Systemic infection of Kudoa lutjanus n. sp. (Myxozoa: Myxosporea) in red snapper Lutjanus erythropterus from Taiwan.
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 microm in width and 7.3 +/- 0.53 microm 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 microm in length and 2.2 +/- 0.49 microm 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.
Wang
Pei-Chi
PC
Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan.
Huang
Ju-ping
JP
Tsai
Ming-An
MA
Cheng
Shu-Yun
SY
Tsai
Shin-Shyong
SS
Chen
Shi-De
SD
Chen
Shih-Ping
SP
Chiu
Shih-Hau
SH
Liaw
Li-Ling
LL
Chang
Li-Teh
LT
Chen
Shih-Chu
SC
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000469:parasitology; D017931:DNA Primers; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D004196:Disease Outbreaks / Q000662:veterinary*; D056890:Eukaryota / Q000166:cytology* / Q000235:genetics*; D005393:Fish Diseases / Q000453:epidemiology* / Q000469:parasitology* / Q000473:pathology*; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D008969:Molecular Sequence Data; D010473:Perciformes; D010802:Phylogeny; D011529:Protozoan Infections, Animal / Q000453:epidemiology / Q000473:pathology*; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013045:Species Specificity; D033761:Spores, Protozoan / Q000648:ultrastructure; D013624:Taiwan / Q000453:epidemiology; D014781:Viscera / Q000469:parasitology
D017931:DNA Primers; D021903:DNA, Ribosomal Spacer