Mosquito-Borne Viruses

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There are 85 species of mosquitoes found in Texas. Genus Culex is the mosquito that typically carries the West Nile Virus and Saint Louis Encephalitis Virus.  The most common specie of Culex in North Texas is Culex quinquefasciatus, which is the primary vector of West Nile Virus. Other species that can carry West Nile Virus are Culex restuans and Culex tarsalis, which are also found in North Texas. Aedes is a genus of mosquitoes associated with carrying and transmitting Zika and Chickungunya viruses.

Has mosquito-borne virus been detected in Keller?
Mosquitoes collected from five traps around the city are tested weekly by the Tarrant County Public Health Department for West Nile Virus and Saint Louis Encephalitis Virus. There is no testing for Zika virus, or other viruses that are known to be imported, offered by the Tarrant County Public Health Department at this time. Presence of imported viruses in local areas are confirmed by a positive human case. 

There has been 1 positive mosquito test for West Nile Virus in 2019.

Week Trap Location(s) Block Ground Spraying Dates
 Aug. 12 7000 Shady Grove Road  Aug. 15 & 16 


If any mosquito trapped within the Keller city limits tests positive for West Nile Virus or Saint Louis Encephalitis Virus - or if the city is notified of any confirmed human cases that have been transmitted locally (signifying its presence in the local mosquito population) - notification will be posted on the city’s website and social media accounts.

Have there been Human Cases of Mosquito-Borne Illnesses in Keller this Year?

There have been no human cases of West Nile Virus confirmed by the Tarrant County Public Health Department in 2019.

Tips to protect yourself against mosquito-borne viruses

The easiest and best way to avoid mosquito-transmitted diseases is to prevent mosquito bites, which can be accomplished by eliminating breeding grounds and adult mosquitoes on your property as well as actively protecting yourself and your family against bites when you are outside. For a full list of tips, visit the following pages: 

Virus Symptoms
No Symptoms in Most People - Approximately 80 percent of people who are infected with mosquito-borne virus will not show any symptoms.

Milder Symptoms in Some People - Up to 20 percent of the people who become infected have milder symptoms that can last for as short as a few days, though even healthy people have become sick for several weeks. These symptoms include:
• Fever
• Headache
• Body aches
• Nausea
• Vomiting
• Swollen lymph glands
• Skin rash on the chest, stomach and back

Serious Symptoms in a Few People – about 1 in 150 people infected may develop severe illness. These symptoms may last several weeks, and neurological effects may be permanent. Severe symptoms can include:
• High fever
• Headache
• Neck stiffness
• Stupor
• Disorientation
• Coma
• Tremors
• Convulsions
• Muscle weakness
• Vision loss
• Numbness
• Paralysis

Zika Virus
Zika Virus is spread to people primarily through the bite of an infected Aedes species mosquito. The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting for several days to a week after being bitten by an infected mosquito. Zika Virus infection during pregnancy can cause a serious birth defect called microcephaly, as well as other severe fetal brain defects. Pregnant women should consult with their health care provider if they decide to travel.

For more information on Zika virus, visit the CDC Zika Virus page

What should I do if I think I have a mosquito-borne virus?
Contact your doctor. There is no specific treatment or vaccine currently available for mosquito-transmitted diseases. In cases with milder symptoms, people experience symptoms such as fever and aches that pass on their own, although even healthy people have become sick for several weeks. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment, including intravenous fluids, help with breathing and nursing care. Pregnant women and nursing mothers are especially encouraged to talk to their doctor if they develop virus symptoms.  

Mosquito-transmitted viruses can only be confirmed by a doctor. The City of Keller will report confirmed cases of the virus upon notification by the Tarrant County Public Health Department.

Additional Suggested Resources: 
Centers for Disease Control and Prevention West Nile Virus Fact Sheet
Texas Department of State Health Services West Nile Virus Facts
Tarrant County Public Health West Nile Virus Information
CDC Zika Travel Information

To report suspected mosquito breeding sites in Keller, please call 817-743-4080 between 8 a.m. and 5 p.m. Monday through Friday, or email After 5 p.m., please call 817-743-4200.