• Journal of fish pathology
• /
• v.18 no.2
• /
• pp.119-124
• /
• 2005

Two species of myxosporean parasites - Parvicapsula anisocaudata and an unidentified myxosporean were found in the lumina of renal tubules and the tubular epithelium, respectively, from cultured olive flounder, Paralichthys olivaceus in Korea. The latter was also seen in interstitial tissue of spleen and interrenal gland of the head kidney. Group of pseudoplasmodia of P. anisocaudata were firmly attached on the epithelium of renal tubules through pseudopodia. In the renal tubule epithelium, a group of unidentified myxosporean trophozoites, which were 2-3 times larger than intraluminal trophozoites of P. anisocaudata, was observed. The parasites being burst out into the lumen was occasionally encountered with partial break of the epithelium. Although infection of P. anisocaudata and unidentified myxosporean parasites did not induce any cellular reaction of the host, occlusion of renal tubules and rupture of renal epithelium would impact negatively on the renal functions of severely infected fish.

• Journal of fish pathology
• /
• v.31 no.2
• /
• pp.123-129
• /
• 2018

Parvicapsula anisocaudata, a myxosporean parasite, is presumably one of causative agents of emaciation in olive flounder Paralichthys olivaceus in Korea. In this study, we report a case of unusual abdominal distension due to exceptionally enlarged liver in farmed olive flounder. For the identification of the causative agent, bacteria and nucleic acids of virus that are possibly present were attempted to isolate from internal organs of five fish sampled from a fish farm in Jeju. Although a few bacterial colonies were isolated from some samples, there was no evidence that fish were primarily affected by virus and/or bacteria. From histopathological analysis, myxosporean were found in almost all internal organs, particularly in the stomach. The causative agent was identified as P. anisocaudata by sequencing a part of small subunit rRNA. This study contains a very unusual case of olive flounder heavily and systemically infected with P. anisocaudata, showing excessively enlarged liver with a small amount of ascitic fluid.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.5
• /
• pp.660-667
• /
• 2021

In recent years, myxosporean infection from the cultured olive flounders Paralichthys olivaceus, have been frequently observed in Jeju island, South Korea. This study aimed to compare histopathological and molecular-biological methods of examining myxosporean infection from these flounders. Samples were obtained from affected individuals exhibiting emaciation or abdominal distention and a polymerase chain reaction (PCR) indicative of Parvicapsular anisocaudata, Enteromyxum leei and Kudoa septempunctata were initiated. Histopathological examination were conducted with H&E stained tissue sections, and then in-situ hybridization (ISH) reaction were processed with selected sections using P. anisocaudata, E. leei, K. septempunctata and Scuticociliate probes. Renal and intestinal tissue degeneration were common symptoms associated with all samples. Sever glomerular and renal tubular degeneration were evident, as were intestinal epithelial desquamation and spore formation in the epithelial cells. The results of conventional PCR analysis and ISH reactions revealed differences, and we suspect that various microparasites may have been associated with the symptoms manifested.

• Journal of fish pathology
• /
• v.17 no.3
• /
• pp.179-189
• /
• 2004

Morphological structure and sporogenesis of myxosporean parasite, Parvicapsula anisocaudata from cultured olive flounder, Paralichthys olivaceus were examined by light and transmission electron microscopies. Numerous round early stages, spindle-shaped disporic or monosporic pseudoplasmodia, asymmetrical thin-walled mature spores were found inthe lumen of renal tubule and urinary bladder. Long pseudopodia or short projections from cytoplasm of pseudoplasmodia make the parasite attach firmly to host tissues. Spore development was mono- or disporous with no pansporoblast formation. Sporoplasmic cell was partially surrounded by two capsulogenic cells, and capsulogenic cells were enveloped by two flattened valvogenic cells. Capsulogenesis and valvogenesis followed general patterns seen in that of other myxosporean.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2002.05a
• /
• pp.551-552
• /
• 2002

• Journal of fish pathology
• /
• v.33 no.1
• /
• pp.55-62
• /
• 2020

In order to search candidates for the treatment of myxosporean emaciation disease of olive flounder, Paralichthys olivaceus, in vitro and in vivo experiments were conducted using products such as Coxi-stop, Coxiclin, and BLEAN80. In the case of Coxi-stop, whose major component is toltrazuril, in vitro experiment using BF-2 cells showed a tendency of reducing the activity of myxosporea and did not exhibit cytotoxicity such as cell lysis. In the in vivo activity measurements, the experimental group immersed with Coxi-stop showed a lower cumulative mortality rate than the control group, this result is similar to the previous report that toltrazuril has a therapeutic effect on parasitic fish disease. This study suggests that toltrazuril is a potential candidate for the treatment of emaciation disease of olive flounder.

