CBS Local – There are a few drawbacks to the calendar shifting to the summer months, like the influx of ticks and infections like Lyme Disease. Now doctors are cautioning of another, potentially fatal tick-borne disease: Powassan Virus.

Powassan virus is even more serious than Lyme, as it causes inflammation to the brain. For the reported cases, 15 percent of those infected have died and another 50 percent have had some form of a neurological disability. As of right now, there’s no cure.

Symptoms include fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties and seizures.

“About 15 percent of patients who are infected and have symptoms are not going survive,” Dr. Jennifer Lyons, chief of the division of neurological and inflammatory diseases at the Brigham and Women’s Hospital, said, via CNN. “Of the survivors, at least 50 percent will have long-term neurological damage that is not going to resolve.”

The recent proliferation of Powassan virus cases is because deer ticks have begun carrying it, and deer ticks bite more regularly than other ticks.

deer ticks Powassan Virus: The Rare, Deadly Tick Borne Disease Thats Scaring Doctors

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“There are some experimental therapies we try when somebody comes in and they get here early enough, and we get the therapy started early enough, but we have no idea if any of that works,” Lyons said.

Thankfully, the ticks carrying the disease are not a majority. Far from it. According a report out of Maine, 7 percent of ticks carry the disease and another from New York that found about 1-2 percent do so. Compare that to Lyme Disease, where it’s estimated that about 20 percent of all ticks carry it.

At this point, the only human cases of Powassan have been transmitted by a tick bite.