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

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

Tegumental ultrastructures of Echinochasmus japonicus were observed by scanning electron microscopy. The worms were recovered from albino rats which were experimentally infected with the metacercariae obtained from Pseudorasbora parva. Followings are summarized findings. The worms were minute and plumpy gourd-shaped with attenuated anterior and round posterior end. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. Head crown was armed with 24 collar spines which were embedded in cytoplasmic pockets. The spines were arranged in a row with an interruption at dorsomedian line, however, the 2nd and the 4th spines were outstretched more than others. Oral and ventral suckers were muscular with numerous type II sensory papillae, and genital pore opened between the two suckers. Tegumental spines were spade-shaped with broad base and pointed tip. They were compact in ventro-lateral tegument or dorsal surface of anterior body. The were not found between the two suckers and dorsal surface of posterior body. Two types of sensory papillae, uni-ciliated (Type I) and roundly swollen sensory papillae (Type II), were observed. The type I papillae were chiefly distributed on ventral surface of tegument and type II were on the lips of suckers. Arrangement of collar spines, shape and distribution of tegumental spines or sensory papillae are regarded as characteristic features of E. japonicus.
parasitology-helminth-trematoda ; Echinochasmus japonicus ; electronmicroscopy

This study was undertaken to evaluate the role of peritoneal exudate cells in the transfer of immunity against the liver fluke, Clonorchis sinensis in the inbred BALB/c mice. Ten donor mice were divided into 2 groups. One group consisted of 5 mice was infected orally with 20 metacercariae of C. sinensis, and the other group was injected intraperitoneally with 20 excysted larvae. Thirty days after immunization, the peritoneal exudate cells were obtained from the donor mice. Twenty recipient mice were divided into 4 equal groups for the purpose of primary immunization. The mice of Group I were injected intraperitoneally with 2 x 10(6) peritoneal exudate cells of the donor mice infected orally, those of Group III were injected intraperitoneally with 2 x 10(6) peritoneal exudate cells of the donor mice injected intraperitoneally. Those of Group II were injected orally with 20 metacercariae of C. sinensis. The group IV mice served as controls. Four days after the primary immunization all recipient mice were challenged orally with 20 metacercariae of C. sinensis, and then killed 30 days after the challenging infection. When the peritoneal exudate cells were injected into the recipient mice, pronounced reduction in eggs per gram of the feces was found in the mice of Group I and Group II, but no reduction in those of Group III. In the worm burdens of C. sinensis, the number of flukes found in the mice of Group II was only significantly less than those in the control group(IV). In addition the number of plaque forming cells per spleen in the mice of Group II was found larger than those in Group I. It is likely that donor peritoneal exudate cells transferred to the recipients might result in the production of relative immunity.
parasitology-helminth-trematoda ; Clonorchis sinensis ; immunology ; mouse

As a series of systematic classification for Korean common liver fluke, Fasciola sp., karyotype was investigated by means of the modified air-drying technique and of the regular Giemsa staining, Also, C-staining method was applied for detailed karyological analysis from the germ cells of the fluke. The following is a brief summary of the leading facts gained through the experiment. Korean Fasciola sp. was classified into three types based on their chromosomal complements; individuals with 20 or 30 chromosomes and with a 20/30 mosaic constitution. Worms having 30 chromosomes represent a triploid form with 3 sets of 10 basic chromosomes, while those with 20 chromosomes were diploid and mosaic individuals were 2n/3n mixoploid. The frequency of the individual type calculated is as follows; 67.45% of 212 flukes examined was of diploid, 10.85%, triploid, and the rest, 21.7%, mixoploid, respectively. In many cases, two or three types were found in the peculiar bovine host while single type inhabitant was about 20% out of 52 cases. The twenty chromosomes consisted of 1 parir of large metacentrics, 4 pairs of medium-sized subtelocentrics, and 5 pairs of small submetacentrics, while constitution of the thirty chromosomes was nearly interpreted as a triploid form with 3 sets of 10 basic chromosomes. The high centromeric indexes of both types are the first pairs among all the examined, and 37.93% was of diploid and 47.93%, triploid, respectively. In mixoploid individuals, constitution of the chromosomes of diploid or triploid cells was the same as that of diploid or triploid individuals. All the chromosomes of the germ cells in both types showed C-band around the centromeic region and especially the chromosomes no's 3, 7, and 8 showed a remarkable C-band distinguished from other chromosomes. The variance for the sizes of the worms and the eggs were not parallel with three different genotypes in Korean common liver fluke.
parasitology-helminth-trematoda ; Fasciola sp. ; karyotype ; taxonomy

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

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

The present study was undertaken to observe the morphological changes of Clonorchis sinensis obtained from experimentally infected rats treated with praziquantel (Biltricide) which is a new anthelmintic agent with high activity against a broad spectrum of cestode and trematode species. For this study, the rats were infected experimentally with about 50 metacercariae of C. sinensis and were given praziquantel a single dose of 600 mg per kg of body weight at 5 weeks after infection. The Clonorchis worms were isolated from the bile ducts of the rats which were autopsied on the 4th day after treatment. After isolation the parasites were observed their shape and motility in the medium of 37 C physiological saline solution, and then the fine structure of the tegument of C. sinensis was studied by means of light, scanning and transmission electron microscope. The findings of the observation were compared with those of untreated parasites. The results are as follows: All the isolated worms moved actively in the medium of physiological saline solution (37 C). A majority of the parasites obtained from the treated rats showed a large balloon shaped structure on the surface between oral and ventral suckers. But such structure has never seen in the parasites obtained from control rats. By the scanning electron microscopic observation, the regular pattern of the tegumental ridges was significantly changed on the outer surfaces of parasites obtained from the treated rats as compared with those of the control rats. By the transmission electron microscopic observation, the numerous mitochondriae in the syncytial tegumental layer of the treated parasites appeared to be degenerated and formed small vacuoles, and the tegumental ridges were also degenerated and showed somewhat flattened. In the parasites obtained from the treated rats, a different size of vacuoles interspersed in the distal part of the syncytial tegument and also in subepithelial region of the urinary bladder. These vacuoles are fused each other and lead to the disruption of the apical region of syncytial tegument along the basement layer. Finally the basement layer was dislocated. So that the tegumental layer appeared as a large balloon.
parasitology-helminth-trematoda ; Clonorchis sinensis ; chemotherapy