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

To understand the mode of transmission in clonorchiasis, a survey was made in Kim-hae Goon, South Kyong-sang Do (=Province). The mathematical analysis of the age prevalence was done on the egg positive rates. And another analysis for the comparison was also made to the cited data from two areas, North Kyong-sang Do and Ko-yang Goon, Kyong-gi Do. Some catalytic models of H. Muench (1959) were applied to the observed age prevalence. Because the both parameters, such as force of infection(a) and loss of positivity(b) were considered to be constant for a long period in the surveyed area, the two stage catalytic model by Muench was chosen to the analysis. In the surveyed area, Kim-hae Goon where the egg positive rates were 56.2 percent and 61.2 percent (by Kim, 1974), the constant values of 'a' were found to be 0.051 and 0.089 respectively. In other words, the force of infection was 51, 89 per 1,000 susceptibles. The values of 'b' were found to be 0.006 and 0.005. This means that the rates of disappearance from egg positive cases to negative were 6 and 5 per annum per l,000 positive cases in above area. Therefore, the two catalytic curves were expressed by the following equations, y = 1.133 {e(-0.006t) - e(-0.051t)} and y = 1.047 {e(-0.005t) - e(-0.089t)} respectively. In the cases of North Kyong-sang Do and Ko-yang Goon, Kyong-gi Do where the egg positive rates of clonorchis shown as 27.7 percent and 15.2 percent by Shin (1964) and Kim (l974), the curves were expressed by y = 1.769 {e(-0.010t) - e(-0.034t)} and y = 2.857 {e(-0.020t) - e(-0.027t)} respectively. From the above mathematical analyses by age prevalence in clonorchiasis, it was considered that the mode of transmission of clonorchiasis in the surveyed area, Kim-hae Goon presented more rapid pattern than those of North Kyong-sang Do and Ko-yang Goon, Kyong-gi Do.
parasitology-helminth-trematoda ; clonorchiasis-Clnorchis sinensis ; epidemiology ; transmission

A study was carried out to figure the cases and to observe the endemic status of clonorchiasis and metagonimiasis in endemic areas in Korea. Total 13,373 inhabitants living in 40 villages along 7 main rivers and 9 small streams were subjected to stool examination. They were selected randomly among the riverside population. Their specimens were examined both by cellphane thick smear method and Stoll's egg countung technique. This study was performed during the period from May 1979 to April 1980. The results obtained are as follows: The egg positive rate of any kind of helminths was 58.7% out of 13,373 examned cases, and the egg positive rates by each helminth were; Clonorchis sinensis 21.5%, Metagonimus yokogaqai 4.8%, large type Metagonimus eggs 0.4%, Ascaris lumbricoides 22.9%, Trichuris trichiura 35.2%, hookworm 0.2%, Taenia sp. 0.5%, Hymenolepis nana 0.07%, Paragonimus westermani 2 cases, Fasciola sp. 4 cases, Echinostoma sp. 1 case and Hymenolepis diminuta 1 case respectively. Many endemic foci of clonorchiasis were revealed along the 7 major rivers. The egg positive rates of each river basin differed from each other significantly; Nagdonggang 40.2%, Yeongsangang 30.8%, Seomjingang 17.3%, Hangang 15.7%, Tamjingang 15.9%, Geumgang 12.0% and Mangyeonggang 8.0%. The cases of clonorchiasis were estimated in range 830,000 to 890,000 in riverside areas of the 7 rivers. By grading the infection intensity, 64.7% was in Grade I(EPG 0-900), 28.6% in Grade II (EPG 1000-9,900), 5.5% in Grade III (EPG 10,000-29,900) and 1.3% in Grade IV (EPG over 30,000). The proportion of the cases in Grade III and IV was 6.8% among positive cases. Therefore 60,000 cases at least were regarded to suffer from it clinically. Males of 30-60 years of age showed higher positive rate and heavier burden of infection. This makes clonorchiasis more important socially because the patients lose their social productivity. A few endemic foci of metagonimiasis were detected newly by egg detection; Samcheong 28.5% egg positive rate, Uljin 21.3%, Yeuongdeog 46.3%, Milyang 6.7%, Yeongil 9.2% and Geoje 18.2%. The mean EPG values were in range of 320-7, 120 by the focus. The egg positive rate and proportion of EPG Grade varied greatly by the area, and mean proportion of the positive cases were 69.7% in Grade I, 24.1% in Grade II, 5.0% in Grade III and 1.2% in Grade IV. Males of 30-60 years were infected in higher rate also. The large sized eggs of Metagonimus were found also in upper basin of Hangang and Geumgang mainly. They were regarded as eggs of M. takahashii which is mediated by the cyprinid fishes. Its significance should be studied further. Clonorchiasis and metagonimiasis should be realized as important public health problems in Korea by their wide distribution, high prevalence rate and heavy infection intensity. Comprehensive measures against them are needed urgently.
parasitology-helminth-trematoda ; clonorchiasis ; metagonimiasis ; Clonorchisis sinensis ; Metagonimus yokogawai ; epidemiology

