One Health (OH) is a crucial concept, where the interference between humans, animals and the environment matters. This review article focusses on the role of horses in maintaining the health of humans and the environment. Horses' impact on environmental health includes their influence on soil and the biodiversity of animal and plant species. Nevertheless, the effect of horses is not usually linear and several factors like plant-animal coevolutionary history, climate and animal density play significant roles. The long history of the relationship between horses and humans is shaped by the service of horses in wars or even in mines. Moreover, horses were essential in developing the first antidote to cure diphtheria. Nowadays, horses do have an influential role in animal assisted therapy, in supporting livelihoods in low income countries and as a leisure partner. Horses are of relevance in the spillover of zoonotic and emerging diseases from wildlife to human (e.g., Hendra Virus), and in non-communicable diseases (e.g., post-traumatic osteoarthritis in horses and back pain in horse riders). Furthermore, many risk factors-such as climate change and antimicrobial resistance-threaten the health of both horses and humans. Finally, the horse is a valuable factor in sustaining the health of humans and the environment, and must be incorporated in any roadmap to achieve OH.
Keywords: One Health; horse-human-ecosystems; noncommunicable diseases (NCDs); risk factor interactions; zoonosis.