will not show any symptoms, but there is no way to know in advance if you will develop an illness or not.

Source: Centers for Disease Control and Prevention

2012 West Nile outbreak

Tarrant County: 280 cases, 11 deaths

Dallas County: 405 cases, 18 deaths

Denton County: 181 cases, two deaths

Collin County: 63 cases, four deaths

Johnson County: 13 cases

Parker County: 6 cases

Travis County: 146 cases, four deaths

Harris County: 71 cases, four deaths

Texas: 1834 cases, 86 deaths

U.S.: 5,387 cases, 243 deaths

Sources: Centers for Disease Control and Prevention, Texas Department of State Health Services, Tarrant County Public Health Department

West Nile in Tarrant County

2011: Two cases, no deaths

2010: No cases reported

2009: 32 cases, three deaths

2008: 16 cases, no deaths

2007: 25 cases, no deaths

2006: 53 cases, seven deaths

2005: Five cases, no deaths

2004: No deaths attributed to virus

2003: 22 cases, no deaths

2003: No deaths attributed to virus

2002: One death attributed to virus

Source: Tarrant County Public Health Department

2012 West Nile

virus outbreak

in Tarrant County

280 cases, 11 deaths

Changes in 2013

150 fixed traps

50 mobile traps

Mosquito surveillance program will start in late April or May instead of June.

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FORT WORTH -- After being overwhelmed last year by a deadly outbreak of West Nile virus, officials in Tarrant County and North Texas will "prepare for the worst" this season and take action earlier and more aggressively.

Expanded trapping and testing of mosquitoes, quick treatment of standing water and better coordination across counties are all planned.

Instead of waiting for human cases to sound the first alarm of the mosquito-borne illness, Tarrant County will closely monitor the little pests, officials say.

That switch will speed the response by eliminating the two- to three-week lag between when a person is infected and the case is first reported to the health departments.

"This year, we are going to be dealing with mosquitoes, so that will be real-time information," said Health Director Lou Brewer of the Tarrant County Public Health Department, which recorded 280 West Nile virus cases and 11 deaths in 2012.

Texas was the epicenter of the largest West Nile outbreak in U.S. history last year, with 1,834 cases and 86 deaths, according to the Texas Department of State Health Services.

Nationally, there were a record 5,387 cases and 243 deaths, according to the Centers for Disease Control and Prevention.

The outbreak was most virulent in North Texas, with another 405 cases and 18 deaths in Dallas County, 181 cases and two deaths in Denton County and 63 cases and four deaths in Collin County.

"There was no place else in the nation that had an outbreak like ours," said Bing Burton, director of the Denton County Health Department, which had the highest per capita rate of cases.

The state health department has also re-examined "how to step up our game" if another outbreak emerges, spokeswoman Carrie Williams said.

"We made changes on the fly last year, and there is a benefit of experience. We had our worst year, and there is value in being real-time tested for a disaster," she said.

The agency is also doubling its capacity for mosquito testing and will be using a faster, streamlined method to detect the virus in mosquitoes, Williams said. She said the department is moving to a more efficient, coordinated computer system for managing human case information.

Tarrant County will spend more than $500,000 over the next two years to help fight the virus, said County Administrator G.K. Manius.

"All counties got off to late start last year because we had never seen anything like this before," he said. "There's lessons learned, and I think we are addressing them.

"First, we're starting earlier, and second, we're not targeting illnesses, we're targeting mosquitoes.

"Third, we're coordinating our efforts regionally with Dallas, Collin and Denton counties. We want to get on top of this thing and get on it early and try to knock down the amount of illnesses and deaths."

Tracking trouble

The biggest change in Tarrant will be the addition of 150 fixed-location mosquito traps, said Dr. Anita Kurian, associate director for the health department. The mosquito surveillance program will start in late April or May instead of June, she said.

The traps will be placed where there have been a high number of human cases or lots of reports of mosquito activity, Kurian said.

Another 50 mobile traps will be shifted around in response to field operations and citizen complaints. "Mosquitoes don't stay static; they move around," she said.

In 2012, county health officials relied on 30 to 50 mobile trapping units.

"The biggest takeaway from last year was that it was imperative to have a formal mosquito surveillance system in order to be ahead of the curve of the outbreak," Kurian said.

In addition, the county will implement year-round surveillance at 20 of the fixed-trap locations.

Dallas County is expanding its surveillance program as well, and Denton County will begin testing for the first time this year, Burton said.

"Preparation and prevention is by far the most important thing," he said.

"We have a unified front this year. We are comparing notes and talking about our education messages. We're talking about our testing plans. We are working to be better prepared," Burton said.

More help might be on the way in the Texas Legislature through Senate Bill 186, introduced by Sen. John Carona, R-Dallas, which would allow local governments to treat stagnant water at uninhabited residential properties.

In Tarrant County, the prevention battle will take to the streets and back roads, Manius said, with county and municipal road crews and code compliance officers aggressively treating standing pools of water with larvicide, Manius said.

"It doesn't need to be at a point where we know West Nile is out there; if we have a standing puddle of water, we are going to treat it,'' he said. The county is also adding two spray trucks and two $7,500 devices to test mosquito pools for the virus.

"We're also hiring two new personnel. We'll now have a dedicated unit of vector control," said Manius, adding that Tarrant County will spend $263,000 this year and $250,000 in 2014 to combat the virus.

Ready to spray

Aerial spraying could be another weapon deployed by Tarrant County if another outbreak emerges, Brewer said.

Dallas and Denton counties used aerial spraying in 2012. Tarrant considered it, but decided to stick with targeted ground spraying, she said.

"We always realized that people would be saying, 'Why is Dallas doing one thing and Tarrant doing another?''' he said.

"We actually considered aerial spraying at a point last season. We were doing targeted ground spraying, but the consensus in this county was that we would rather not if we don't have to," Brewer said, adding that the CDC agreed with the ground strategy because it was yielding good results.

With the benefit of experience, the state health department will be able to more quickly ramp up for questions about aerial spraying, Williams said.

"A lot of factors have to come into play before that decision is made ... It's ultimately a local decision," she said.

The Tarrant health department has developed a phased guideline for response based on mosquito surveillance. Aerial spraying would be considered in phase three where there is a high probability for an outbreak.

Aerial spraying would move from "considered" to "recommended" in phase four, meaning an outbreak is in progress, Brewer said.

Burton said that a recent CDC report found that aerial spraying had been effective

The cause of the 2012 West Nile outbreak has not been identified, but Burton said he's encouraged that, historically, such events don't occur in consecutive years.

A nagging concern is that this year's weather is following last year's pattern, Brewer said.

"There are lots of theories about last year. We had a very warm winter and it was wet and then it was dry, but nobody knows for sure," she said.

"We do know that this winter has been very similar to last winter, so I think it would behoove all of us to prepare for the worst and hope for the best."

Steve Campbell, 817-390-7981

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