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

Anthelmintic effect of niclosamide [N-(2-chloro-4-nitrophenyl)-5-chloro-salicylamide)] on Metagonimus infection was carried out to the cases in area of Seomjin-river. The drug, one tablet contains 0.5 g of niclosamide was supplied from Bu-gwang pharmaceutical company in Seoul. Sixty five cases were divided into three groups by the regimen: Group l given 2 g(4 tablets) for one day, Group II for two successive days and Group III for three successive days. Stool examination was done before and 2-3 weeks after the drug administration by formalin-ether concentration and Stoll's dilution egg counting techniques. The results were as follows: Egg negative conversion (cured) and egg reduction (more than 80 percent decrease) rates were 28.6 percent, 10.7 percent in group I, and 31.8 percent, 27.3 percent in group II. But of those in group III treated for three successive days, 73.3 percent was cured and 26.7 percent showed egg reduction, and the general egg reduction rate was 95.1 percent. The results in the present trial suggested that the niclosamide has anthelmintic efficacy when it is used in 2 g for more than three successive days.
parasitology-helminth-trematoda-Metagonimus yokogawai ; niclosamide-chemotherapy-metagonimiasis

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

An epidemiological study on Metagonimus yokogawai infection was performed in Samcheok-gun, Kangwon province during the period from November 1983 to October 1984. Formalin-ether concentration technique and Stoll's dilution egg counting method were employed to figure out the prevalence and infection intensity of M. yokogawai infection. The results are summarized as follows: The prevalence of M. yokogawai infection was 13.3 percent among 1,172 examined ; 18.0 percent (114 out of 632) in male and 7.8 percent (42 out of 540) in female. The prevalence rates were different by stream; 15.5 percent in Ohsip-chon (stream), 11.8 percent in Maeup-chon and 1.6 percent in Gagok-chon. Along the basin of Oship-chon; 8.2 percent at the lower reaches in Samcheok-eup, 25.9 percent at the middle reaches in Miro-myon and 6.2 percent at the upper reaches in Dogeoe-eup, respectively. By age group, the highest rate (18.3-20.2 percent) was observed in 30-49 years of age (male : 24.1-28.7 percent, female 11.2-13.2 percent). By social strata, the positive rate was 15.0 percent (120 out of 799) in general inhabitants and 9.7 percent (36 out of 373) in school children. Intensity by EPG count in feces was 419 in average; the light infection (less than 400 EPG) was 70.4 percent, moderate infection (401-1,000 EPG) 19.4 percent and heavy infection (more than 1,001 EPG) 10.2 percent respectively. All the 67 sweetfish (length 10.3-18.5 cm) which were caught from Ohsip-stream were infected with metacercariae of M. yokogawai and the number of metacercariae detected were 382 per fish in average (323 in June and 382 in September). Experiences of intake of raw fresh-water fish [Plecoglossus altivelis and Leuciscus (Tribolodon) sp.] were present in 50.3 percent (354 out of 704) of the inhabitants along Ohsip-stream according to questionnaire study. The results of this survey indicated that the middle reaches of Ohsip-stream in Miro-myon, Samcheok-gun is the endemic region for M. yokogawai infection.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; epidemiology ; metagonimiasis ; human ; Plecoglossus altivelis ; Leuciscus sp.

The infection of Metagonimus yokogawai has been known to be present nationwidely and endemic in some parts in Korea. In order to select a highly effective compound against Metagonimus infections, the therapeutic effects were observed in 156 cases who were treated with several anthelmintic i.e. bithionol, niclosamide, niclofolan and praziquantel. All of the above drugs showed highly effective to the treatment of metagonimiasis by a single or two medication days. The egg reduction rates were in the range of 80.2 to 100 per cent. However, relatively low cure rates(8.3 to 37.5 percent) were observed in the groups treated by two doses of 30 mg/kg of bithionol, a single day treatment with 100 mg/kg of niclosamide and two doses of 1.0 mg/kg of niclofolan. On the other hand, the high cure rates were observed at the following dose rates of each drugs, i.e. the cure rate of 66.7 percent was obtained at two doses of 100 mg/kg of niclosamide, 88.9 percent of cure rate was observed at two doses of 2.0 mg/kg of niclofolan and a single dose of 10 and 20 mg/kg of praziquantel were shown as 85.0 percent and 88.0 percent of cure rates respectively. But the complete radical cure was obtained in the group treated by two doses of 20 mg/kg of praziquantel in 10 metagonimiasis cases. From the above results praziquantel was shown as the most highly effective against metagonimiasis and it was well tolerated without any side effect. Therefore, praziquantel is a very promising drug for mass treatment against metagonimiasis.
parasitology-helminth-trematoda ; Metagonimus yokogawai-metagonimiasis ; bithionol ; niclosamide ; niclofolan ; praziquantel ; chemotherapy

