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 21–27 March 2026 and includes updates on respiratory virus epidemiology in the EU/EEA, chikungunya, dengue, avian influenza, invasive meningococcal disease, and aedes aegypti detection in Luxembourg, and measles.