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NH has its fourth case of Jamestown Canyon virus this year

An adult from Epsom, NH, tested positive for the virus. They have been discharged and are recovering at home. This is NH's fourth case this year.
Credit: Getty Images/iStockphoto

CONCORD, N.H. — The New Hampshire Department of Health and Human Services (DHHS) and the Division of Public Health Services (DPHS) say they have identified New Hampshire's fourth case of the Jamestown Canyon virus.

An adult from Epsom, NH, tested positive for the virus. The patient was hospitalized with a fever, abdominal and neck pain, and a headache. They have been discharged and are recovering at home.  

The Jamestown Canyon virus (JCV) is transmitted by infected mosquitos. There are no vaccines to prevent the virus and treatment consists of supportive care. 

The arboviral risk level indicates the risk of transmission of these infections to people from mosquitoes. The risk level for the 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. 

“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.”

The first case appeared in July in an adult in Loudon, who was hospitalized for neurological symptoms and recovered at home. The second detection of JCV was in an adult from Bow. They weren't hospitalized, but experienced fever and mild neurological symptoms, NH DHHS said. 

In addition to JCV, NH DHHS says risk for infection in NH by Eastern Equine Encephalitis virus (EEEV) and West Nile Virus (WNV) will continue to increase through the summer and fall until mosquitoes are no longer biting. 

People can be infected and not develop any symptoms, or only develop very mild symptoms for all of the mosquito-borne diseases present in NH. 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.

RELATED: VERIFY: What you should know about mosquito-borne EEE virus

Prevention guide for mosquito and tick diseases:

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.
  • Ticks
  • 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.
  • Consider avoiding outdoor activities in the early morning and evening, when mosquitoes are most likely to be biting.
  • 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, which 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.

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