West Nile Virus

West Nile virus has become a serious concern in our community.  This is in large part due to the record outbreak of West Nile virus in North Texas during the summer of 2012.  Over 580 confirmed human cases resulted in 23 deaths in Collin, Dallas, Denton and Tarrant counties last year.  The U.S. Centers for Disease Control and Prevention evaluated this outbreak and provided feedback to improve state and local response.  This guidance has been incorporated into Corinth's program. Our success depends heavily on a strong partnership with our community.

What is the City doing to monitor West Nile?

The City of Corinth has contracted with Vector Disease Control who is using an aggressive and scientific approach to control the mosquito populations by utilizing larvacide to manage breeding sites at the larval stage.  On a weekly basis, during mosquito season, Corinth utilizes gravid traps to capture mosquitos overnight.  The captured mosquitos are transported to Vector Disease Control in Richardson for species identification and testing for West Nile Virus. Those trap sites are as follows: 

  1. The Woods Park
  2. Meadowview Pond
  3. Community Park (drainage area between football and Corinth Parkway)
  4. Thousand Oaks Pond
Click here to view a map of the testing sites.

Test results are produced in the form of a weekly vector index report.  A vector index is a measure of infectivity that takes into account the following information:

  • Vector species composition- Key species carrying West Nile Virus in our region.
  • Vector species population density- Vector abundance relative to trapping effort.
  • Vector species infection rate- Proportion of vectors infected with West Nile Virus.
The City Manager is authorized to approve adulticiding (spraying) in the City of Corinth if the vector index reaches 4.5 or higher for any one area.  When triggering mechanisms are met for spraying, a minimum of two days advance notice of intent to spray will be advertised on electronic message boards near major intersections around the trapping site.  Information will also be posted on the City’s website, Facebook page, and Twitter account.  Application of the pesticide will be a .5 (1/2) mile radius of the selected site. 

We encourage you to sign up for Notify Me in order to receive information on positive tests and fogging. Select Corinth News under the News Flash section to receive these specific updates.

Click here to view all positive tests for West Nile virus.

Chemical Information

When the City does approve fogging for West Nile, the chemical used is called Bacillus Thuringiensis.  Click on the link below to view the chemical label and the Material Data Safety Sheet (MDSD) for Bacillus Thuringiensis.  

Bacillus Thuringiensis MSDS


  Click here to view the City of Corinth Mosquito Policy.

We provide BTI briquettes FREE of charge to our residents.

The City treats water that cannot be eliminated with a biological mosquito larvicide called Bacillus Thuringiensis Israelensis (BTI).  The Corinth Public Works Department offers BTI briquettes that residents can pick up, free of charge, to use in the mosquito control effort.  Each address will be limited to two (2) briquettes per month while supplies last.  The briquette will treat 100 square feet of surface water for 30 days.  To apply, simply drop the briquette in standing water.  Residents will be required to show their driver’s license or a current City of Corinth utility bill to prove Corinth residency.  You may pick up the briquettes at 1200 North Corinth Street Monday through Thursday during the hours of 8:00 AM to 5:00 PM and on Friday between the hours of 8:00 AM and 11:00 AM.

You may want to call ahead to ensure we still have a supply of briquettes on hand before driving to the service center. The phone number for Corinth’s Public Works Service Center is 940-498-3249.

What is West Nile virus?

West Nile virus is a virus commonly found in Africa, West Asia and the Middle East.  It is not known how long it has been in the United States, but the Centers for Disease Control and Prevention (CDC) believe the virus probably has been in the eastern United States since early summer 1999.  It is closely related to the St. Louis encephalitis virus found in the United States.  The virus can infect humans, birds, mosquitoes, horses and some other animals. 

How can I reduce my risk of getting West Nile virus?

Preventing mosquito bites is the best way to avoid becoming infected with the West Nile virus. Remember the "Four D's" of Defend, Dress, Dusk to Dawn, and Drain:
  • Defend yourself by applying an approved mosquito repellent.

    • Spray exposed skin and clothing with repellent. 
    • Click here for information on choosing an appropriate repellent. 
  • Dress in long sleeves and long pants when you are outside. 
  • Stay indoors from the period of dusk through dawn, times when infected mosquitoes are most active.
  • Drain standing water in your yard; old tires, flower pots and clogged rain gutters are mosquito breeding sites.
  • Also very important to be sure that doors and window are sealed properly and that screens are in place to protect your home from intruding mosquitoes.

What are the symptoms of West Nile virus?  

Most people infected with West Nile virus will not have any signs of illness.  Twenty percent of people who become infected will have only mild symptoms such as fever, headache, body aches and occasionally a skin rash on the trunk of the body.

The symptoms of severe infection (West Nile neuroinvasive disease) include headache, high fever, neck stiffness, disorientation, muscle weakness and paralysis.  Only about 1 out of 150 people infected with West Nile virus will develop this more severe form of the disease.  

The incubation period of West Nile virus in humans is 3-14 days.  Symptoms of mild disease may last a few days.  Symptoms of severe disease may last several weeks, although neurological effects may be permanent.  Rarely, death can occur.

How is it spread?

West Nile virus is spread by the bite of an infected mosquito and can infect people, horses, many types of birds and some other animals.  There is no evidence that West Nile virus can be spread from person to person or from animal to person.

Who is at risk for West Nile virus?

People older than 50 have the highest risk of severe disease and people with with weakened immune systems are at an increased risk for West Nile virus.

How likely am I to be bitten by an infected mosquito?

Less than 1 percent of those bitten by infected mosquitoes become severely ill. If you have the symptoms mentioned above, contact your doctor immediately.

Please take a moment to review this interactive video to learn more about mosquitoes and how you can reduce mosquito breeding sites on your property.


Additional Resources:

The Centers for Disease Control and Prevention (CDC):

Texas Department of State Health Services:

Dallas County Health and Human Services Website:

How to Repel Mosquitoes Safely

West Nile virus videos in American Sign Language:

Para Información en Espanol: