The detection of West Nile virus in mosquitoes signals the start of the seasonal risk for residents in the North Shore area. While the current human risk level remains low, the virus can cause severe illness in some cases, particularly among older adults and individuals with weakened immune systems. Last year, the region recorded its highest infection rate, with 56 out of every 1,000 mosquitoes testing positive. The virus spreads through mosquito bites, and the risk increases as the summer progresses and temperatures rise. Migratory birds may also contribute to the spread of the virus.