• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.5
• /
• pp.740-751
• /
• 2020

In the aquaculture industry, few studies are analyzing big data for intrinsic meaning. Fishcare Laboratory (www.fishcare.kr) diagnostic data from 2016-2018 was analyzed for scuticociliatosis (caused by Miamiensis avidus) outbreak patterns in cultured olive flounder Paralichthys olivaceus in Jeju, Korea. The scuticociliatosis monthly occurrence ratio is reported in the summary table after preparing and filtering the basic dataset model. Nonparametric test results suggest differences in the water temperature, body length, and weight between groups with and without scuticociliatosis. Data distribution visualization revealed that shorter body length and lighter weight increased the occurrence of scuticociliatosis. The association rule mining technique was applied to determine the primary clinical signs of mixed scuticociliatosis and bacterial infections. Venn diagrams were used to report clinical signs and suggest commonalities. These results may help diagnose and treat fish and provide a decision-making reference.

• Journal of fish pathology
• /
• v.22 no.1
• /
• pp.45-52
• /
• 2009

Zebrafish was firstly applied to an experimental model for scuticociliatosis caused by Philasterides dicentrarchi, a facultative parasitic ciliate in cultured marine fish. The susceptibility of zebrafish to infection of P. dicentrarchi was assessed by intraperitoneal injection of the ciliates, which produced typical symptoms of scuticociliatosis and significant mortality. The potential use of zebrafish as a model to evaluate the vaccine efficacy against scuticociliatosis was analyzed by immunization of zebrafish with the ciliates lysate. Furthermore, the effect of different adjuvants, such as Quillaja saponin (QS), Montanide, and Freund’s incomplete adjuvant (FIA) on the protective efficacy of the vaccine was investigated. Groups of zebrafish injected with QS or Montanide alone showed higher survival of fish against challenge test compared to control fish. The results suggest that adjuvant-mediated enhancement of innate immune responses play important roles in protection of fish against scuticociliatosis. The considerably high survival in the fish immunized with the antigen alone indicates that the ciliate lysate itself is highly immunogenic to zebrafish, which can elicit protective immune responses. The protective potential of the antigen, ciliate lysate, was enforced through combined administration with adjuvants including QS, Montinide and FIA. No or low mortalities in the groups of fish immunized with the antigen plus adjuvants suggests that the adaptive immune responses of zebrafish might be accelerated by the adjuvants or the protective potential of the antigen and adjuvants might synergistically interact. In spite of several shortcomings such as difficulties in sampling of serum and leucocytes enough to routine immunological analyses, zebrafsih might be the most convenient experimental animal for scuticociliatosis.

• Journal of fish pathology
• /
• v.28 no.3
• /
• pp.165-169
• /
• 2015

Occurrence of Scuticociliatosis in olive flounder farm of Jeju was monitored from 2007 to 2014. As a result, 23.8~36.4% of referred samples were diagnosed as Scuticociliatosis. Based on fish size, the highest incidence (50.5%) was found in fish with size of 10~20 cm.

• Journal of fish pathology
• /
• v.16 no.2
• /
• pp.135-138
• /
• 2003

The research was carried out to know the occurrence trend of scuticociliatosis and mortality of fingerlings in flounder. The diseased fish were collected from on-land rearing farms lind hatcheries of flounder in Jeju Island from January 1991 to December 2001. Occurrence of scuticociliatosis was about 10% of total occurred diseases from 1991 to 1996, but increased to 34.5% in 2001. Although monthly occurrence of scuticociliatosis was not related to season from 1999 to 2001, the highest occurrence was revealed in July and August. Mixed infections of bacteria including Vibrio sp. Edwardsiella tarda, Streptococcus sp., and Flexibacter sp. with scuticociliates were observed. Among the bacteria, Vibrio sp. was the highest frequency(40.1%), and the lowest one(10.1%) was Streptococcus sp., Mortality of fingerlings by scuticociliates was different sharply according to size of fish. Mortality of infected fingerlings below 7 cm of total length was 53.8%, while that of normal fingerling above 7 cm of total length was 13.2%. When fish were grown above 25 cm, mass mortality by scuticociliates infection was decreased markedly.

• Journal of fish pathology
• /
• v.15 no.2
• /
• pp.93-97
• /
• 2002

The scuticociliate, a histophagous ciliate, is known to cause high cumulative mortalities in juvenile olive flounder Paralichthys olivaceus rearing in land-based tank facilities. This study examined effects of bath treatment of 3 chemical agents including formalin, hydrogen peroxide and sodium chloride. and freshwater against scnricociliates infected olive flounder. Although 100 ppm formalin and freshwater did not completeIy eliminale ue scuticociliates within the internal organ of fish, chemicals were effective to prevent scuticociliatosis from spreading. It confirms the efficacy of the chemical with treating the diseased fish for at least 4 consecutive days.

