TULSA, OK – [August 1, 2025] – The Tulsa Health Department has confirmed the first mosquito trap in Tulsa County has tested positive for West Nile Virus (WNV) this season. Although this detection comes later in the year than usual, it is a routine occurrence and not cause for alarm. Positive mosquito samples are identified in Oklahoma each summer. Currently, there have been no confirmed cases of WNV in humans in Tulsa County this year, but five cases across the state this year.

“While it’s later than we typically expect to see our first positive trap, this serves as a reminder that West Nile Virus remains a seasonal presence in our area,” said Micheal Morrison, vector control coordinator. “We continue to emphasize the importance of prevention and personal protection to reduce risk.”

Mosquitoes can transmit diseases like West Nile virus, so public health officials strongly encourage the use of insect repellent containing DEET to protect yourself.

THD operates a nationally recognized mosquito surveillance program to confirm when mosquito-borne illnesses are present in the community. Mosquito traps are set weekly in various locations throughout Tulsa County. Samples are collected and tested weekly for the presence of mosquito-borne illnesses. The Tulsa Health Department operates on an efficient budget to control mosquito populations during the spring and summer by surveillance and treats instead of spray.

The objective of the surveillance is to detect the presence of mosquitoes, determine abundance, species, make a risk assessment, and provide a basis for control. Control methods include larviciding and spraying when necessary. Public health is the primary driver for preventing disease infection in Tulsa County.

“When a positive trap is detected, our vector control team evaluates the area for targeted adult mosquito control,” added Morrison. “If spraying is scheduled, we notify affected neighborhoods through the Nextdoor platform to ensure residents are informed in advance.”

The months of July through October are typically the highest risk months for exposure to WNV in Oklahoma, however THD proactively begins a mosquito surveillance program in late April or May.

“We begin setting mosquito traps as part of our surveillance program beginning in early May to monitor for West Nile virus, and to identify any positive mosquitoes as early as possible within the season,” said Morrison. “Our mosquito control program recognizes the importance of preventing mosquito-borne illness by educating the public on bite prevention, dumping any standing water, and identifying areas of concern. THD is prepared to act in the affected areas as soon as weather conditions allow.”

West Nile virus is spread through the bite of an infected mosquito, which feeds on infected birds and then transmits the virus when biting humans, horses, and some other mammals. Symptoms of WNV include sudden onset of fever, headache, dizziness and muscle weakness.

“West Nile virus can lead to illness and death in some cases,” said Morrison. “It is important to take steps to prevent mosquitos from biting you and your family. Prevention is made easy by following a few simple steps.”

Precautions to take against mosquito bites are the following:

Dump and drain items such as buckets, cans, pool covers, flower pots, and tires from holding standing water so mosquitoes don’t have a place to breed.

Use an insect repellent containing DEET or other CDC approved repellents on exposed skin and clothing when you go outdoors, particularly if you are outside between dusk and dawn when mosquitoes are more likely to bite. (Insect repellent with permethrin should be used on clothing only.)

Wearing long sleeves and long pants that are loose-fitting and made of light colors.

Repair or install window and door screens to keep mosquitoes out of your home.

Encourage your friends and neighbors to dump and drain and to use repellents.

Clean leaves and debris from rain gutters regularly to ensure they are not clogged.

To place a complaint about mosquitoes in your area or to report standing or stagnant water in your area, please call 918-582-9355 or submit an online environmental complaint form. Making a report does not guarantee immediate action but provides the vector control team data to determine locations for traps. Trapping and testing will continue until the numbers of mosquitoes subside in the fall months.

“It is very important that community members do their part to dump standing water, to prevent mosquitoes from having breeding sites available to them,” said Morrison. “Standing water can occur in several places such as bird baths, toys, kiddie pools, trash cans, buckets, inverted grill lids, planters, bowls, etc. Our department is here as a resource if you would like help inspecting your property for possible mosquito breeding locations.”

Click here for our interactive data page that includes a map of WNV positive trap locations in Tulsa County. This is updated weekly typically on Fridays during the mosquito surveillance season.

The 2025 mosquito season by the numbers:

1 trap samples tested positive for West Nile Virus 288 trap samples have been tested so far this season 17,305/11,961* mosquitoes collected for testing/mosquitoes tested *approximately 0 human cases of WNV in Tulsa County 5 human case of WNV in Oklahoma

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