• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.100-103
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• 1998

A survey on the incidence of metacercariae infection of Clonorchis sinensis in the fresh water fish, Pseudorasbora parva which is well known as the second intermediate host for this fluke was carried out in the upper stream of Phoung-tack stream, Kyungki province during the period of October to November 1997. Forty fish in P. parva were collected by netting, or using the bait in transparent bowls from the two different districts located in Osung-myun, Phoungtack-gun and transported to the laboratory. The body length and weight were measured. They were from 5.0 to 7.6 cm in length and 1.0 to 5.0 g in weight. A total of 40 P. parva were divided 3 groups by the size (70-79, 60-69 and 50-59 mm) and were digested by artificial digestion with pepsin-Hcl solution in a 36$\circ$C incubator and then examined the infection density of metacercariae of the fresh water fish under a binocular dissecting microscope. The incidence of metacercariae infection in P. parva was 406 of 40 examined and the metacercariae detection rate showed 77.5%. The average number of metacercariae detected in P. parva was 10.2. The results of the survey indicate that Clonorchis sinensis infection may occur by consuming raw fresh water fish caught from the upper stream of Phoungtackho, Kyungki province.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.283-285
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• 1996

Six metacercariae were found from the gill filaments of Conger myriaster purchased at Mokpo-shi in korean on September, 1996. Based on the morphology of the excysted specimen. we identified them as metacercariae of Heterophyosis continua, C. myriaster is a new intermediate host H. continua in the literature.

• Parasites, Hosts and Diseases
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• v.54 no.3
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• pp.363-368
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• 2016

We describe here the mass death of predatory carp, Chanodichthys erythropterus, in Korea induced by plerocercoid larvae of Ligula intestinalis as a result of host manipulation. The carcasses of fish with ligulid larvae were first found in the river-edge areas of Chilgok-bo in Nakdong-gang (River), Korea at early February 2016. This ecological phenomena also occurred in the adjacent areas of 3 dams of Nakdong-gang, i.e., Gangjeong-bo, Dalseong-bo, and Hapcheon-Changnyeong-bo. Total 1,173 fish carcasses were collected from the 4 regions. To examine the cause of death, we captured 10 wondering carp in the river-edge areas of Hapcheon-Changnyeong-bo with a landing net. They were 24.0-28.5 cm in length and 147-257 g in weight, and had 2-11 plerocercoid larvae in the abdominal cavity. Their digestive organs were slender and empty, and reproductive organs were not observed at all. The plerocercoid larvae occupied almost all spaces of the abdominal cavity under the air bladders. The proportion of larvae per fish was 14.6-32.1% of body weight. The larvae were ivory-white, 21.5-63.0 cm long, and 6.0-13.8 g in weight. We suggest that the preference for the river-edge in infected fish during winter is a modified behavioral response by host manipulation of the tapeworm larvae. The life cycle of this tapeworm seems to be successfully continued as the infected fish can be easily eaten by avian definitive hosts.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.11-18
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• 1983

As a part of observation on the suitability as a second intermediate host of Clonorchis sinensis, various infection experiments were tried to Cyprinus carpio nodus. The results obtained were summarized as follows: 1. The cercariae which attempted to contact with Cyprinus carpio nodus in the water were observed under the stereomicroscope. After contact, cercariae began to separate its tails from the bodies at 4 minutes increasingly, and then the numbers ranged to 80% at 13 minutes after the encounter. But very few cercariae could actually invade into the epidermis of the fish. 2. When Cyprinus carpio nudes were exposed to a number of cercariae in the beaker, only a few cercariae could invade through the epidermis. Most of the invaded cercariae were killed before forming the cyst. Also rare encysted cercariae were found to be dead within 48 hours. 3. Cyprinus carpio nudes were reared with Parafossarulus manchouricus shedding numerous cercariae in the indoor aquarium. When observed after 12 days, to determine the susceptibility, no metacercaria was found infected. 4. Cyprinus carpio nudum were reared with Parafossarulus manchouricus shedding numerous cercariae in Kimhae lake for 2 months in summer of 1982, in order to check the natural infection. No metacercaria of Clonorchis sinensis was found from the fish. 5. In the cases of control fish, Pseudoraibora larva, numerous cercariae were inspected on the course of invasion through epidermis of the fish under the stereomicroscope. And many metacercariae were also found from the Ssh whenever they were kept in beaker, indoor aquarium, or the lake for natural infection. The results suggested that Cyprinus carpio kudus might not be proper intermediate host of Clonorchis sinensis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.23-30
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• 2018

Kudoa septempunctata, a myxosporean parasite that infects olive flounder Paralichthys olivaceus is known to cause Kudoa food poisoning. Entire trunk muscle (ETM) is used for diagnosis of the parasite in fish and this method demands sacrifice of the host, causing a loss of commercial value. We developed a non-destructive method that uses a plastic syringe-style implanter to draw the sample, called the part-point muscle (PPM) sampling technique. We validated the PPM method in fish infected with K. septempunctata at the level detectable by the ETM method. We confirmed that the PPM method is equally sensitive in comparison to the ETM method for diagnosing K. septempunctata spores in olive flounder muscle. Our study also confirmed that the parasite is uniformly distributed in the dorsal muscle of infected fish. Over a period of 1 month, we observed no mortality of the host fish used for sampling by the PPM method. Thus, our studies demonstrate that the PPM sampling technique is an efficient, non-destructive method for diagnosing K. septempunctata in olive flounder.

