This survey was undertaken to determine the recent prevalence of lung fluke, Paragonimus westermani, in the three localities of Wiseong county, Kyungpook Province, Korea and to compare the prevalence among the residents in the same areas between 1924 and 1980. The three localities, Ku-seong, Sam-chun, and Um-ji villages (dong) have been known as the endemic areas of Paragonimus westermani. The surveys were made on the general population. They were examined using intradermal test with Paragonimus westermani antigen, and the diagnosis of paragonimiasis was made depending on the positive intradermal reaction. The sputum examination could not be performed beacause the residents were inaccessible. The prevalence of Paragonimus westermani among the residents in the three communities varied from 1.4 percent to 7.9 per cent, with an average of 4.0 per cent. Whereas, the average reported by Ichinomiya in 1924 was 4.7 percent. There are no significant differences in the sex and age specific rates of infection between 1924 and 1980. With the abundant density of Semisulcospira snails and crayfish in Sam-chun stream and the high rate of infection with Paragonimus westermani among the residents in the village, it is found that Sam-chun village, one of the three localitied in Wiseong county, where Ichinomiya (1924) surveyed, was still the endemic focus of Paragonimus westermani.
parasitology-helminth-trematoda ; Paragonimus westermani ; paragonimiasis ; epidemiology

In order to determine the epidemiological patten of the liver fluke, Clonorchis sinensis, the locality where the snail, Parafossarulus manchouricus, is abundant, the infestation rates for the cercarial and metacercarial larvae of digenetic trematodes in the snail and fish hosts, and the prevalence of Clonorchis sinensis among the residents in the vicinity of river Taewha, Kyungnam Province, Korea were studied from March 1979 to September 1980. Four snail habitats were found in the river Taewha. The population density of the snail per square meter of the habits ranged from 10 to 500, with an average of 150. Among the 4 snail habitats, three, Baek-cheon, Sa-yeon and Taewha had snails infected with the cercaria of Clonorchis sinensis, and the proportion of infested snails in the three habitats was very low, the average being 0.59 per thousand. Four species of fresh-water fish, the bullhead, Coreobagrus brevicorpus, the Korean shiner, Gnathopogon atromaculatus, the flat bitterling, Paracheilognathus rhombea, and the striped shiner, Pungtungia herzi among ten species of fish examined harbored the metacercaria of Clonorchis sinensis. The intensity of infestation with the cyst of Clonorchis sinensis in the four species of fish was low. The approximate number of the cysts per gram of flesh was between 3.5 in Paracheilognathus rhombea and 21.5 in Gnathopogon atromaculatus. Seven kinds of laval tremathodes, Clonorchis sinensis, Cyathocotyle orientalis, Echinochasmus species, Exorchis oviformis, Metacercaria hasegawai, Metagonimus yokogawai and Metorchis orientalis were found from ten species of fish examined. In general, the infestation rates for the encysted larvae of digenetic trematodes varied from fish to fish. The infection rate for Clonorchis sinensis among the residents in the vicinity of river Taewha was relatively high, 22.2 percent by the formalin-ether sedimentation technique, and the difference in the rate of infection between males and females found to be siginificant(t>2). Of these, the rate was 12.4 per cent in 483 elementary school children and 17.7 percent in 761 middle and high school students. The results obtained in the present study indicate that endemic foci of Clonorchis sinensis exist in the river Taewha and the prevalence of the liver fluke among the residents is still high.
parasitology-helminth-trematoda ; Clonorchis sinensis ; epidemiology

