A Case Report of Lobomycosis-Like Disease in a Stranded Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) in Kinko-Wan, Kagoshima, Japan
In addition to the well-known resident populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Mikura Island3,4 and Amakusa,6 smaller populations in Kagoshima Bay (ca 50) and Noto Peninsula (8) have been reported from the mainland of Japan. A dolphin was found stranded probably live about 11:00 on 15 May 2013 in Kinko-wan, Kagoshima, Kyushu, Japan. When one of the authors (KS or NK) arrived the animal was identified as T. aduncus and it had already died. It was a large male, with total body length of 2.7 m. The animal was known as a member of Kinko-wan populations. Serious skin lesions were found on the top of melon, around blowhole, both flippers and the area caudal to the anal-genital region. The appearance of these skin lesions made us suspect lobomycosis. Lobomycosis (lacaziosis) is a chronic fungal disease of the skin and subcutaneous tissues that occurs in dolphins especially Tursiops truncatus and T. aduncus in various parts of the world and humans under natural conditions.1 This skin disease in dolphins is characterized by grayish, whitish to slightly pink, verrucous lesions, often in pronounced relief that may ulcerate.5 The etiologic agent, Lacazia loboi, is a yeast-like organism that is found richly within lesions,7 Loboa loboi2.
About 30 hours after death, the animal was examined pathologically at National Museum of Nature and Science, about 80 km northeast to Tokyo, transported by a refrigerating truck with +4°C. During the necropsy, the skin lesions were found to be in the cutaneous and subcutaneous areas of the skin. Nearly all of the lymph nodes such as the superficial cervical, pulmonary marginal, pancreatic and around the rectum were severely swollen and edematous. The lungs, especially right one demonstrated severely edematous and adhered to the pleura, and had many nodes, which were yellowish white in color and various in size, the largest one was 20 cm in diameter. The rest of organs showed no significant changes. Microscopically, the lesions of the skin showed granulomatous reaction and hyperkeratosis that is similar to that of the references of lobomycosis; however, the fungus organism was not found in HE stain. The lung demonstrated severe suppurative pneumonia with numerous neutrophils, macrophages and lymphocytes surrounding the necrotic parenchyma with many bacteria. PCR analysis was done to confirm viral skin diseases caused by pox virus and papilloma virus. PAS stain and Gomori methenamine silver stain were done to confirm the fungus organism in skin lesions. This case is a first record of lobomycosis like disease of Indo-Pacific bottlenose dolphin in Japan.
The authors would like to express our gratitude for great help of Kagoshima City Office and the staff of Kagoshima City Aquarium to collect an animal.
* Presenting author
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