LACONIA — Although fall brings colder temperatures and fewer mosquitos and ticks, the danger of illnesses carried by them has not yet passed as recent announcements by the state Department of Health an Human Services show.

On Wednesday, DHHS announced that an adult from Laconia tested positive for Jamestown Canyon virus. This is the second identification in a person in the Granite State this year.

This mosquito-borne disease was first identified in a Kingston resident on Aug. 8.

Jamestown Canyon virus is transmitted by infected mosquitoes. There are no vaccines to prevent the virus.

The arboviral risk level for Laconia has been increased to high. The arboviral risk level indicates the risk of transmission of these infections to people from mosquitoes. The surrounding towns of Belmont, Gilford, Meredith, Tilton and Sanbornton were also increased to moderate.

“There are still mosquitos present this time of year that can transmit a variety of infections, including Jamestown Canyon Virus,” said Dr. Benjamin Chan, state epidemiologist. “It is important for residents and visitors to continue to take precautions to protect themselves from mosquito bites.”

Jamestown Canyon virus is a mosquito-borne pathogen that circulates widely in North America primarily between deer and mosquitoes but can also infect humans. Reports in humans have been increasing over the last several years.

This is New Hampshire’s eighth case of Jamestown Canyon virus since the first report of the disease in 2013. Most illnesses caused by Jamestown Canyon virus have been mild, but moderate-to-severe central nervous system involvement has been reported, including fatal infections.

In addition to Jamestown Canyon virus, risk for infection by Eastern Equine Encephalitis  and West Nile Virus will continue to increase until mosquitoes are no longer biting.

Last week, the state announced that a horse from Francestown has tested positive for Eastern Equine Encephalitis virus infection — the second finding of EEE in a horse this year; the first was identified on Aug. 28 in Northwood. The same mosquitoes that can cause disease in horses are also capable of causing disease in humans.

Since it was first identified in the state in 2004, there have been 15 human infections with EEE identified in NH; the last human case of EEE in NH was in 2014, when there were three cases. There have been no Eastern Equine Encephalitis infections identified yet this season in humans.

The arboviral risk level for Francestown wsaincreased to high, and surrounding towns of Bennington, Deering, Francestown, Greenfield, Lyndeborough, New Boston and Weare will increase to moderate. The arboviral risk level indicates the risk of transmission of these infections to people from mosquitoes.

“It is critical to keep using personal protective measures like insect repellent this time of year until we have a hard frost statewide,” said Lisa Morris, director of the Division of Public Health Services. “We want everyone to enjoy outdoor activities while taking the appropriate steps to prevent mosquito bites that may cause serious and potentially fatal illnesses.”

Biting mosquitoes will continue to be a disease concern until there are two, statewide, hard frosts. Tick bites remain a concern while temperatures are above freezing and ticks are not covered by snow.

Residents 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 mosquito-borne diseases.

Early symptoms can include flu-like illness including fever, muscle aches, headaches and fatigue. People infected with Jamestown Canyon virus, Eastern Equine Encephalitis  and West Nile Virus can develop more serious central nervous system disease, including meningitis or encephalitis.

If you or someone you know is experiencing flu-like symptoms, including including fever, headache, weakness, and muscle and joint pains, contact your local medical provider. Eastern Equine Encephalitis typically causes a more serious disease than West Nile Virus and carries a high mortality rate for those who contract the serious encephalitic form of the illness. There is no specific treatment for the disease.

Any horse that resides in or travels to New Hampshire during mosquito season is also at risk of becoming infected with Eastern Equine Encephalitis, West Nile Virus or Jamestown Canyon virus. Because of this risk, it is recommended that horse owners consult with their veterinarians to discuss appropriate vaccination schedules based on their risk factors.

Anyone with questions about vector-borne illnesses can call the DHHS Division of Public Health Services Bureau of Infectious Disease Control at (603) 271-4496 between 8 a.m. and 4:30 p.m., Monday through Friday. More information can also be found online at

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