• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.65-75
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• 2015

Clonorchis sinensis habitating in the bile duct of mammals causes clonorchiasis endemic in East Asian countries. Parkin is a RING-between-RING protein and has E3-ubiquitin ligase activity catalyzing ubiquitination and degradation of substrate proteins. A cDNA clone of C. sinensis was predicted to encode a polypeptide homologous to parkin (CsParkin) including 5 domains (Ubl, RING0, RING1, IBR, and RING2). The cysteine and histidine residues binding to $Zn^{2+}$ were all conserved and participated in formation of tertiary structural RINGs. Conserved residues were also an E2-binding site in RING1 domain and a catalytic cysteine residue in the RING2 domain. Native CsParkin was determined to have an estimated molecular weight of 45.7 kDa from C. sinensis adults by immunoblotting. CsParkin revealed E3-ubiquitin ligase activity and higher expression in metacercariae than in adults. CsParkin was localized in the locomotive and male reproductive organs of C. sinensis adults, and extensively in metacercariae. Parkin has been found to participate in regulating mitochondrial function and energy metabolism in mammalian cells. From these results, it is suggested that CsParkin play roles in energy metabolism of the locomotive organs, and possibly in protein metabolism of the reproductive organs of C. sinensis.

• Parasites, Hosts and Diseases
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• v.31 no.1
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• pp.7-12
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• 1993

Metaceriae of Parvatrema timondavidi (Digenea; Grmnophallidae) were found from Tapes phillippinarum, one of the most common marine clams in Korean. T. were philippinarum was collected from a fishery market in seoul, and all of the clams eximined were found to contain many gymnophyallid metacercariae. To get adult worms, 10 ICR mice were fed with 100 metacercariae each and sacrificed by cervical dislocation at 7, 10 and 14 mice were morphologically characterized by oval body shape, lage oral sucker with lateral located genital pore from the venttral sucker. Based on these characters they identified as P.timondawvidi Bartoli, 1964. this study first confirms the presence of P. timondawcidi metacercartae in T.philippinarum in Korea.

• Parasites, Hosts and Diseases
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• v.30 no.1
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• pp.1-14
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• 1992

In order to observe the antigenic localization in the tissues of Paragonimus westermani of deve- lopmental stages, immunogoldlabeling method was applied using serum of the cats which were infected with isolated metacercariae from Cambaroides similis. The sectioned worm tissues from orch developmental stage were embedded in Lowicryl HM20 medium, stained with infected semi IgG and protein A gold complex(particle size: 12 nm) and observed by electron microscopy. In the young adult worm tissue of 4 weeks after infection with metacercariae, the gold particles were specifically concentrated on the tegumental syncytium and cytoplasm of the tegumental cells as well as the secretory granules in the parenchymal tissue. The antigenic materials in the adult worm tissue were specifically concentrated on the secretory granules in the parenchymal tissue, the cytoplasm between granules in the vitelline gland and the epithelial lamella in the lumen of the caecum.

• Parasites, Hosts and Diseases
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• v.52 no.1
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• pp.27-33
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• 2014

Mucosal immune responses against Pygidiopsis summa (Trematoda: Heterophyidae) infection were studied in ICR mice. Experimental groups consisted of group 1 (uninfected controls), group 2 (infection with 200 metacercariae), and group 3 (immunosuppression with Depo-Medrol and infection with 200 metacercariae). Worms were recovered in the small intestine at days 1, 3, 5, and 7 post-infection (PI). Intestinal intraepithelial lymphocytes (IEL), mast cells, and goblet cells were counted in intestinal tissue sections stained with Giemsa, astra-blue, and periodic acid-Schiff, respectively. Mucosal IgA levels were measured by ELISA. Expulsion of P. summa from the mouse intestine began to occur from days 3-5 PI which sustained until day 7 PI. The worm expulsion was positively correlated with proliferation of IEL, mast cells, goblet cells, and increase of IgA, although in the case of mast cells significant increase was seen only at day 7 PI. Immunosuppression suppressed all these immune effectors and inhibited worm reduction in the intestine until day 7 PI. The results suggested that various immune effectors which include IEL, goblet cells, mast cells, and IgA play roles in regulating the intestinal mucosal immunity of ICR mice against P. summa infection.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.197-202
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• 1989

