Date: November 05, 2021


Public Information Office
(603) 271-9389

DHHS Identifies Three Additional Jamestown Canyon Virus Cases Of The 2021 Arboviral Season In New Hampshire

Concord, NH - The New Hampshire Department of Health and Human Services (DHHS), Division of Public Health Services (DPHS) is announcing that three adults from Loudon, Pittsfield and Rumney, NH, have tested positive for Jamestown Canyon virus (JCV) , a viral infection transmitted through the bite of an infected mosquito. These are the second, third and fourth detections of JCV in persons in the State this season.

Persons infected with JCV from Rumney and Pittsfield were hospitalized with neurological symptoms; they have been discharged and are recovering at home. The person infected from Loudon was not hospitalized and is currently in good health.

The arboviral risk level for cities and towns indicates the risk of transmission mosquito-borne diseases to people. The arboviral risk level for Loudon, Rumney and Pittsfield will be increased to high. The risk level for surrounding towns of Wentworth, Warren, Ellsworth, Campton, Plymouth, Groton, Dorchester, Chichester, Gilmanton, Barnstead, Strafford, Northwood, Pembroke, Concord and Canterbury will increase to moderate. The risk level for the surrounding town of Epsom will remain moderate.

“With these three JCV infections happening in early fall, it is important to remember the season of mosquitos is longer than just the summer months. Mosquitos can continue to transmit infections like Jamestown Canyon Virus until there is a mosquito-killing hard frost,” Dr. Benjamin Chan, NH State Epidemiologist stated. “Residents and visitors of New Hampshire should take steps to avoid mosquito bites from the time the snow melts in the spring to the hard-frosts of fall.”

JCV is a mosquito-borne pathogen that circulates widely in North America primarily between deer and mosquitoes but can also infect humans. In addition to JCV, Eastern Equine Encephalitis virus (EEEV) and West Nile Virus (WNV) can also be spread to people through mosquito bites.

People can be infected and not develop any symptoms, or only develop very mild symptoms for all three mosquito-borne diseases. Early symptoms can include fever, muscle aches, headaches, and fatigue. More serious central nervous system disease, including meningitis or encephalitis can occur with these diseases. If you or someone you know is experiencing symptoms, including fever and headache, contact your local medical provider. There are no vaccines to prevent JCV and care consists of treating symptoms to keep the individual comfortable.

Reports of JCV in humans have been increasing over the last several years as recognition and testing for this virus has increased. New Hampshire has detected eighteen cases 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 NH, human cases of JCV have been recorded as early as mid-May and as late as early November.

Anyone with questions about vector-borne illnesses can call the DPHS Bureau of Infectious Disease Control at (603) 271-4496 from 8 AM to 4:30 PM, Monday through Friday. More information can also be found online


Prevention Guidelines for Mosquito and Tick Diseases
NH Department of Health and Human Services, Division of Public Health Services

  • Eliminate habitat and breeding locations.
    • Mosquitoes
      • Mosquitoes lay their eggs in standing water. Remove outdoor items that hold water (old tires, cans, plastic containers, ceramic pots).
      • Drill holes in the bottom of outdoor recycling containers, clean roof gutters and ensure proper drainage.
      • If not in use, empty and/or cover swimming pools, wading pools and hot tubs.
      • Turn over wheelbarrows and change water in birdbaths at least twice weekly.


      • Minimizing areas where hosts for the ticks, such as rodents and deer, can congregate to eat, sleep or feed.
  • Be aware of where mosquitoes and ticks live.
    • Weeds, tall grass, and bushes provide an outdoor home for mosquitoes and ticks, alike.
    • Make sure that doors and windows have tight-fitting screens. Repair or replace all screens in your home that have tears or holes.
    • Resting mosquitoes can often be flushed from indoor resting sites by using sweeping motions under beds, behind bedside tables etc. and once in flight, exterminated prior to sleeping at night.
    • Avoid tick-infested areas. If in tick-infested areas, walk in the center of trails to avoid contact with overgrown grass, brush, and leaf litter at trail edges.
  • Protect yourself from bites.
    • When outside, wear protective clothing such as socks, long-sleeved shirts, and long pants (preferably tucked in socks). Light-colored clothing helps you spot ticks.
    • Wear insect repellents, such as one containing 30% or less DEET (N,N-diethyl-methyl-meta-toluamide), Picaridin, para-menthane-diol, IR3535, or 2-undecanone or oil of lemon eucalyptus.
      • Treat clothing with permethrin, ideal for hunters as it is odorless when dry.
    • Vitamin B, ultrasonic devices, incense, and bug zappers have not been shown to be effective in preventing mosquito bites.
    • Shower as soon as possible after spending time outdoors.
    • Check for ticks daily, on you and your pets. Ticks can hide under the armpits, behind the knees, in the hair, and in the groin.
    • Wash and dry clothing after being outdoors. Tumble clothes in a dryer on high heat for 10 minutes to kill ticks on dry clothing. If the clothes are damp, additional time may be needed.
    • Early removal of ticks can reduce the risk of infection. Inspect all body surfaces carefully, and remove attached ticks with tweezers. Monitor your health closely after a tick bite and be alert for symptoms of illness. Contact your physician to discuss testing and treatment.