• Parasites, Hosts and Diseases
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• v.25 no.2
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• pp.129-140
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• 1987

The present study was undertaken to demonstrate the surface structure of Paragonimus westermani metacercaria in Korea with special reference to the distribution of sensory papillae. Metacercariae were isolated from crayfish, one of the second intermediate tost of P. westermani in Bogil island, Chollanam-do (Province), Korea, where has been known as an endemic area of human paragonimiasis. Isolated metacercariae were encysted and examined with light. scanning and transmission electron microscopes for morphological features. On the surface of iBetacercariae, three types of sensory FaFillae were identified. Large domed papillae ($3~5{\mu\textrm{m}}$), which were covered with wrinkled plasma n!embrane of the worm, were distributed on the oral and ventral suckers only. On the oral sucker, these large domed papillae were 12~13 in number. On the other hand large domed papillae on the ventral sucker were constantly 6 in number and hexagonal in distribution. Small domed papillae ($2~3{\mu\textrm{m}}$), of which surface was more smooth than those of large ones, were distributed symmetrically on the ventral (30~32 pairs) and dorsal surfaces (40~42 Pairs). Ciliated Papillae ($0.8~1.5{\mu\textrm{m}}$) were observed about 5~6 in number around the oral sucker and 3~5 pairs each on the ventral and dorsal surface of the body. Single Fcinted spines covered the entire surface of the body except around the excretory pore. Spines on the anterior fart of the body were 0.9~2.0${\mu\textrm{m}}$ in length and $45~55/100{\mu\textrm{m}}$2 in number, and were gradually reduced in length ($0.4~1.4{\mu\textrm{m}}$) and in nuns.her ($12~27/100{\mu\textrm{m}}$2) toward the posterior part. The body wall of p. westermoni metacercariae was consisted with anucleated syncytium layer, fibrous interstitial layer and musclar layer. In the anucleated syncytium, biconcave ($0.15~0.55{\mu\textrm{m}}$) and spherical ($0.08~0.16{\mu\textrm{m}}$) secretory granules, which were transferred from epidermal cells via protoplasmic tubules, mitochondria and rihoEorses, T-ere observed. Spines originated around the basement membrane protruded externally. Epidermal cells were consisted with a nucleus and a cytoplasm, and connected to syncytium with protoplasmic tubules. In the cytoplasm many secretory granules, mitochondria, Golgi complex, endoplasmic reticula, ribosomes and lipid droplets were observed.

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.165-172
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• 1995

A transmission electron microscopic study was performed on the ultrastructure of the tegumental layer of GymophoLloines seoi (Digenea: Gymnophallidae) metacercarlae and adults. The metacercariae were obtained from naturally infected oysters, Crcssosoea gigas, and the adults from experimentally infected C3H mice. The tegumental layer generally revealed a small number of foldings, numerous small vacuoles, sines, and muscle bundles. Beneath the muscle layer, nuclei of the tegumental cells were located. There was little difference in the structure of the tegument between the metacercariae and adults. The oral sucker, having well-developed muscle layers, showed a similar structure to the ventral sucker except numerous foldlngs in the ventral sucker. The ventral pit was surrounded by a thin spcpiu layer, where a number of microtubules and mitochondria were seen. Around the ventral pit located well-developed circular and longitudinal muscles. The results showed that the ultrastructure of the tegumental layer of G. seoi metacercariae and adults revealed little difference from other trematodes in general. The ventral pit, a peculiar structure of this trematode, seems to function as a sphincter or an accessory adhesive organ.

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.657-664
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• 2019

We identified the echinostome metacercariae in Chinese mystery snails, Cipangopaludina chinensis malleata, from Xiengkhuang Province, Lao PDR with morphologies of adult worms recovered. Total 20 snails were examined with artificial digestion method and then the collected metacercariae were orally infected to a mouse and a rat. Adult worms recovered from experimental animals were observed with a light microscope and a SEM. The metacercariae were round, 125×123 ㎛ in average size, with a moderately thick cyst wall, collar spines distributed in the head collar and excretory granules in 2 canals of excretory tube. Adult flukes (3-week-old in a rat) were elongated, ventrally curved and 5.310×1.023 mm in average size. Head collar distinct, bearing 43 collar spines with 5 end group ones on each side. Oral sucker subterminal, prepharynx very short, pharynx well developed, and esophagus relatively short. Cirrus sac well developed, with a saccular seminal vesicle, and ventral sucker very large. Ovary round and on the median line of the body. Testes tandom and elongated. Eggs operculated, elliptical and 90×57 ㎛ in average size. In the SEM observation, the head crown prominent, with 43 collar spines resembled with horns of younger stag. Scale-like tegumental spines were densely distributed on the surface between the head collar and ventral sucker, and their densities were decreased posteriorly. Conclusively, the metacercariae detected in C. chinensis malleata from Lao PDR were identified as those of Echinostoma macrorchis based on the morphological characteristics of adult worms.

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1154-1159
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• 1991

Anomalous systemic venous return to the right atrium is clinically innocuous and cause no functional disturbances or physiologic abnormalities by themselves and consequently require no treatment but may be surgical importance. We experienced a case of adult TOF combined with anomalous systemic venous drainage. Rudimentary right SVC with draining left sided vertical vein and IVC with separately drained left vein was revealed at operation time. With the bicaval cannulation, large sucker was used for drainage of blood from the left hepatic vein. Postoperative angiocardiogram showed above findings and combined double inferior vena cava at lumbar level.

• 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.55 no.1
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• pp.39-45
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• 2017

The present study was performed to reveal the morphological characteristics and molecular phylogenetic position of Platynosomum fastosum Kossack, 1910. A total 167 specimens of P. fastosum were collected in 8 (4.9%) out of 163 sets of gall-bladders and bile ducts of cats. The number of worms was 1-105 per infected cat. This species was characterized by having a long and slender body, slightly larger ventral sucker than the oral sucker, indistinct prepharynx, small pharynx, short esophagus, bifurcation midway between 2 suckers, and ceca extending to the posterior end of the body. The length of the partial sequences of ITS1 and 5.8S rDNA of P. fastosum were 990 bp, GC-rich. AT/GC ratio was 0.9, there were 9 polymorphic sites, and intraspecific variations ranged from 0.1% to 0.9%. Phylogenetic analyses by neighbor-joining phylogram inferred from ITS1 rDNA sequences revealed that the genetic distance between P. fastosum specimens ranged from 0.3 to 1.5% while the smallest interspecific distance among dicrocoeliid species was 20.9 %. The redescription and genetic characters of P. fastosum are taxonomically important to recognize future different species of the genus Platynosomum showing high intraspecific and morphological variability.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.111-122
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• 1985

The present study was performed to observe the ultrastructure of the integument of adult Paragonimus westermani. Dogs experimentally infected with 60 metacercariae of F. westermani were autopsied 4 months after the infection. Adult p. westermani were extracted from the dogs and the fine structure was studied by means of scanning and transmission electron microscope. The findings are as follows: 1. Scanning electron microscopic findings showed that the spines and the papillae are distributed at whole body surface but the well developed spines or papaillae are shown around the oral sucker and ventral sucker. 2. At the end of the body, excretory pore was found, the shape was irregular. 3. Transmission electron microscopic findings showed that plasma membrane, tegument, basal lamina, connective tissue, circular muscle layer, longitudinal muscle layer. nerve axon and tegumental cell were observed. 4. In higher magnification, plasma membrance and bar-shaped granules were found at the outer surface of the tegument.

• Parasites, Hosts and Diseases
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• v.46 no.2
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• pp.87-90
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• 2008

Gynaecotyla squatarolae (Digenea: Microphallidae) adult flukes were recovered from experimental chicks at day 4-6 post-infection and their tegumental ultrastructure was observed with a scanning electron microscopy. They were pyriform in shape, and their anterior halves were concaved ventrally. The whole body surface was covered with tegumental spines, which were wide and 16-17 digitated between oral and ventral suckers. The density of spines and number of digits decreased posteriorly. The oral sucker was subterminal and the excretory pore was at the posterior end of the worm. Two ventral suckers were similar in appearance and protruded near midline of the worm. The genital atrium was dextral to the small ventral sucker. The dorsal surface was covered with tegumental spines, but the spines were sparser than on the ventral surface. On the middle portion of the dorsal surface, a small opening presumed to be the Laurer's canal was seen. From these findings, it has been confirmed that the adult G. squatarolae has unique characteristics in the surface ultrastructure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.173-178
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• 1980

Cercaria larvae of Bacciger harengulae which is parasitic to Meretrix lusoria, rapes japonica and Solen strictus were studied in terms of their morphology and incidence of infection rate. The host bivalves were collected from Naechodo, Okgu-gun during the Period from January to November in 1980. The tail of the cercaria bears 27 pairs of tufts of setae, the tufts being composed of 6 fine rays. Oral sucker, intestine, ventral sucker and a pair of testes are distinctive. The excretory duct bears numerous granules of various size, and the flame-cell arrangement is represented by a formula 2[(3+3)+(3+3)]=24. The cercaria is somewhat similar to the previously known Cercaria pectinata . It is however conformed that present cercaria belongs to Bacciger harengulae. Infection rate showed seasonal variation and host selectivity. Higher infections were observed in Solen strictus, and lower in Meretrix lusoria. Generally, the larger bivalves over 2-3 years old showed the higher infection rate.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.287-294
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• 2017

The present study was performed to record new definitive hosts of Isthmiophora hortensis, and to describe morphological characteristics derived from a variety of worm samples for clarification of its taxonomic validity. Morphological characteristics with dimensions were observed in worm samples (n=21) from naturally infected wild animals, including a raccoon dog Nyctereutes procyonoides from Gimhae-si (City), Gyeongsangnam-do, stray cats and a striped field mouse from several localities, and a wild boar Sus scrofa, from Gurye-gun (County), Jeollanam-do. In addition, adult flukes (n=45) recovered in albino rats experimentally infected with the metacercariae from a freshwater fish species were also subjected to morphological studies. The mean ratios of the body length (BL) to body width (BW) were 5.86 and 5.76 in worms from wild animals and experimental rats, respectively. Those of the ventral sucker to oral sucker were 2.92 and 3.01 in worms from 2 groups. The mean percentages of the hindbody length (HBL) to BL were 42.1 and 41.2 in 2 groups. Those of uterine fields to BL were 9.8 and 12.2 in the 2 worm groups. By the present study, the 2 species of wild animals, the raccoon dog and wild boar, have been added as new definitive hosts for I. hortensis. The morphological characteristics of adult flukes derived from a variety of host source were redescribed to support the taxonomic validity of this echinostome species.