California Serogroup Arbovirus

Jamestown Canyon Virus

California serogroup viruses are a group of viruses spread through bites of infected mosquitoes. Jamestown Canyon (JC) virus is the primary virus of this group found in mosquitoes in Connecticut. JC virus disease rarely occurs in people in Connecticut or the United States. There is no vaccine to prevent or medicine to treat JC virus infection. The best way to prevent getting sick from JC virus is to prevent mosquito bites.

• CDC: About Jamestown Canyon Virus
• Where Has Jamestown Canyon virus (JC) Been Found?

• Clinical Testing and Diagnosis
• Connecticut Provider Reporting Information
• Connecticut Laboratory Reporting Information
• Directory of Clinical Testing Services provided by the State Public Health Laboratory
• State Public Health Laboratory Contacts for additional information

In 2000, encephalitis was added to the state-wide reportable disease list, which included the California serogroup viruses (CSV). Jamestown Canyon is the most common CSV in mosquitoes in Connecticut. Since 2000, one case of JC virus has been reported to the Connecticut Department of Public Health (DPH).

• Connecticut Annual Infectious Diseases Statistics
• National Jamestown Canyon Virus Data

• The Connecticut Agricultural Experiment Station conducts mosquito trapping and tests for viruses including Jamestown Canyon virus during June to October each year.
• Mosquito Trapping and Arbovirus Testing Program
• Current Mosquito Testing Results
• Past-Years Summaries of Mosquito Testing Results
• Identification Guide to the Mosquitoes of Connecticut
• Connecticut Mosquito Management Program
• Mosquito FAQs
• Repellents FAQs
• Workplace Safety - Mosquito-Borne Diseases in Workers

Last updated 2/11/2026