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

Prevalence study of Metagonimus yokogawai infection, survey of intermediate hosts of Metagonimus yokogawai and food habits of raw sweetfish among inhabitants along Boseong river (120 km), Jeonra Nam Do (province) were carried out. The results are summarized as follows: Among 360 examined, the egg positive case were 128(35.6 percent); male 112(46.7 percent), female 16(13.3 percent). The prevalence rates were different by geographical areas; 42.4 percent in down stream, 49.4 percent in middle stream and 13.3 percent in upper stream. By ages, highest rate, 53.6-59.1 percent was observed among 30-49 group (male 69.6-73.0 percent, female 15.8-35.5 percent). Eggs per gram of feces were 2,084 (200-12,280) in average; down stream 1,708, middle stream 2,590, upper stream l,550. By social strata, the prevalence showed differences; 24.8 percent in primary schoolchildren, 78.4 percent in school teacher and local officers, 30.6 percent in general inhabitants. Clonorchis sinensis infected cases in the areas were 21(5.8 percent) out of 360 examined, and 90.5 percent of them showed mixed infection with Metagonimus yokogawai. Cercariae of Metagonimus yokogawai from the lst intermediate host, Semisulcospira sp., in down and middle streams were detected from 32 snails (5.9 percent) out of 545 examined. All the 22 Plecoglossus altivelis which were caught from the down stream were infected with metacercariae of Metagonimus yokogawai. The number of the metacercariae detected was 22,650 per fish in average, and the number increased from August to October. Experiences of raw sweetfish intake of the inhabitants were found in 208(58.4%) among 356 interviewed by questionaire form (male 76.7 percent, female 20.7 percent). Means of acquisition of the sweetfish were mostly by purchase 68.8 percent, and seasonally in summer. Reason of the raw sweetfish intake was due to the flavor, 83.2 percent. The fish were mixed in soy sause with vinegar before the intake.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; metagonimiasis ; epidemiology

An epidemiological investigation was conducted on Metagonimus yokogawai infection in Hadong Gun (County), Gyeongsang Nam Do, Korea, and following findings were obtained. Overall prevalence rate of Metagonimus yokogawai infection was 29.1 percent from a total of 1,163 inhabitants examined. By area of river and stream, Seomjin-gang R.: 9.5 percent (out of 95 inhabitants examined) in Jeondo Ri in the lower river, 19.9 percent (156) at Dugog Ri near Hadong town, and 90.8 percent (65) in Tab Ri of Hwagae Myeon where Hwagae-cheon Stream joins; Hwagae-Cheon Stream: 42.2 percent (45) in Yonggang Ri of the middle stream and 27.5 percent (72) in Daeseong Ri of the upper stream; Hoengcheon-gang R.: 54.7 percent (161) in Gojeol Ri of the lower river, 40.6 percent (128) in Hoengcheon Ri of the middle stream, and 5.4 percent (93) in Jungi Ri of the upper stream, and 43.8 percent (89) in Uge Ri located along a tributary of the Hoengcheon-gang R. and 4.0 percent (101) in Jangam Ri which is located about 4 km away from the river; Deogcheon-gang R.: 18.5 percent (54) in Munam Ri; Gwangog-cheon Stream: 2.8 percent (107) in Gwangog Ri. The difference in prevalence rate of the infection by area was correlated with the opportunity and amount of raw eating of sweetfish by the inhabitants in the respective areas. By age and sex, the overall prevalence rate increased from young age group and reached a peak at 20-29 age group and then the rate decreased gradually. In high endemic areas, however, a peak level of the rate lasted up to 40-49 age group in male. On the other hand, in low endemic areas, the rate was significantly lower in female, though moderate level of the infection was seen in male. The overall prevalence rate was higher in male than in female and the difference was greater in middle age groups. The most significant mode of infection by the inhabitants was the raw eating of sweetfish which commonly harbour metacercariae of M. yokogawai during summer through autumn. Besides, it was noted that the infection can be acquired through contamination with the metacercariae on food of various side-dish and kitchen utensils as well as on hands of a cook when such fish are prepared or handled. The inhabitants usually begin to acquire infection from early June of a year when fishing of sweetfish opens and acquire infection more frequently in July and August when fish are caught more productively and favored for raw consumption by inhabitants. From September, sweetfish are no more favored for raw consumption and accordingly are dried and cooked in this season. The infection in the sweetfish Plecoglossus altivelis as the second intermediate host was first observed from May with low level of infection and the intensity of infection in a fish rapidly increased until reaching a peak in October when sweetfish season normally ends. The first intermediate host snail of M. yokogawai in this area was Semisulcospira coreana (Martens) which is widely distributed in the streams and rivers in this locality.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; metacercaria ; Plecoglossus altivelis ; epidemiology

There are a number of eating-houses in the basin of river Ahnseong that sell rawsweetfish, Plecoglossus altivelis, to local residents and visitors. These facts called attention to the possibility of wide spread of metagonimiasis in that area. In an attempt to determine whether the metacercaria of Metagonimus yokogawai does present in the sweetfish caught in the river Ahnseong, a total of 77 fish were examined in the period from April to September 1978. All the fish were infected with the encysted larvae. The average number of larvae persweetfish was 1,815, of which the metacercaria rate for the fluke in the flesh was 56.9 per cent and in the scale, 30.5 per cent. These results indicate that all the sweetfish in the river Ahnseong harbour the metacercaria of Metagonimus yokogawai.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; metacercaria ; Plecoglossus altivelis ; epidemiology

