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

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

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

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

In order to observe the antigenic fractions in saline extract of adult Paragonimus westermani, proteins in the crude extract were separated by sodium dodecyl sulfate-polyacylamide gel electrophoresis (SDS-PAGE) in reducing conditions. The separated protein fractions were transferred to nitrocellulose paper on which 20 sera from human paragonimiasis were reacted and immunoblotted. Out of 15 stained protein bands in SDS-PAGE, 7 reacted with the sera. Of 14 reacted bands, 30 kilodalton(kDa) band was the most frequently reacted (95%) and was a strong antigen. Protein bands of 23 and 46 kDa were also strong antigens. Bands of over 150 kDa, 120 kDa, 92 kDa, 86 kDa, 74 kDa, 62 kDa, 51 kDa, 32 kDa, 28 kDa, 16.5 kDa and 15.5 kDa were also reactive but their frequencies of the reaction were variable.
parasitology-helminth-trematoda ; Paragonimus westermani ; immunology ; antigen ; electrophoresis

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

The effect of praziquantel on P. westermani exposed in vitro was observed by stereomicroscope, light microscope and scanning electron microscope. Following results were found. The worms incubated in 0.01 micro-g/ml praziquantel were moving after 26-hour incubation. However, all of them were immobilized immediately after incubation in solutions over 0.1 micro-g/ml concentration. All of the exposed worms showed severe vacuolization not only in tegument but in subtegument, intestine, ovary, testis, Mehlis' gland and excretory bladder. Vacuoles in tegument burst out to form craters. As incubation time went on, tegumental structure was disintegrated severely. The worms exposed to praziquantel were observed to be immobilized and be vacuolized of all tissues. Disintegration of reproductive organs suggests that praziquantel have suppressive effect on egg production when the flukes are not killed. The drug effects were found more related with incubation time than with drug concentration.
parasitology-helminth-trematoda ; Paragonimus westermani ; electronmicroscopy ; chemotherapy ; praziquantel

Recent results of mass stool examination for parasitic infections revealed 0.01-0.0001 percent of Paragonimus egg positive rate in Seoul school-children. This survey was carried out to understand the infection status of intermediate hosts and their relations to human paragonimiasis in Seoul. Twelve mountainous streams in the outskirts of Seoul were surveyed. From all streams, Semisulcospira libertina, the snail intermediate host was not detected. From 7 streams 132 crayfishes, Cambaroides similis, the second intermediate host were collected. From them no metacercaria was found. The results indicated that crayfish in district of Seoul is no more an infection source of paragonimiasis. Possible factors related with the ecology of intermediate hosts were briefly discussed from the epidemiological view point.
parasitology-helminth-trematoda ; Paragonimus westermani ; host ; Semisulcospira libertina ; Cambaroides similis

In the survey of l1,005 subjects in l3 villages of Che Ju lsland, 1,450 persons were egg-positive by repeated sputum examinations. The response rate to intradermal test ranged 50-80 per cent of the population and to sputum examination for skin positive 60-70 per cent in the first survey done in l964. 93 per cent of all egg-positive was treated with 40 mg/kg body weight of bithionol on alternate days for 10-15 doses in l965. Follow-up studies were carried out in one year, three-year, five-year, and eight year after the mass treatment. The one year follow-up study covered 86.5 per cent of all treated cases in all villages but only a part of the population of a few villages in further follow-up studies. In this paper only the result obtained from the age group of 7-18 years, the common population studied in every follow-up for the purpose of comparison, is presented. Intermediate hosts of P. westermani were examined at the same time. In one year follow-up it was found that 91 per cent of egg-positive treated became negative. Three parameters, skin reaction, sputum examination, and infection status of intermediate hosts by area and year were used for comparison. Skin positive rate showed gradual decrease with more marked drop in Kang Chung where more thorough survey and mass treatment (about 43 per cent of all infected persons estimated among whole population) were carried out than other areas (only 20-30 per cent). The proportion of intermediate skin reation (60-100 mm(3) wheal size) increased markedly indicating decreased dose of infection which corresponds to the dropped infection rate and average number of metacercaria in crabs. Egg-positive rate in sputum examination done for skin positive reactors also presented similar pattern to skin reaction although it should be taken account that the result of 1964 was from repeated sputum examinations but that of other years from a single examination. Increased proportion of intermediate skin reaction which has much lower egg-positive rate probably played major role in decreased egg-positive rate. The infection rate of snail started to drop about one year earlier than crab; crab infection rate and intensity started to drop about four year after the mass treatment. The duration needed to show the change of infection status in intermediate hosts after the mass chemotherapy may correspond to the duration of survival of the parasite in the intermediate hosts. With the data available presently, it is difficult to determine on what point of the curve the present status is situated (on decreasing phase or increasing phase?), how far the rate will go down if it is on decreasing phase, and how long would it take in returning to the original status without further management. The result of follow-up study, however, strongly indicate that continous and intense chemotherapy may be able to put the paragonimiasis under control. Further follow-up study on total population including survey on changes of environment and eating habits is planned.
parasitology-helminth-trematoda-Paragonimus westermani ; chemotherapy ; control ; bithionol

In order to observe the protein compositions of soluble extracts of P. westermani, and their changes during early developmental stages, the crude saline extracts of 4, 6, 8, 10 and 12 week-old worms which were harvested from experimentally infected dogs were analysed by disc-PAGE. The results were as follows: A total of 15 bands were identified from electrophoregrams of respective developmental stages. Of them, 5 bands were recognized throughout the developmental stages. The number and protein amount of identified bands changed according to the worm development from 4 weeks to 12 weeks. However, the banding patterns of 4 and 6 week-old worms and 8 and 10 week-old worms were similar each other. Of 15 identified bands, band 1 was recognized only in 12 week-old worms whereas bands 3, 4, 8, 9, 10, 11 and 15 gradually lowered their amount according to development to disappear in 12 week-old. In addition, band 5 became a major band in 12 week-old while band 6 turned to a minor band at tha same age. The possible relations of changing patterns of protein bands with worm development were discussed.
parasitology-helminth-trematoda ; Paragonimus westermani ; immunology ; protein ; electrophoresis