West Nile Virus Detected Across 22 Connecticut Cities

In Connecticut, heavy rainfall and high humidity are boosting mosquito populations, with West Nile virus detected in 22 towns and peak season running mid-August to September; last year saw activity in 37 towns and six human cases in 2025. New Haven and Fairfield counties are currently the areas with the highest virus activity in mosquitoes. In New York City, a confirmed West Nile case has led to targeted mosquito spraying in South Brooklyn. In Montgomery County, Pennsylvania, the health office reports West Nile virus found in a mosquito sample, prompting advisory updates. Researchers in Germany at the Bernhard Nocht Institute for Tropical Medicine are building mathematical models to forecast spread and mosquito dynamics, identifying a corridor of spread from eastern states toward the north and west and noting that some risks may be predicted years in advance. Across Europe, West Nile virus is transmitted between birds and mosquitoes, with concerns about mild to severe human disease and horses, as the virus has been spreading northward and westward in recent years.