The Brief Mosquitoes in Wauwatosa recently tested positive for West Nile virus for the first time since tracking began in June. West Nile virus has been detected in four Wisconsin counties this year, though no human cases are reported. West Nile was recently found in mosquitoes in Wauwatosa. MosquitoWest Nile virus detectedWhat we know:"We’re entering the weeks where the West Nile Virus is magnified enough in our environment where we’re going to start seeing cases of it," said Tony Gustin, also known as "The Bug Whisperer." West Nile virus cases"The life cycle is pretty amazing for the West Nile virus," Gustin said.