• Parasites, Hosts and Diseases
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• v.23 no.2
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• pp.197-202
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• 1985

During 8 April 1983 to 9 April 1985, a total of 181 domestic cats (Felis catus domestica Linnaeus) of unknown localities in Korea were purchased at Seoul Chung-ang market, and the internal organs were dissected for helminth infections. In the results, three kinds of trematodes of family Heterophyidae (Ohdner, 1914) were obtained from small intestine of domestic cats and identified as follows; five adult worms of Heterophyopsis continua (Onji et Nishio, 1916) from three hosts, two hundreds and twenty three adult worms of Pygidiopsis summa Onji et Nishio, 1916 from seven hosts and twenty six adult worms of Heterophyes heterophyes nocens (Onji et Nishio, 1916) from three hosts. Among them, Heterophyopsis continua and Pygidiopsis summa had not been proved as natural infections of cats in Korea.

• Parasites, Hosts and Diseases
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• v.45 no.3
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• pp.205-211
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• 2007

The infection status of mullets Mugil cephalus (n = 139) and gobies (n = 35) Acanthogobius fIavimanus with metacercariae of Heterophyes nocens and Pygidiopsis summa was examined in 11 western, southern, and eastern coastal areas of the Republic of Korea, using a digestion technique. Heterophyid metacercariae were highly prevalent in mullets from western and southern coastal areas; Shinan-gun (100% for H. nocens and 100% for P. summa), Muan-gun (93% and 100%), Buan-gun (42% and 75%), Seocheon-gun (73% and 53%), Ganghwa-gun (47% and 100%), Sacheon-shi (47% and 77%), and Gangjin-gun (50% and 70%, respectively). Only 1 (10%) of 10 mullets from an eastern coastal area, i.e., Donghae-shi, was positive for P. summa metacercariae. Metacercarial densities were the highest in the trunk of mullets for H. nocens and the gill for P. summa. Gobies from Muan-gun were positive for H. nocens (40%) and P. summa metacercariae (40%), and gobies from Seocheon-gun revealed H. nocens metacercariae (20%). The metacercarial density was remarkably higher in mullets than in gobies. The results revealed that H. nocens and P. summa metacercariae are prevalent in mullets and gobies from coastal areas of the Republic of Korea, and the prevalence and intensity of infection vary according to geographical locality.

• Parasites, Hosts and Diseases
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• v.24 no.1
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• pp.55-62
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• 1986

The growth and development of Pygidiopsis summa were studied in experimental rats and mice, and a special reference was given to its morphological characters differed from the type species, P. genata. The metacercariae were obtained from young mullets (Mugil sp.), and total 21 rats and mice infected each with 1,000 metacercariae. Worms of various ages of infection, from 3 to 28 days, were subjected to a microscopic observation. The worms grew rapidly and remarkably in size up to 10 days of infection, to become 0.53~0.82mm long and 0.31~0.39mm wide, but nearly stopped the growth thereafter. Their genital organs developed more rapidly and fully matured within 3~5 days. At 3 days several eggs were found in uterus. The presence of two groups of small spines, 5~6 on the right and 7~9 on the left side of the genital apparatus, was a new finding in this study and considered a distinct character of P. summa. The morphology of ventral sucker and intestinal ceca was also different from P. genata. This study confirms the validity of the species, P. summa.

• 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.40 no.3
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• pp.107-112
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• 2002

A scanning electron microscopic study was performed on the surface ultrastructure of Pygidiopsis summa (Digenea: Heterophyidae) adults. Metacercariae were collected from gills and muscles of mullets (Mugil cephalus) caught in a known endemic area, and adult flukes were harvested from dogs after 8 weeks of experimental infection. The worm was calabash form with its posterior part broader than the anterior part. Tegumental spines were densely distributed over the body surface, except on the suckers and genital apparatus, and around the excretory pore. Well differentiated spines were observed on the anterior half of the body, with 14-16 tips ventrally, and 19-20 tips dorsally. On the oral sucker. three pairs of type I sensory papillae (uni-ciliated knob-like swellings) and one pair of type II sensory papillae (aciliated round-swellings) were observed on the anterior and posterior parts of the lip, respectively. On the lip of the ventral sucker, one pair of type II sensory papillae was distributed only on its posterior part. Sperms were seen emerging from or entering into the genital apparatus. The results showed that the surface ultrastructure of P. summa was unique among the heterophyid trematodes, especially in digitation of tegumental spines and in distribution of sensory papillae on oral and ventral suckers.