This study was undertaken to evaluate the status of human paragonimiasis in Kang Hwa Gun, Kyunggi Do, Korea from March 1973 to October 1975 by the use of intradermal screening test with Veronal buffered saline antigen. A total number of 7,352 (male 3,936; female 3,4l6) consisting of 3,447 primary school children, 2,689 middle school students, l,008 high school students of 9 Myuns out of 13 Myuns of this County and 208 residents of all age group in Kilgeong-Ri, Yangdo Myun were examined by the intradermal test with Paragonimus antigen. In order to detect Paragonimus egg, the sputum and the stool examinations were undertaken on the residents in Kilgeong-Ri. The infestation rate of crayfish with Paragonimus metacercaria was also examined in Konneung and Jeongha village in Kilgeong-Ri. The following results were obtained in this survey: As a whole, 16.6 per cent of the examiners showed positive reaction with sexual difference of 16.1% in male and 14.8 per cent in female. In age groups, the highest positive rate showed in middle school age group (17.1 per cent) than primary school (14.0 per cent) and high school age group (11.4 per cent). In regional differences of positive rates, the highest rate (28.4 per cent) showed at Yangdo Myun followed by Kilsang Myun (27.0 per cent), Hwado Myun (25.0 per cent), and Naega Myun(20.8 per cent). In the result of 208 residents Kilgeong-Ri, the positive of 36.1 per cent in male and 20.2 per cent in female. The highest positive rate showed in 10 to 19 age group (41.5 per cent). Among the residents in Kilgeong-Ri, Paragonimus eggs were detected in 11 residents by the sputum and the stool examinations. The infestation rate of crayfsh with Paragonimus metacercariae was 100 per cent (41 out of 41 crayfishes) in Konneung village, and 84.6 per cent (9 out of 13 crayfishes) in Jeongha village, Kilgeong-Ri The fluctuation of the infection rate of crayfish with Paragonimus metacercariae was decreased in Konneung village in 2 years after the treatment with Bilevon against 10 paragonimiasis patients.
parasitology-helminth-trematoda ; epidemiology-paragonimiasis ; Paragonimus westermani ; crayfish-Cambaroides similis

Studies were conducted in rivers in Kyungpook Province, Korea from July 1970 to September 1974 to determine the stations where Parafossarulus manchouricus, the intermediate snail host of Clonorchis sinensis, are abundant, and the infection rates of these snails with the cercaria of Clonorchis sinensis. Snail collections were made during four consecutive summers(July to September in each year). Ten snail habitats were found. The population density of the snails per square meter of the river bottom ranged from 25 to 250. The highest population of snails was encountered at the Dong-chon station. Cercaria studies by means of the immersing and crushing technics indicated surprisingly low rate of Clonorchis sinensis infection among the snails examined. The proportion of infected snails in Kyungpook Province was 0.8 per thousand of all snails examined. Results indicated that the Parafossarulus manchouricus exists in limited areas within the rivers under study and the infection of the snail with the cercaria of Clonorchis sinensis is very low.
parasitology-helminth-trematoda ; Clonorchis sinensis ; Parafossarulus manchouricus ; snail ; epidemiology

