A New Hampshire resident has been hospitalized in Maine with Eastern equine encephalitis, a potentially deadly disease carried by mosquitoes, according to the Maine Center for Disease Control and Prevention.

The patient, an individual in his or her 50s whose identity is being withheld in accordance with confidentiality laws, contracted the viral illness in New Hampshire, according to Maine CDC Director Dr. Sheila Pinette. The patient is being treated at Maine Medical Center in Portland, which can provide the high level of care the individual needs, she said.

The rare illness, transmitted by the bite of an infected mosquito, can lead to encephalitis, or inflammation of the brain, resulting in death in one out of every three human cases.

EEE has no cure. Treatment consists of supportive care, including mechanical ventilation, IV fluids, and medication to control seizures and reduce brain swelling.

“The patient’s quite ill,” Pinette said.

New Hampshire public health officials confirmed that state’s first human case of EEE in five years in an adult from Conway on Aug. 21.

Severe cases of EEE begin with a sudden headache, high fever, chills, and vomiting. The illness may then worsen, causing disorientation, seizures or coma.

Most individuals infected with the virus experience no symptoms of illness, according to the U.S. CDC. Approximately half of those who do display symptoms of EEE will suffer mild to severe permanent neurological damage.

Two Vermont residents died from the disease in 2012.

Maine has never recorded a human case of EEE. A visitor to the state from Massachusetts died from the disease in 2008.

The illness reappeared in Maine after killing 15 horses in 2009. In 2012, a flock of 30 farm-raised pheasants in Lebanon died from EEE. Last year, the virus led to the deaths of two horses in Maine.

While horses can be immunized against EEE, there is no vaccine for humans.

So far this year, EEE hasn’t appeared in Maine’s mosquito testing pools, Pinette said. But it was present last year in York County, and she urged Mainers to avoid bites from mosquitoes, which can also carry West Nile virus.

Maine CDC recommends the following preventive measures to protect against mosquito-borne illnesses:

— Avoid spending time outdoors at dawn and dusk when many species of mosquitoes are most active.

— Use an EPA-approved repellent when outdoors and always follow the instructions on the product’s label. Lemon eucalyptus oil is a natural alternative.

— For children under three, use netting on strollers.

— Wear protective clothing when outdoors, including hats, long-sleeved shirts, pants and socks.

— Use screens on windows and doors to keep mosquitoes out of the home, and patch any holes.

— Empty standing water where mosquitoes can breed, such as from flower pots, tire swings, buckets and barrels.