By NewsDesk  @infectiousdiseasenews

On Friday, two states reported Jamestown Canyon virus (JCV) in mosquitoes:


Mosquitoes recently collected in Bay, Oakland and Saginaw counties have tested positive for Jamestown Canyon virus (JCV) at the Michigan Department of Health and Human Services Bureau of Laboratories (MDHHS BOL). These are the first infected mosquito pools detected for 2021.

This is an image of female (left) and male (right) Aedes aegypti mosquitoes. Female A. aegypti mosquitoes can carry chikungunya virus.

The JCV virus is spread to people through bites from infected mosquitoes. Most cases occur from late spring through mid-fall. Illness can develop within a few days to two weeks following a bite from an infected mosquito. While most people do not become ill, initial symptoms can include fever, headache and fatigue. In rare cases, it can cause severe disease in the brain and/or spinal cord including encephalitis and meningitis.

While the JCV is found throughout much of the U.S., cases have been increasing in the Midwest. This likely reflects increased awareness and testing but may also be due to an increase in the presence of the virus in the environment. This is the first year that the MDHHS BOL is offering virus testing of mosquito pools collected by local health departments and county mosquito control programs. Testing is being offered to improve detection and notification of mosquito-borne viruses.

New Jersey: Jamestown Canyon virus reported in Sussex County resident

New Hampshire

The New Hampshire Department of Health and Human Services (DHHS) is announcing that a mosquito batch collected in Bow, NH has tested positive for Jamestown Canyon Virus (JCV).

Although humans have been previously diagnosed, this represents the first-ever detection of JCV in mosquitoes in New Hampshire. Testing mosquitoes for JCV has not been part of routine surveillance in New Hampshire, but this summer the State has launched a pilot project in collaboration with the NH Department of Natural and Cultural Resources (DNCR), Cornell University and the Northeast Regional Center of Excellence in Vector-Borne Diseases (NEVBD) to estimate the prevalence of JCV in disease-carrying species throughout Central New Hampshire. To date in 2021, DHHS has not identified JCV in a human.

Since the first report of the disease in the State in 2013, New Hampshire has identified 14 cases of JCV. Nationally, there are about 15 human cases of JCV diagnosed each year. There are no vaccines to prevent JCV and treatment consists of supportive care.

New Hampshire health officials offer the following prevention Guidelines 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.


  • 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.