West Nile Virus

What is West Nile Virus?

West Nile Virus (WNV) is a potentially serious virus most commonly spread by infected mosquitoes. Mosquitoes become infected when they feed on infected birds. WNV can cause fever, inflammation of the brain, the lining of the brain, and the spinal cord. WNV can be transmitted year-round in Texas.

What are the symptoms of WNV?

  • There are no symptoms in majority of those who contact WNV. Up to 80 percent of people infected with WNV do not develop symptoms.
  • Febrile illness - About 20 percent of infected people will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or a rash. Most people with this type of WNV disease recover completely, but fatigue and weakness can last for weeks or months.
  • Severe symptoms in a few people. Less than one percent of infected people develop inflammation of the brain or surrounding tissues. The symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis.

How does WNV spread?

WNV often spreads by the bite of an infected mosquito. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding, and pregnancy. WNV is not spread through casual contact such as touching or kissing a person infected with the virus.

What happens if a trap tests positive for WNV?

The first positive test for WNV will be monitored by City crews and within twenty-four hours crews will use adulticiding, a type of insecticide used to control adult mosquitoes, in addition to the City’s normal larviciding program. As part of adulticiding, crews will use foggers in creek banks and City parks in the quarter-mile area where a positive trap is found. Prior to this taking place, residents will be notified via Blackboard connect to alert them of the fogging and positive test.

Is there a vaccine available to protect people from WNV?

Currently, there is no WNV vaccine available.

How soon do people get sick after getting bitten by an infected mosquito?

The incubation period is usually two to six days but ranges from two to 14 days.

Who is at risk for serious illness if infected with WNV?

Cancer, diabetes, hypertension, and kidney disease patients are at a greater risk.

What is the treatment for WNV disease?

Pain relievers can reduce fever and relieve some symptoms. People with milder symptoms typically recover on their own. In more severe cases, patients often hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing care.

How can people reduce the chance of getting infected?

To reduce your risk of getting the WNV:

  • Use DEET-based insect repellents when outdoors.
  • Wear long sleeves and pants at dusk, dawn, and during the day when mosquitoes are most active.
  • Install or repair screens on windows and doors and make sure they are bug-tight. 
  • Check your property for standing water. Check the saucers under potted plants, roof gutters, flat roofs, old tires, toys, garbage cans and dumpsters, anything that might hold water and not be emptied out regularly.
  • Clean and change the water regularly (several times per week) in birdbaths, wading pools, pet dishes, and planters.
  • Treat any standing water that can't be drained with BTI-available at most home and garden stores.