Black-legged tick

Scott Bauer / U.S. Department of Agriculture

In the Granite State, the black-legged tick is the most likely to transmit Powassan virus to people, according to state officials.

A Kingston resident has tested positive for Jamestown Canyon virus and Powassan virus, in the state’s first such identification of either rare disease this year, the N.H. Department of Health and Human Services announced Thursday.

Both viruses are vector-borne — spread by an organism between hosts — with Jamestown Canyon virus transmitted by infected mosquitoes and Powassan virus by infected ticks.

From spring until fall, New Hampshire residents and visitors are at risk for a number of different infections from the bite of mosquitoes and ticks, and this case highlights the risk from both,” Dr. Benjamin Chan, the state epidemiologist, said in a news release. “In addition to Jamestown Canyon virus and Powassan virus, there are a number of other viral and bacterial infections that can be transmitted by mosquitoes and ticks in New Hampshire, and we recommend that residents and visitors continue to take basic steps to prevent mosquito and tick bites in order to stay healthy.”

Those steps include:

Wearing mosquito and tick repellent with DEET (at 20 to 30 percent), picaridin, or oil of lemon eucalyptus

Tucking shirts into pants and pants into socks when outside

Making your property less desirable to mosquitoes by removing the standing water where they breed and less hospitable to ticks by cutting grass short.

Checking regularly for ticks and removing any you find. (Powassan virus can be transmitted to a person within 15 minutes of a tick attaching, the release says.)

The Kingston resident, who is an adult, marks the state’s seventh known human case of Jamestown Canyon virus since it was first identified in New Hampshire in 2013 and the fourth case of Powassan virus, according to the state agency. There’s no vaccine for either virus, and illness is treated only by supportive care.

In severe cases, both viruses can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes around the brain and spinal cord), according to the public health agencies.

The Kingston resident hadn’t engaged in any recent travel outside New Hampshire and has spent significant time outside, the release says.

Questions can be directed to the N.H. Department of Health and Human Services’ Bureau of Infectious Disease Control during business hours Monday through Friday at 271-4496.