Differentiation of invasive strains of Entamoeba histolytica according to their pathogenicity has been a topic of long debate, but now the pathogenic species only is regarded as E. histolytica while the non-pathogenic species is E. dispar. The present study applied immunoblot to differentiate infections of the two species among microscopically-detected cyst-passers in Korea. The crude extract of E. histolytica separated in 5-20% gradient gels, revealed many fractions of 94, 81, 71, 50, 44, 38.5, 37.5, 29, 19, and 18 kDa when the cysteine proteinase inhibitor, E64, was supplemented. The serum IgG antibody of proven E. histolytica cases reacted with the antigenic fractions of 117, 110, 99, 68, 66, 60, 54, 52, 46, and 45 kDa. Sera of PCR confirmed 3 cases of E. dispar reacted only to the 117 kDa fraction of the E. histolytica crude extract which was regarded as non-specific. To the antigen of monoxenic E. dispar, sera of E. dispar and E. histolytica cases showed the same immunoblot reactions. The serum IgA antibody reacted with several antigenic fractions of both E. histolytica and E. dispar, but IgM and IgE antibodies showed no reaction to either antigen. Sera of 24 symptomless amebic cyst-passers were screened with the E. histolytica antigen; two were found to be infected by E. histolytica and 22 were by E. dispar. The present findings suggest that in Korea most asymptomatic cyst passers of E. histolytica are carriers of E. dispar. Immunoblot using E. histolytica antigen is a good technique for the differentiation of E. histolytica and E. dispar infections.
parasitology-protozoa ; Entamoeba histolytica ; Entamoeba dispar ; immunoblot ; pathogenecity

School children between 6 to 12 years of age were studied for the presence of Entamoeba histolytica cysts in a period of 6 months, form March to August 1980. Fecal specimens collected form urban and rural children were examined first by the Lugol stained technique and then by the Faust's iron alum hematoxylin method. A total of 731 specimens were examined. Of these 26.9 per cent, 197 specimens, harbored the cysts. The demonstration rate for the cysts by age group varied from 19.6 to 43.5 per cent. The demonstration rate in boys was 24.4 per cent and in girls 29.8 per cent. Similarily, the rate in urban and rural area was 32.4 and 24.1 per cent, respectively. It was found in the present study that there were no significant differences in the age and sex rates of demonstration between urban and rural children but there was a predominance of the small race of Entamoeba histolytica over the large race.
parasitology-protozoa-Entamoeba histolytica ; entamoebiasis-epidemiology ; cyst

The metabolism of Entamoeba histolytica would be affected by various environmental factors, and alteration of the environment was known to affect the fine structure of E. histolytica. The present study was designed electronmicroscopically to investigate the ultrastructure and enzyme activities in the axenic and conventional strains of E. histolytica. The trophozoites of axenically cultivated HK-9 strain and conventional YS-27 and YS-49 strains of E. histolytica were collected and fixed with 4 percent paraformaldehyde/0.1 M cacodylate buffer (pH 7.4). After washing them by centrifugation, 1 percent warm agar was added in the sediment. Solidified agar with the trophozoites was cut into 1 mm(3) cubes, and incubated in the various substrates to observe enzyme activities. Then, the specimen was post-fixed with 3 percent glutaraldehyde/0.1 M cacodylate buffer (pH 7.4) and 1 percent osmium tetroxide/0.1 M cacodylate buffer (pH 7.4), dehydrated in ascending ethanol series and embedded in epoxy resin. These were sectioned on an ultramicrotome and observed with a transmission electron microscope. The procedures for the observation of the fine structure were same as the above, except for the incubation in the substrate. The sections were stained with uranyl scetate and lead citrate. For the observation of the surface of the amoebae, scanning electron microscopy was carried out. The results obtained in the present study are summarized as follows: The fuzzy coat around double-layered plasma membrane of E. histolytica was more irregularly and densely distributed in the conventional strains (YS-27, YS-49 strains) than in the axenic strain (HK-9 strain). The endosomes, button bodies and chromatin material were surrounded by a double-layered nuclear membrane having scattered nuclear pores. The paranuclear body, mono- or double-layered vacuoles, vacuolar membrane whorls, rosette-like cylindrical bodies, aggregation of cylindrical bodies and helical bodies were found in the cytoplasm of the amoebae. Helical bodies and glycogen granules were generally abundant, while a few smooth endoplasmic reticula were observed in the cytoplasm. Alkaline phosphatase activity was mainly demonstrated in the plasma membrane, limiting membranes of vacuoles and smooth endoplasmic reticula. ATPase activity was observed in the nucleus, limiting membranes of vacuoles and vacuolar membrane whorls. Acid phosphatase activity was commonly demonstrated in the limiting membranes an contents of vacuoles, lysosome-like organelles, plasma membrane and the button bodies in the nucleus. The activity was more weakly demonstrated in the HK-9 strain than in the other conventional strains of E. histolytica. No peroxidase activity was observed in the amoeba strains employed in the present study. With a scanning electron microscope, no distinct structural differences were observed between the amoeba strains. All the trophozoite forms of the amoebae showed crater-like depressions and rugged features on the outer surface.
parasitology-protozoa ; Entamoeba histolytica ; electronmicroscopy ; alkaline phosphatase

