Healthy ecosystems support the well-being of all organisms on Earth. Yet, the overexploitation of natural resources for human needs and profit has resulted in widespread ecosystem degradation, loss of biodiversity, and climate emergency, which pose fundamental threats to planetary well-being. Impoverished ecosystems may become dysfunctional and fail to provide for the needs of many organisms, including humans and wildlife. Changes in ecosystem functioning and wildlife distributions affect the prevalence and spread of pathogens, with consequences for the health and well-being of human and wildlife communities alike. Increasing contact between humans and domestic and wild animals enable pathogen spillover, while global trade and travel distribute pathogens to new areas. Human activities thus provide favourable conditions for pandemics and trigger cascading consequences for ecosystems worldwide. A better integration of ecosystem health into public health and conservation planning could alleviate disease burden and improve well-being of all organisms on the planet.