A new NASA study has found that the 2015-2016 El Niño event triggered regional disease outbreaks throughout the world. El Niño is an irregularly recurring climate pattern characterised by warmer than usual ocean temperatures in the equatorial Pacific, which creates a ripple effect of anticipated weather changes in far-spread regions of Earth. During the 2015-2016 event, changes in precipitation, land surface temperatures and vegetation created and facilitated conditions for transmission of diseases, resulting in an uptick in reported cases for plague and hantavirus in Colorado and New Mexico, cholera in Tanzania, and dengue fever in Brazil and Southeast Asia, among others. The study underscores the importance of existing seasonal forecasts, which can be used to take preventive measures to minimise the spread of disease.