This study was performed to observe the susceptibility of dogs and cats as definitive hosts of Paragonimus ilektsuenensis. The metacercariae of this luke were obtained from Sesarma dehaani collected at a focus near the mouth of Sumjin river in November, 1986 and February, 1987. The larvae isolated from the crabs were introduced Per os into 7 albino rats, 2 dogs and 3 cats. The adults were recovered from the experimental animals, End they were morphologically observed and measured. The results were as follows: 1. The recovery rate of adult worms at 42 days after infection was 53.3% from three albino rats, 21.0% from a dog and 12.7% from two cats. Most of the worms were recovered from the worm capsules in the lungs. 2. The size of worms recovered from albino rats, a dog, and cats 42 days after infection aver-aged $6.3{\times}3.2mm,{\;}6.3{\times}3.0mm,{\;}or{\;}6.2{\times}3.5mm$, respectively. There were little differences in the morphology of worms by different experimental animals. 3. The size of eggs from a dog was $88.9{\times}49.3{\mu\textrm{m}}$, and that from cats was $84.3{\times}53.7{\mu\textrm{m}}$ on average. Dogs and cats were good definitive hosts of p. iloktsuenensis. This fact suggests that human infection by this luke may be possible if the metacercariae were ingested.

• Parasites, Hosts and Diseases
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• v.42 no.1
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• pp.19-26
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• 2004

We investigated the induction of resistance to Clonorchis sinensis infection by prior infection in rat and hamster models. Animals were challenged with C. sinensis metacercariae, then treated with praziquantel and reinfected. Worm recovery rate in reinfected animals was used to estimate resistance to reinfection. The determined resistance rates to reinfection in rats and hamsters were 97.7% and 10.3%, respectively. In rats, cure from the primary infection of C. sinensis increased resistant to reinfection, and the greatert the worm burden and the longer the duration of primary infection, the higher was the resistance rate. For primary infection doses of 10, 40 and 100 metacercariae per rat, the resistance rates were 87.4%, 93.8% and 98.4%, respectively. The resistance rates in rats after 2 or 8-week primary infection were 78.7% and 95.3%, respectively. All worms recovered from reinfected rats were immature. When cured rats were administered with methylprednisolone, resistance to reinfection became impaired. These findings indicate that rats develop a high degree of resistance to reinfection by C. sinensis after cure. The growths and maturations of reinfected worms were also impaired.

• Parasites, Hosts and Diseases
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• v.56 no.3
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• pp.247-257
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• 2018

The aim of this study was to conduct a freshwater snail survey in Mae Lao agricultural basin to assess the diversity with a focus on habitat types and their larval trematode infections. Snails were collected and examined in 14 sites of Mae Lao agricultural basin from August 2016 to October 2017. A total of 1,688 snail individuals were collected and classified into 7 families, 8 genera, and 12 species. Snail diversity and habitat types were higher in rice paddies than irrigation canals and streams. The most abundant species was Bithynia siamensis siamensis, representing 54.6% of the sample. Three species of snails act as first intermediate host were found with cercarial infections. They were Filopaludina sumatrensis polygramma, B. s. siamensis, and Melanoides tuberculata. The cercariae were categorized into 7 types; echinostome, monostome, gymnocephalous, virgulate, parapleurolophocercous, pleurolophocercous and megalurous cercariae. Parapleurolophocercous cercariae constituted the most common type of cercariae recovered, contributing 41.2% of all infections in snails. Echinostome metacercariae infections were found in 6 snail species with 7.6% prevalence. In addition, the metacercaria of avian trematode, Thapariella sp. were found in Filopaludina spp. snails and B. funiculata with a prevalence of 0.5%. This is the first report for Thapariella metacercariae in the snail host, B. funiculata, and also confirmed that viviparid and bithyniid snails act as the second intermediate hosts of this trematode. This work will provide new information on the distribution and intermediate host of trematode in this area.

