Mosquito Team Aims to Zap West Nile Risk

Jun 5, 2014

A joint effort to trap mosquitoes, identify potential risk from West Nile Virus, and inform residents continues this summer in Georgetown. The City of Georgetown and the Williamson County and Cities Health District started trapping mosquitoes in early May. So far this year there have been no positive tests for West Nile in mosquitoes collected in Georgetown. Testing will continue through the fall.

Each week, traps are placed in different locations in Georgetown by City employees in Transportation Services. The traps are collected by an employee with the Health District and taken to Texas Department of State Health Services lab in Austin for analysis. The Health District also is trapping mosquitoes in other parts of Williamson County this year in an expansion of the monitoring effort. Results are posted to the Health District website at

The Health District brings new expertise to the team this year with the addition of Catherine Zettel Nalen, an integrated mosquito management program specialist. Zettel Nalen is identifying trap locations, analyzing sampling data, and leading community outreach efforts to reduce the risk of West Nile Virus in Williamson County.

At a recent talk in Georgetown, Zettel Nalen emphasized the important role that each resident can play in reducing mosquito breeding areas and increasing personal protection against bites. “Check your yards and empty any container that can hold water,” she said. That can include clogged gutters, wheelbarrows, drain pipes, or toys left in the yard. Bird baths and plant saucers should be emptied twice weekly to prevent the formation of mosquito larvae.

For rain barrels or low-lying areas, Zettel Nalen suggested the use of larvicides such as mosquito dunks. They contain a naturally-occurring bacteria that is harmless to people, pets, fish, wildlife, or other insects. The larvicide disks are available at local hardware stores.

While the City is using the larvicide disks in drainage ponds and areas with standing water, Zettel Nalen highlighted the role each resident plays. “Studies have found that 25 percent of mosquito complaints can be traced to the caller’s own property.”

So far this year, there have been no human cases of West Nile Virus in Texas. The peak of West Nile Virus activity in mosquitoes and in human cases tends to be in the late summer or fall.

According to the Health District, 80 percent of those who become infected with West Nile Virus do not have any symptoms. Of those who become infected, only 1 in 150 cases have the most serious symptoms.

The City and Health District continue to promote these four steps to reduce mosquito populations and Fight the Bite:

  • Dawn and Dusk are times to stay indoors when mosquitoes are most active.
  • Dress in long sleeves and pants when outdoors (especially at dawn or dusk).
  • Drain standing water in flower pots, pet dishes, or clogged gutters so mosquitos don’t have a place to breed.
  • Defend against mosquito bites with an EPA-approved insect repellant.

For more information on the mosquito monitoring and outreach effort, visit the Williamson County and Cities Health District website at For more information on West Nile virus and the response in Texas, go to the Texas Department of State Health Services website at

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