This study was undertaken to evaluate the effects of health education and anti-Clonorchis campaign conducted in Kyungpook Province and to compare the prevalence of Clonorchis sinensis among the residents in the same areas for the period 1964-1976. Both surveys were made on all age groups of residents ranging from 0 to over 60 years of age. They were examined using primarily intradermal tests with Clonorchis and Paragonimus antigens and followed by stool examinations. The definitive diagnosis of clonorchiasis was made on the recovery of Clonorchis eggs from the stools. A marked reduction in the prevalence was encountered in the youngest age group, but there is no significant difference in the older age groups. The overall prevalence rate for clonorchiasis was reduced from 27.7 to 19.6 per cent in a period of 10 years. It is found that clonorchiasis is less prevalent in Kyungpook Province than it was a decade ago and it continued to decline.
parasitology-helminth-trematoda ; Clonorchis sinensis-clonorchiasis ; Paragonimus westermani ; epidemiology

In Korea, Clonorchis sinensis infection is still highly prevalent because case detection in the field is difficult and the detected cases used to be incompletely cured due to treatment failure. The present study tried to control clonorchiasis in an endemic village by repeated treatments with praziquantel every 6 months and to evaluate sonography as a diagnostic measure. By stool examinations, the egg positive rate in the endemic village was 22.7%, but it decreased to 19.6% at 6 months, 15.1% at 12 months. 12.2% at 18 months, 6.3% at 24 months, 11.4% at 30 months, and 6.3% at 42 months after the beginning of repeated praziquantel administration. The sonography showed 61 (49.6%) positive cases of 123 screened residents: among egg-positives the sonography positive rate was 52.2% and among egg-negatives it was still 49%. The rate among cured cases was 64.3% after 6 months, 50.0% after 12 months, 50.0% after 18 months, and 66.7% after 24 months. In a non-endemic village, 64 residents were found egg-negative by fecal examination, but 20 (31.3%) of them were positive by sonography. The present findings indicate that control of clonorchiasis in an endemic village by repeated praziquantel treatment for 42 months is still insufficient and sonography is of little value for diagnosis of clonorchiasis.
Animal ; Antiplatyhelmintic Agents/administration & dosage* ; Clonorchiasis/ultrasonography* ; Clonorchiasis/prevention & control ; Clonorchiasis/epidemiology ; Follow-Up Studies ; Human ; Korea/epidemiology ; Parasite Egg Count ; Praziquantel/administration & dosage* ; Prevalence ; Sensitivity and Specificity ; Treatment Failure

This study investigated freshwater fish for their current infection status with metacercariae of Clonorchis sinensis in Korea. Twenty-one species of freshwater fish (n = 677) were collected from 34 regions nationwidely from February 2007 to June 2008. They were individually examined by digestion technique. Eight species of freshwater fish from 17 different regions were recognized positive for the metacercariae of C. sinensis. The positive rates (range of metacercariae number per fish) of fish by the species were as follows: 48% (1-1,142) in Pseudorasbora parva, 60% (1-412) in Pungtungia herzi, 15.7% (1-23) in Pseudogobio esocinus, 29% (1-7) in Acheilognathus intermedia, 21% (1-4) in Odontobutis interrupta, 33% (1-6) in Zacco temmincki, 3.6% (1-4) in Zacco platypus, and 26.3% (1) in Hemibarbus labeo. The two species, P. parva and P. herzi, are able to be the index fish for estimation of C. sinensis transmission in a certain locality. Still several species of freshwater fish are briskly transmitting C. sinensis infection in many riverside areas of southern Korea.
Animals ; Clonorchiasis/epidemiology/parasitology/*veterinary ; Clonorchis sinensis/*isolation & purification ; Fish Diseases/epidemiology/*parasitology ; Fishes ; Fresh Water ; Korea/epidemiology

