• Parasites, Hosts and Diseases
• /
• v.49 no.1
• /
• pp.39-44
• /
• 2011

The infection status of marine fish and cephalopods with Anisakis simplex third stage larva (L3) was studied over a period of 1 year. A total of 2,537 specimens, which consisted of 40 species of fish and 3 species of cephalopods, were purchased from the Cooperative Fish Market in Busan, Korea, from August 2006 to July 2007. They were examined for A. simplex L3 from the whole body cavity, viscera, and muscles. A. simplex L3 were confirmed by light microscopy. The overall infection rate reached 34.3%, and average 17.1 larvae were parasitized per infected fish. Fish that recorded the highest infection rate was Lophiomus setigerus (100%), followed by Liparis tessellates (90%), Pleurogrammus azonus (90%), and Scomber japonicus (88.7%). The intensity of infection was the highest in Gadus macrocephalus (117.7 larvae per fish), followed by S. japonicus (103.9 larvae) and L. setigerus (54.2 larvae). Although abundance of A. simplex L3 was not seasonal in most of the fish species, 10 of the 16 selected species showed the highest abundance in February and April. A positive correlation between the intensity of L3 infection and the fish length was obvious in S. japonicus and G. macrocephalus. It was likely that A. simplex L3 are more frequently infected during the spring season in some species of fish. Our study revealed that eating raw or undercooked fish or cephalopods could still be a source of human infection with A. simplex L3 in Korea.

• Parasites, Hosts and Diseases
• /
• v.60 no.2
• /
• pp.79-96
• /
• 2022

The infection nature of Clonorchis sinensis metacercariae (CsMc) in freshwater fish hosts is closely related to the transmission of human clonorchiasis. This article reviewed the infection characteristics of CsMc in freshwater fish in the Republic of Korea (Korea). The status of CsMc infection was examined in a total of 17,792 cyprinid fish of 49 species in 9 water systems, which included Hantan-/Imjin-gang, Han-gang, Geum-gang, Mangyeong-gang, Yeongsan-gang, Tamjin-gang, Seomjin-gang, Nakdong-gang, and streams in the east coastal areas from 2010 to 2020. The infection status of CsMc was examined according to cyprinid fish species and water systems, after which analyzed by endemicity and susceptibility index. The high endemicity was shown in the cyprinid fish from 3 regions (6.1%) in the upper reaches of Nakdong-gang, such as Banbyeon-cheon (stream), Yongjeon-cheon, and Wi-cheon. The moderate levels were observed in fishes from 8 regions (16.3%), and low endemicity was shown in fishes from 20 regions (40.8%). No CsMc were detected in fish from 18 regions (36.7%). The susceptibility of CsMc in index fish, Puntungia herzi, was found to be a reliable index without examination of other fish species. CsMc infection rates were closely related to subfamily groups in the cyprinid fish hosts in a highly endemic area. In Korea, a total of 58 fish species in 10 families has been listed as the second intermediate hosts for C. sinensis. This review provides several novel features of CsMc infection and clarifies the species of second intermediate freshwater fish host in Korea.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.4
• /
• pp.1184-1193
• /
• 2015

Monitoring for megalocytivirus infection was conducted for ten months from March to December in 2013 in 15 aquatic farms culturing, red sea bream, rock bream, rock fish and black sea bream around Tongyoung coastal area in Korea, to assess spatial and temporal variability of detection prevalence, and to explore possible links with seawater temperature. In nested-PCR targeted major capsid protein (MCP) gene, asymptomatic megalocytivirus infection was detected in the externally healthy farmed fish with a significant prevalence in range from 0 to 58.3% for ten months. Higher prevalence of megalocytivirus (46.7% - 57.1%) was observed in high water temperature season from September to November than that in other months with lower prevalence of 0.0% to 20.0%. Even though an acute infection of megalocytivirus was occurred in rock bream (positive in the first PCR) with high mortality in one of fifteen farms, there was no expansion or transmission of the disease to the rock fish and red sea bream culturing in net cage just proximal to the rock bream cage in which disease outbreaked. Nucleotide sequence analysis of the cloned MCP gene isolated asymptomatically infected rock fish revealed that the megalocytivirus in this study was clustered together with the rock bream iridovirus (RBIV) under the subgroup II of the genus megalocytivirus (Iridoviridae), which is known to be the major megalocytivirus strain in Korea. The typical histopathological signs were not found in the spleen of rock fish asymptomatically infected by megalocytivirus. Experimental infection of rock bream with the spleen homogenate of the rock fish infected asymptomatically did not induce any mortality unlike the homogenate of infected rock bream with hih mortlity. However, these results may suggest that the asymptomatic infection of megalocytivirus in other fish species can be a potential risk threatening aquaculture industries as a transmission factor of megalocytivirus to susceptible fish species, especially rock bream.

