Mosquito Trap Tests Positive for West Nile Virus in Granger

October 7, 2020 – A mosquito trap sample collected in the City of Granger 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 Oct. 7 from the Texas Department of State Health Services lab in Austin. 

The positive sample was taken from a trap site near N. Colorado St. This is the second time this season that a sample from that location has tested positive for West Nile virus. The last date a positive sample was collected was Sept. 1. 

In 2020, there have been 15 mosquito trap samples that have returned as positive for West Nile Virus in Williamson County – the highest ever recorded since the program started in 2012. There have been three human cases of West Nile virus reported in Williamson County this year.  

Symptoms of infection may include fever, headache, and body aches, a skin rash on the trunk of the body, and swollen lymph nodes. Those age 50 and older and/or with compromised immune systems are at a higher risk for severe symptoms, which may include stiffness, disorientation, coma, tremors, vision loss, paralysis, and in rare cases, death.  

Mosquitoes are present in Central Texas year-round, but the population is largest and most active from May through November. During this period, WCCHD monitors the mosquito population and tests for mosquito-borne viruses. 

“Dumping any amount of standing water around your home and using insect repellent when outdoors, especially at dawn and dusk, is highly recommended to keep yourself and your family safe from mosquito-borne illness,” said Jason Fritz, WCCHD Integrated Vector Management Program Lead 

The most important way to prevent West Nile Virus is to reduce the number of mosquitoes where people work and play. Health officials strongly encourage everyone to remain vigilant about protecting themselves from mosquito bites and preventing mosquito breeding on their personal property. Mosquitoes breed in standing water, needing as little as one teaspoon. By draining all sources of standing water in and around your property, you reduce the number of places mosquitoes can lay their eggs and breed. 

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-approved 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