The infection rates with cercaria and metacercaria of the Clonorchis sinensis in snail and fish hosts, and the prevalence among the inhabitants in the lower Nag Dong river in Busan were investigated in the period from June 1981 to March 1982. The stool examination and E.P.G. count for prevalence and intensity of clonorchiasis were done by cellophane thick smear and Stoll's egg count methods. The prevalence rate of clonorchiasis among inhabitants of 3 towns in Bug Gu, was 38.4% among a total of 1,384 persons examined. By town, the prevalence in Gu Po was 25.4% out of 330 persons examined, 39.3% in 438 examined in Gang Dong and 44.8% out of 616 in examined in Myeng Ji respectively. According to sex, the male(41.9%) showed relatively higher rate than female(35.3%). By age, increase of rate was observed as increase in age. The highest rate was 80.7% in 50-59 years group. The intensity of infection was light: 89.1% of examined cases were below 10,000 E.P.G. ; by area 80.9%(Gu Po), 80.2%(Gang Dong), 97.3%(Myeng JI). Out of fresh water fish species collected, 2 species were not infected with metacercaria. The metacercarial detection rate from fish in low Nag Dong river showed 100% in Pseudorasbora parva, Pseudogobio esocinus(41.4%), Hemibarbus labeo(37.1%), Acheilognathus limbata(33.3%) and Erythroculter erthropterus(4.5%) respectively. The mean number of metacercaria per gram of muscle was 21.2 in P. parva, P. esocinus(15.0), H. labeo(11.9), A. limbata(6.3), and E. erythropterus(1.6) respectively. Though 7 area along Nag Dong river were surveyed for Parafossarulus manchouricus, the snails were not found at all areas except for one area, Seo Nam stream; and the cercaria was infected 0.9% out of 708 examined.
parasitology-helminth-trematoda ; Clonorchis sinensis ; clonorchiasis-epidemiology ; host

The present survey was undertaken to observe the geographical distribution of metacercaria among the sweetfish, Plecoglossus altivelis, the most important second intermediate host of Metagonimus yokogawai, which were collected during the period from 1983 to 1984 in south-eastern coastal areas of Korea. The results obtained were summarized as follows: A total of 668 sweetfish collected from 70 chons (=streams) in the above coasta1 areas was examined for the metacercariae, and 432(64.7 percent) among them were infected with metacercariae of M. yokogawai. The mean number of metacercariae in a fish was in the range from 0 to 29,604 and the mean number of the metacercariae in a fish was 640.3. It was observed that the mean infection rate showed 46.4 percent in Gangweon-Do (=province). The infection rates varied from stream to stream showing 100 percent in Namdae stream(Gangnun-city), Obsib-stream(Samchok-gun) and Dongmak, 95.0 percent in Hosan stream, 90.0 percent in Gungchon stream, and Namdae stream (Yangyang-up), 80.0 percent in Hwasang stream, 50.0 percent in Daebong stream, 45.0 percent in Yonghwa stream, 30.0 percent in Sangchon stream and Sachon stream, 20.0 percent in Munam stream and Okgyoe stream, 15.0 percent in Imweon stream, 10.0 percent in Namchon stream. And no metacercarial infections in their fish host were found in the areas of Mulchi stream, Sangun stream, Gosamun stream, Jonchon stream snd Gagok stream. It was observed that the mean infection rate showed 50.9 percent in Kyongsangbuk-Do(=province). The infection rates also varied from stream to stream showing 100 percent in Songchon stream, Osib stream (Yongdok-gun) and Daejong stream, 60.0 percent in Pyonghae stream snd Gunmu stream, 50.0 percent in Buhwung stream, 25.0 percent in Nagok stream, 20.0 percent in Oangbi stream, 10.0 percent in Namhodong stream. And no metacercarial infections in their fish host were found in the areas of Namdae stream (Uljinup) and Choksan stream. It was observed that the mean infection rate showed 67.6 percent in Kyongsangnam-Do(=province). The infection rates varied from stream to stream showing 100 percent in Taehwa river, Hwiya river, Inchon stream, Miryang river, Nam river, Hwagae stream, Koha stream, Sosang stream, and Tongchon stream, 90.9 percent in Yoncho stream, 90.0 percent in Hoihwa stream, 80.0 percent in Chindong stream, 66.7 percent in Chingyo stream, 40.0 percent in Hoyam river. And no metacercarial infections in their fish host were found in the areas of Chinjon stream, Sanchon stream and Jukchon stream. It was observed that the mean infection rate showed 94.6 percent in Chollanam-Do(=province). The infection rates varied from stream to stream showing 100 percent in Dongchon stream, Isachon stream, Somjin river (Goksong-gun), Somjin river (Kurye-gun), Sosi stream, Gokchon stream, Kohung stream, Kwansan stream, Youi stream, Unjon stream and Apnae stream, 92.3 percent in Tamjin river, 90.9 percent in Okkok stream, 84.6 percent in Songgun stream. And no metacercarial infections in their fish host were found in the area of Yongok stream. On the other hand, the infection rate showed 100 percent in Inchon river of Chollabuk-Do (=province) and Kangon stream of Cheju-Do (=province).
parasitology-helminth-trematoda ; Metagonimus yokogawai ; epidemiology ; Plecoglossus altivelis