STEVENS COUNTY, Wa. --- Some mosquitos near the Kettle Falls day use and group site campground at Lake Roosevelt National Recreation Area tested positive for West Nile virus, according to the Washington Department of Health.

In a release from the National Park Service, officials warn visitors that the conditions at the lake have been “optimal” for mosquitos this year, and they have been dealing with an “extraordinarily large mosquito population.”

NPS recommends anyone who thinks they may have come into contact with the virus to check with the Centers for Disease Control and Prevention. Officials also recommend visitors wear loose fitting, long-sleeved shirts and pants along with repellant.