Here, we provide an update on the significant progress towards understanding transmission of Mycobacterium ulcerans, the causative agent of the neglected tropical skin disease, Buruli ulcer. We review the evidence that Buruli ulcer is an enzootic infection among Australian native possums, and we discuss the role of mosquitoes in transmit the infection to humans. We show how studies of M. ulcerans transmission – following the dramatic emergence of Buruli ulcer in temperate south-eastern Australia – are being supported by adherence to One Health principles, with interdisciplinary research teams uncovering connections between human health, animal health, and the environment. We also discuss some of the distinctive features of M. ulcerans revealed by genomics that should be considered when thinking about how this pathogen is spreading.