• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.72-78
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• 1985

A total of 220 tadpoles was captured in 6 areas and total 117 frogs, Rana nigromacuzata, were collected in 11 areas in Korea. They were examined for their infection status by the metacercariae of Fibricola seoulensis by peptic digestion technique and by histological observation with hematoBylineosin staining. This study was carried out from August, 1983 to September, 1984. Followings are the results. 1. The tadpoles of R. nigromaculata were positive for the metacercariae from 3.3% to 100% by area. The number of metacercariae per infected tadpole ranged from 1 to 584, and the mean number Per tadpole ranged from 7.6 to 221 by area. 2. The metacercariae from 16 tadpoles were counted by the body portion. A great majority of the metacercariae was collected from abdominal cavity, 98.3% of 484 counted larvae. And 6(1.2%) larvae were from proximal tail and 2(0.4%) from trunk. 3. Histological sections of tadpoles showed many metacercariae in abdominal cavity but none in other parts. The larvae were free in the spaces among intestinal loops or around primitive liver. A few larvae were in duct-like tissues near trunk wall. There was little infiltration of inaammatory cells. 4. The metacercarial infection rates of frogs ranged from 0% to 100% by area. The larval burden was 1 to 470 by infected frogs, and mean number ranged from 1 to 175.6 by area. By above results, it is suggested that the cercariae of F. seoulensis may infect R. nigromaculata already in the stage of tadpole. Almost all of the metacercariae were concentrated in abdominal cavity of tadpoles. According to the infection status of frogs, this nuke is prevalent almost nationwidely in rice paddies in Korea.

• Parasites, Hosts and Diseases
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• v.51 no.1
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• pp.107-114
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• 2013

Fishborne trematode (FBT) metacercariae were investigated in fish from 3 Provinces of Lao PDR. Total 242 freshwater fish of 40 species were collected in local markets of Luang Prabang (59 fish of 16 species), Khammouane (81 fish of 19 species), and Saravane (97 fish of 14 species), and each of them was examined by artificial digestion method. Four species of metacercariae (Opisthorchis viverrini, Haplorchis taichui, Haplorchis yokogawai, and Centrocestus formosanus) were detected. O. viverrini was detected in 35 fish (14.5%), and their density was 252 per infected fish (Luang Prabang, 88 metacercariae in 5 fish; Khammouane, 187 in 6 fish; Saravane, 303 in 24 fish). H. taichui was found in 102 fish (42.1%), and their density was 485 per infected fish (Luang Prabang, 260 metacercariae in 38 fish; Khammouane, 1,084 in 23 fish; Saravane, 359 in 41 fish). H. yokogawai was detected in 92 fish (38.0%), and their density was 222 per infected fish (Luang Prabang, 362 metacercariae in 17 fish; Khammouane, 126 in 20 fish; Saravane, 214 in 55 fish). Metacercariae of C. formosanus were found in 8 fish (3.3%), and their density was 3 per infected fish. In the present study, it has been confirmed that FBT metacercariae, in particular, H. taichui, H. yokogawai, and O. viverrini, are highly prevalent in fish from Luang Prabang, Khammouane, and Saravane Province, Lao PDR.

• Journal of Environmental Health Sciences
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• v.30 no.4
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• pp.344-346
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• 2004

During a survey of the helminth parasites of fresh water fishes in Willamette River, metacercariae of Neascus spp. were found on examination of muscle, spinal cord, fin and skin of Chiselmouth, Acrocheilus alutaceus. One hundred percent of 19 Chiselmouth examined were found to be infected with digenetic trematodes. The prevalence of infection was higher in muscle, varying from $95\%\;and\;100\%$. Higher levels were present in muscle, such that the $100\%$ level being found in upper anterior, lower anterior and posterior. Small numbers of metacercariae were found on the fin and skin. The commonest sites of infection were the musculature and spinal cord. Intensities of Neascus spp. metacercariae tended to be and high levels in muscle and spinal cord. Those were low levels occurred in the fin and skin. There was a high degree of Neascus spp. in the occurrence of digenetic trematode from Chiselmouth.

• Parasites, Hosts and Diseases
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• v.37 no.1
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• pp.55-57
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• 1999

During the period from October 1996 to November 1998, the infection status of Paragonimus westermani metacercariae in freshwater crayfish (Cambaroides similis) collected from Bogildo (islet), Wando-gun, Chollanam-do, which is known for an endemic area of P. westermani in Korea, were examined. The average infection rate of Paragonimus metacercariae in crayfish was 88.6%, and mean number of metacercariae per infected crayfish was 30.2. This metacercarial density was the highest in the group of weight in 7.1-9.0 g. These results suggest that the natural life cycle of P. westermani is still well-preserved in Bogildo.