• Parasites, Hosts and Diseases
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• v.46 no.2
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• pp.77-82
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• 2008

Fishborne zoonotic metacercariae have not been reported from brackish water and marine fish from Vietnam waters although these parasites are common in the country's freshwater fish. Both wild-caught and cultured grouper (Epinephelus coioides and Epinephelus bleekeri), and mullet (Mugil cephalus) from brackish and marine waters located in Khanh Hoa province in central coastal Vietnam were examined, and found positive for zoonotic trematode metacercariae. From grouper, Heterophyopsis continua and Procerovum varium were recovered. The prevalence of H. continua ranged from 2.0 to 6.0% and that for P. varium ranged from 11.6 to 15.8%. Mullet were infected with Pygidiopsis summa and H. continua; both of these species are new records for Vietnam. The prevalence of P. summa in mullet was generally high, ranging from 17.6 to 75.5%, and was significantly higher than the prevalence of H. continua (2.5 to 32.4%). There were no significant differences in the prevalence of metacercariae between grouper from natural or cultured habitats, indicating that the highest risk of infection occurs in the wild-caught state prior to their placement in culture. Further, there was no difference in metacercarial prevalence between the 2 species of grouper. Infected wild-caught seed were only observed from January to October. Monthly variation in prevalence suggests seasonal variation in mullet infections occurs in this region with the highest transmission taking place from October to December. Basic investigations on the ecology and epidemiology of these intestinal flukes need to be carried out to determine their significance as a public health problem and the aspects of their biology that may be vulnerable to control interventions.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.7-13
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• 2006

Heterophyid metacercarial infections in brackish water fishes, i.e., perch, shad, mullet, redlip mullet, and goby, of Jinju-man (Bay), Kyongsangnam-do, Korea, were investigated using a digestion technique. Among 45 perch (Lateolabrax japonicus), the metacercariae of Heterophyopsis continua were found in $55.6\%$ (18.5 metacercariae per fish), Stictodora spp. in $28.9\%$ (3.6), and Metagonimus takahashii in $6.7\%$ (17.0). The metacercariae of H. continua were detected in 23 $(65.7\%)$ of 35 shad (Konosirus punctatus). Among 15 mullet (Mugil cephalus), the metacercariae of Pygidiopsis summa were found in $100\%$ (105.9 metacercariae per fish), Heterophyes nocens in $40.0\%$ (8.5), H. continua in $13.3\%$, and Stictodora spp. in $6.7\%$. Among 12 redlip mullet (Chelon haematocheilus), the metacercariae of P. summa were detected in $91.7\%$ (1,299 metacercariae per fish), H. nocens in $16.7\%$, and Stictodora spp. in $16.7\%$. Among 35 gobies (Acanthogobius flavimanus), the metacercariae of Stictodora spp. were found in $82.9\%$ (44.5 metacercariae per fish), and H. continua in $25.7\%$ (2.8). The adult flukes recovered from a cat experimentally infected with metacercariae from perches were compatible with M. takarashii. The results confirm that the estuarine fish in Jinju-man (Bay) are heavily infected with heterophyid metacercariae. Furthermore, it was found for the first time that the perch acts as a second intermediate host for M. takahashii.

