• Parasites, Hosts and Diseases
• /
• v.27 no.4
• /
• pp.253-260
• /
• 1989

Metacercariae of the genus Stictodora encysted in the head tissue of Acanthogobius navimanus (the gobies) caught at Sachun-gun, Kyongnam Province, were identified to be Stictodora Zari Yamaguti, 1939 (Trematoda: Heterophyidae), a new parasite fauna in Korea. The metacercariae were 0.39∼,0.43 mm by 0.32∼0.35 mm in size, long elliptical, and with a thin and transparent cyst wall. Total 200 metacercariae were collected from 50 gobies. In order to obtain adult worms two kittens and a Puppy were infected each with 34∼100 metacercariae, and total 33 adults were recovered between the day 4 and day 8 post-infection. The S. sari adults measured 0.95∼1.18 mm long and 0.26∼0.32 mm wide and the eggs in uteri 0.028∼0.033 mm by 0.017∼0.020 mm. The most characteristic morphological feature of these flukes was the presence of a gonotyl and gonotyl spines arranged in two groups; densely crowded group of 30~40 spines and linearly-arranged one of 30∼40 spines, together of which made a comma(or reversed comma) shape along the lateral margin of the gonotyl. It has been proved by this study that 5. sari is distributed in southern coasts of Korea.

• Parasites, Hosts and Diseases
• /
• v.33 no.1
• /
• pp.1-8
• /
• 1995

Gymnophalkides seoi has drawn medical attentions since the discovery of the first human case and a highly endemic area on a southwestern coastal island of Shinan- gun, Korea. Marine bivalves especially oysters were strongly suspected as the source of infection. In this study the oysters, Crassostrea girns, naturally produced (rom the endemic area were examined whether they contain gymnophallid metacercariae. All of 50 oysters examined were infected with the metacercaviae of a gymnophallid, with the metacercarial density per oyster of 610 on average (2-4,792 in range). Later they were identified as G. seoi by obtaining adult worms from experimental mice. The metacercariae were unencysted, and firmly attached on the mantle surface of the oysters with their oral sucker. In sectioned specimens they were equipped with the ventral pit, a peculiar organ of the genus Gymophalloides, and non-muscular genital pore which was connected dorsally to the seminal vesicle. The seminal vesicle was in a great majority mono-sac. By this study, it has been confirmed that the oyster is a 2nd intermediate host of G. seoi as well as the major source of human infection with this fluke.

• 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.

• Animal cells and systems
• /
• v.8
• /
• pp.42-42
• /
• 2004

• Parasites, Hosts and Diseases
• /
• v.33 no.4
• /
• pp.305-312
• /
• 1995

A species of metacercariae recovered from the fresh-water fish, collected from Kaumji (Pond), Kaechonji (Pond) and Ssanggyechon (River), Uisong-gun, Kyongsangbuk-do, Korea, was identified as Clinostomum compzcnatum by morphological observation and experimental infection to chicks. The excysted metacercariae, tongue-shaped and progenetic, were 3.28-4.27 mm in length and 0.94-1.46 mm in width. The adult flukes recovered from the chicks four days after infection were 4.20-4.86 mm long and 1.14-1.49 mm wide. Twelve species of the fresh-water fish were found to be infected with the metacercariae. The infection rate ranged from 1.6% (Zacco temminkii) to 88.9% (Acheilognathus rhombec and Microphwsogobio voluensis) . The intensity was highest in Cnrqssius curatus (13.0/fish infected) and the abundance (relative densityl was highest in A. rhombea (7.8/fish examined). This survey demonstrated for the first time the source of human infection by C. complnnntum in Korea.

• Parasites, Hosts and Diseases
• /
• v.38 no.1
• /
• pp.9-15
• /
• 2000

A scanning electron microscopic study was performed on the surface ultrastructure of metacercariae and adults of Metagonimus takahashii. Metacercariae were collected from the scale of crucian carp (Carassius auratus) , and adult flukes were harvested 1-4 weeks after infection to rats. In excysted metacercariae. the oral sucker had type I (numerous) and type II (seven in total) sensory papillae. Tegumental spines were dense and digitated into 5-7 points on the surface anterior to the ventral sucker, but became sparse and less digitated posteriorly toward the end of the body In adults, seven type II sensory papillae were characteristically arranged around the lip of the oral sucker, and on the inner side of the lip four small and two large type I sensory papillae were symmetrically seen on each side (12 in total). Tegumental spines on anterior two-thirds of the body. were digitated with 9-12 tips ventrally and 8-13 tips dorsally. Sperms entering into the Laurer's canal were observed. The results show that the surface ultrastructure of M. takuhashii is generally similar to those of M. yokogawai and M. miyatai except for the digitation of tegumental spines.