• Journal of fish pathology
• /
• v.17 no.2
• /
• pp.145-149
• /
• 2004

The definitive identification of ciliate species by morphological characteristics relies on time-consuming and laborious staining techniques. Therefore, in this study, we discriminated 3 scuticociliatosis causing species - Pseudocohnilembus persalinus, Uronema marinum and Philasterides dicentrarchi - in cultured olive flounder by multiplex PCR. The multiplex PCR based on the species-specific amplification of small subunit ribosomal RNA (SS rRNA) gene sequence enabled us to distinguish the 3 scuticociliate species in a simple and rapid manner, even in the sample containing the three species simultaneously. These data suggest that the multiplex PCR strategy would make it possible to avoid the cumbersome and time-consuming procedures of morphological analysis for the definitive identification of scuticociliates.

• Journal of fish pathology
• /
• v.20 no.1
• /
• pp.93-98
• /
• 2007

The prevalence of the scuticociliatosis in flounder farms of Jeju island was surveyed for ten years from 1995 to 2004. The occurrence ratio had maintained as less than 10% until mid 1990s, and shown increasing trends to year 1998. The ratio was equivalent to over 40% of overall disease occurrences in flounder farms since year 2000. The monthly infection rates by the scuticociliates indicated relatively higher levels from May to September, and mixed infection phenomena with bacterial disease of vibriosis were common.

• Journal of fish pathology
• /
• v.34 no.1
• /
• pp.47-53
• /
• 2021

Scuticociliates are one of the serious parasitic threats faced by the marine aquaculturists worldwide. To date, Uronema nigricans, Philasterides dicentrarchi, Miamiensis avidus, Uronema marinum, and Pseudocohnilembus persalinus have been reported as the important culprit species causing scuticociliatosis in fish. The present paper reports the finding of an additional scuticociliate isolate from the gill of diseased olive flounder Paralichthys olivaceus in Korea. Based on the morphological characteristics, a scuticociliate in this study was identified as Paranophrys marina. Phylogenetic analysis placed P. marina as a sister lineage to three species of Pseudocohnilembus and Mesanophrys carcini within the order Philasterida.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.1
• /
• pp.15-22
• /
• 2018

Alpha-pinene is an organic compound that possesses antibiotic and anti-parasitic activities. In this study, we developed a layered nanocomposite to combat against Miamiensis avidus which causes scuticociliatosis in the olive flounder Paralichthys olivaceus. We used a solid-solid reaction to develop the layered nanocomposite, incorporating-pinene ($C_{10}H_{16}$) into organically modified montmorillonite. We used cetyltrimethylammonium cations as the interlayered modifier for the adsorption of hydrophobic pinene molecules. The X-ray diffraction patterns of the nanocomposite structure showed that the basal spacing increased from $9.6{\AA}$ to $30.4{\AA}$. Interestingly, the fraction of ${\alpha}$-pinene released remained constant for a long period of time (228 h) due to the layered nature of the nanocomposite. Additionally, optical microscopic images of the treated scuticociliatids revealed that their cells were lysed, and this effect increased with the increasing concertration of ${\alpha}$-pinene. Histopathological assessment of ${\alpha}$-pinene nanocomposite-treated olive flounder gills revealed no significant morphological changes, even at the highest concentration of the ${\alpha}$-pinene. The nanocomposite has several advantages, including easy handling, high solubility, low toxicity, and the easy formulation of granules or powder, which improve the pesticidal activity of ${\alpha}$-pinene. Collectively, our results suggest that ${\alpha}$-pinene nanocomposite may be a useful treatment against scuticociliatosis.

• Fisheries and Aquatic Sciences
• /
• v.5 no.1
• /
• pp.1-4
• /
• 2002

The modulatory effects of oxytetracycline treatments at high concentrations on the infection potential of scuticociliates in cultured juvenile olive flounder (Paralichthys olivaceus) and density of the ciliates in culturing water were investigated. The groups bathed with 400 and 500 ppm of oxytetracycline showed significantly lower intensities of scuticociliates on the fish and considerably lower number of the ciliates in culturing water when compared with the control group. However, the intensity of scuticociliates on the fish in the group bathed with 300 ppm of oxytetracycline was not significantly different with that of the control group in spite of considerably lower number of scuticociliates in culturing water than in that of the control group. Although the intensities of scuticociliates on the fish intubated orally with 400 and 500 mg/kg of oxytetracycline were lower than that of the control group, there were no statistical significances. In contrast, the fish fed 300 mg/kg of oxytetracycline showed significantly lower intensity of scuticociliates when compared with other groups. The results of this study suggest that oxytetracycline treatments can modulate occurrence of scuticociliatosis in fish farms probably through change of bacterial density, damaging to scuticociliatosis and immuno-suppression of fish.