Invasive candidiasis caused by Candida tropicalis in an endangered Ryukyu long-furred rat (Diplothrixlegata)

The Ryukyu long-furred rat (Diplothrix legata) is an endemic rodent species restricted to the Ryukyu Islands, Japan, and is classified as Endangered on the IUCN Red List. In 2024, a debilitated rat bearing a wound suggestive of a snakebite was found in the wild on Amami Oshima Island and was admitted to a veterinary hospital, where it subsequently died despite supportive care. Histological and ultrastructural examinations revealed coagulative necrosis with a proliferation of yeast-like fungi in the liver and kidneys. Polymerase chain reaction analysis of lesions identified the causative agent as Candida tropicalis, a dimorphic yeast. The injury and the associated high-stress conditions following transfer to a captive environment and corticosteroid administration for the management of a suspected venomous snakebite may have contributed to immunosuppression, predisposing the animal to opportunistic infections with C. tropicalis. To our knowledge, this is the first report of natural C. tropicalis infection in a member of the Muridae family, and invasive candidiasis caused by C. tropicalis is a potentially fatal opportunistic infection in injured wildlife.