PORTLAND, Ore. (KOIN) — Three cases of a rare, fatal brain disease have been reported by public health officials in Oregon’s Hood River County.

Over the past eight months, cases of Creutzfeldt-Jakob disease have been identified, though the Hood River County Health Department indicated on Friday that it’s uncertain whether these cases are connected.

As initially reported by The Oregonian/OregonLive, two of the cases have led to fatalities. Nexstar’s KOIN attempted to get verification from the Hood River County Health Department but did not receive an immediate reply.

No other details about the local cases were immediately available.

The health department in Hood River County, through a Facebook post about the investigation, assured the public that the risk remains “extremely low.”

What is Creutzfeldt-Jakob disease?

Creutzfeldt-Jakob disease is the result of a prion, a type of infectious protein, triggering a body’s normal proteins to misfold, according to the Centers for Disease Control and Prevention. There is no treatment or cure, and will typically lead to death within a year from when symptoms begin.

A neurodegenerative disorder, CJD is characterized by Alzheimer’s-like symptoms, though they get worse “much faster,” the Mayo Clinic writes. Specifically, symptoms can include memory loss, coordination issues, trouble speaking, and personality changes, according to the Mayo Clinic.

Hood River County health officials say most cases of CJD can happen without a known reason, but sometimes it can be inherited by running in families and in very rare cases, it can be spread through certain medical exposures or by eating infected beef. The latter is often referred to as “variant CJD,” the CDC says.

A report published last year suggested two hunters contracted Creutzfeldt-Jakob disease after eating venison from deer infected with chronic wasting disease, also a prion disease. The researchers behind the study noted the causation was “unproven” and that further investigation is needed.

Authorities in Oregon have not yet said what may have caused the recent cases. The rate of CJD diagnoses in the U.S. is about one person per million, the CDC estimates.

Nexstar’s Michael Bartiromo and dy Bink contributed to this report.