Leptospirosis is a water-related bacterial disease with a high incidence in Southeast Asia. People usually become infected through exposure to water contaminated by the urine of infected animals, mainly rats and mice. Researchers have revealed the relationship between rodents’ environment and infection by leptospirosis bacteria. They showed that, whereas people mainly get infected in rice fields, the bacteria are present in a variety of environments, and particularly at the frontiers of fields and forests.