• Parasites, Hosts and Diseases
• /
• v.62 no.1
• /
• pp.1-29
• /
• 2024

This article analyzed the infection characteristics of metacercariae of Metagonimus spp. (MsMc) in fish from 9 major water systems in Korea. A total of 19,568 fish in 87 species were examined over a period of 10 years (2011-2020). MsMc were detected in fish from all 44 survey areas in 9 water systems. Most of the surveyed sites showed very low and low infection levels (66.7%), while 33.3% of the areas, such as Tamjin-gang and Seomjin-gang, revealed moderate and high infection levels. High endemicity depends on the abundance of susceptible fish species, especially sweet smelt (Plecoglosus altivelis). The susceptibility index (SI) with MsMc in index fish, Zacco spp., was very low and low levels in 62.0%, moderate in 28.0%, and high in 10.0% regions. The SI was highest in the following order: Yeongam-cheon (283.8), Hoeng-cheon (192.3), Togyo-jeosuji (131.2), Deokcheon-gang (119.1), and Joyang-gang (106.3). The recent infection status of MsMc in P. altivelis was analyzed by the survey localities. In addition, except for P. altivelis, 9 fish species were highly infected with MsMc in some survey areas, including Zacco platypus, Z. koreanus, Z. temminckii, Opsariichthys uncirostris, Rhynchocypris oxycephalus, Carassius auratus, Acheilognathus rhombeus, Onchorhynchus masou, and Tribolodon hakonensis. In Korea, 74 fish species (15 families) are collectively listed as second intermediate hosts of Metagonimus spp. This review provides several novel characteristics of MsMc infection and clarifies the fish species of second intermediate host of Metagonimus spp. in this country.

• Parasites, Hosts and Diseases
• /
• v.59 no.5
• /
• pp.531-536
• /
• 2021

The prevalence and intensity of Opisthorchis viverrini metacercariae (OvMc) were investigated in fish from 3 southern administrative regions along the Mekong River in Cambodia, i.e., Phnom Penh, Takeo, and Kandal Provinces from 2017 to 2020. A total of 295 freshwater fish (24 species) were transported to our laboratory with ice and examined using the artificial digestion method. In Phnom Penh, among 4 fish species positive for OvMc, 9 (23.7%) of 38 specimens examined were infected, and their intensity of infection averaged 4.3 metacercariae per infected fish. In Takeo Province, among 10 fish species positive for OvMc, 24 (38.1%) out of 63 fish examined were infected, and their intensity of infection was av. 14.4 metacercariae per infected fish. In particular, all of 3 Osteochilus schlegelii fish examined were infected, and their infection intensity was high, 34.7 metacercariae per fish. In Kandal Province, among 6 fish species positive for OvMc, 46 (90.2%) out of 51 specimens examined were infected, and their infection intensity was 24.0 metacercaraie per infected fish. All fish of Systomus orphoides (n=17), Barbonymus altus (n=14), and Rasbora aurotaenia (n=2) were infected, and their intensity of infection averaged 37.7, 21.6, and 18.5 metacercariae per fish, respectively. Metacercariae of Haplochis yokogawai, Haplorchis taichui, and Centrocestus formosanus were detected in fish from Takeo and Kandal Provinces. From these results, it has been confirmed that a variety of fish species from Phnom Penh, Takeo, and Kandal Provinces are commonly infected with OvMc, and preventive measures to avoid human O. viverrini infection should be performed in Cambodia.

• Journal of fish pathology
• /
• v.34 no.1
• /
• pp.9-15
• /
• 2021

Rock bream (Oplegnathus fasciatus) is a highly valued aquaculture species in Korea. However, the aquaculture industry suffers huge economic losses due to rock bream iridovirus (RBIV) infection in summer. The objective of this study was to determine genetic diversity and relationships of DNAs isolated from two groups of rock bream after RBIV infection using five microsatellite (MS) markers. The first group of fish died early and the second group of fish died later after RBIV infection. In this experiment, 90 fish (5.1±1.0 cm and 4.1±1.3 g) were injected with 50 μl of RBIV (10⁴ TCID⁵⁰/ml) and maintained at 26℃ for 15 days. Genomic DNAs were extracted from fins of 20 fish that died earlier or later after RBIV infection. These DNAs were subjected to genotyping using five MS markers (CA-03, CA3-05, CA3-06, CA-10, and CA3-36). Of these markers, CA3-05 (early death group), CA3-06 (late death group), and CA3-36 (both early and late death groups) showed different alleles distribution rates. In-depth studies are needed to provide valuable information for selecting RBIV-resistant fish. In conclusion, microsatellite marker distribution pattern differences between early- and late- death groups of rock bream after RBIV infection showing different RBIV susceptibilities were determined using MS markers and genotyping. Results of this study suggest that MS markers could be used to facilitate the selection of RBIV resistant rock bream.

