West Nile Virus Detected at Three Island Crossing State Park

August 19, 2025
FOR IMMEDIATE RELEASE

West Nile Virus Detected at Three Island Crossing State Park

Glenns Ferry, Idaho — The Idaho Department of Parks and Recreation (IDPR) and Three Island Crossing State Park are alerting the public that West Nile virus has been detected in a mosquito collected from a surveillance trap within the park. The positive test was confirmed by Elmore County Pest Abatement on Monday, August 18.

Ongoing Surveillance & Positive Detection in Glenns Ferry

Elmore County Pest Abatement has maintained a regular mosquito surveillance program in Glenns Ferry for several years. One surveillance trap is set weekly at Three Island Crossing State Park—typically placed near the river in the day-use area. Mosquitoes from this trap were tested by the Idaho Bureau of Laboratories and found to be positive for West Nile virus.

So far in 2025, only one mosquito sample from the park has tested positive for the virus. Additional positive samples have been confirmed in two other locations in Glenns Ferry, indicating increased activity in the area this season.

These detections are part of a broader pattern of West Nile virus activity, which has also been confirmed across seven southern Idaho counties and neighboring Malheur County, Oregon, according to the Idaho Department of Health and Welfare.

Increased Mosquito Control Efforts

“We've been treating the park and surrounding areas throughout the mosquito season,” said Jason Kinley, Superintendent of Elmore County Pest Abatement. “We’re applying larvicides to standing water and using fogging machines at night, all while taking care to minimize any impact on people and beneficial insects.”

Standing Water Treatments: Targeted applications of larvicides are being used to reduce mosquito populations. These treatments are highly selective and designed to affect only mosquito larvae, with negligible impact on other organisms or insects in the water.

Nighttime Fogging Applications: Fogging is done using general-use insecticides in a fine aerosol form that remains airborne. These are applied at night to protect beneficial insects like honeybees, dragonflies, and butterflies from insecticide exposure. Kinley emphasized that while making fogging applications, Elmore County Mosquito Abatement makes every attempt to avoid occupied campgrounds and areas when visitors are present.

“If we see campers in tents or people sitting by the fire, we shut the fogging machine off,” said Kinley. “Our goal is always to avoid exposing people. For example, last Friday, because the park was busy, we chose not to enter the campgrounds at all.”

Fogging operations are strategically timed based on weather, wind, and mosquito activity. Applications are generally avoided on weekends to reduce disruption.

Visitor Awareness & Safety

Flyers with prevention tips are posted at the park entrance, visitor center, and near restrooms. Updates will be shared via the Elmore County Pest Abatement's Facebook page.

Fight the Bite

The Idaho Department of Health and Welfare (DHW) recommends these precautions:

• Wear repellent containing DEET, Picaridin or Oil of Lemon Eucalyptus (all EPA-approved repellents) according to the label.
• Remove standing water around your home - this is where mosquitoes like to breed.
• Cover up your skin with clothing between dusk and dawn, when mosquitoes are most active.

Learn more about symptoms and other resources on DHW’s West Nile Virus webpage.

Elmore County Mosquito Abatement Updates https://www.facebook.com/ECMAD

Contact

Elmore County Pest Abatement
Jason Kinley, Superintendent
Office: 208-587-2154
jkinley@elmorecountyid.gov