The purpose of this advisory is to update clinicians on the risk of West Nile virus (WNV) activity in Maine and other arbovirus activity in the U.S. and abroad. It is also to remind clinicians to consider testing for mosquito-borne arboviruses in patients presenting with unexplained encephalitis, meningitis, or fever (≥100.4°F or 38°C), particularly among patients who have recently traveled. Although Maine is experiencing statewide drought conditions and cooler temperatures, arboviral infections can still occur in late fall and winter. Maine people may acquire infections while traveling to other states or internationally and develop symptoms after returning to Maine.