West Nile Virus (WNV)

West Nile Virus (WNV) is a flavivirus found in Africa, West Asia, and the Middle East. It was first detected in the eastern United States in 1999. WNV can infect humans, birds, mosquitoes, horses, and some other mammals.

Most people infected with WNV do not get sick. Some may have mild flu-like symptoms, while rare cases can affect the brain and spinal cord, causing encephalitis or death.

How to Protect Yourself from West Nile Virus

Preventing mosquito bites is the best way to avoid infection. Follow the “Four D’s”:

1. Defend: Apply an approved mosquito repellent on exposed skin and clothing whenever you are outdoors.
   Learn about choosing a mosquito repellent.
2. Dress: Wear long, loose, light-colored clothing, including long sleeves and pants.
3. Dusk to Dawn: Stay indoors during the hours when mosquitoes are most active.
4. Drain: Remove standing water in your yard, such as old tires, flower pots, and clogged rain gutters, which serve as mosquito breeding sites.

Also, ensure doors and windows are sealed properly and that screens are in place to keep mosquitoes out of your home.

Symptoms of West Nile Virus

• Mild illness (about 20% of infected people): Fever, headache, body aches, occasional rash on the trunk.
• Severe illness (West Nile neuroinvasive disease, 1 in 150 people): Headache, high fever, neck stiffness, disorientation, muscle weakness, and paralysis.

Incubation period: 3–14 days.

• Mild symptoms may last a few days.
• Severe symptoms may last several weeks; neurological effects can be permanent.
• Rarely, WNV can be fatal.

How WNV is Spread

WNV is transmitted by the bite of an infected mosquito. It cannot be spread from person to person or from animal to person.

Who is at Risk

• People over 50 years old
• Individuals with weakened immune systems

Less than 1% of people bitten by infected mosquitoes develop severe illness. Contact your doctor if you experience symptoms.

Carrollton’s P.E.S.T.S. Program – Fight the Bite

Partnership: Carrollton collaborates with residents and businesses to address mosquito concerns and WNV. Report mosquito problems: call 972-466-3420 or submit an email report.

Education: Public education is key to reducing risk. From May to September, signs in medians, intersections, and parks remind residents of the Four D’s.

Surveillance: Fourteen fixed testing sites monitor mosquito populations and WNV activity. Collected mosquitoes are sent to labs for identification and testing.
View a map of testing sites.

Treat Standing Water: Animal Services and Community Services identify and treat breeding sites with larvicide (mosquito dunks). Standing water on streets or sidewalks is not treated.

Spraying: Ground spraying with a permethrin-based product occurs only in areas with WNV-positive mosquitoes. This method is safe for residential neighborhoods when applied under low wind conditions.

More information about permethrin products

Additional Resources

• Centers for Disease Control and Prevention (CDC) – West Nile Virus
• Texas Department of State Health Services – WNV Information
• Dallas County Health and Human Services
• Dallas County Arbovirus Surveillance Report
• Mosquito Safari – Educational Video

For questions or comments, click here to contact Carrollton Animal Services, or call 972-466-3420 to speak with staff.