• Parasites, Hosts and Diseases
• /
• v.26 no.4
• /
• pp.263-274
• /
• 1988

Recent patterns of infection with digenetic larval trematodes in fresh- water and brackish-water ask were studied in three locations of the river Taewha during the period from April to October, 1988, and compared with the data reported previously in the same river, 0(16 species of fish examined, the encysted larvae of Cyathocotyle orientalis were found most frequently from 9 species of fresh.water fish. The metacercariae of Echinochasmus sp. , Metacercaria hasegawai and Metagonimus yokogawai were found from 8 species, those of Clonorchis sinensis from 7 species, and Exorchis oviformis and Metorchis orientalis from 5 species of fish. The infection rates of fish with C. sinensis metacercariae were not lower than those reported in 1980, whereas their intensity of infection was found lowered in 3 species, Ccreobagrus brevicorpus, Gnathopogon atromaculatus, and Funtungia herzi. The infection rates of 3 species of fish with M. yokogawai metacercariae were lower than the results in 1982, while the rate was higher in 2 species, Zacco platypus, and Z. temmincki, and rather stationary in Flecoglossus altivelis. The intensity of infection in several species of fish appeared rather higher than in 1980. The encysted larvae of C. orientalis, Echinochasmus sp., E. oviformis and Metacercaria hasegawai showed variations in infection rates of fish in 1980 and in the present study. It was found that the rate of infection with digenetic larval trematodes in fresh- water fish was still relatively high in the river Taewha, and the metacercarial burden in the fish varied greatly by different fish in 1980 and in the present study.

• Korean Journal of Veterinary Service
• /
• v.20 no.3
• /
• pp.307-312
• /
• 1997

To investigate the species and infection rate of Tripartiella sp in three species of freshwater fish, carp(Cyprinus carpio), goldfish(Crassius auratus) and Korean catfish(Parasilurus asotus), fish cultured in the fish farms next to Yosu and in the western area of Chunbuk province in Korea was examined from April to June, 1996. The infection rate was evaluated after observing the gill and mucous from 130 fish under the microscope. The species of Tripartiella was identified on the basis of the shape and number of denticle according to methods of Bychowsky(1985) after staining the parasites with 2% methyene blue solution. All the detected-parasite was classified as Tripartiella differed from Trichodina reported previously in our country. T carassii, T californica, T rhombi from Goldfish, T rhombi from common carp, T californica from Israeli carp and T bychowsky from Korean catfish were observed. In the fish from the fish farms in the western area of Chunbuk province, the infection rate of Tripartiella sp was ranged from 6.7% to 100%, but in neither carp nor goldfish from the farms next to Yosu the parasite detected.

• Journal of fish pathology
• /
• v.36 no.2
• /
• pp.303-310
• /
• 2023

Yellow goosefish (Lophius litulon) is one of the important commercial fisheries target species in Korea, and commonly consumed as braised or stew. The microsporidian Spraguea is known to infect the nervous system of lophiid fish, forming numerous visible whitish xenomas. This parasite is commonly found in lophiid fish worldwide, but there is no information on the infection status of this parasite in Korea. We obtained commercially available chopped packs of lophiid fish from several fish markets and investigated their prevalence of infection. The isolated xenomas were crushed and purified as mature spore suspension. Microscopic observation and PCR were conducted to visualize and identify them. The host fish was also identified by DNA bar cording analysis. All the specimens were heavily infected and microscopic observation with Giemsa or Chromotrope 2R stain revealed tiny oval shapes of typical microsporidian spores. PCR analysis targeting the partial SSU rDNA showed that our specimen belongs to the genus Spraguea clade. But clear identification at the species level was not possible, due to the insufficient information of gene sequences available in GenBank. In addition, all of our host fish specimen was identified as yellow goosefish. This is the first report of a microsporidian parasite Spraguea infection in yellow goosefish from Korea.

• Fisheries and Aquatic Sciences
• /
• v.3 no.1
• /
• pp.49-51
• /
• 2000

This study was performed to confirm the relationship between viral propagation and apoptosis by the infection of marine birnavirus strain (MABV NF-4) on chinook salmon embryo (CHSE-214) cells. After 6 hr viral infection, MABV was detected by PCR method. Also, as a result of DNA assay on the cells, MABV infection resulted in a typical feature of apoptosis, DNA fragmentation. The results suggest that MABV replicated to high concentrations during the early stage of infection induces apoptosis.