November 30, 2021 – A mosquito trap sample collected in the City of Leander has tested positive for West Nile virus. This testing is part of Williamson County and Cities Health District’s (WCCHD) Integrated Vector Management program. The positive test was indicated in lab results received on November 29 from the Texas Department of State Health Services lab in Austin.

The positive sample was taken from a trap site near Devine Lake Park on Waterfall Ave. The last date a positive sample was collected from this location was November 2016. This is the tenth reported West Nile virus positive trap of the 2021 season in Williamson County.

Mosquitoes are most active from May-November, but until temperatures remain below 50 degrees for several days or there is a hard freeze it remains important to eliminate mosquito breeding sites.

What you can do:

Eliminating places where mosquitoes can breed and reducing the chances of mosquito bites are the most effective lines of defense against exposure to West Nile Virus. As part of its Fight the Bite campaign the Health District recommends the 3 Ds of mosquito safety:

  • Drain standing water in flowerpots, pet dishes, or clogged gutters so mosquitoes don’t have a place to breed and treat water that can’t be drained,
  • Defend by using an EPA-registered insect repellent, and
  • Dress in long sleeves and pants when outdoors.

For more information, go to the WCCHD website at or visit the Texas Department of State Health Services West Nile website at