The Health Service Executive North West has confirmed that a patient in its care has presented with symptoms, which may be caused by CJD. Diagnosis has not yet been confirmed.
There are two types of CJD, sporadic and Variant CJD, which is caused when a person has consumed BSE infected food.
To date only two cases of Variant CJD have been confirmed in Ireland.
The HSE North West says that as this patient is unwell it asks that family be afforded privacy at this time.
RTÉ News understands that the patient concerned is an elderly man living in north Donegal.