DHHS Identifies First Jamestown Canyon Virus Case Of The 2020 Arboviral Season In New Hampshire

Concord, NH – The New Hampshire Department of Health and Human Services (DHHS) is announcing that an adult from Loudon, NH, tested positive for Jamestown Canyon virus (JCV). The person was hospitalized with neurological symptoms, has since been discharged and is recovering at home. This is the first detection of a mosquito-borne disease in the State this year. JCV is transmitted by the bite of an infected mosquito. There are no vaccines to prevent JCV and treatment consists of supportive care.

The arboviral risk level for Loudon will be increased to high. The arboviral risk level indicates the risk of transmission of these infections to people from mosquitoes. The surrounding towns of Gilmanton, Chichester, Canterbury, Barnstead, Pembroke, Pittsfield, Concord, Northfield, and Belmont will increase to moderate.

"In addition to the ongoing COVID-19 pandemic, there are other infectious disease threats to New Hampshire residents, including from mosquito and tick bites. Jamestown Canyon Virus is one of the infections that is able to be transmitted by mosquito bites in New Hampshire,” said Dr. Benjamin Chan, State Epidemiologist. “When people are out of their homes, they should continue to take steps to not only protect themselves and others from COVID-19, but also protect themselves from mosquito and tick bites.”

Jamestown Canyon virus is a mosquito-borne pathogen that circulates widely in North America primarily between deer and mosquitoes but can also infect humans. Reports in humans have been increasing over the last several years as recognition and testing for this virus has increased. This is New Hampshire’s tenth case of JCV since the first report of the disease in the State in 2013. Many illnesses caused by JCV are mild, but moderate-to-severe central nervous system involvement requiring hospitalization have been reported, including fatal infections.

In addition to JCV, risk for infection in NH by Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV) will continue to increase through the summer and fall until mosquitoes are no longer biting. Residents of and visitors to New Hampshire should continue to protect themselves and their family members. 

People can be infected and not develop any symptoms, or only develop very mild symptoms for all mosquito-borne diseases present in New Hampshire. Early symptoms can include flu-like illness including fever, muscle aches, headaches, and fatigue. People infected with JCV, EEE, and WNV can develop more serious central nervous system disease, including meningitis or encephalitis. If you or someone you know is experiencing flu-like symptoms, including fever and headache, contact your local medical provider.

Anyone with questions about vector-borne 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. More information can be found online at www.cdc.gov.