• Journal of fish pathology
• /
• v.34 no.2
• /
• pp.161-168
• /
• 2021

Quantitative analysis of myxosporean parasites (Enteromyxum leei and Parvicapsula anisocaudata) were performed using real-time PCR on the internal organs (head kidney, body kidney, intestine, spleen, brain, liver, heart, muscle, blood, and eye) of emaciated Paralichthys olivaceus from farm-A. The highest DNA copy number of E. leei was shown in the intestine (1.3 × 10⁸ copies/mg tissue) of emaciatied P. olivaceus and DNA copy number in the other internal organs (1.3 × 10³~4.6 × 10⁵ copies/mg tissue) showed lower than in intestine. From the result of real-time PCR for P. anisocaudata, it was considered mildly infected, due to the low DNA copy numbers of the head kidney (1.3 × 10³ copies/mg tissue) and body kidney (9.1 × 10³ copies/mg tissue). In order to investigate whether myxosporean parasites can be detected in a non-invasive way, quantitative analysis of E. leei and P. anisocaudata from rearing water of three farms were performed by real-time PCR. The DNA copy number of E. leei from rearing water of farm-A and farm-B were 8 × 10⁴ and 5 × 10⁵ copies/L, respectively. However, it was not detected in farm-C. For P. anisocaudata from rearing water, farm-A, farm-B and farm-C showed 0, 2.0 × 10⁶ and 5.1 × 10⁶ copies/L, respectively.

• Journal of fish pathology
• /
• v.31 no.2
• /
• pp.101-107
• /
• 2018

Quantitative analysis of a myxosporean parasite, Parvicapsula sp. in internal organs (kidney, intestine, spleen, brain and liver) from non-emaciated (farm-A) or emaciated (farm-B and farm-C) olive flounder Paralichthys olivaceus were performed by real-time PCR. The highest DNA copy number ($1.7{\times}10^7copies/mg$ tissue) was detected in kidney of the emaciated olive flounder from farm-C, while the DNA copy number was below detection limit in all the organs of the olive flounder from farm-B. There was not positive result in all of organs from olive flounder in farm-A. PCR and histopathological analysis were also performed using the same specimen and showed same results as those by real-time PCR.

• Parasites, Hosts and Diseases
• /
• v.57 no.2
• /
• pp.127-134
• /
• 2019

Sinuolinea capsularis Davis, 1917 is myxosporean that infect the urinary system of the host fish. Insufficient morphological and molecular data of S. capsularis exits, and it is therefore difficult to make an accurate identification of the parasite. We tried a series of morphological and molecular analysis to identify an myxosporean isolated from urinary bladder of cultured olive flounder, Paralichthys olivaceus, from Jeju island in the Republic of Korea. Some of them were observed under a light microscope and SEM, and remain samples were used molecular and phylogenetic analysis. Mature spores were subspherical, measuring $13.9{\pm}0.6{\mu}m$ in length and $13.8{\pm}0.8{\mu}m$ in width. Two spherical polar capsules on opposite sides in the middle of the spore had a diameter range of $4.3{\pm}0.4{\mu}m$. Scanning electron microscopy revealed that spores a severely twisted the suture line. By the morphological comparison and analysis, it was identified as S. capsularis. In addition, we obtained the partial 18S rDNA of S. capsularis and first registered it in NCBI. Phylogenetic analysis showed that S. capsularis clustered with Zschokkella subclade infecting the urinary system of marine fish, and it supported the infection site tropism effect on phylogeny of marine myxosporeans as well as the origin of Sinuolinea is not monophyly.

• Journal of fish pathology
• /
• v.36 no.2
• /
• pp.395-401
• /
• 2023

Myxosporeans are widespread cnidarian endoparasites in marine and freshwater ecosystems and several species were reported to be a threat to cultured fish causing serious diseases with mass mortality. In the present study, we found a myxosporean species in the genus Thelohanellus from the gills of the cultured common carp (Cyprinus carpio) fingerling for the first time in Korea. The morphological observation showed 500 ㎛ ~ 1 mm size, oval to circular shaped plasmodia containing spores which are pyriform at the anterior end and round at the posterior end (average size 20.1 ㎛ × 9.1 ㎛), with 5 to 6 turns of a single polar filament located in the polar capsule with an average size of 10 ㎛ × 4.6 ㎛. The 18S rRNA sequence was closest to the sequence of T. wangi among Thelohanellus species infecting gills but was not completely identical. Based on the morphological characteristics and molecular analysis results, we classified the present myxosporean parasite as Thelohanellus sp., temporarily. The prevalence and infection intensity of Thelohanellus sp. in the common carp fingerling were very high, which was thought to be the main cause of high mortality.