• Journal of fish pathology
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• v.29 no.1
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• pp.1-5
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• 2016

Isopods are parasitic crustaceans that pose serious threat to fisheries. Several studies have tried to explore the host-pathogen relationship between marine fishes and isopods. The present study aims to understanding the secondary infections in marine fishes pertaining to isopods. To assess the secondary infection in infected fishes, parasite infested and healthy tissues of fishes were collected. The samples were subjected to standard microbiological procedure to identify the presence of pathogenic bacteria and fungi. Our results showed the branchial region had the higher microbial load of non-sporulating cenocytic fungi in infected fishes. Moreover, fungal strains isolated from the parasitic lesion confirmed that the parasitation and body lesion facilitates the entry of several pathogenic microbes at the damaged host tissue. More over the immune regulation of fish fights back by producing minute cysts, trying to encapsulate the growing fungus. But this may eventually lead to systemic infestation and death of the fish.

• Journal of fish pathology
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• v.33 no.1
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• pp.15-21
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• 2020

We found skin flukes in snubnose pompano (Trachinotus blochii) from a public aquarium and attempted clear identification of them to the species level by morphology and molecular analyses. Skin flukes were collected from snubnose pompano showing dyspnea, anorexia and mild hemorrhage on the skin. All the fish samples (n=2) were infected with the flukes on the skin, gill and eyes, covered with excessive mucus. The isolated worms were transferred for making slide specimen and PCR amplification targeting 18S rDNA, 28S rDNA, mitochondrial cytochrome c oxidase subunit 1 (mt cox1) and cytochrome b (Cytb) genes for further analyses. Morphology and measurements data of our slide specimen coincided with those of Neobenedenia girellae. The sequence data of 2 genes (28S rDNA and Cytb) and the phylogenetic trees revealed that our specimen consistently belonged to the N. girellae clade. For 18S rDNA and mt cox1 genes, there was no sequence of either of these 2 Neobenedenia species from the type host available in GenBank. This is the first record of N. girellae in snubnose pompano, but it is still unclear if the snubnose pompano is a natural host for N. girellae or not because N. girellae is known to have an unusual broad host range and the host-switching can occur particularly in captive conditions such as aquarium or aquaculture facilities.

• Journal of fish pathology
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• v.30 no.2
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• pp.71-78
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• 2017

The glycoprotein of novirhabdoviruses is known to play a critical role in the determination of host specificity. Viral hemorrhagic septicemia viruses (VHSVs) in different genotypes have different glycoprotein sequences and show different preferences for specific cell lines. In this study, to know whether the glycoprotein is solely responsible for the host cell preference of VHSV, a recombinant VHSV expressing vesicular stomatitis virus (VSV) glycoprotein instead of VHSV IVa glycoprotein (rVHSV-VSV-G) was generated by reverse genetics and inoculated into several fish cell lines, then, cytopathic effect (CPE) and viral growth caused by rVHSV-VSV-G infection were compared with those caused by rVHSV-wild that was previously generated and has the same genomic sequence with wild-type VHSV except a few nucleotides. The plaque numbers of rVHSV-VSV-G were significantly higher in EPC, BF-2 and GF cells than those of rVHSV-wild. However, in HINAE cells (originated from olive flounder), rVHSV-VSV-G titer was significantly lower than rVHSV-wild titer, and both recombinant VHSVs were not grown well in CHSE-214 cells. Although statistical significances were detected in the titers between rVHSV-wild and rVHSV-VSV-G in several cell lines, the cell line-preference order of rVHSV-VSV-G was not different from that of rVHSV-wild. These results suggest that the replacement of VHSV glycoprotein may not completely change host cell preference, and other regions of VHSV might also involve in the determination of host cell preference.

• 한국해양학회지
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• v.29 no.1
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• pp.1-4
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• 1994

The fish host, Acanthogobius hasta, was sampled monthly (April 1990 to March 1991) from Wando Islands, Korea, and examined for the parasitic Copepod Acanthochondria brevicorpa. Prevalence was positively correlated with fish length; parasitic copepods were only found in fishes > 24 cm TL. distinct seasonal variation in prevalence and intensity of A. brevicorpa infection was observed, although no data were available in April, June and July 1990 when no A. hasta was caught. Averaged over all samples, of the 83 fishes caught, 34.9% were infected with a mean intensity of 3 copepods per host No A. brevicorpa was found on the host between August and October. Ovigerous females of the Copepod were found between February and May, with an abundance peak in May. Young copepodids (Ci to CIII) of A. brevicorpa were not present throughout the year, but only late copepodids of CIV and CV were found on the fish in March and May. Results from the present study suggest that A. brevicorpa mainly produces larvae in spring, and may have a life cycle including additional hosts.

• Journal of fish pathology
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• v.34 no.1
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• pp.55-61
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• 2021

One of the major problems in fish production is that parasite-induced episodes of disease can result in significant impacts to the health of stock, mortalities and, economical losses. Seabreams are economically important fish in both the capture fishery and aquaculture sectors in Oman and represent potential species for aquaculture. The current study set out to investigate infection of polyopisthocotylean monogeneans on the gills of wild goldlined seabream, Rhabdosargus sarba, caught from Musairah region in Oman. The prevalence, mean intensity and abundance of polyopisthocotyleans on 145 fish was found to be 52.41%, 5.65 and 3.04, respectively. Three species of microcotylid parasite were isolated, one being Atrispinum acarne while the remaining two species require further study to identify them. There was no significant difference in the infection rate between host sex, however, parasite burdens were higher on larger sized fish (p<0.05) and were found to favour the first gill arch (p< 0.05). The study found that the sample of Rhabdosargus sarba landed in the waters around Musairah are heavily infected, with a predominantly immature population of microcotylids. Further work is required to better understand the potential risk each species poses to the health of its host before a decision is made on the suitability of new candidate fish species for commercial aquaculture.