Mosquito-borne Diseases

Connecticut Mosquitoes


Mosquito-borne diseases are those spread by the bite of an infected mosquito. These diseases can be caused by viruses or a parasite. Viruses cause the majority of mosquito-borne diseases, and there are no medications to treat the symptoms caused by these viruses. Some mosquito species found in Connecticut are capable of spreading viruses that can cause disease in humans. Illness associated with these diseases ranges from mild to significant, and some can cause death. In Connecticut, surveillance is conducted to identify travel-related diseases (diseases acquired out of the state or out of the country) and diseases that can be spread by mosquitoes in the state. The Connecticut Department of Public Health conducts surveillance for the following mosquito-borne diseases:


California Serogroup viruses (e.g. Jamestown Canyon, LaCrosse)

Chikungunya virus  


Eastern Equine Encephalitis


Saint (St.) Louis Encephalitis

West Nile virus

Yellow fever

Zika virus


The most effective way to avoid getting sick from mosquito-borne diseases is to prevent mosquito bites.


National Mosquito-borne viral disease Surveillance Summary


Connecticut Mosquito Management Program


The Connecticut Mosquito Management Program is a collaborative effort involving the Department of Energy and Environmental Protection, Connecticut Agricultural Experiment Station, Department of Public Health, Department of Agriculture, and the University of Connecticut Department of Pathobiology and Veterinary Science. The program provides information about the species of mosquitoes found in Connecticut and guidance about how to protect yourself and your community from mosquitoes and mosquito-borne diseases.

Mosquito FAQs

West Nile virus FAQs

Eastern Equine encephalitis FAQs

Repellents FAQs


Connecticut Agricultural Experiment Station


The Connecticut Agricultural Experiment Station conducts mosquito trapping across the state during June through October. Mosquitoes are tested for viruses that can cause human disease, including those found in Connecticut such as Eastern Equine Encephalitis virus, Jamestown Canyon virus, and West Nile virus 


Mosquito Trapping and Arbovirus Testing Program

Current Mosquito Testing Results
Past-Years Summaries of Mosquito Testing Results

Identification Guide to the Mosquitoes of Connecticut  

Vector-borne Disease Symposium - Symposium of Mosquito-Borne Disease in Connecticut, held on April 11, 2019.


Additional Resources


Connecticut Provider Reporting Resources

Reporting of Diseases, Emergency Illnesses, Health Conditions, and Laboratory Findings

Connecticut Provider Reporting Information

Connecticut Laboratory Reporting Information

Current List of Reportable Diseases


Data Statistics

Connecticut Annual Infectious Diseases Statistics

National Arbovirus Surveillance System (ArboNET)


National Resources
Workplace Safety - Mosquito-Borne Diseases - NIOSH
Vector Control Resources - CDC EHS



This page last updated 8/9/2023