The Tsushima leopard cat, a species found only on Tsushima island in Nagasaki Prefecture, is on the brink of extinction, and the current population is thought to comprise just 80-110 cats. The Ministry of the Environment is engaged in conserving the species through a plan to breed individuals in captivity and then release them into the wild, but there is a significant threat from habitat competition with domestic cats and infectious diseases with high fatality rates, such as feline immunodeficiency virus (FIV). In order to avoid extinction, veterinary care and other measures will be crucial in preventing infection from domestic cats and preventing deaths in the released population from traffic accidents and the like. This project will eradicate infectious diseases from the habitat area, ensure that domesticated animals in the region are being kept appropriately, and implement veterinary health care measures such as emergency care for protected populations after traffic and other accidents, and support for animals released back into the wild. These measures will contribute to avoiding the extinction of the Tsushima leopard cat and creating a breeding population, as well as provide important information for taking measures against invasive species all over the world.