Mosquitos In NH Test Positive For Jamestown Canyon Virus

KEENE, NH — The New Hampshire Department of Health and Human Services has identified the first batch of mosquitoes in 2023 to test positive for Jamestown Canyon Virus, officials said in a news release Friday.

The batch was collected in Keene on June 6, according to officials.

JVC is transmitted by the bite of an infected mosquito. The bite risk level for Keene—which indicates the risk that a mosquito will transmit these infections to a person in Keene—will be increased from baseline (no current activity detected) to low, according to officials.

Reports of JCV in humans have increased in North America over the last several years as awareness of and testing for it have increased, officials said. Since the first report of the disease in the State in 2013, New Hampshire has identified 19 cases of JCV. There are no vaccines to prevent JCV and treatment consists of supportive care.

"This finding of the first identification of Jamestown Canyon Virus in New Hampshire serves as a reminder that when enjoying the outdoors, mosquito bite prevention is key in safely enjoying the outdoors,” Deputy State Epidemiologist Dr. Elizabeth Talbot said in the news release. “As soon as mosquitoes emerge in the spring, residents and visitors can take steps to protect their health and their family’s health, including using an effective insect repellant, wearing protective clothing, and minimizing outdoor exposure at dawn and dusk, when mosquitoes are most active.”

In addition to JCV, the risk for infection in NH by Eastern Equine Encephalitis and West Nile Virus may increase through the summer and fall until mosquitoes are no longer biting, according to officials.

For all mosquito-borne diseases present in New Hampshire, an infected person may not develop any symptoms or only develop very mild symptoms, officials said. Early symptoms can include flu-like illness, including fever, muscle aches, headaches, and fatigue. People may progress to more serious central nervous system diseases, including meningitis or encephalitis. Individuals experiencing flu-like symptoms, including fever and headache, are encouraged to contact a healthcare provider.

Residents and visitors of New Hampshire should continue to protect themselves and their family members. Guidelines can be found at the DHHS.

Anyone with questions about these illnesses can call the DHHS Division of Public Health Services’ Bureau of Infectious Disease Control at (603) 271-4496 from 8 AM to 4:30 PM, Monday through Friday. For more information, visit the DHHS or www.cdc.gov