Metacercariae were found from 6 samples among 4,382 Parlemon nipponensis which were caught at Podu, Kohung, Korea. The metacercaria was inclined as a larval stage of Paragonimus westermani by following reason: Semisulcospira libertina was the only one species which lives in Podu area. No other metacercaria except Paragonimus westermani were found from the craw or cray fish which were caught in the endemic aera. Metacercariae, ovary, testes and cuticular spines resmbled the characteristics of Paragonimus westermani, which have been described by previous workers.
parasitology ; helminth ; trematoda ; Paragonimus westermani ; metacercaria ; epidemiology

Ultrastructural studies on the integument of digenetic trematodes were investigated by several workers (Senft et al., 1961; Bjorkman and Thorsell, 1964; Burton, l966; Erasmus, l968; Morris and Threadgold, 1967, l968). Clonorchis sinensis is a common parasite of human beings in the Far East. But as far little has been written on ultrastructure of the integument of this parasite. This study was carried out systematically to elucidate the ultrastructure of the integument of adult C. sinensis, and the results are summarized as follows: The integument of C. sinensis was organized in two parts; the epidermis and the muscular layer. The apical surface and basal surface of the epidermis were covered with typical plasma membrane and irregularly invaginated from the surface. Plasma membrane at perisuckers was extremely folded and appeared as if the epidermis might be divided with the layer. The syncytial epidermis contained mitochondria and numerous secretory bodies, and which was connected by cytoplasmic processes to nucleated epidermal cells lying in the parenchyma. The mitochondriae, the secretory bodies, the granular endoplasmic reticulum, the Golgi bodies and the free ribosomes were present in the perinuclear cytoplasm of epidermal cells, but no organelle was observed in processes of epidermal cell except some secretory bodies. The fibrous layer consists of argentophile fiber and collagenous fiber, in which the circular muscle bundles and longitudinal muscle bundles were embedded. Bundles of muscle fiber are weIl developed at the perisucker, and mitochondriae in this portion contain many cristae as compared with any other parts of C. sinensis.
parasitology-helminth-trematoda-Clonorchis sinensis ; ultrastructure ; electronmicroscopy

A status survey on Metagonimus yokogawai infection along the Tamjin River basin, South Cholla Do, Korea was conducted from September to November 1977. The snail intermediate host, Semisulcospira sp., the fish host, Plecoglossus altivelis and the inhabitants in three villages in Jangheung and Kangjin Guns were examined for detection of this trematode infection respectively. The results could be summarized as follows: Out of 452 snails, Semisulcospira sp., 105 (23.2%) were found positive for rediae and/or cercariae of M. yokogawai in Jangheung Gun. All of 20 sweetfishes, P. altivelis were infected with metacercariae of M. yokogawai and the mean number per fish was 15,688 and per gram of fish muscle, 234. Out of 606 inhabitants in three villages, 160(26.4%) persons were found infected with M. yokogawai and the mean E.P.G counts per infected cases were 2,078. Sixty cases (9.8%) were positive for ova of Clonorchis sinensis with mean E.P.G., 846, frequently mixed-infected with M. yokogawai. From the above results, it was turned out that the Tamjin River basin is one of the endimic foci of metagonimiasis in Korea. The relatively low infection rate of human host in spite of much higher infection of intermediate hosts were considered to be due to the less population of sweetfishes in the Tamjin River than in the Sumjin River basin.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; epidemiolgy

In order to study host-parasite relationship in trematode, the susceptibility in rabbits of Clonorchis sinensis were examined. A certain number of metacercariae of C. sinensis were administered orally to rabbits, and rats and dogs were used to compare with rabbits. the results were summerized as follows: The rabbits were successfully infected with metacercariae of C. sinensis in all case of the groups given 10 to 500 each. But the highest recovery rate of the worm was 33.0 percent in the case given 100 metacercariae. In the early stage of infection, the worms were hardly found, but 10 days after the infection, the number of worms were detected easily. Three months after the infection, the recovery rate of worms was 31.3 percent in the rabbits given 300 metacercariae. The recovery rates of the worms in two months after the infection were 27.4 percent in rabbits, 51.0 percent in rats and 54.6 percent in dogs. Morphologically the body length and the body width markedly increased in the period until 10 days after the infection, and after that the genital organs began to get mature gradually while the growth of the body showed down. The measurement of adult C. sinensis recovered from the animals two months after the infection was the largest in rabbits followed by rats and the worms from dogs showed the smallest measurement.
parasitology-helminth-trematoda ; Clonorchis sinensis ; rabbit ; biology

In this study the authors examined the protein components at various stages of Clonorchis sinensis, and those of tegument and metabolite of adult Clonorchis by using SDS-polyacrylamide gel electrophoresis and immunodiffusion. The following results were obtained: The protein components of C. sinensis were gradually changed during its development. A considerable change occurred during the initial 7 days after the metacercarial infection. Two bands of protein of about 97,000 molecular weight (MW) and 178,000 MW were unique to excysted metacercaria of C. sinensis. Other 2 bands of protein of 23,000 and 25,000 MW which were absent in metacercariae, might be associated with the development of sex organs in adult. In the metabolite, some components of tegumental proteins were detected. And this tegumental protein components in metabolite seems to be the major antigenic components reacting with infected rabbit antiserum by immunodiffusion. Twenty bands of protein were detected in the isolated adult tegument. Among them 6 bands were in 97,000-65,000 MW, 3 bands in 56,000-53,000 MW and 5 bands in 37,000-30,000 MW. On the other hand, in metabolic products of adult C. sinensis, 17 bands were detected.
parasitology-helminth-trematoda ; Clonorchis sinensis ; biochemistry ; protein

The egg laying capacity of Fibricola seoulensis was observed in mice and rats. In mice, the mean number of eggs produced by an adult worm a day was 116 at the first week after infection, 123 at the 2nd week and 42 at the 3rd week. Thereafter, the capacity of about 20 eggs/worm/day was maintained up to one year period. In rats, it generally produced more eggs; 49 at 1 week, 250 at 2 weeks, 216 at 4 weeks, 327 at 6 months and 11 at one year after infection. It survived longer than a year in mice and rats.
parasitology-helminth-trematoda ; Fibricola seoulensis ; egg

The pattern of sensory papillae, chaetotaxy, of the cercaria of Clonorchis sinensis was observed. The chaetotaxy was as follows; 5-6 Ci l, 4-5 Ci 2, 5-6 Ci 3 at lst row, 4 Cii 1, 2 Cii 2, 4 Cii 3, 5-6 Cii 4 at 2nd row, 3-4 Ciii 1, 2-3 Ciii 2 at 3rd row, and 2 Civ 1, 2-3 Civ 2, 2-3 Civ 3, at 4th row, in cephalic region; 2 AiV, l AiD, 2 AiiV, 1 AiiD, 2 AiiiV, 2 AiiiD, 1 AivV, 1 AivD, 1 PiiD, l PiiiD, in ventral(V) and dorsal(D) portions of body. Caudal region revealed 2-2-2-2 formula.
parasitology-helminth-trematoda ; Clonorchis sinensis ; cercaria

The present study was performed to observe the ultrastructure of the integument of adult Paragonimus westermani. Dogs experimentally infected with 60 metacercariae of P. 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: 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 suckrer and ventral sucker. At the end of the body, excretory pore was found, the shape was irregular. 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. In higher magnification, plasma membrane and bar-shaped granules were found at the outer surface of the tegument.
parasitology-helminth-trematoda ; Paragonimus westermani ; electron microscopy

As a series of studies to clarify clonorchicidal substances in body surface mucus of some fresh-water fishes, the substance in the epidermal mucus of Cyprinus carpio was isolated by silica gel column and thin layer chromatography and analyzed for its chemical nature. Wormicidal trial was done in vitro, and the results obtained are summarized as follows: The mucus was extracted by ethyl ether and separated into 4 fractions by column chromatography using benzene as solvent. The second fraction with yellowish red colour among them showed the strongest clonorchicidal effect. The yellowish red fraction obtained by column chromatography was then fractionated into 6 spots by thin layer chromatography with petrol. ether/chloroform(30/70, v/v), and the Rf. 0.714 spot among the 6 spots showed the strongest effect. The Rf. 0.714 spot was further fractionated into 6 spots by thin layer chromatography with benzene/acetone (90/10, v/v), and the Rf. 0.800 spot among the later 6 spots revealed the strongest effect. The Rf. 0.800 spot was chromatographed on column with benzene and 2 fractions were obtained. The second fraction of light brown colour represented the final purified fraction. By these purification procedures, clonorchicidal substance was purified 15-fold with 0.03 percent yield from the mucus of C. carpio, and 10mg of the final fraction killed the cercaria in 26 min, the metacercaria in 115 min, and the adult in 443 min. Infra red and nuclear magnetic resonance spectrometric analysis of the purified substance revealed that the substance belongs to an ethyl ester of unsaturated fatty acid with 2 double bonds, 15 methylene groups and l methyl group.
parasitology-helminth-trematoda ; Cyprinus carpio ; mucus ; toxicology

The authors carried out histochemical studies on Clonorchis sinensis, especially, histochemical demonstration of carbonic anhydrase activity. Kurada's method was applied for the histochemicl staining in this study. The result obtained were summerized as follows : Carbonic anhydrase activity was intensely positive in oral sucker cells, reticular tissue cells, epithelium of the intestine and testes, more or less intensely positive in vitelline gland cells and yolk of eggs as well.
parasitology ; histochemistry ; trematoda ; helminth ; Clonorchis sinensis