Authorities have confirmed the first case of West Nile virus in Pinal County during Arizona’s mosquito season. It’s the first confirmed case outside of Maricopa County, the state’s most populous county. Health officials said this week that the case was found in a county resident. The virus is transmitted by mosquitoes. About 20% of people exposed to it have minor symptoms such as headaches, fevers, aches, nausea and fatigue. People over the age of 60 or those with certain conditions like diabetes, hypertension and cancer are more likely to become severely ill from the virus.