Hillsborough County Man Tests Positive for Rare Tick, Mosquito-borne Viruses

A man from Hillsborough County tested positive for the Jamestown Canyon virus and the Powassan virus, marking the first time either of the diseases were found in New Hampshire, state Public Health Director José Montero announced Aug. 1.

Jamestown Canyon virus is borne by infected mosquitoes, while Powassan is transmitted by infected ticks.

"While this is our first announcement of Jamestown Canyon virus and Powassan virus in New Hampshire, these have been in the U.S. for a while and Powassan was found in Maine and Vermont previously so this is not entirely unexpected," Montero said in the state announcement.

"There are many mosquito- and tick-borne illnesses and unfortunately we are probably going to continue to see cases of them, which makes prevention steps all the more important. The same precautions we now take for Lyme and West Nile and EEE are effective against these viruses as well. So, as people enjoy New Hampshire we are urging them to use an effective repellent and do regular tick checks."

The announcement comes as New Hampshire recorded its first case of West Nile Virus of 2013; a batch of infected mosquitoes were detected in Pelham, but no person was found infected.

Like WNV, Jamestown Canyon Virus is a mosquito-borne pathogen that circulates widely in North America, primarily between deer and mosquitoes, according to Montero. Most reported human illnesses, while rare, have been mild, but "moderate-to-severe central nervous system involvement has been reported."

Powassan virus is more similar to WNV, but is transmitted by ticks.

Fewer than 60 cases of Powassan have been found in the U.S. and Canada since its discovery in 1958, according to the state.

More from Montero's announcement:

"In New Hampshire, Ixodes scapularis, or the blacklegged tick or more commonly deer tick, is capable of transmitting the virus to people. A tick needs to be attached to a person for a sufficient amount of time before it can cause disease. The time interval for Powassan virus is not known, but it is likely shorter than the time needed for Lyme disease (24–48 hours). Some people who are infected may experience mild illness or no symptoms. Powassan virus can also infect the central nervous system and cause brain inflammation."

Prevention Tips
"Residents and visitors to New Hampshire should protect themselves and their family members by using an effective mosquito repellant that contains 30% DEET, wearing long sleeves and pants at dawn and dusk when mosquitoes are most active, and removing standing water from around your house so mosquitoes do not have a place to breed. Repellents with picaridin, IR3535 and some oil of lemon eucalyptus and para-menthane-diol products also provide protection."

For more information, the state DHHS maintains a phone line at: 1-866-273-6453 during regular office hours during the week.