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

The metacercariae of an echinostomatid fluke were detected from a freshwater fish, Odontobutis obscura interrupta caught from the Seom river system, Wonseong-gun, Kangwon-do, and experimenally infected into rats to obtain the adult worms for the species identification. A total of 32 metacercariae was detected from 10 fishes (27.8 percent) out of 36 O. obscura interrupta caught from the river. The average size of metacercariae was 153.4 x 149.0 micrometer. Also, it was uniquely specific that thickened membrane was formed around the metacercarial cyst wall. The rats orally infected with those metacercariae were sacrificed 20 days after infection to get the adult worms. The mean length and width of the adult worms were 0.75 cm and 0.13 cm, respectively. The number of collar spines on circumoral disk was 26 to 28, and the end group spines at lateral sides of the oral sucker were 4 on each side. The echinostomatid flukes observed in this study were all identified as Echinostoma hortense according to the morphologies of the cirrus sac, ovary, vitellaria and testes of the adult worms and the shape of eggs. On the other hand, O. obscura interrupta is one of the fresh-water fish that are preferably eaten raw by the rural inhabitants. Although no human case of E. hortense infection by eating O. obscura interrupta has been experienced yet, the possibility is strongly suggested in this study.
parasitology-helminth-trematoda ; Echinostoma hortense ; metacercariae ; Odontobutis obscura interrupta ; rat

Two cases of human Echinostoma hortense infection were found in Seoul Paik Hospital. Their stools revealed echinostomatid eggs. After treatment with praziquantel (single does of 10-12 mg/kg) and purgation with magnesium salt, total 21 flukes were collected in one case. The flukes were 5.9-7.5 mm long, had 27-28 collar spines around their head, laterally deviated ovary and two tandem testes. They were identified as E. hortense Asada, 1926. The cases are 38-year and 20-year old men residing in Seoul, whose hometown is Chungsong-gun and Seungju-gun, Kyongsangbuk-do respectively. They had eaten raw flesh of various kinds of fresh water fishes (both cases) and/or salamander (latter case), which are considered possible sources of this fluke infection. They experienced abdominal discomfort and/or diarrhea. Hematology revealed 22 percent eosinophilia in the latter case, but it became 5 percent after the treatment. Echinostomatid eggs were not found after the treatment in both cases. These are the 4th and 5th human cases of E. hortense infection in Korea.
parasitology-helminth-trematoda ; Echinostoma hortense ; case report ; praziquantel ; intestine

An epidemiological study was performed to know the infection status of E. hortense among the human residents and fish intermediate hosts in Chongsong-gun, Kyongsangbuk-do. Out of 263 people examined, 59(22.4 per cent) were positive for the eggs of E. hortense. Total 152 fresh water tishes (9 species) were examined, and Odontobutis obscura interrupta, Misgurnus angullicaudatus and Squalidus coreanus were found to harbour the metacercariae of E. hortense. Juvenile or adult E. hortense were expelled from 35 out of 54 cases treated with praziquantel. The number of worms per individual ranged from l to 649, with the average burden of 51. The eosinophil count of infected persons ranged 1-24 per cent (6 per cent in average). The number of eggs per day per worm (EPDPW) in human host was estimated about 1,478. The results showed that Chongsong-gun is an endemic area of E. hortense.
parasitology-helminth-tematoda ; Echinostoma hortense ; Hippeutis cantori ; epidemiology

Echinostomatid eggs were found from a 21-year old man, whole native village is Munkyong-gun, Kyongsangnam-do during fecal examination in October 1983. The eggs were detected again one week later concommitantly with the eggs of Clonorchis sinensis. He had no subjective symptoms related with these fluke infections. He was treated with praziquantel(Distocide) 20 mg/kg in single dose and purgated with magnesium salt. One echinostomatid fluke and 4 adults of C. sinensis were collected from the diarrheal stools. After morphological observation, the echinostomatid fluke was identified as Echinostoma hortense Asada, 1926. This is the first record on human E. hortense infection in Korea.
parasitology-helminth-trematoda ; Echinostoma hortense ; case report ; echinostomiasis ; praziquantel

The worm development and egg laying pattern of Echinostoma hortense(Trematoda: Echinostomatidae) were studied in albino rats and the brief clinical course was observed in human volunteers. A total of 21 rats were infected with 20-69 metecercariae each and two humans were with 7 and 27 metacercariae, which were collected from loaches. For recovery of worms, the rats were sacrificed at irregular intervals from the 6th to 150th day after infection and the human volunteers were treated with praziquantel and purged with magnesium salt on the 26-27th day. The stools of the rats and humans were examined for the eggs. The results were as follows: The worm recovery rate from the rats was not affected by the increase of infection time but varied individually; 9.1-50.0% (31.1% in average). From humans, 14.3% and 37.0% (32.4% in average) of challenged were recovered. In the rats, it was revealed that the worms rapidly grew for the first 14 days to become 7.59 mm in average length and 1.17 mm in average width but the growth became much slower thereafer until the 150th day; 7.95 mm in length on the 21th day, 9.04 mm on the 28th day, 10.21 mm on the 49th day and 12.62 mm on the 150th day. During the early stage of infection, the growth of genital organs(male or female) was expressed as sigmoid curves whereas non-genital organs(such as suckers) was simply as straight lines. The prepatent period of this fluke was 10-12 days in the rats and 16-17 days in men. After the start of oviposition, the egg production by the worms remarkably increased, reached maximum on the 32-33th day, followed by decrease thereafter. The maximum value of E.P.G./worm was 390. The major subjective symptoms in human volunteers were abdominal pain and diarrhea during the early stage of infection. The results show that human is as susceptible as the rats to E. hortense infection and the amount of egg production in the rats is greatly affected by the age of worms.
parasitology-helminth-trematoda ; Echinostoma hortense ; rat ; biology ; metacercaria