The present report deals with the behaviour of mast cells in mice in the course of Entamoeba histolytica infection by the strains. Mice weighing about l6 gm were used for three experimental groups; control, sham infection and experimental. The experimental group was infected with Entamoeba histolytica trophozoites directly into cecum by laparotomy. Strains isolated from three hepatic amoebic abscess cases were used. Mesenteric samples from the region of terminal ileum were fixed in methyl alcohol and stained with Pugh's solution. The ulcers in cecum were examined. Changes in number and structure of mesenteric mast cells and blood eosinophils were as follows. The number of mast cell in mesenteric tissues of the infected group increased from first day of the infection and persisted up to 34th day of the observation period. Degranulation and disruption of mast cells increased in the infected group compared with groups of the sham operation and the contro1, but showed no difference by the strains of Entamoeba histolytica. The blood eosinophilia was observed in the infected group and persisted until the observation period. Ulcers in cecum were found in all the infected groups. The results above indicate that mast cells are keenly related with the course of Entamoeba histolytica infection.
parasitology-protozoa- Entamoeba histolytica ; mast cell ; pathology ; mouse ; amoebiasis ; cecum

Tinidazole (Fasigyn), a new drug which is active in vitro and in vivo against Entamoeba histolytica, was used in 30 Korean patients with acute and chronic intestinal amoebiasis. In aute amoebic dysentry eight of ten patients given tinidazole 150 mg q.i.d. for 10 days were cured clinically and parasitologically. In chronic intestinal amoebiasis, the parasitological cure was obtained 6 out of 10 patients given150 mg q.i.d. for 10 days and 8 out of 10 in patients given 300 mg q.i.d. for 7 days. Tinidazole is well tolerated and is free from serious toxicity. There was no significant alteration in blood count, liver function tests and urine analysis of any of the patients treated with tinidazole.
parasitology-protozoa-Entamoeba histolytica ; chemotherapy-Tinidazole ; drug ; Tinidazole

Total 9 cases of extraintestinal amoebiasis, amebic liver abscess and amebic lung abscess, were treated with metronidazole. The diagnosis and progress check were done by (1) stool examination, (2) size and pain of liver, (3) hematological examination, (4) urinanalysis, (5) X-ray or liver scanning (6) examination of aspirated pus from liver and (7) immobilization test of E. histolytica. Results are summarized as follows: Amebic hepatitis: Metronidazole was given to 3 cases with daily dose of 0.9-1.2 gm for 3-7 days. Clinical symptoms were completely restored by the treatment. Amebic lung abscess: One case was treated with metronidazole for 3 days with the daily dose 1.2 gm. X-ray findings showed remarkable improvement by the treatment. An additional administration of the drug for 6 days resulted complete resolution of the pneumonic changes. Amebic liver abscess: Four cases were treated with metronidazole. The daily doses were 0.4-2.4 gm and continued for 2-10 days. Aspiration of the abscess for 1-10 times or continuous drainage of pus were performed during the course supplementarily. All cases were recovered to normal by the combining treatment. No remarkable side effect was noticed by the drug administration, and no relapse was experienced up to date.
parasitology-protozoa-Entamoeba histolytica ; chemotherapy ; metronidazole ; liver ; lung ; amoebiasis

A survey on the prevalence of intestinal protozoan cysts was conductcd in Jeonlanam Do (Province), Korea in 1981. A total of 4,116 specimens was collected from 2,035 male and 2,086 female inhabitants in 4 urban and 7 rural areas. Each case was selected randomly to represent 1,000 inhabitants referred to the census in 1980. Formalin-Ether sedimentation technique was employed to concentrate the cysts and one Lugol's iodine stained smear was examined for each case. The results were summarized as follows: The cases who passed out protozoan cysts of any kind were 9.1 percent out of total 4,116 examined, and cumulative positive rate was 11.0 percent. Among the positive cases, 16.5 percent were infected by two or more species of protozoa. Total 5 species of cysts were detected and the positive rates were as follows; Entamoeba histolytica 1.4 percent, E. Coli, 4.9 percent, Endolimax nana 2.5 percent, Iodamoeba butschlii 0.4 percent and Giardia lamblia 1.9 percent. The cyst positive rates varied greatly by the surveyed area. The positive rate in rural area was 11.6 percent compared with 5.7 percent in urban area. The highest rate was found 14.5 percent in Gurye Gun (County) and the lowest 3.6 percent in Mogpo Si (City). Female showed much higher positive rate than male as 11.8 percent compared with 6.4 percent and the cumulative rate 14.2 percent and 7.6 percent respectively. By age group, the rate was highest as 13.9 percent in 40-49 years and next 12.5 percent in over 60 years group. The cyst prevalence rate diminished remarkably in Jeonlanam Do compared to previous records. However, the finding that 20.2 percent of females of 40 years were the carrier of protozoan cysts was an important information in public health point of view.
parasitology-protozoa ; Entamoeba histolytica ; Entamoeba coli ; Endolimax nana ; Iodamoeba butschlii ; Giardia lamblia ; epidemiology ; intestine