A large-scale survey was conducted to investigate the infection status of fresh water fishes with Clonorchis sinensis metacercariae (CsMc) in 3 wide regions, which were tentatively divided by latitudinal levels of the Korean peninsula. A total of 4,071 freshwater fishes were collected from 3 regions, i.e., northern (Gangwon-do: 1,543 fish), middle (Chungcheongbuk-do and Gyeongsangbuk-do: 1,167 fish), and southern areas (Jeollanam-do, Ulsan-si, and Gyeongsangnam-do: 1,361 fish). Each fish was examined by the artificial digestion method from 2003 to 2010. In northern areas, only 11 (0.7%) fish of 2 species, Pungtungia herzi and Squalidus japonicus coreanus from Hantan-gang, Cheolwon-gun, Gangwon-do were infected with av. 2.6 CsMc. In middle areas, 149 (12.8%) fish were infected with av. 164 CsMc. In southern areas, 538 (39.5%) fish were infected with av. 159 CsMc. In the analysis of endemicity in 3 regions with an index fish, P. herzi, 9 (6.2%) of 146 P. herzi from northern areas were infected with av. 2.8 CsMc. In middle areas, 34 (31.8%) of 107 P. herzi were infected with av. 215 CsMc, and in southern areas, 158 (92.9%) of 170 P. herzi were infected with av. 409 CsMc. From these results, it has been confirmed that the infection status of fish with CsMc is obviously different among the 3 latitudinal regions of the Korean peninsula with higher prevalence and burden in southern regions.
Animals ; Clonorchiasis/epidemiology/parasitology/*veterinary ; Clonorchis sinensis/*isolation & purification ; Fish Diseases/*epidemiology/parasitology ; Fishes ; Fresh Water ; Korea/epidemiology ; Metacercariae ; Prevalence

The duration of infection, frequency of eating raw fresh water fishes, and a series of liver function tests were studied in a group of 23 Korean symptomless cases with Clonorchis sinensis, and compared with those in a control group of uninfected persons. Of 23 lightly infected cases, 11 cases who had been infected for 10 to 20 years was found the highest in percentage(47.8), and 2 had been infected for over 30 years. The frequency of eating raw fresh water fishes ranged from 2 to 35 times. The range of Stoll egg-counts in 23 cases varied from 600 to 8,600 eggs per gram of feces and the average value was approximately 2,800 eggs. A series of liver function tests examined showed normal value in all cases. These results showed no difference in either infected group and its contol group.
parasitology-trematode-Clonorchiasis sinensis, epidemiology ; egg per gram ; liver function test

An epidemiological survey conducted from March 1977 to October 1978, revealed that in the river Taeka running through Seong-ju county, Kyungpook Province, one habitat of the snail, Parafossarulus manchouricus, was found. The snail population in the habitat was very low, and no Clonorchis sinensis cercaria was found in the snails examined. Seven species of fresh-water fish caught were examined for the presence of the metacercaria of Clonorchis sinensis. Of these, 3 species of fish, the Korean shiner, Gnathopogon atromaculatus, the gudgeon, Pseudogobio esocinus, and the striped shiner, Pungtungia herzi harbored the encysted larvae. The rate and intensity of infection with the metacercaria in the fish was, on the whole, low. The prevalence of Clonorchis sinensis among the residents in Seong-ju county was also low. The overall infection rate for the fluke in 1,012 residents was found to be 13.4 per cent. The infection rate for Clonorchis sinensis in males and females was 17.1 and 9.2 per cent, respectively. This difference was statistically significant ( t > 2). It is found that Clonorchis sinensis is less prevalent in Seong-ju county than in the other counties of Kyungpook Province, Korea.
parasitology-helminth-trematoda ; Clonorchis sinensis-clonorchiasis ; epidemiology ; Gnathopogon atromaculatus ; Pseudogobio esocinus ; Pungtungia herzi

This special issue is devoted to a review of the current state of knowledge of clonorchiasis. Sections deal with: the biology of Clonorchis sinensis; geographical distribution, with particular regard to Korea; epidemiology; pathogenesis; clinical features; diagnosis; prevention and control; chemotherapy.
review ; parasitology-helminth-trematoda ; Clonorchis sinensis ; clonorchiasis ; epidemiology ; pathogenesis ; liver ; diagnosis ; chemotherapy ; praziquantel ; control ; hetol ; di