Mosquito-control measures detailed by region's cities, counties

By MONETTE TAYLOR | South Central Texas Edition

Mosquitoes can transmit West Nile Virus, along with other encephalitises to humans and horses. Pesticides, larvicides, and measures such as dumping standing water are used to control the insect.

April 3, 2003 -- With warm weather and spring rains, can mosquitoes and the threat of West Nile Virus (WNV) be far away?

According to various news sources within South Central Texas, agricultural producers and other citizens need to be aware of the threat of another seven months or so of fighting off mosquitoes, which transmit the virus.

Crows have been found to carry the West Nile virus that first landed in New York and rapidly spread across the United States, last year.

This year, veterinarians, health officials and county and municipal governments are warning the public to be on guard of dead crows, and ask that they notify the authorities, if they find one.

According to reports from the Seattle Times, " ... since 1999, when the first U.S. case was reported in a human, the virus has spread steadily westward from the East Coast, carried by more than 100 species of birds."

In 2002, over 4,000 cases of WNV in humans were reported in North America.

After a mosquito bites an infected bird, they threaten any horses and humans they bite with the potentially deadly virus. In humans, symptoms of the virus include fever, headache, exhaustion, nausea, muscle ache, swollen lymph glands and, sometimes, a rash. Records indicate that one in 150 people infected may develop WNV, an encephalitis, which can be fatal.

One method of deterring mosquitoes is with the spraying of pesticides in large populated areas.

In Hays County, Robert Piper, chief of sanitation, said in San Marcos, they normally spray on request, but urge control by private citizens through use of larvicide and watching for standing water.

When there are complaints of high mosquito populations, Piper said they spray the areas requested. During wet weather, he said they may receive 15 to 20 calls a day for help with mosquito control, and during dryer weather, only a few a week.

In Fayette County, Shawn Rayburn city manager of La Grange, said the city will continue to spray city streets and municipal areas through the height of mosquito season. He said there are some citizens who request to be informed of the spraying schedule so that they can remain in an enclosed

area. Often, the media is used to inform citizens of spraying schedules.

"It's part of the normal course of business," said Rayburn.

One night of spraying costs between $700 to $800, yet only 10 to 15 percent of mosquitoes are actually killed, according to Rayburn.

Another method to control mosquitoes is the use of larvicides, or dunks, which are placed in standing water. These are available at stores for the public, and they are the choice in Kerr County.

Sharon Swindle, a health specialist in Kerrville, reported that with all of the streams in the area, they do have a problem with mosquitoes, but larvicides are the only thing the city uses to combat the problem. As of this date, while cases of WNV were all around the area last year, Kerr County had no reported cases verified.

In all areas, citizens, whether in urban or rural areas, are urged to make sure and drain "anything" that holds standing water, including old tires, buckets, wheelbarrows, plastic covers, toys and plant saucers. You are urged to empty bird baths, wading pools, fountains and animal troughs once a week and clean and chlorinate swimming pools and hot tubs.

For citizens who enjoy the outdoors, they are encouraged to use insect repellent before going outside, and the repellents containing the chemical N,N-diethyl-m-toluamide (DEET) has been identified as the most effective. Users should be sure to read all directions, especially when making applications on children.

In Galveston County, Extension Agent Corrie Bowen said mosquito control is "something we take very seriously" in the area. They apply pesticides through the air and on the ground, but said the first line of defense is eliminating all standing water and the use of larvicides. Last year, Galveston reported positive testing for WNV in one bird, one human, four mosquitoes, and seven horses.

Other areas, such as Wimberley in Hays County, want no part of any kind of pesticide spraying, noting the number of "chemically sensitive" people who moved to the area to avoid any more pollution of the air.

The Texas A&M Agriculture News recently published an article warning residents to "take precautions," now, against mosquito-borne diseases.

"We never run out of mosquitoes ... at least in this part of Texas ... we just change species with the season," said Dr. Jim Olson, entomologist with the Texas Agricultural Experiment Station.

He urged producers to be sure and vaccinate their equine population, now, and make sure to give boosters, annually. Protection usually takes about six weeks after the initial two shots ... usually given about four weeks apart.