The egg laying capacity of Fibricola seoulensis was observed in mice and rats. In mice, the mean number of eggs produced by an adult worm a day was 116 at the first week after infection, 123 at the 2nd week and 42 at the 3rd week. Thereafter, the capacity of about 20 eggs/worm/day was maintained up to one year period. In rats, it generally produced more eggs; 49 at 1 week, 250 at 2 weeks, 216 at 4 weeks, 327 at 6 months and 11 at one year after infection. It survived longer than a year in mice and rats.
parasitology-helminth-trematoda ; Fibricola seoulensis ; egg

The pattern of sensory papillae, chaetotaxy, of the cercaria of Clonorchis sinensis was observed. The chaetotaxy was as follows; 5-6 Ci l, 4-5 Ci 2, 5-6 Ci 3 at lst row, 4 Cii 1, 2 Cii 2, 4 Cii 3, 5-6 Cii 4 at 2nd row, 3-4 Ciii 1, 2-3 Ciii 2 at 3rd row, and 2 Civ 1, 2-3 Civ 2, 2-3 Civ 3, at 4th row, in cephalic region; 2 AiV, l AiD, 2 AiiV, 1 AiiD, 2 AiiiV, 2 AiiiD, 1 AivV, 1 AivD, 1 PiiD, l PiiiD, in ventral(V) and dorsal(D) portions of body. Caudal region revealed 2-2-2-2 formula.
parasitology-helminth-trematoda ; Clonorchis sinensis ; cercaria

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

The tegumental ultrastructures of Echinostoma hortense adults were observed by scanning electron microscopy. The worms of 4 weeks of age were harvested from albino rats experimentally infected with the metacercariae obtained from the loach. The results were as follows: The worms were leaf-like and their anterior end portion, including oral sucker and head crown, ventrally curved to face posteriorly. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. The oral sucker had roundly swollen (type II) sensory papillae on the ventral half of its lip and uni-ciliated knob-like (type I) sensory papillae, arranged in 2-3 rows, on the dorsal outer surface. Aspinous ventral sucker had many of type I papillae arranged in a circular band on its outer surface. The tegument around the genital opening was of similar feature to the ventral sucker, but sensory papillae were hardly found around the former. Scale-like spines with broad base and round tip were distributed densely on the tegument anterior to the ventral sucker but they became sparse in posterior half of the ventral surface, finally to disappear at posterior extremity. A few number of type I papillae were observed on the ventral surface. The results suggest that the tegument of E. hortense is similar to that of other echinostomes especially E. revolutum. But the number and arrangement of collar spines, and/or the type and distribution of sensory papillae seem characteristic features of E. hortense differed from other echinostomes.
parasitology-helminth-trematoda ; Echinostoma hortense ; electron microscopy

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

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

The authors carried out histochemical studies on Clonorchis sinensis, especially, histochemical demonstration of carbonic anhydrase activity. Kurada's method was applied for the histochemicl staining in this study. The result obtained were summerized as follows : Carbonic anhydrase activity was intensely positive in oral sucker cells, reticular tissue cells, epithelium of the intestine and testes, more or less intensely positive in vitelline gland cells and yolk of eggs as well.
parasitology ; histochemistry ; trematoda ; helminth ; Clonorchis sinensis

Adult Clonorchis sinensis were collected from the biliary passage of nine cases of medico-legal autopsies. The worms were washed repeatedly with tap water and rinsed twice with physiological saline. Incubation took place in Tyrode's medium in order to recover live worms. The number of worms surviving in the medium was determined. The rate of surviving worms showed an unexpectedly high percentage (22.8%) in those cases autopsied 2 days after death. The surviving worm burden dropped sharply to 6.3 and 9.2 percent for those samples taken 5 days after death.
parasitology-helminth-trematoda ; Clonorchis sinensis ; autopsy

As a series of studies to clarify clonorchicidal substances in body surface mucus of some fresh-water fishes, the substance in the epidermal mucus of Cyprinus carpio was isolated by silica gel column and thin layer chromatography and analyzed for its chemical nature. Wormicidal trial was done in vitro, and the results obtained are summarized as follows: The mucus was extracted by ethyl ether and separated into 4 fractions by column chromatography using benzene as solvent. The second fraction with yellowish red colour among them showed the strongest clonorchicidal effect. The yellowish red fraction obtained by column chromatography was then fractionated into 6 spots by thin layer chromatography with petrol. ether/chloroform(30/70, v/v), and the Rf. 0.714 spot among the 6 spots showed the strongest effect. The Rf. 0.714 spot was further fractionated into 6 spots by thin layer chromatography with benzene/acetone (90/10, v/v), and the Rf. 0.800 spot among the later 6 spots revealed the strongest effect. The Rf. 0.800 spot was chromatographed on column with benzene and 2 fractions were obtained. The second fraction of light brown colour represented the final purified fraction. By these purification procedures, clonorchicidal substance was purified 15-fold with 0.03 percent yield from the mucus of C. carpio, and 10mg of the final fraction killed the cercaria in 26 min, the metacercaria in 115 min, and the adult in 443 min. Infra red and nuclear magnetic resonance spectrometric analysis of the purified substance revealed that the substance belongs to an ethyl ester of unsaturated fatty acid with 2 double bonds, 15 methylene groups and l methyl group.
parasitology-helminth-trematoda ; Cyprinus carpio ; mucus ; toxicology

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