Two cases of human Echinostoma hortense infection and their probable infection source were identified by praziqantel (Distocide) treatment of the patients and by examining two kinds of fresh water fish which were eaten raw by them. The result of the research can be summarized as follows: The patients, each aged 31 and 30, were residing in the same house in Wonju City, Kangwon Province. The first case was hospitalized due to epidemic hemorrhagic fever (E.H. fever) and the second case was healthy but had slight degree of abdominal pain and diarrhea from time to time. In the stool examination, eggs of E. hortense (114.3 x 71.0 micrometer average from the first case and 119.1 x 68.3 micrometer average from the second) were found. By administering single dose of praziquantel (10~15 mg/kg) and purgation with magnesium salt to them, six adults of E. hortense were collected from the diarrheal stools of the second case. By examining 84 Moroco oxycephalus and 20 Carassius carassius which were captured at the place where the two patients had captured and eaten the fresh water fish, the metacercariae of Echinostoma sp. were found from 3 (3.5 percent) M. oxycephalus. After the experimental infection of 3 isolated metacercariae to one albino rat three adults of E. hortense were recovered. By the present study, the two patients revealing the echinostomatid eggs in their stools were proven to be infected with E. hortense and to be the second and third human cases of this fluke infection in Korea. Moroco oxycephalus harboured the metacercariae of E. hortense and appeared to be a new second intermediate host.
parasitology-helminth-trematoda ; Echinostoma hortense ; case report ; intermediate host ; rat ; Moroco oxycephalus ; Carassius carassius

The infection status of the loaches, Misgurnus anguillicaudatus, with the metacercariae of Echinostoma hortense, was studied in Korea. A total of 154 loaches purchased at 4 local makets (Seoul, Kimhae, Naju-gun and Kangjin-gun) were examined their infection rate as well as the density and location of the metacercariae in the fish body. The results are as follews: The loaches carrying the metecercariae of E. hortense were 64 (41.6%) in total number and the metacercarial density ranged 1-29 per infected loach with an average value of 8.1. The highest infection rate and metacercarial density were obtained from the loaches purchased at Kangjin-gun, Jeonranam-do. The metacercaria of E. hortense were chiefly distributed in the distal intestinal wall and the adjacent mesentery, the perianal tissues, and the head and gill of the loaches examined. From the results, it is concluded that the loach is one of the important second intermediate hosts of E. hortense in Korea, and their infection rate and metacercarial density are considerably high.
parasitology-helminth-trematoda ; Echinostoma hortense ; Misgurnus anguillicaudatus ; metacercaria ; epidemiology ; intermediate host

A study was carried out to evaluate the house rats in southern Korea as reservoir host of intestinal trematodes, in 13 different areas: 7 in inland and 6 in brackish-water zones, during the period from August 1980 to August 1981. A total of 170 house rats was captured; 101 rats from inland and 69 from brackish-water zones. They consisted of 129 Rattus norvegicus, 22 R. rattus rufescens, and 19 unidentified. The infection status of the rats were as follows: Total 29 rats (17.1%) were infected by one or more kinds of intestinal trematodes; 27 from inland and 2 from brackish-water zones by areas. Rats in inland were more heavily infected. The intestinal trematodes collected from rats were identified as Echinostoma hortense, E. cinetorchis, Plagiorchis muris, Fibricola seoulensis, Clonorchis sinensis and Metagonimus yokogawai. As a reservoir host, the rats were very important in Echinostoma hortense and E. cinetorchis infection. Rats infected with these trematodes were found widely in southern Korea, and its infection rates were the highest among the discriminated flukes. In this study, no rats were found to be infected with Heterophyes and Pygidiopsis even in endemic areas. The negligible importance of rats as reservoir host of these heterophyid should be reevaluated in the future.
parasitology-helminth-trematoda ; rat- Rattus norvegicus-Rattus rattus rufescens ; zoonosis ; epidemiology ; Echinostoma hortense ; Echinostoma cinetorchis ; Plagiorchis muris ; Fibricola seoulensis ; Clonorchis sinensis ; intestine ; Metagonimus yokogawai

One hundred and two stray dogs in Ejungbu City of Kyunggi-Do, Korea were examined to reveal out the degree of natural helminthic infection of small intestine. Helminthes were collected at autopsy, by scraping the intestinal contents. The collected worms were classified by their morphological characteristics. Out of 102 examined, 72 dogs were infected with any helminthes. The common helminthes were Dipylidium caninum (47 percent), Ancylostoma caninum (26 percent), Toxascaris leonina (16 percent) and Toxocara canis (13 percent). Taenia pisiformis (9 percent), Echinostoma hortense (4 percent), E. cinetorchis (2 percent), Spirometra mansoni (2 percent) were also found. One dog was incidentally found to be infected with Clonorchis sinensis. The prevalence of Toxascaris leonina was relatively high in this study over Toxocara canis, and its significance was discussed. Dogs were firstly described as the reservoir hosts of Echinostoma hortense and E. cinetorchis in Korea.
parasitology-helminth-nematoda-trematoda ; cestoda ; dog ; epidemiology ; morphology ; Dipylidium caninum ; Ancylostoma caninum ; Toxascaris leonina ; Toxocara canis ; Taenia pisiformis ; Echinostoma hortense ; Echinostoma cinetorchis ; Spirometra mansoni ; reservoir host ; intermediate host