• Applied Microscopy
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• v.41 no.3
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• pp.205-213
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• 2011

Numerous anisakids were parasitic near the digestive tract of the black rockfish, Sebastes schlegeli and some anisakids observed on the liver of the host. Anisakids in the host were identified three species (Hysterothylacium sp., Anisakis simplex, A. pegreffii) and Hysterothylacium sp. was the high occurrence of anisakid worms in the host. Hysterothylacium sp. was shorter and thinner than A. simplex. Both of anisakids observed lip, mouth, nerve ring, excretory pore and excretory duct in the anterior portion. In the mid portion, anisakids had esophagus, ventriculus and intestine and especially, Hysterothylacium sp. had intestinal ceacum and ventricular appendage. There was conical nodulose apex at the end of the posterior portion in Hysterothylacium sp. and spine in A. simplex. SEM examination revealed that there was three lip near the mouth of Hysterothylacium sp. Dorsal lip was approximately 65 ${\mu}m$ and paried lateroventral lip were approximately 60 ${\mu}m$ in the width. All lips were found double papilla (approximately 8 ${\mu}m$ in the width). The body width of the Hysterothylacium sp. and A. simplex was approximately 480 ${\mu}m$ and 900 ${\mu}m$ respectively. The hight of the lateral alae was about 7 ${\mu}m$ and width of papilla on the cornical nodulose apex was about 3.3 ${\mu}m$ in Hysterothylacium sp. The hight of spine was approximately 20 ${\mu}m$ in A. simplex. There was mainly Hysterothylacium sp. in the intestinal lumen of the host. The nematod worms were parasitic near the mucosal fold and in the submucosal. In the mucosal epidermal layer, it was increased mucous cells by the infection of the parasites.

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.699-704
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• 2019

Anisakiasis (anisakidosis) refers to a foodborne zoonosis caused by ingesting raw or undercooked marine fish or cephalopods infected with anisakid larvae. The present study was performed to investigate the prevalence of anisakid larvae in anchovies (Engraulis japonica) purchased from 2 local markets in Gyeongsangnam-do, the Republic of Korea (=Korea), during 2018-2019. Anchovies were transported to our laboratory and examined by pepsin-HCl artificial digestion technique followed by microscopic observations and molecular analyses. The overall prevalence of anisakid larvae was 19.5% (39/200), from which a total of 51 larvae (av. 1.3 larvae/infected anchovy) were recovered. Sequencing of the larvae targeting the ITS region, including ITS1, 5.8S rRNA, and ITS2 genes confirmed the species of larvae as Anisakis pegreffii (54.9%; 28/51), Hysterothylacium sinense (23.5%; 12/51), and Hysterothylacium aduncum (21.5%; 11/51). The results suggested that anchovies could be a potential source of human anisakiasis in Korea.

• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.26.1-26.8
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• 2016

Background: The nematode species belonging to genus Anisakis occur at their third larval stage in numerous marine teleost fish species worldwide and known to cause accidental human infection through the ingestion of raw or undercooked fish or squids. They may also draw the attention of consumers because of the visual impact of both alive and dead worms. Therefore, the information on their geographical distribution and clear species identification is important for epidemiological survey and further prevention of human infection. Results: For identification of anisakid nematodes species isolated from largehead hairtail (Trichiurus japonicus), polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of internal transcribed spacers of ribosomal DNA were conducted. Mitochondrial cytochrome c oxidase subunit 2 gene was also sequenced, and phylogenetic analysis was conducted. From the largehead hairtail (n = 9), 1259 nematodes were isolated in total. Most of the nematodes were found encapsulated throughout the viscera (56.2 %, 708/1259) or moving freely in the body cavity (41.5 %, 523/1259), and only 0.3 % (4/1259) was found in the muscles. By PCR-RFLP, three different nematode species were identified. Anisakis pegreffii was the most dominantly found (98.7 %, 1243/1259) from the largehead hairtail, occupying 98.7 % (699/708) of the nematodes in the mesenteries and 98.1 % (513/523) in the body cavity. Hybrid genotype (Anisakis simplex ${\times}$ A. pegreffii) occupied 0.5 %, and Hysterothylacium sp. occupied 0.2 % of the nematodes isolated in this study. Conclusions: The largehead hairtail may not significantly contribute accidental human infection of anisakid nematode third stage larvae because most of the nematodes were found from the viscera or body cavity, which are not consumed raw. But, a high prevalence of anisakid nematode larvae in the largehead hairtail is still in concern because they may raise food safety problems to consumers. Immediate evisceration or freezing of fish after catch will be necessary before consumption.

• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.207-211
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• 2019

Anisakiasis is a zoonotic disease induced by anisakid nematodes, and endoscopic inspection is used for a diagnosis or remedy for it. Anisakis simplex, Anisakis physeteris, and Pseudoterranova decipiens had been reported to be the major species causing human infections, particularly, in Japan. However, in Korea, recent studies strongly suggested that Anisakis pegreffii is the major species of human infections. To support this suggestion, we collected anisakid larvae (n=20) from 20 human patients who were undergone gastrointestinal endoscopy at a health check-up center in Korea, and molecular identification was performed on the larvae using PCR-RFLP analysis and gene sequencing of rDNA ITS regions and mtDNA cox2. In addition, anisakid larvae (n=53) collected from the sea eel (Astroconger myriaster) were also examined for comparison with those extracted from humans. The results showed that all human samples (100%) were identified as A. pegreffii, whereas 90.7% of the samples from the sea eel were A. pegreffii with the remaining 9.3% being Hysterothylacium aduncum. Our study confirmed that A. pegreffii is the predominant species causing human anisakiasis in Korea, and this seems to be due to the predominance of this larval type in the fish (sea eels) popularly consumed by the Korean people. The possibility of human infection with H. aduncum in Korea is also suggested.

• Journal of fish pathology
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• v.25 no.3
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• pp.189-197
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• 2012

A survey was conducted to investigate infection of anisakid nematode larvae in 243 wild marine fishes caught from the southern coastal area of Korea between 2010 and 2012. The samples comprised fishes from 9 orders, 30 families and 50 species. Total infection rate of anisakid nematode larvae was 10.7% (26/243 fish), which comprised from Yeosu, 7.4% (7/95) in 2010 and 22.7% (5/22) in 2011; from Jeju, 8.2% (5/61) in 2011; from Wando, 40.9% (9/22) in 2012. Anisakid nematode larvae were not detected in Tongyoung and Wando samples in 2011. Molecular identification of the 89 worms from 26 fish was conducted by PCR-RFLP and/or sequence analysis of internal transcribed spacer (ITS) region of ribosomal DNA. From the results, 6 kinds of anisakis species were identified: Anisakis pegreffii (infection rate: 53.9%, 48/89 worms), Hysterothylacium aduncum (38.2%, 34/89), H. fabri (3.4%, 3/89), hybird (A. simplex X A. pegreffii) (2.4%, 2/89), A. simplex (1.1%, 1/89) and Raphidascaris lophii (1.1%, 1/89). The rate of single infection was 80.8% (21/26 infected fish), while 19.2% (5/26) showed mixed infection with 2 to 3 different anisakis species.

• Parasites, Hosts and Diseases
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• v.35 no.1
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• pp.19-24
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• 1997

The infection status of anisakid larvae was examined in 290 marine fish of 25 species and in 108 cephalopods of 3 species purchased in Bayuquan region, Yingko city nearby the coast of the Bohai Sea from may to August 1992. A total of 7,327 laivae were collected from 156 fish of 19 species and 8 squids of one species. The 3rd-stage larvae of Anisokis simplex were collected from 121 fish (63..4%) of 15 species (N : 191) and from 8 squids (14.8%) of one species (N : %4), and they were total, 5,992 (81.8%). Out of remaining 1,335 larvae, 154 (2.1%) were classified as Rvnnqscnris type B from 23 fish of 4 species, 1,013 (13.8%) as avnnosccris type C from 79 fish of 13 species, 164 (2.2%) as Hvsterothylacium China type V from 20 fish of 4 species, 3 (0.04%) as Raphinoscnris from 3 fish of 2 species and one was Pseunotewonovc necipiens larva. Key words: Bohai Sea, Anisokinae, larvae , Anisckis, HvsterothWLacium, Thwnnascaris, Raphinqscaris , Pseudoterranova.

• Journal of Life Science
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• v.19 no.9
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• pp.1328-1332
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• 2009

Anisakidosis is caused by anisakid nematodes (family Anisakidae) larvae which can cause not only direct tissue damage but also a severe allergic response related to excretory-secretion products. Lots of different species of anisakid larvae, including Anisakis simplex, Contracaecum, Goezia, Pseudoterranova, and Hysterothylacium, cause the anisakidosis. But it is difficult to diagnosis the species of larvae since the morphologies of larval anisakid nematodes are almost indistinguishable. In order to diagnosis the differential infections of larval anisakid nematodes, polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) of 18S rDNA - was conducted. Three major species of anisakid larvae including A. simplex, C.ontracaecum spp, and Goezia spp. were collected from mackerel (Scomber japonicus), mullet (Mugil cephalus), founder (Paralichthys olivaceus), eel (Astroconger myriaster) and red sea bream (Pagrus major). PCR amplified 18S rDNA from each species of anisakid larvae was digested with eight restriction enzymes including Taq I, Hinf I, Hha I, Alu I, Dde I, Hae III, Sau96 I, and Sau3A I. The original sizes of PCR amplified 18S rDNA were 2.0Kb in both anisakid larvaes and Goezia. Restrction enzymes including Hinf 1, Alu 1, Hha I, Dde 1 and Hae III cut differently and distinguished the A. simplex and Contracaecum type C'. However, Contracaecum type A showed two different restriction enzyme cutting patterns by Taq 1, Hinf I, Alu 1, and Dde 1. One of the patterns was the same as those of A. simplex, Contracaecum type C' and Goezia and the other was unique. These results suggest that PCR-RFLP pattern by Hinf 1, Alu 1, Hae I, Dde 1 and Hae III can be applied to differential diagnosis of human infection with A. simplex and Contracaecum type C'. Contracaecum type A needs further study of classification by morphological characteristics and genetic analysis.