A brain-infecting myxozoan, Kudoa yasunagai (Hsieh & Chen, 1984), was identified using both morphological and molecular methods in a marine fish from Van Phong Bay, Khanh Hoa province, Vietnam. Cysts containing spores were observed in the brain of one out of 10 Siganus virgatus (Valenciennes) individuals (10%). The myxospores were radially symmetrical, containing a majority of 7 equal shell valves and polar capsules. | ACADEMIA JOURNAL OF BIOLOGY 2024 46 1 87 97 DOI 2615-9023 19453 THE FIRST RECORD OF Kudoa yasunagai Hsieh amp Chen 1984 Myxosporea Multivalvulida PARASITIZING THE BRAIN OF BARHEAD SPINEFOOT Siganus virgatus Valenciennes FROM VIETNAM Nguyen Ngoc Chinh1 Sho Shirakashi2 1 Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Ha Noi Vietnam 2 Aquaculture Research Institute Kindai University 3153 Shirahama Nishimuro Wakayama 649-2211 Japan Received 20 November 2023 accepted 19 March 2024 ABSTRACT A brain-infecting myxozoan Kudoa yasunagai Hsieh amp Chen 1984 was identified using both morphological and molecular methods in a marine fish from Van Phong Bay Khanh Hoa province Vietnam. Cysts containing spores were observed in the brain of one out of 10 Siganus virgatus Valenciennes individuals 10 . The myxospores were radially symmetrical containing a majority of 7 equal shell valves and polar capsules. The spores measured µm in length µm in width and µm in thickness. Polar capsules measured µm in length and µm in width containing a filament inside. The SSU rDNA sequence from the Vietnamese specimen showed gt identity with K. yasunagai from Japan and Australia. This report marks a new geographical and host record for K. yasunagai. Keywords Kudoidae brain marine fish SSU rDNA Khanh Hoa province. Citation Nguyen Ngoc Chinh Sho Shirakashi 2024. The first record of Kudoa yasunagai Hsieh amp Chen 1984 Myxosporea Multivalvulida parasitizing the brain of barhead spinefoot Siganus virgatus Valenciennes from Vietnam. Academia Journal of Biology 46 1 87 97. https 2615-9023 19453 Corresponding author email shirakashi@ 87 Nguyen Ngoc Chinh Sho Shirakashi INTRODUCTION MATERIALS AND METHODS The Barhead spinefoot Siganus virgatus Fish sampling and parasite collection Valenciennes Perciformes Siganidae is a Ten .
