State health officials are reminding residents to use preventative measures before heading outdoors, with three mosquito- and tick-borne viruses reported in southern New Hampshire within the past two weeks.

On Aug. 8, the N.H. Department of Health and Human Services announced that an adult Kingston resident had contracted Jamestown Canyon virus and Powassan virus, marking the first identification of either in the state this year.

Five days later, the health department said batches of mosquitoes that had been collected in Pelham had tested positive for the virus that causes Eastern equine encephalitis. New Hampshire hasn’t had a human case of the potentially fatal disease since 2014.

Kingston and Pelham are in Rockingham and Hillsborough counties, respectively, with the latter nestled on the New Hampshire-Massachusetts border.

All three viruses are vector-borne — spread by an organism between hosts — with Jamestown Canyon virus and EEE transmitted by infected mosquitoes and Powassan virus by infected ticks.

Jake Leon, spokesman for the state health department, said EEE is typically found in mosquito batches every summer, but a human testing positive for it is rare. Since 2004, there have been 15 confirmed cases in the state.

And finding Powassan or Jamestown Canyon virus in the same person is definitely out of the ordinary.

This is New Hampshire’s seventh known human case of Jamestown Canyon virus since it was first identified in New Hampshire in 2013 and the fourth case of Powassan virus, according to the state agency. As with EEE, there’s no vaccine available, and illness is treated only by supportive care.

Though there is no direct threat to the Monadnock Region, Leon said everyone should be vigilant.

“It’s hard to say or anticipate if and when [these diseases] would hit in a particular part of the state, but August into September, there’s going to be a lot of mosquitoes,” Leon said. “This is the time of year a lot of these illnesses are beginning to be diagnosed in New Hampshire.”

Tick infections are also a risk, Leon said, and can be even more harmful for the host than those caused by mosquitoes.

The majority of Powassan cases are seen in the Northeast and upper Midwest, and approximately half of the people who become sick from the virus have permanent neurological symptoms, such as recurrent headaches, muscle wasting and memory problems, the agency’s website states.

“It’s still tick season, and the diseases related to ticks can be very difficult for individuals who contract them,” Leon said. “Take those necessary precautions.”

The agency recommends wearing mosquito and tick repellent with 20 to 30 percent DEET, picaridin, or oil of lemon eucalyptus; tucking shirts into pants and pants into socks when outside; removing the standing water where mosquitoes breed; and cutting grass short to make it less hospitable for ticks.

The agency also suggests checking regularly for ticks, removing any you find and taking a shower once heading back inside.

Leon said he understands how burdensome wearing long-sleeved shirts and pants on a 90-degree day can be, but it can make all the difference.

Luckily, in recent years, he said he thinks people have put more effort into prevention.

“Part of it is the greater awareness,” Leon said. “I think hikers and those who enjoy outdoor activities are becoming more and more aware.”

More information is available from the N.H. Department of Health and Human Services’ Bureau of Infectious Disease Control during business hours, Monday through Friday, at 271-4496.

Olivia Belanger can be reached

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