Mosquitoes in Vermont | Vermont Department of Health CLOSE Translations for you Mosquitoes in Vermont Mosquito-borne Diseases Mosquitoes in Vermont Prevent Mosquito Bites Eastern Equine Encephalitis Jamestown Canyon Virus West Nile Virus During the summer months, mosquitoes are regularly monitored at sites around the state for mosquito-borne diseases. Each week, mosquitoes are collected at various locations by the Vermont Agency of Agriculture. These collections of mosquitoes are tested for arborviruses - mosquito-borne viruses - that may affect Vermonters: West Nile Eastern equine encephalitis , and Jamestown Canyon . The Health Department summarizes mosquito testing results and reports of human and animal illnesses every week during the summer and early fall, and compiles data each year in an annual surveillance report. View map in full screen Important Links Tick Activity in Vermont 2025 Surveillance for Viruses Spread by Mosquitoes What does this graph tell me? Lines represent historic (2002–2024) average percentage of mosquito pools positive for WNV (solid line) and EEE (dotted line). Bars show the percentage of mosquito pools positive in the current year. Historically, the percentage of mosquito pools positive for an arbovirus increases in late August and peaks in mid-September. Mosquito Surveillance Results Collection week # of Mosquito Pools* Tested # of EEEV Positive Pools # of WNV Positive Pools # of JCV Positive Pools June 8-14 144 June 15-21 172 June 22-28 172 June 29-July 5 172 July 6-12 172 July 13-19 172 1 (St. Albans) 1 (Rutland) July 20-26 172 July 27-August 2 172 2 (St. Albans, Stowe) 2 (Marshfield, Whitingham) August 3-9 172 3 (Newport, Rockingham, St. Albans) August 10-16 172 11 (Vergennes, Montpelier, Essex Junction, Alburgh, St. Albans, Bennington, Brighton) August 17-23 172 7 (Stowe, Alburgh, St. Albans, Highgate) August 24-30 172 2 (Vergennes, Morristown) August 31-September 6 172 7 (Hardwick, Vergennes, St. Albans, Essex Junction) 1 (Rutland) September 7-13 172 3 (Swanton, Vergennes) 8 (Alburgh, Fairfax, Essex Junction, Montpelier, St. Albans) September 14-20 172 6 (Rockingham, St. Albans, Essex Junction) September 21-27 208 6 (St. Albans, Essex Junction, Vergennes) September 28-October 4 161 October 5-11 122 1 (St. Albans) Year-to-date 3,043 54 *A mosquito pool is a group of 1-50 mosquitoes of the same species, collected at the same trap location, on the same date. Animal Surveillance One case of WNV in a raven was reported from Brattleboro. One suspect (non-confirmed) case of EEE in a horse was reported from Brownington. Vermont veterinarians: Free EEE and WNV testing in animals is available. Human Surveillance One human case of JCV was reported from Windsor County. No human cases of EEE or WNV have been reported in 2025. Aedes albopictus Surveillance The Aedes albopictus (Asian tiger) mosquito can carry and transmit Zika, dengue, and other arboviruses. It has an estimated geographic range that includes southern Vermont. After four consecutive years of detections at a single trap site in Windham County, spanning several weeks of detection each year, Aedes albopictus is considered established (locally-reproducing) at this location. Annual Surveillance Reports 2025 Mosquito-borne Virus Surveillance Report 2024 Mosquito-borne Virus Surveillance Report 2023 Mosquito-borne Virus Surveillance Report 2022 Arbovirus Surveillance Report 2021 Arbovirus Surveillance Report 2020 Arbovirus Surveillance Report 2019 Arbovirus Surveillance Report 2018 Arbovirus Surveillance Report 2017 Arbovirus Surveillance Report Topics: Disease Reporting Mosquito-borne Diseases March 13, 2026