The ECDC Communicable Disease Threats Report (CDTR) is a weekly bulletin for epidemiologists and health professionals on active public health threats. This issue of the ECDC Communicable Disease Threats Report (CDTR) covers the period 7-13 December 2024 and includes updates on measles, chikungunya, avian influenza, mpox, West Nile virus, circulating vaccine-derived poliovirus type 2, hepatitis A, suspected viral haemorrhagic fever in Sierra Leone, an unknown disease in the Democratic Republic of Congo, and an overview of respiratory virus epidemiology in the EU/EEA.