West Nile in Abilene; case numbers statewide not unusual

Sept. 25--ABILENE, Texas -- A pool of mosquitoes trapped in south Abilene has tested positive for the West Nile virus, but officials say a bit of caution can help stave off potential problems.

Meanwhile, the number of cases of the viral illness statewide this year -- 128 -- is tracking far behind last year's total of 379 cases and is closer to the 183 reported in 2013.

Those totals are dwarfed by a massive 1,868 cases statewide in 2012, the greatest number in a 10-year period, using figures provided by the Texas Department of State Health Services.

Chris Van Deusen, a press officer with the Texas Department of State Health Services, said there are no unusual trends in this year's numbers.

"This is the time of year where we start to see fewer positive mosquito pools, though it's certainly not too late to continue to see cases," he said.

West Nile virus is spread by the bite of an infected mosquito and can infect people, horses, many types of birds and some other animals, according to the DSHS.

"As long as mosquitoes are active, we can continue to see West Nile being transmitted, so people should still take the usual precautions to keep themselves from being bitten," Van Deusen said, though with cooler temperatures mosquitoes will be less active. That hasn't been the case this month in Abilene, where a high temperature of at least 90 degrees was reported on 19 of the first 23 days.

Cases tend to happen in the late summer or early fall. According to the U.S. Centers for Disease Control and Prevention, weather is an important modifier of West Nile virus transmission.

"This probably came from the last little rain, the showers we had a week or 10 days ago," said Dr. Peter Norton, the medical authority for the city of Abilene.

The illness can be fatal, though it's not life-threatening to most who get it, Norton said.

In fact, fully 80 percent will not have any signs of illness.

Those who do have symptoms likely will suffer mild effects, such as fever, headache, body aches, occasional skin rash on the trunk of the body and swollen lymph glands.

Only 1 percent will have a severe infection, though that can be life-threatening.

Symptoms of a severe infection include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

This year, six people have died statewide from the illness, mirroring 2014's numbers. The greatest number of deaths was in 2012, with 83, while the lowest number was a single death in 2008.

There is no evidence that West Nile virus can be spread from person to person or from animal to person.

Tracking the source

The Abilene mosquitoes were collected Sept. 15, and are the first to test positive in 2015. The Texas Department of State Health Services Zoonosis Laboratory in Austin notified the City's Animal Services of the positive test result Wednesday.

Aaron Vannoy, Abilene's Animal Services manager, said the city used specialized traps to specifically capture female mosquitoes of the genus Culex that were ready to lay eggs.

Culex mosquitoes serve as vectors of a variety of illnesses that can be transferred to birds, people and animals.

"West Nile virus is brought to us by birds," Vannoy said. "The Culex mosquito likes to hid in the canopies of tress, thus feeding on the birds."

After they feed, the mosquitoes may harbor the virus inside of them, transferring it to a human if they bite them, Vannoy said.

"Once they (mosquitoes) have blood fed, they fly down to home levels and like to hang out close to humans," Vannoy said. "Each person need to take personal precaution to help prevent them from contracting the disease."

The city has been trapping each week since March, he said, collecting in five locations.

The city plans to continue spraying the area around the infected area Friday. Spraying on Saturday will be evaluated due to weather concerns.

"What we have here is just a positive mosquito, so they'll spray that area for three days," Norton said.

It is also important to eliminate or drain any water that stands for more than three days, he said.

"What we need to emphasize for the public is they need to keep breeding areas to a minimum," Norton said. "Take the saucers out from under their plants, have no standing water anywhere."

Effective mosquito repellents contain DEET, Picardin or Oil of lemon eucalyptus.

Residents also should limit outdoor activities during dawn and dusk when many mosquitoes are most active and wear covering clothing if they have be outside.

Copyright 2015 - Abilene Reporter-News, Texas