• Parasites, Hosts and Diseases
• /
• v.55 no.4
• /
• pp.445-449
• /
• 2017

The prevalence of Centrocestus formosanus metacercariae was investigated in ornamental fish purchased from a pet shop in Chiang Mai, Thailand, including Carassius auratus (goldfish), Cyprinus carpio (Koi), Poecilia latipinna (Sailfin Molly), Danio rerio (Zebrafish), and Puntigrus tetrazona (Tiger barb). The parasite species was identified by the morphology of worms as well as by a molecular approach using ITS2. The results showed that 50 (33.3%) of 150 fish examined were infected with the metacercariae. The highest prevalence was found in C. auratus (83.3%), and the highest intensity was noted in C. carpio (70.8 metacercariae/fish). The most important morphological character was the presence of 32-34 circumoral spines on the oral sucker. The phylogenetic studies using the rRNA ITS2 region revealed that all the specimens of C. formosanus in this study were grouped together with C. formosanus in GenBank database. This is the first report on ornamental fish, C. carpio, P. latipinna, D. rerio, and P. tetrazona, taking the role of second intermediate hosts of C. formosanus in Thailand. Prevention and control of metacercarial infection in ornamental fish is urgently needed.

• Parasites, Hosts and Diseases
• /
• v.21 no.2
• /
• pp.187-192
• /
• 1983

In order to clarify infestation Pattern for the encysted larvae of digenetic trematodes from fresh-water fishes, this survey was carried out from March to September, 1983. A total of 380 fishes of 32 species wore collected with netting at the three reaches, upper, middle and lower in Mangyeong riverside area. After the fishes were dissected into small scraps, they were pressed under cover glass and examined-for the presence of those of digenetic trematodes with a microscope. The resillts obtailled were as follows; Out of a total of 380 knishes inspected, 320 fishes(84%) from 31 species were found positive with, digenetic trematode metacercariae; more than 10 species of the metacercariae Ivere detected in Pseuderasbora parva; .Gnnthepegen mtajimae, Microphysogokio yaluensis, Cultriculus eigenmanni and Gnnthopogon coreanus (more than 8 species) ; Aphyocypris chinensis (8 species) and etc. respectively. Clonorchis sinensis metacercariae were found positive from 93 fishes (25%) from 12 species and detection rates in other species of digenetic trematode metacercariae from various fishes were; Exorchis oviformis, 261 fisles (57%) from 28 species; Cyathocotyle criensalis, 47 fishcs (12%) from 12 species; Metorchis orientalis, 21 fishes (6%) from 12 species; Metagonimus yokogawai, 164 fishes (43%) from 26 species; Pseudesorchis major, 71 fishes (19%) from 18 species; Metacercaria haiegawai, 77 fishes (20%) from 25 species; Centrocestus armatus, 24 fishes (6%) from 7 species; Echinochasmus japonicus, 2 fishes (0.5%) from 2 species, and unidentified species, 34 fishes (9%) from 15 species respectively. The sums of average number of the encysted larvae of all species found in fish body/gram showed 83 in P.parva, Cobitis taenia (74.2), A. chinensis (28.5), Pseudoperilampus uyekii (26.6), G. majimae (19.6) and etc. respectively and the average peak number of each metacercaria in fish body/gram showed 21.7 C. sinensis, 245. ovifcrmis, 15, 3 M, crientalis and 6.1 5. japonicus in P. parva. 42.7 C. orientalis and 25.1 M. yohogawai in C. taenia; 8.3 C. armatus and 8.3 M. hasegawai in P. uyekii. 6.3 P. major in Carassius carassius, and 2.9 unidentified species in G, niajimae respectively.

• Parasites, Hosts and Diseases
• /
• v.23 no.1
• /
• pp.18-23
• /
• 1985

The infection stasus of the loaches, Misgurnus anguillicaudatus, with the metacercariae of Echinostoma hortense, was studied in Korea. A total of 154 loaches purchased at 4 local markets (Seoul, Kimhae, Naju-gun and Kangjin-gun) were examined their infection rate as well as the density and location of the metacercariae in the fish body. The results are as follows: 1. The loaches carrying the metacerariae of E. hortense were 64 (41.6%) in total number and the metacercarial density ranged 1-29 per infected loach with an average value of 8.1. The highest infection rate and metacercarial density were obtained from the loaches purchased at Kangjin-gun, Jeonranam-do. 2. The metacercariae of E. hortense were chiefly distributed in the distal intestinal wall and the adjacent mesentery, the perianal tissues, and the head and gill of the loaches examined. From the results, it is concluded that the loach is one of the important second intermediate hosts of E. hortense in Korea, and their infection rate and metacercarial density are considerably high.

• Parasites, Hosts and Diseases
• /
• v.44 no.3
• /
• pp.243-246
• /
• 2006

In order to determine the current infection status of pond smelts, Hypomesus olidus, and other freshwater fishes with trematode metacercariae, a total of 4,861 pond smelts and 18 other freshwater fishes, collected from the Soyang and Uiam Lakes in Gangwon-do, the Unam Lake in Jeollabuk-do, the Jangseong Lake in Jeollanam-do, the Uirim-ji (lake) in Chungcheongbuk-do, and the Andong Lake in Gyeongsangbuk-do, were individually digested with 1 % pepsin-HCI and examined under a dissecting microscope. In all pond smelts caught from the 6 lakes, we were unable to detect any known human infectious trematode metacercariae in Korea. However, in other freshwater fishes, such as, Squalidus japonicus coreanus (Unam Lake), and Zacco platypus (Jangseong Lake) and Opsariichthys uncirostris amurensis (Jangseong Lake), metacercariae of human-infecting trematodes, i.e., Clonorchis sinensis and Metagonimus sp. were detected, respectively.