This issue of the ECDC Communicable Disease Threats Report (CDTR) covers the period from 12-18 May 2019 and includes updates on poliomyelitis, chikungunya virus disease and dengue, measles, monkeypox, dengue, Ebola virus disease, influenza, Rift Valley fever, Crimean-Congo haemmorhagic fever and Legionnaires' disease.