(CBS Local) — A 61-year-old New York man developed an extremely rare and fatal brain disorder after he ate squirrel brains, according to a new report.

The unnamed victim was taken to a hospital in Rochester, New York in 2015 after his ability to think and was losing touch with reality. He also could no longer walk.

His family described him as an avid hunter who had dined on squirrel brains. However, it was not clear if the man had consumed the entire squirrel brain or just squirrel meat that was contaminated with parts of squirrel brain, according to Dr. Tara Chen, a medical resident at Rochester Regional Health and lead author of the report.

Chen presented the report October 4 at IDWeek, an annual meeting of infectious diseases professionals.

Tests indicated that this was a “probable” case of variant Creutzfeldt-Jakob disease (vCJD), a fatal brain condition caused by infectious proteins called prions, because of the MRI finding and a test that showed specific proteins in the patient’s cerebrospinal fluid, which often indicate the disease.

Only a few hundred cases of vCJD have ever been officially reported, most tied to consumption of contaminated beef in the United Kingdom in the 1980s and 1990s.

Only four confirmed cases of vCJD had been reported in the United States, according to the Centers for Disease Control and Prevention (CDC).

There are three forms of Creutzfeldt-Jakob disease (CJD) and one form, which includes vCJD, is caused by exposure to infected tissue from the brain or nervous system tissue.

Symptoms include depression, anxiety, memory loss, personality changes, impaired thinking, difficulty swallowing and difficulty speaking.