• Parasites, Hosts and Diseases
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• v.47 no.2
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• pp.189-191
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• 2009

Four feral cats and a raccoon dog purchased from a local collector on Aphaedo Island, Shinan-gun, where human Gymnophalloides seoi infections are known to be prevalent, were examined for their intestinal helminth parasites. From 2 of 4 cats, a total of 310 adult G. seoi specimens were recovered, Other helminths detected in cats included Heterophyes nocens (1,527 specimens), Pygidiopsis summa (131), Stictodora fuscata (4), Acanthotrema felis (2), Spirometra erinacei (15), toxocarids (4), and a hookworm (1). A raccoon dog was found to be infected with a species of echinostome (55), hook-worms (7), toxocarids (3), P. summa (3), and S. erinacei (1). No G. seoi was found in the raccoon dog. The results indicate that feral cats and raccoon dogs on Aphaedo are natural definitive hosts for intestinal trematodes and cestodes, including G. seoi, H. nocens, and S. erinacei, It has been first confirmed that cats, a mammalian species other than humans, play the role of a natural definitive host for G. seoi on Aphaedo Island.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.55-66
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• 1991

A numerical taxonomy was studied on a group of heterophyid trematodes and analysis was made on the following species: Metagonimus yokogawai (3 OTU, Operational Taxonomic Unit) , Metagcnimus Miyata Type (3 OTU), Metagonimus takahashii (2 OTU), Heterophyes dispar (2 OTU), Heterephyes heterophyes (1 OTU), Heterophyes nocens (2 OTV), Heterophyopsis continua (1 OTU), Pygidiopsis summa (3 OTU), Stellantchasmus falcatus (2 OTU) and Stictodora sari (2 OTU). Twenty-six morphological characters were measured and their values were expressed as relative ratios. Similarity and correlation matrix among each individuals were calculated. Clustering analysis by Ward's method and factor analysis were performed using the SAS (Statistical Analysis System) package. As a results, the groups belonging to the genus of Metegenimus were divided into three phonons (Awetegonimus yokogawai, Metegcnimus Miyata Type, M. takahashii) , and Metagonimus Miyata Type was classified as the level of subspecies of M. takahashii. The groups belonging to the genus Heterophyes were clearly divided into three phonons (Heterophyes dispar, H. heterephyes, H. nocens), and H. nccens was classified as not a subspecies level of H. heterophyes but a distinct species. Other species were classified as distinct phonons. From these results, the appllcr lion of numerical taxonomy on trematode classification is considered to be a great aid to determine the limit of taxa.

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.681-690
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• 2019

The infection status of digenetic trematode metacercariae (DTM) was investigated in fishes from coastal lakes in Gangwon-do, the Republic of Korea (Korea). All fishes collected in 5 lakes were examined with the artificial digestion method. More than 10 species, i.e., Metagonimus spp., Pygidiopsis summa, Centrocestus armatus, Metorchis orientalis, M. taiwanensis, Clinostomum complanatum, Echinostoma spp., Stictodora spp., Diplostomum sp. and Diplostomid No. 1. by Morita (1960), of DTM were detected in fishes from 5 coastal lakes in Gangwon-do. Metagonimus spp. metacercariae were found in 52 (41.3%) out of 126 sea rundace, Tribolodon hakonensis, from 5 lakes, and their density was 14.6 per fish infected. P. summa metacercariae were detected in 48 (84.2%) out of 57 mullets from 5 lakes, and their density was 316 per fish infected. C. armatus metacercariae were detected in 7 (14.6%) T. hakonensis and 3 (15.0%) Tridentiger brevispinis from Hyang-ho, and 5 (19.2%) Acanthogobius flavimanus from Gyeongpo-ho. Stictodora spp. metacercariae were found in 4 fish species, i.e., Tridentiger obscurus, Tridentiger trigonocephalus, Chelon haematocheilus, and Acanthogobius lactipes, from Gyeongpo-ho. Total 15 C. complanatum metacercariae were detected in 2 (9.1%) crucian carp, Carassius auratus, from Songji-ho. M. taiwanensis metacercariae were found in T. hakonensis from Hyang-ho and Gyeongpo-ho and in Pseudorasbora parva from Gyeongpo-ho. Total 11 M. orientalis metacercariae were detected in 3 (6.3%) T. hakonensis from Hyang-ho. From the above results, it was confirmed that various species of DTM are infected in fishes from coastal lakes in Gangwon-do, Korea.