 West Nile virus has been identified in a pool of mosquitoes collected in Grand Forks. Although positive test rates for the virus remain low at this time, residents are encouraged to take extra precautions to avoid being bitten by mosquitoes. The Culex tarsalis mosquito is most active in the few hours after sunset. To help reduce your risk of getting West Nile virus, use insect repellent that contains DEET,