• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.227-234
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• 1991

We surveyed 12 migrating large egrets, Egretta alba modesta, for their infection status with intestinal trematodes, from June to September, 1990. All of them were infected with one or more flukes. Total 5 species were identified. Their infection rates and total numbers of worms were Metagonimus sp. 67% and 1, 412, Centrocestus armatus 67% and 2, 306, Echinochasmus japenicus 50% and 99, Strigea falconis 83% and 635, and a diplostomid cuke 33% and 36. The number of worms in a bird was in the range from 6 to 896. This is the first record that the egret is a reservoir host of Metagonimus sp., C. armatus, E. japonicus, and S. falconis. S. falconis is a new parasite fauna in Korea. Migrating birds must play an important role in the transmission and spreading of these intestinal trematodes in Korea.

• Parasites, Hosts and Diseases
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• v.60 no.5
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• pp.361-365
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• 2022

We report a species of diplostomid fluke recovered from 3 carcasses of wild Korean raccoon dog, Nyctereutes procyonoides koreensis, in Korea. A total of 107 diplostomid flukes were recovered from the small intestines of Korean raccoon dogs, which were obtained from the Gangwon Wildlife Medical Rescue Center. Worms fixed with 10% neutral formalin were subjected to microscopic observation and those fixed in 70% ethanol were used for molecular genomic analysis. The worm was divided into 2 separate parts, forebody and hindbody, with a total length of 3,020-4,090 (3,855) ㎛ and a width of 1,210-1,770 (1,562) ㎛. The boat-shaped forebody has a pair of characteristic tentacular appendage, 2 suckers, holdfast organ, and vitelline follicles. The oval to cylindrical hindbody has reproductive organs. The ovary was round or elliptical and located in the anterior of the testes. Two large testes were slightly segmented and tandemly arranged, occupying almost half of hindbody. The short uterus contained a relatively small number of unembryonated eggs sized 130-140×85-96 ㎛. The partial sequence of 18S rRNA of this fluke was consistent with Alaria alata. Based on the morphological and molecular characteristics, the diplostomid flukes recovered from the small intestine of Korean raccoon dogs were identified as A. alata (Digenea: Diplostomidae).

• Parasites, Hosts and Diseases
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• v.58 no.1
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• pp.81-86
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• 2020

Trematode specimens were collected from the intestine of a herring gull, Larus argentatus, which was found in a critical condition on the shore of a small island (Yubu-do, Seocheon-gun, Chungcheongnam-do) located at the western coast of the Korean peninsula. Total 11 specimens of intestinal flukes, including 3 Cryptocotyle lingua (Heterophyidae), 1 Himasthla alincia (Echinostomatidae), 5 Cardiocephaloides medioconiger (Strigeidae), and 2 Diplostomum spathaceum (Diplostomidae), were recovered. C. lingua was morphologically characterized by the presence of a large ventrogenital apparatus and 2 obliquely tandem testes. H. alincia had an elongated body and a head collar equipped with 31 collar spines. C. medioconiger had a bisegmented body and a voluminous copulatory bursa containing the seminal vesicle and ejaculatory duct. D. spathaceum also had a bisegmented body and its vitellaria extended up to the anterior border of the tribocytic organ. It is of note that C. lingua is potentially zoonotic that can occur in birds and humans. Three of them, i.e., C. lingua, C. medioconiger, and D. spathaceum, are new trematode fauna in Korea. Studies on trematode fauna of migratory birds should be continued in Korea.

• Parasites, Hosts and Diseases
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• v.51 no.1
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• pp.99-106
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• 2013

In 2005, we reported the infection status of 438 stray cats with various species of intestinal helminths, including nematodes (4 species), trematodes (23 species), and cestodes (5 species) in the Republic of Korea. However, morphologic details of each helminth species have not been provided. In the present study, we intended to describe morphologic details of 13 trematode species which were either new fauna of cats (10 species) or new fauna of not only cats but also all animal hosts (3 species). The worms were fixed in 10% neutral buffered formalin under a cover slip pressure, stained with Semichon's acetocarmine, and then observed using a light microscope equipped with a micrometer. The 13 subjected species included members of the Heterophyidae (Stellantchasmus falcatus, Stictodora fuscata, Stictodora lari, Centrocestus armatus, Procerovum varium, and Cryptocotyle concava), Echinostomatidae (Echinostoma hortense, Echinostoma revolutum, Echinochasmus japonicus, and Stephanoprora sp.), Diplostomidae (Neodiplostomum seoulense), Plagiorchiidae (Plagiorchis muris), and Dicrocoeliidae (Eurytrema pancreaticum). By the present study, Cryptocotyle sp. and Neodiplostomum sp. recored in our previous study were identified as C. concava and N. seoulense, respectively. Three species, P. varium, C. concava, and Stephanoprora sp., are new trematode fauna in Korea.

