The OC Health Care Agency has confirmed that an Anaheim resident tested positive for West Nile virus (WNV), marking the first human infection reported in Orange County this year. Because there are no human vaccines or targeted antiviral treatments available for WNV, avoiding mosquito bites remains the definitive line of defense. A Look at Orange County’s West Nile Virus HistoryWest Nile virus activity varies from year to year depending on local weather patterns, bird populations, and mosquito density. Understanding WNV Symptoms and Fatality RatesThe vast majority of individuals who contract West Nile virus—roughly 80%—will remain completely asymptomatic and never realize they were infected. Severe symptoms include high fevers, neck stiffness, profound confusion, muscle weakness, tremors, or sudden paralysis.