To study the basic pathological changes of small intestine in metagonimiasis, light- and electron microscopic studies were made, using a total of 21 cats which were experimentally infected with metacercariae of Metagonimus yokogawai. The metacercariae were obtained from naturally infected sweetfish (Plecoglossus altivelis) by digestion technique. The cats were divided in control, light-infection(10,000 metacercariae infected) and heavy-infection(50,000 metacercariae infected) groups. Cats were killed at the 5th, 10th, 15th day, and 4th, 8th and 10th week after the infection. And the small intestine was prepared for the study. Pathological studies comprised gross examination, worm distribution pattern, light microscopic examination and both transmission and scanning electron microscopic examinations. The results obtained were summarized as follows. Gross morphologic changes were the most marked during the first 2 weeks after infection. The gross abnormalities were severer in the heavily infected animals. The changes were dryness and listlessness of serosal surface due to dehydration, mushy and/or watery intestinal content, effacement of transverse nodes and enlargement of mesenteric lymph folds and Peyer's patches. After 4 weeks of infection, these changes became less marked showing a tendency to return to normal. The sectioned flukes were distributed from duodenum to proximal ileum. However, individual variation was marked in distribution. In the heavy-infection group, the locality of parasitism tended to extend more distally. The locality of M. yokogawai in the intervillous space was mostly in the lower-most portion of intervillous space, where they compressed and eroded epithelial cells probably due to mechanical damage to the structure. Very rarely the worms were found in lumen of Lierberkuehn's crypt, and reaching, in two occasions, into proprial lymphoid tissue. Light-microscopically the lesion was restricted in mucosa: Early mucosal changes were shortening, blunting, fusion, and thickening of the villi, crypt hypertrophy with consequent decrease of villus/crypt ratio, as well as stromal changes of edema, capilliary ectasia and marked inflammatory cell infiltration of lymphocytes and plasma cells. Goblet cells were markedly reduced in number as with depletion of its cytoplasmic content. In the later stages of infection, mucosa restored its normal configuration in spite of persistent parasitism of the worms. At the infection stage of 5-15 days, there was significant shortening of the microvillous height with varible destruction of glycocalyx in electron microscopic examination. With lapse of infection time, microvilli became to restore the normal pattern. With these morphological changes, it appears that diarrhea in experimental metagonimiasis would be related to the decrease of absorptive surface of the small intestine particularly in the early phase of infection. The significant changes seen in villi and microvilli might be due to massive intrusion or invasion of Metagonimus worms into the crypts, causing direct mechanical and possible host-immune response to the small bowel mucosa.
parasitology-helminth-trematoda ; metagonimiasis ; Metagonimus yokogawai ; pathology ; cat-intestine ; edema ; lymphocytes ; plasma cells ; goblet cell

In order to observe the feasibility of serologic diagnosis of metagonimiasis, saline extracts of metacercariae and 4-week old adults were prepared. Sera from 25 experimentally infected cats were collected from 3 days to 12 weeks after infection. Their levels of specific IgG antibody were measured by ELISA together with 3 sera from non-infected cats. Specific IgG antibody levels began to rise in 7 days after infection, reached their peak in 2-4 weeks and made a plateau thereafter. Cats infected with hundreds of adult worms showed minimal rise of the antibody level. Adult antigen was superior to metacercarial antigen in detecting the specific IgG antibody.
parasitolgy-helminth-trematoda ; cat ; metagonimiasis ; Metagonimus yokogawai ; IgG ; enzyme-linked immunosorbent assay

The intestinal lesions were studied in dog metagonimiasis by reinfection. The metacercariae of M. yokogawai were collected from naturally infected sweetfish. A total of twenty dogs were divided into three groups; control, primary infection and reinfection groups. The 18 dogs were infected with 10,000 metacercariae; the 5 dogs in primary infection group were killed at the 5 days in 1 week, 4 weeks, 6 weeks after the infection. The remaining 13 dogs were kept for nine weeks, and challenged again with 5,000 metacercaricae. The reinfected dogs were killed at the 1 day, 3 days, 5 days and 1 week, 2 weeks, 4 weeks, 6 weeks, 8 weeks respectively. The chronologic changes of the intestinal lesions in both groups, the worm recovery rate, and distribution patten were examined by gross observation, light and scanning electron microscopies. From the results, it was inferred that the so-called spontaneous and/or self cure phenomena were of negligible importance in metagonimiasis in dogs. In the chronologic observations of pathologic process in intestine, it was also suggested that the host immunity tend to recover the intestinal integrity. And early invasion of young worm to the Lieberkuhn's crypt was considered as the primary cause of lesions of vill(Abstract is summarized again.)
parasitology-helminth-trematoda ; Metagonimus yokogawai ; metagonimiasis ; dog ; histology ; pathology ; electron microscopy ; intestine