• Parasites, Hosts and Diseases
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• v.43 no.4 s.136
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• pp.161-164
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• 2005

A survey was performed in order to determine the infection status of the metacercariae of heterophyid fluke in two goby species, Boleophthalmus pectinirostris and Scartelaos sp., collected from Gangjin-gun, and Shinan­gun, Sooncheon-shi, Jeollanam-do, Republic of Korea. A total of three metacercariae of Heterophyopsis continua was found in only one B. pectinirostris $(10.0\%)$ from Gangjin-gun. Heterophyes nocens metacercariae were detected in 24 B. pectinirostris $(96.0\%)$ and 14 Scartelaos sp. $(63.6\%)$ from Shinan-gun. Heterophyopsis continua metacercariae were found in 11 B. pectinirostris $(44.0\%)$ and 21 Scartelaos sp. $(95.5\%)$ from Shinan-gun. Stictodora fuscata metacercariae were detected in 18 B. pectinirostris $(72.0\%)$ from Shinan-gun. No metacercariae were detected in 20 B. pectinirostris from Sooncheon-shi. From the above results, this study is the first to prove that B. pectinirostris and Scartelaos sp. serve as the second intermediate hosts of some heterophyid flukes in Korea.

• Parasites, Hosts and Diseases
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• v.46 no.2
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• pp.109-112
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• 2008

A parasitological investigation on trematode metacercariae was made on 62 freshwater fishes of 13 species in northern Thailand; Cyclocheilichthys apogon, Puntioplites proctozysron, Labiobarbus siamensis, Barbodes gonionotus, Barbodes altus, Henicorhynchus siamensis, Osteochilus hasselti, Notopterus notopterus, Mystacoleucus marginatus, Anabas testudineus, Systomus orphoides, Morulius chrysophykadian, and Hampala macrolepidota. The fish were caught over the summer period (February-May 2007) from 2 Chiang Mai water reservoirs, i.e., the Mae Ngad (UTM 47Q E 503200, 47Q N 2119300) and the Mae Kuang Udomtara (UTM 47Q E 513000, 47Q N 2092600) Reservoirs in Chiang Mai province, Thailand. The prevalence of heterophyid (Haplorchis taichui and Haplorchoides sp.) metacercariae in these fish was 83.9% and 74.2% in the Mae Ngad and Mae Kuang Udomtara Reservoirs, respectively. The highest intensity of heterophyid metacercariae in H. siamensis in the Mae Ngad was 120.4 and that in P. proctozysron in the Mae Kuang Udomtara was 180.0. The fish, A. testudineus, C. apogon, and M. chrysophykadian, were not found to be infected with H. taichui metacercariae. The results show that the freshwater fish in Chiang Mai water reservoirs are heavily infected with H. taichui and Haplorchoides sp. metacercariae.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.273-278
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• 1996

An epidemiologic survey along the several sites of southern coastal areas of Korean peninsula was performed to know the infection status of Pcnlotremc app. metacercariae in Tapes phiLlppirlawm. The clams were purchased from 13 coastal areas in Kyongsangnam- do alld Chollanam-do. in September, 1990. Each of them was digested with pepsin-HCI solution and examined under a stereomicroscope for the recovery of metacercariae. A total of 232 (77.3%) out of 300 examined clams were proved to have 1 to 273 Pawatrema app. metacercariae (54.7 in average). None of the clams from Samoan-myon Kosong-gun and Dolsan-up. Yochon-gun was infected with metacercariae. However, all of the clams from Yonghyon-myon, Sachon-guu, Dohwa-myon, Kohung-gun, Ahllyang-myon. Changhung- gun and Chiryang-myon. Kangiin-gun were infected with average 71, 31, 80 and 42 metacercariae respectively. Of the clams from Kohyon-myon, Namhae-gun, Doam-myon, Kangiin-gun and Kusan-myon. Uichang-guil examined, 97.5%. 95.0% and 90.0% were infected with about 117. 76 and 28 metacercariae. In other 4 surveyed areas. Seolchon rlyoll, Namhae-gun, Hwayang-myon. Yochon-gun Byollyang-myon, Sungju-gun and Bukpyong-myon, Haenam-gun. 55.0%-80.0% of clams were positive. and their average intensity of infection ranged from 6 to 25 metacercariae. From these results, it was confirmed that Tcpes philippincrum from southern coastal areas of Korea are highly infected by Parvatrema spp. metacercariae.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.447-453
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• 2015

