The rating of the risk of West Nile virus infection has been elevated to Risk Level 2- high risk. This is based on the Centers for Disease Control guidelines for a phased response to West Nile virus surveillance data. The high-risk rating is based on sustained infections in local mosquitoes and moderate densities of vector mosquito populations capable of transmitting the virus.

This week the City of Laramie has detected West Nile virus in 2 mosquito samples collected in rural areas outside the City limits. One sample was collected northwest of the city and the other sample was collected from Rock River. Four additional West Nile positive samples were collected in the local area during the time period from August 7th to August 12th.

Preliminary testing is conducted with the Rapid Analyte Measurement Platform, or RAMP testing equipment. Confirmatory testing was conducted on the samples from last week by the Wyoming State Veterinary laboratory to verify these positive samples. Three of the four samples were confirmed using RT-PCR for verification.

Technicians have tested a total of 82 mosquito sample pools throughout the summer season. No avian, equine or human cases have been reported to Wyoming Department of Health in Albany County.

Although total mosquito numbers are currently low, vector mosquitoes that can effectively transmit the virus make up a greater percentage of the mosquito population in late summer due to the overwintering and reproduction cycles of these species. Current surveillance locally shows low to moderate numbers of vector mosquitoes being collected at trap locations adjacent to the Big Laramie River and in some rural locations. Residential surveillance sites within the city limits report low vector numbers.

Mosquito control will be conducting full neighborhood fogging this week in response to the latest surveillance data. A decision to return to perimeter fogging in the outlying neighborhoods will be made next week after trap data and subsequent RAMP testing is evaluated. Mosquito Control is also currently performing targeted fogging operations to control vector mosquitoes in areas of higher vector densities and areas where citizens often recreate in the evening hours. Targeted areas include: parks and recreation areas, golf courses, and the Laramie River Greenbelt Trail. “No Spray” zones will continue to be honored at this time.

Citizens are reminded that West Nile can infect people of all ages but the elderly may be at the greatest risk for a serious infection. Locally, the mosquitoes that transmit WNV are most active at dusk and citizens should limit activities in areas with high mosquito populations during this time. Repairing screens, especially in sleeping rooms, and using personal protection such as proper clothing and insect repellent containing DEET can also reduce the risk. Further Wyoming West Nile Virus information can be found on line at: or the Centers for Disease Control website:

Hotline information regarding chemical applications on City owned properties will be updated daily at 4pm. Call 721-5056 or click on the Mosquito and Chemical Application hotline tab on the City of Laramie home page. For further information contact Keith Wardlaw, Mosquito Control Crew Supervisor at 721-5258 or David Schott, Parks Manager at 721-5264.