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DHHS Identifies Fourth Jamestown Canyon Virus Case of the 2020 Arboviral Season in New Hampshire
State Joint Information Center
(603) 223-6169

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Issued by Bureau of Infectious Disease Control
Publish Date:
October 2, 2020

Concord, NH - The New Hampshire Department of Health and Human Services (DHHS), Division of Public Health Services (DPHS) is announcing that an adult from Epsom, NH, tested positive for Jamestown Canyon virus (JCV) Adobe Acrobat Reader Symbol. The arboviral risk level Adobe Acrobat Reader Symbol for Epsom will be increased to high.

The arboviral risk level indicates the risk of transmission of these infections to people from mosquitoes. The risk level for surrounding town of Deerfield will increase to moderate. The risk level for the surrounding towns of Northwood, Pittsfield, Chichester, Pembroke and Allenstown will remain moderate.

The patient was hospitalized with a fever, abdominal and neck pain, and a headache. They have been discharged and are recovering at home. This is the fourth detection of JCV 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 rest and monitoring for escalating symptoms.

“This is the fourth detection of Jamestown Canyon Virus infection in our State this year, and it serves as a good reminder that until we experience a mosquito-killing hard frost this fall, the risk for mosquito-transmitted viral infections continues,” said Dr. Benjamin Chan, NH State Epidemiologist. “JCV is one of three mosquito-transmitted infections that can be acquired in the State and all can cause severe neurologic illness. It remains important for residents and visitors to protect themselves and their families by preventing mosquito bites.”

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) Adobe Acrobat Reader Symbol and West Nile Virus (WNV) Adobe Acrobat Reader Symbol will continue to circulate 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 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.

Reports of JCV in humans have been increasing over the last several years as recognition and testing for this virus has increased. This is New Hampshire’s twelfth 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 New Hampshire, 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 at and


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

1. Eliminate habitat and breeding locations.


  • 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.

2. 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.

3. 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.

For more information on mosquito-borne diseases, visit the DHHS Website at

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New Hampshire Department of Health and Human Services
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