• Parasites, Hosts and Diseases
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• v.27 no.4
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• pp.231-248
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• 1989

The growth and development of the metacercariae of F. seoulensis cultivated in vitro or on the chick chorioallantois were assessed by comparison with the optimum process of maturation in albino rats and new born chickens. The process of maturation was divided for convenience into six stages: Stage 1 ; cell multiplication, Stage 2; body shaping, Stage 3; separation of genital anlagen, Stage :1 organogeny, Stage 5; gametogony, and Stage 6: oviposition. In Hank's and Tyrode's .solutions, the metacercariae were alive up to 200 days or more at $4^{\circ}C$ without any development. The in vivo maturation process in rats or chicks was as follows: stage 1 from 6 hours; stage 2 from 24 hours; stage 3 from 48 to 72 hours; stage 4 from 3 to 4 days; stage 5 from 4 to 5 days; and stage 6 from 5 to 8 days. Despite unsuccessful infection of the metacercariae to 12 day old chicks, fully mature worms of stage 5 or 6 were recovered from new born chicks (1 to 2 days old), The metacercariae of F. seoulensis grown in vitro were up to stage 3 and no further maturation was observed. Of various media employed, the medium NCTC 109 (Gibco) or NCTC 135(Gibco) supplemented with 20% egg yolk or 20% whole egg macerate or 0.5% yeast was basically required for the earlier development of the fluke. It took 16.1 days(in average) to reach the stage 3 after cultivation. The metacercariae cultivated on the chorioallantoic membranes of 6∼13 day old chick embryo at 37∼38℃ showed their full development up to stage 5 or 6. However, the worms were in general remarkably retarded, compared with those grown in rats or chickens. In the experiments of worm transplant, although the transfer was failed from in vitro culture to in vivo of rats(Per os), the transplants from in vitro culture to the chorioallantois and from the choriollantois to in vivo of rat host were successful with or without development of the transferred worms. In the present study, it was observed that the metacercariae of F, seoulensis can be maintained in vitro media with poor development as well as fully matured in 1 to 2 day-old chicks or on the chorioallantois at a very low rate.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.235-240
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• 1990

During an investigation on intestinal flukes of house rats in Yangyang-gun, Kangwon-do, a total of 6 species of trematodes belonging to 3 families; Echinostom-atidae (Echinostoma hortense, E. cinetorchis, E. revolutum and Echinoparyphium recurvatum), Diplostomidae (Fibricoza seoulensis) and Plagiorchiidae (Plagiorchis muris), were recovered from two adult rats. E. revolutum and E. recurvatum were new trematode faunae of rats in Korea. 5. revolutum had an elongated body, 5.3∼6.Omm long and 1.0∼1.3mm wide. The total number of collar spines was 35∼37 including 5 end group ones on each ventral corner. Its coiled uterus contained numerous eggs.5. recurvatum also had an elongated body, 3.5∼4.7 mm long and 0.50∼0.65 mm wide. It had total 45 collar spines including 4 end group ones. The uterus toras short with only a few eggs. It has been first confirmed by this study that E. revolutum and E. recurvatum are indigenously distributed among house rats in Korea. Kef lords: Echinostoma revolutum, Echinoparyphium recurvatum. new fauna. house rats, Yangyang-gun ( Kangwon-do )

• Parasites, Hosts and Diseases
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• v.31 no.4
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• pp.301-314
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• 1993

An electron microscopic study was performed to observe the ultrastructure of the tegument of U seoulensis. The outer surface of the tegument was covered with a tnlaminated plasma membrane. The electron-dense cytoplasmic layer was $2.5{\;}\mu\textrm{m}$ wide In the anterior portion and contained numerous vacuoles, mitochondriae and granular materials in its matrix. The basement layer was 330 nm wade or so, and Its numerous extensions protruded into the cytoplasmic layer. The sensory organ was composed of a small vesicle of $1.7{\;}{\times}{\;}1.1{\;}\mu\textrm{m}$ in dimensions, which possessed a cilium of $1.2{\;}{\times}{\;}0.19{\;}\mu\textrm{m}$ in size. The pharynx was composed of the epithelial layer of about $0.5{\;}\mu\textrm{m}$ wide, well developed muscle layer and basement layer. The tegument of the oral sucker was composed of a cytoplasmic layer of $0.4-0.5{\;}\mu\textrm{m}$ width, a narrow basement layer, a well developed muscle layer and tegumental cells. Some kinds of secretory granules that seemed to be originated from the cells of the oral sucker were observed In the parenchymal portions of the adjacent cells. The tribocytic organ consisted of numerous microvilli. The microvilli were 5 nm wide and heptalaminated. Two types of secretory granules originated from the gland cells of tribocytic organ were observed In the tegument and parenchyme. The tegumental cells were irregular in shape, and of which nuclei were multifarious.