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 Virus, Eastern Equine Encephalitis and in 2024, we began testing mosquitos for Jamestown Canyon virus (JCV). 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.

Check out the Mosquito Surveillance Map


2024 Surveillance for Viruses Spread by Mosquitoes

graph depicting 2024 mosquito surveillance results; testing for West Nile Virus, Eastern Equine Encephalitis Virus, and Jamestown Canyon Virus
What does this graph tell me?
  • Lines represent historic (2002–2023) 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 9-152600N/A
June 16-222300N/A
Year-to-date4900N/A

*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

  • No animal cases of WNV and EEE have been reported in 2024.
     

Vermont veterinarians: Free EEE and WNV testing in animals is available. 

Human Surveillance

  • No human cases of WNV and EEE have been reported in 2024.

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

 

Topics:
Disease Reporting | Mosquito-borne Diseases
Last Updated: