The Hongcheon river system flows down through the Hongcheon area of Kangwon-do, and reaches to the Cheongpyeong Dam in Kyonggi-do. Stool specimens from the inhabitants residing along the Hongcheon river basin were examined to detect infection rate of Metagonimus sp., and the intermediate hosts were collected to detect larval stages. The results obtained were as follows: Thirty-nine (33 males and 6 females) out of 529 (314 males and 215 females) inhabitants were infected with Metagonimus sp., showing a total positive rate of 7.4 per cent. In eight areas surveyed, the specimens from Kulji-ri of Bukbang-myon at the middle part of the river showed the highest positive rate of 26.9 per cent (14 positives out of 52) (males; 38.2per cent). The specimens from Mogog-ri of Seo-myon at the downstream of the river showed a positive rate of 10.4 per cent (13 positives out of 125) (males;12.6 per cent). The positive rates in other regions were less than 10 per cent. The density of the first intermediate host, Semisulcospira sp., was the highest in Kulji-ri of Bukbang-myon (10-20 snails per m(2)), and the infection rate of Metagonimus cercariae in the snails was 10.7 per cent(13 positives out of 121 snails). The infection rate of Metagonimus metacercariae in Zacco platypus, the fresh water fish favorably eaten raw by the inhabitants, was 68.2 per cent (30 positives out of 44 fishes), and most metacercariae were detected under the scales (89.9 per cent). Adult flukes were obtained from the small intestine of a rat, 15 days after infection with the metacercariae obtained from Z. platypus. These adult flukes were identified to be the same srecies as those obtained from human hosts. By this survey, new endemic areas of Metagonimus infection were discovered along the Hongcheon river basin and the main source of infection was the fresh water fish, Z. platypus.
parasitology-helminth-termatoda ; Metagonimus sp. ; epidemiology ; metacercaria ; Zacco platypus

The prevalences of the fluke belonging to genus Metagonimus have been reported along the upper stream of inhabitants by several workers since 1980, however the taxonomical problems of the fluke was not yet settled. The larval flukes; cercaria and metacercaria as well as their intermediate hosts, and adult were studied in order to identify the Metagonimus in the areas. The results obtained are summarized as follows: The snails, Semisulcospira globus were collected from the three different localities along the upper stream of the River. The cercariae were found from 125(7.2%) out of 1,730 snails by natural emerging method, and were identified into 5 species including Metagonimus sp. (3.7%), Pseudexorchis major(1.4%), Cercaria nipponensis (0.9), Cercaria incerta (0.6%) and Cercaria yoshidae(0.6%). Cercariae of Metagonimus species had four to five oral spines on its anterior of the first line. The cercariae of Metagonimus were experimentally exposed to goldfish. Infection rate was 22.9% out of 105 goldfish, and the encysted metacercariae were found in fins(86.7%) and on scales (13.7%) of the fishes, but not in their muscle, head or visceral organs. Seven species of fish were caught in the Daecheong reservoir and the upper stream. Infestations with metacercaria of Metagonimus were found 100% in Opsariichtys bidens and the parasitized numbers of the metacercariae were observed from 250 to 2,400 per fish. In the upper stream, Zacco temmincki, Z. platypus and Pseudogobio esocinus were infected 100% with the metacercaria, on the other hand, the fishes caught in the reservoir showed the lower infestation rates, and a few metacercariae found in the fishes Carassius carassius and Cyprinus carpio in the reservoir and the stream. The majority of metacercariae was detected only on the scales of fishes. In order to know the infectivity and the distribution patterns in the intestine of hosts, rats and dogs were infected with the metacercariae obtained from O. bidens and Z. platypus. In addition the metacercariae obtained from Z. temmincki, P. esocinus and goldfish were given to the rats. The recovery rates of the worms in the small intestine of dogs were higher (63.3-65.8%) than those of the rats (3.5-31.6%). The flukes were found mostly in the middle and the lower part of small tntestine of the rats and the dogs, but no worm was collected in the upper part of the intestine of rats. The size of adult flukes varied by the hosts. In the adult flukes, oral sucker was smaller than ventral sucker, and the right and left testes were located diagonally, the uterine tubules circled around the upper left testis. The average egg size was 29.1 x 17.7 micro-meter. According to the above results, the flukes belonging to genus Metagonimus distributed along the Geum River was concluded to be identical with Miyata type of M. yokogawai as that Saito had proposed.
parasitology-helminth-trematoda ; Metagonimus sp. ; epidemiology ; cercaria ; metacercaria ; Zacco temmincki ; Zacco platypus ; Pseudogobio esocinus ; Opsariichtys bidens ; Carassius carassius ; Cyprinus carpio

The author studied the infection rates of Clonorchiis sinensis in the inhabitants of Kyungpook Province, and surveyed infestation rates of Clonorchis metacercarias in the twelve kinds of fresh water fishes for the purpose of the eradication. plan of clonorchiasis of Kyungpook Province. The examination was continued from April 1960 to October 1962 with 24,252 inhabitants ranging from four months to over sixty aged. All the family were tested intradermally with Clonorchis antigen and then confirmed the eggs by M.G.L. technique. The results of the examination were summarized as follows. I. The infection rate of the inhabitants; In the people tested, 27.7 percent was infected with Clonorchis sinensis. There were no remarkable differences in the infection rates among each Districts; River side inhabitants(Yungchun-Gun 23.6 percent, Andong-Gun 27.4 percent), paddy field inhabitants(Yungchun- Gun 23.6 percent, Sangchu-Gun 29.1 percent) and mountain side inhabitants (Chungsong-Gun 23.8 percent, Yungyang-Gun 27.7%). However, the infection rates of the river side peoples were slightly higher than that of the districts far from the river. The infection rate of the male was 34.98 percent (4 ,628 out of 12,230), while the female was 18.96 percent (2090 out of 11022). The maximum infection rate of the male group was observed in the 35-39 age group (73.8 %) and in female, 55-59 age group (34.l percent) respectively, however it was gradually decreased in the senile group. II. The infection rates of the family group; Those infected in both husband and wife were 28 percent(357 out of 1,289), husband only was 52 percent (672 out of 1,289) and wife only was 4 percent (50 out of 1,289). The children of the infected parents revealed higher morbidity than that of the non-infected parents. The children of the infected father revealed much morbidity than that of the mother's side. On the contrary, children's morbidity rate of the infected widow was higher than that of the widower. III. The infestation rates of fresh water fishes; The metacercaria of Clonorchis sinensis was found in the flesh exclusive of the Misgurnus anguillicaudatus and Zacco platypus in the 11 kinds of fresh water fishes. The maximum infestation rate of 55.8 percent was revealed at Pseudorasbora parva and next to it was Sarcocheilichthys wakiyae of 5l.7 percent. The number of metacercaria in flesh was decreased as compared to the previously examined level.
parasitology-helminth-trematoda-Clonorchis sinensis ; epidemiology ; Misgurnus anguillicaudatus ; Zacco platypus ; Sarcocheilichthys wakiyae ; Pseudorasbora parva

Recent patterns of infection with digenetic larval trematodes in fresh-water and brackish-water fish were studied in three locations of the river Taewha during the period from April to October 1988, and compared with the data reported previously in the same river. Of 16 species of fish examined, the encysted larvae of Cyathocotyle orientalis were found most frequently from 9 species of fresh-water fish. The metacercariae of Echinochasmus sp., Metacercaria hasegawai and Metagonimus yokogawai were found 8 species, those of Clonorchis sinensis from 7 species, and Exorchis oviformis and Metorchis orientalis from 5 species of fish. The infection rates of fish with C. sinensis metacercariae were not lower than those reported in 1980, wheres their intensity of infection was found lowered in 3 species, Coreobagrus brevicorpus, Gnathopogon atromaculatus, and Puntungia herzi. The infection rates of 3 species of fish with M. yokogawai metacercariae were lower than the results in 1982, while the rate was higher in 2 species, Zacco platypus, and Z. temmincki, and rather stationary in Plecoglossus altivelis. The intensity of infection in several species of fish appeared rather higher than in 1980. the encysted larvae of C. orientalis, Echinochasmus sp., E. oviformis and Metacercaria hasegawai showed variations in infection rates of fish in 1980 and in the present study. It was found that the rate of infection with digenetic larval trematodes in fresh-water fish was still relatively high in the river Taewha, and the metacercarial burden in the fish varied greatly by different fish in 1980 and in the present study.
parasitology-helminth-trematoda ; Cyathocotyle orientalis ; Echinochasmus sp. ; Metacercaria hasegawai ; Metagonimus yokogawai ; Clonorchis sinensis ; Exorchis oviformis ; Metorchis orientalis ; Coreobagrus brevicorpus ; Gnathopogon atromaculatus ; Puntungia herzi ; Zacco platypus ; Z. temmincki

The prevalence of C. sinensis infection along the Nam river, Korea, was 38.7% of 5,291 people examined. Prevalence rates varied from 42% at the upper stream to 34% at the middle stream and 40% at the down stream region. Rates were highest (53.4-54.3%) in the 30-59 years of age group. The positive rates in primary school chidren, school students, teachers and local officers, and other inhabitants were 16.5%, 22.6%, 46.2% and 49.6% respectively. 53.6% of cases were light infected, i.e. less than 4,000/EPG. The cercarial expulsion rate of 5,005 Parafossarulus sp. was 0.34%. Snails naturally infected with C. sinensis expelled about 788 cercariae/day. Ten of 18 species of freshwater fish examined had C. sinensis metacercariae. To prevent clonorchiasis in the endemic areas, the effective health education system is suggested as a control measure. [retyped from English summary]
parasitology-helminth-trmatoda ; Clonorchis sinensis ; clonorchiasis ; epidemiology ; Pseudorasbora parva ; Parafossarulus sp. ; Loxogenes liberum ; Cyathocotyle orientalis ; Notocotylus attenuatus ; Zacco platypus ; Hemibarbus sp. ; Gnathopogon sp. ; Ischikauia steenackeri ; Pseudogobio esocinus

The present work which was investigated in July 1979, was to observe the wormicidal effects of the external mucous substances of 9 species of fresh water fishes (Cyprinus carpio, Parasilurus asotus, Anguilla japonica, Ophicephalus argus, Carassius carassius; golden crusian carp, Misgurnus anguillicaudatus, Zacco platypus, Pseudorasbora parva and Carassius carassius; crusian carp) on cercaria, liberated metacercaria and adult of Clonorchis sinensis. The mucous substances extracted by ether from the above 9 species of fishes were separated into many spots on the silica gel thin layer chromatography, and divided into many fractions in the silica gel column chromatography which used petroleum ether (30 percent) and chloroform (70 percent) as a solvent. On the silica gel thin layer chromatography of ether extracts from 9 species of fresh water fishes, each of the Rf. values which had wormicidal effect on the cercaria of C. sinensis were different from others; Rf. value of C. carassius (crusian carp) was 0.937, 0.709 in O. argus, 0.612 in A. japonica, 0.576 in P. asotus, 0.451 in C. carpio, 0.701 in Z. platypus, 0.385 in C. carassius(golden crusian carp) and 0.15 in P. parva. Time for wormicide was different from each other, too. It took 14 min. in a case of C. carassius(crusian carp), 25 min. in Z. platypus, 26 min. in C. carassius(golden crusian carp), 28 min. in C. carpio, 30 min. in P. asotus, 35 min. in O. argus, 40 min. P. parva and 180 min. in A. japonica. But any of the spots of M. anguillicaudatus did not show wormicidal effect on the cercaria within 10 hours. In the silica gel column chromatography of ether extracts from 9 species of fresh water fishes, the fractions which had wormicidal effect on the metacercaria of C. sienesis were different from each other; in a case of C. carassius(crusian carp), the first fraction only had wormicidal effect, the 2nd in P. asotus, the 3rd in O. argus, the 4th in C. carassius(golden crusian carp), the 2nd in C. carpio and the 4th in P. parva. Time for wormicide was 40 min. in C. carassius(crusian carp), 52 min. in P. asotus, 74 min. in C. carassius(golden crusian carp), 92 min. in O. argus, 95 min. in C. carpio and 140 min. in P. parva, but any of the fractions of A. japonicas, M. anguillicaudatus and Z. platypus did not show wormicidal effect within 10 hours. The fractions which had wormicidal effect on the metacercaria of C. sinensis had also the same effect on the adult, but it took longer time to kill them. It took 3 hours in a case of C. carassius(crusian carp), 4 hrs. in C. carassius(golden crusian carp), 5 hrs. in P. asotus, 6 hrs. and 6 min. in O. argus, 6 hrs. and 10 min. in C. carpio and half and 6 hrs. in P. parva. But any of the fractions of A. japonica, M. anguillicaudatus and Z. platypus did not show wormicidal effect within 24 hrs.
parasitology-helminth-trematoda ; Clonorchis sinensis ; mucous substance ; Cyprinus carpio ; Parasilurus asotus ; Anguilla japonica ; Ophicephalus argus ; Carassius carassius ; Misgurnus anguillicaudatus ; Zacco platypus ; Pseudorasbora parva

The present study was undertaken to determine the pattern of infestation with the encysted larvae of digenetic trematodes in freshwater fish collected in both the natural and fish breeding ponds in Kyungpook Province, Korea. The fish collected in the two natural ponds, Nass-chil, and Sa-il, and three fish breeding ponds, Deok-dong, Mo-gok, and Seongryu-tunnel, were examined from July 1980 to August 1981. The data were compared with the results obtained from freshwater fish caught in the river Kumho by Hwang and Choi(1980). Ten species of fish caught in the ponds were examined for the presence of the larval trematodes. Seven species of the larvae, Clonorchis sinensis, Cyathocotyle orientalis, Echinochasmus species, Exorchis oviformis, Metacercaria hasegawai, Metagonimus yokogawai, and Metorchis orientails and two kinds of undetermined cyst A and B were found. The infestitation rate for Clonorchis sinensis metacercaria in the Korean shiner, Gnathopogon atromaculatus collected in the natural ponds was higher than the rate in the river Kumho by Hwang and Choi(1980), but lower in the fish collected in the breeding ponds. By contrast, the infestation rate in the flat bitterling, Paracheilognathus rhombea in ponds was higher, while there was no change of the rate in the southern top-mouthed minnow, Pseudorasbora parva. The intensity of infestation, expressed as the average number of Clonorchis sinensis metacercaria per gram of flesh, were lower than in the bullhead, Coreobagrus brevicorpus, and Gnathopogon atromaculatus in the ponds in 1981. The intensity was higher in Paracheilognathus rhombea, but no fluctuation in the intensity of infestation in Pseudorasbora parva was observed. The infestation rates and densities for the encysted larvae of digenetic trematodes except for Clonorchis sinensis varied from fish to fish. However, it was found that the rate and intensity of the larval trematodes from all the fish in the ponds was lower than from those in the rivers in Kyungpook Province, Korea.
parasitology-helminth-trematoda ; Clonorchis sinensis ; Cyathocotyle orientalis ; Echinochasmus species ; Exorchis oviformis ; Metacercaria hasegawai ; Metagonimus yokogawai ; Metorchis orientails ; Pseudorasbora parva ; Coreobagrus brevicorpus ; Gnathopogon atromaculatus ; Paracheilognathus rhombea ; Carassius carassius ; Coreoperca herzi ; Cyprinus carpio ; Lipomis macrochirus ; Moroco oxycephalus ; Zacco platypus ; epidemiology

In order to know relationship between the clavate cells of epidermis and infectivity of metacercariae of C. sinensis. histological investigation of epidermis was carried out on the 26 species of fresh-water fish collected from the main rivers in Korea. Results were summarized as it follows: In general clavate cell had a single nucleus at its center. However it was observed in Liobagrus mediadiposalis and Pelteobagrus fuluidraco that clavate cell had two nuclei with and independent so-called light halo of Oxner and in some cases had none of them. In following species; Misgurnus anguillicaudatus, Cobitis taenia, Liobagrus mediadiposalis, Pelteobagrus fuluidraco, Parasilurus asotus and Anguilla japonica, scales were not detected or buried in the dermis layer, and the epidermis was mostly consisted of clavate cells. Among these species, it was observed that no metacercariae were found. In case of Cyprinus carpio, Carassius carassius (crusian carp and golden crusian carp), Sarcocheilichthys czerskii, Pungtungia herzi and Coreoleuciscus splendius, scales were exposed over the epidermis, in which clavate cells were abundantly found. In these species, a few of the metacercariae were detected. On the other hand, no clavate cells were observed in Pseudorasbora parva , Zacco platypus, Microphysogobio koreensis, Gnathopogon majimae, Gnathopogon coreanus, Acheilognathus signifer, Acheilognathus yamatsutae, Cultriculus eigenmanni, Coreoperca herzi, Pseudoperilampus uyekii, Pseudoperilampus notatus and Pseudogobio esocinus. These fishes with exposed scales on the epidermis were well known to serve as the second intermediate hosts of C. sinensis. From the above results obtained, it was suggested that the existance of clavate cells in the epidermis of the fresh-water fish seems to be correlated with the infectivity of the metacercariae of C. sinensis.
parasitology-helminth-trematoda-Clonorchis sinensis ; host ; Liobagrus mediadiposalis ; Pelteobagrus fuluidraco ; Misgurnus anguillicaudatus ; Cobitis taenia ; Liobagrus mediadiposalis ; Pelteobagrus fuluidraco ; Parasilurus asotus ; Anguilla japonica ; Cyprinus carpio ; Carassius carassius ; Sarcocheilichthys czerskii ; Pungtungia herzi ; Coreoleuciscus splendius ; Pseudorasbora parva ; Zacco platypus ; Microphysogobio koreensis ; Gnathopogon majimae ; Gnathopogon coreanus ; Acheilognathus signifer ; Acheilognathus yamatsutae, Cultriculus eigenmanni ; Coreoperca herzi ; Pseudoperilampus uyekii ; Pseudoperilampus notatus ; Pseudogobio esocinu