The infection status of fishborne zoonotic trematode (FZT) metacercariae was investigated in fishes from 2 localities of Lao PDR. Total 157 freshwater fishes (17 species) were collected in local markets of Vientiane Municipality and Champasak Province in December 2010 and July 2011, and each fish was examined by the artificial digestion method. Total 6 species of FZT metacercariae, i.e., Opisthorchis viverrini, Haplorchis taichui, Haplorchis yokogawai, Haplorchis pumilio, Centrocestus formosanus, and Procerovum varium, were detected in fishes from Vientiane Municipality. The metacercariae of O. viverrini were detected in 50 (49.5%) out of 101 fishes (6 species), and their average number was 154 per fish infected. The remaining 5 species of heterophyid metacercariae were detected in 36.8%, 65.8%, 9.4%, 23.9%, and 5.1% fishes examined, and their average densities were 12, 1,038, 4, 15, and 13 per infected fish, respectively. In fishes from Champasak Province, 3 species of FZT metacercariae, i.e., O. viverrini, H. taichui, and H. yokogawai, were detected. Only 2 O. viverrini metacercariae were found in only 1 Barbonymus schwanefeldi. The metacercariae of H. taichui and H. yokogawai were detected in 60.0% and 50.0% of fishes examined, and their average densities were 47 and 28 per fish infected. By the present study, it has been confirmed that several species of FZT metacercariae are prevalent in fishes from Vientiane Municipality, with P. varium being a new member of FZT in Lao PDR. In comparison, FZT metacercariae are less prevalent in fishes from Champasak Province.

• Parasites, Hosts and Diseases
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• v.58 no.1
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• pp.87-91
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• 2020

Gymnophallid metacercariae found in the Manila clam Ruditapes philippinarum ('Banjirak' in Korean) from Gochang-gun, Jeollabuk-do, Korea were morphologically and molecularly confirmed to be Parvatrema duboisi (Dollfus, 1923) Bartoli, 1974. The metacercariae were morphologically characterized by having a large oral sucker, small ventral sucker, genital pore some distance anterior to the ventral sucker, no ventral pit, and 1 compact or slightly lobed vitellarium, which were all compatible with P. duboisi. Some of the metacercariae were experimentally fed to mice, and adult flukes were recovered at day 7 post-infection. The morphology of the adult flukes was basically the same as that of the metacercariae except for the presence of uterine eggs; the uterus was filled with up to 40 eggs. The nucleotide sequences (1,193 bp) from ITS regions (ITS1, 5.8S rDNA, and ITS2) of the metacercariae showed 99.7% identity with P. duboisi and 75.7% identity with Gymnophalloides seoi deposited in GenBank. These results confirmed the presence of P. duboisi metacercariae in the Manila clam R. philippinarum in an estuary region of Gochang-gun, Korea.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.23-33
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• 2021

The infection status of zoonotic trematode metacercariae (ZTM) was surveyed in freshwater fishes from the water systems of Geum-gang (River) in the Republic of Korea (Korea). A total of 1,161 freshwater fishes from 6 local sites of Geum-gang were examined with the artificial digestion method for 4 years (2012-2015). Clonorchis sinensis metacercariae were detected in 122 (37.2%) out of 328 fishes in the positive fish species from 4 surveyed areas, and their mean intensity was 43 per fish infected. Metagonimus spp. metacercariae were found in 432 (51.7%) out of 835 fishes in the positive fish species from all 6 surveyed areas, and their mean intensity was 30 per fish infected. Centrocestus armatus metacercariae were detected in 285 (75.0%) out of 380 fishes in the positive fish species from 6 surveyed areas, and their mean intensity was 2,100 per fish infected. Echinostoma spp. metacercariae were found in 56 (19.7%) out of 284 fishes in the positive fish species from 5 surveyed areas, and their mean intensity was 10 per fish infected. Clinostomum complanatum metacercariae were detected in 98 (57.3%) out of 171 fishes in the positive fish species from only 2 surveyed areas, and their mean intensity was 11 per fish infected. Conclusively, the endemicity of ZTM is not so high in fishes from water systems of Geum-gang in Korea although it is more or less different by fish species, surveyed areas and ZTM species.