Since September 19, 1996, Creutzfeldt-Jakob disease (CJD) and other human subacute spongiform encephalopathies (SSEs), regardless of their cause, have been included on the list of reportable diseases. This reporting requirement has a unique feature: since the diagnosis of the disease is only certain after neuropathological confirmation, the DO applies to any suspicion of the disease based on specific criteria. The definitive diagnosis will only be established after the patient’s death and a possible neuropathological examination. This article will focus solely on the description of the DO; the results in terms of definitive diagnoses will be presented in the following article.