• Applied Microscopy
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• v.15 no.1
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• pp.101-111
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• 1985

A study was undertaken to observe the distribution and ultrastructure of the sensory papillae of the liver and lung flukes which was obtained from experimentally infected rats and dogs. For this study, the rats were artificially infected with metacercariae isolated from Pseudorasbora parve, and the dogs were artificially infected with metacercariae isolated from Cambaroides similis. The liver flukes (Clonorchis sinensis) were collected from the bile ducts of the rats which were autopsied 5 weeks later since infection. The lung flukes (Paragonimus westermani) were collected from the lung of the dogs which were autopsied 3 months later since infection. With the collected worms, ultrastructure of sensory papillae was studied by means of a scanning and transmission electron microscope. The liver flukes were compared with the lung flukes. The results of the observation are as follows. 1. The sensory papillae of the liver flukes was classified into 3 types and most of sensory papillae were distributed on the oral sucker. 2. The sensory papillae of the lung flukes were distinguished 8 types. The sensory papilla type VIII was specifically distributed on the oral sucker and type I, II were distributed on the tegumental surface of the worm. The sensory papillae of the lung flukes were mostly observed between oral sucker and ventral sucker of the worm excusively 3. The sensory papillae of the liver flukes were distributed around the sucker while those of the lung flukes were developed between spine. 4. The sensory papillae were formed by many tegumental ridge in the liver flukes while was made of many small sensory papillae in the lung flukes. 5. The sensory cilia were observed between tegumental ridges in the sensory papilla of the liver flukes and also in lung flukes. And they are alike in that respect. 6. The sensory papillae were not developed in the posterior part of the liver and lung flukes but mostly nerve endings were formed in the tegumental syncytium, and it was connected with neuropile.

• Parasites, Hosts and Diseases
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• v.31 no.4
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• pp.321-330
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• 1993

F. seoulensis were obtained from artificially infected albino rats at 3, 4, 5, 6, 7 days after infection. The worms and metacercariae were washed in physiological saline solution, and fled with 10% neutral formalin. The acetylcholinesterase (AchE) stained by one histochemistry using acetylthiocholine iodide as substrate. Eserine, ism-OMPA and BW284C51 were used as inhibitors of AchE. The nervous system consists of three pairs longitudinal nerve trunks interconnected with excretory plexus in posterior half, and phinmc and oral sucker in anterior half of metacercariae and adults. The longitudinal nerve trunks are interconnected with transverse commissures and numerous circular commissures. Considerable numbers of circular commissures are interconnected with longitudinal nerve trunks tying on the surface of the worms. At each stage of juvenile worms, AchE and nonspecific cholinesterase activites were observed in the oral sucker, ventral sucker, pharynx and nerve system. Isoxymes of AchE in f seoderuts were separated into the two bands, 69 kDa and 132 kDa. The major band was 69 kDa.

• Parasites, Hosts and Diseases
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• v.57 no.4
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• pp.389-397
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• 2019

The infection status of Clinostomum complanatum metacercariae (CcMc) was broadly surveyed in fishes from water systems of Nakdong-gang (River) in the Republic of Korea (Korea) for 5 years. All 4,468 fishes collected were individually examined by the artificial digestion methods. No CcMc were detected in fishes from Naeseongcheon in Yecheongun, Gigyecheon in Gyeongju-si, Gyeongsangbuk-do, and Hamancheon in Haman-gun, Gyeongsangnam-do. In fishes from Wicheon in Gunwi-gun, Gyeongsangbuk-do, CcMc were detected in 180 (15.4%) out of 1,168 fishes and their intensity was 5.8 per fish infected. The prevalences with CcMc in positive fish species from 3 other surveyed areas, i.e., Banbyeoncheon in Yeongyang-gun, Nakdong-gang in Sangju-si and Hoecheon in Goryeong-gun, in Gyeongsangbuk-do were 19.3%, 33.3%, and 19.0% and their intensities were 1.5, 17.6, and 2.6 per fish infected respectively. In fishes from Yangcheon in Sancheong-gun, Gyeongsangnam-do, CcMc were detected in 811 (45.6%) out of 1,779 fishes examined and their intensity was 9.8 per fish infected. The prevalence was most high in Squalidus spp. (97.7%) and followed by acheilognathinid fish (66.8%), Pungtungia herzi (52.0%), rasborinid fish (39.6%) and Hemibarbus spp. (25.9%) from Yangcheon. The intensity was also most high in Squalidus spp. (27.0). The endemicity with CcMc was very low in fishes from water systems of Nakdong-gang in the east coast of Korea. Conclusively, it is confirmed that various fish species act as the second intermediate hosts of C. complanatum, and the endemicities of CcMc are more or less different by the fish species and group from Yangcheon, in Sancheong-gun, Gyeongsangnam-do, Korea.