State health officials consider the public’s risk of contracting a mosquito-borne virus high in Francestown after a horse in town tested positive for Eastern equine encephalitis.

As a result, the risk level in the surrounding communities of Bennington, Deering, Greenfield, Lyndeborough, New Boston and Weare is being increased to moderate, the N.H. Department of Health and Human Services announced in a news release Friday afternoon.

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

Spread by the bite of infected mosquitoes, Eastern equine encephalitis can cause lasting neurologic problems or death. Although 15 human cases of EEE in New Hampshire have been recorded since 2004, the state hasn’t had one since there were three cases in 2014.

The horse in Francestown marks the second time this year EEE has been identified in a horse in New Hampshire, after a similar report out of Northwood in late August. Both horses were euthanized, according to the state health department.

Tips for reducing the risk of infection include either avoiding being outside when mosquitoes are most active — from dusk to dawn — or wearing pants, long-sleeved shirts and socks, and using a mosquito repellent with up to 30 percent DEET, picaridin, para-menthane-diol or oil of lemon eucalyptus.

People can reduce mosquitoes’ presence in their homes by fixing screens and ensuring they’re tight-fitting and by using sweeping motions to get mosquitoes out from behind furniture and under beds and then killing them, according to the state health department.

People can also make their properties less attractive to mosquitoes by eliminating weeds and tall grasses, as well as the standing water where they breed. This includes puddles in tires, rain gutters and recycling containers. The water in birdbaths should be changed twice a week at minimum, and pools and hot tubs should be chlorinated and kept empty and covered if they’re not being used. Garden ponds can either be aerated or stocked with fish.

Anyone with questions about EEE or other viruses spread by mosquitoes or other arthropods (such as ticks) can call the state’s Bureau of Infectious Disease Control at 271-4496.