Systemic infection of Kudoa lutjanus n. sp. (Myxozoa: Myxosporea) in red snapperLutjanus erythropterus from Taiwan

Diseases of Aquatic Organisms

Pei-Chi Wang Ju-ping Huang Ming-An Tsai Shu-Yun Cheng Shin-Shyong Tsai3 Shi-De Chen Shih-Ping Chen Shih-Hau Chiu Li-Ling Liaw Li-Teh Chang Shih-Chu Chen¹ 

关键词: Myxosporea;    Kudoa lutjanus n. sp.;    Brain;    Red snapper;    Lutjanus erythropterus;   

DOI  :  10.3354/dao067115

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: A new species of Kudoa lutjanus n. sp. (Myxosporea) is described from the brain and internal organs of cultured red snapper Lutjanus erythropterus from Taiwan. The fish, 260 to 390 g in weight, exhibited anorexia and poor appetite and swam in the surface water during outbreaks. Cumulative mortality was about 1% during a period of 3 wk. The red snapper exhibited numerous creamy-white pseudocysts, 0.003 to 0.65 cm (n = 100) in diameter, in the eye, swim bladder, muscle and other internal organs, but especially in the brain. The number of pseudocysts per infected fish was not correlated with fish size or condition. Mature spores were quadrate in apical view and suboval in side view, measuring 8.2 ± 0.59 µm in width and 7.3 ± 0.53 µm in length. The 4 valves were equal in size, each with 1 polar capsule. Polar capsules were pyriform in shape, measuring 3.62 ± 0.49 µm in length and 2.2 ± 0.49 µm in width. Mild inflammatory responses or liquefaction of host tissue were associated with K. lutjanus n. sp. infection. The junction of shell valves appeared as overlapping, straight lines. The polar filament formed 2 to 3 coils. A general PCR (polymerase chain reaction) primer for Kudoa amplified the small subunit (SSU) rDNA sequences, and the amplified gene was sequenced. It was evident from the phylogenetic tree that the 3 strains tested, AOD93020M, AOD93028M and AOD93028B, were identical and belonged to the Kudoa SS rRNA subgroup. The evolutionary tree showed that these strains form a unique clade, at a distance from other Kudoa species and myxosporeans. The spore’s morphological and ultrastructural characteristics, as well as the SS rDNA properties of the isolates, were also essentially identical and served to distinguish them from representative Kudoa. It is, therefore, proposed that the strains isolated from the diseased red snapper be assigned to a new species.

【 授权许可】

Unknown