To evaluate the status of intestinal protozoan infections in inhabitants of Gangweon-Do, Korea, a total of 1,310 stool specimens (male 669, female 641) was collected from 2 cities and 3 counties. They were examined routinely 1 time by the method of formalin-ether sedimentation technique. The results were as follows: The positive rate for any kind of the intestinal protozoan cysts was 8.9 percent. A total of 6 kinds of the intestinal protozoan cysts were detected. The prevalence rate of each protozoa were; E. histolytica 0.8 percent, E. coli 7.6 percent, E. nana 1.4 percent, I. butschlii 0.2 percent, G. lamblia 0.5 percent and C. mesnili 0.5 percent. Sogcho-city showed the highest positive rate as 15.2 percent, Myeongju county was the next as 11.3 percent and Weonju-city showed the lowest positive rate as low as 3.9 percent. By age, the highest positive rate was found in 20-29 age group(12.4 percent). Female (9.5 percent) showed a slight higher positive rate than male (8.4 percent).
parasitology-protozoa ; Entamoeba histolytica ; Entamoeba coli ; Endolimax nana ; Iodamoeba butschlii ; Giardia lamblia ; Chilomastix mesnili ; epidemiology ; intestine

This study was undertaken in order to elucidate the prevalences of the intestinal protozoan infection according to localities and the mode of the infestation in the mountainous area of Chollapuk-do, Korea during the year 1970-1971. 8,508 of fecal samples were collected among the inhabitants of the mountainous area, which covered 18 Myens(=Township) from 6 Guns(=County) in the eastern part of Chollapuk-do. Most of the inhabitants of this area were engaged in farming and living under lower economic and poor sanitary conditions. The samples were examined twice repeatedly by iodine stained direct fecal smear method. For the study on the mode of infestation, with the exception of drinking water, the zinc sulfate floatation technic was applied for the examinations of hog-feces, manure heap, garden soil, sewage, dishtowel, dust in room and floor, house fly and house rat. The results were summarized as follows: Among total 8,508 fecal specimens examined, 3,152(37.6 percent) were positive for the intestinal protozoa: E. histolytica 9.8 percent, E. coli 25.6 percent, E. nana 7.2 percent, G lamblia 6.8 percent, I. butschlii 0.6 percent, and C. mensnili 0.7 percent. A single infection of the intestinal protozoa was the highest(68.3 percent), and double infection(22.3 percent) triple, quadruple and quintuple infections were in decreasing order. The highest distribution (39.8 percent) was observed in the group aging 41-50, and the lowest (27.3 percent) in the group above 61. The groups under 10 years showed a relatively high positive rate among all age groups. Sexual distribution of protozoan infection showed slightly higher rate (38.6 percent) in male than that (35.4 percent) of female. Jangsoo-gun showed the highest positive rate (42.9 percent) and Namwon-gun was the lowest (32.5 percent). The prevalence of E. histolytica showed the highest (11.6 percent) in Imsil-gun and the lowest (6.9 percent) in Jangsoo-gun. E. histolytica cysts were found 9.1 percent among total 99 samples of hog feces, 4.8 percent among 78 samples of manure heap, 0.6 percent among 164 samples of fingernail dirt, 5.3 percent among 57 samples of drinking water, 15.8 percent among 19 samples of sewage, 7.1 percent among 42 samples of dishtowel, 0.1 percent among 780 samples of house fly and 5.0 percent among 40 samples of house rat.
parasitology-protozoa ; Entamoeba coli ; Entamoeba histolytica ; Giardia lamblia ; Endolimax nana ; Iodamoeba butschlii ; Chilomastix mesnili ; epidemiology

The present study was designed to elucidate the recent prevalence of the intestinal protozoa and to demonstrate the relationship on prevalence of the surveyed population with their academic career and living conditions. During the period from May to July 1981, total 2,735 fecal specimens were collected from the inhabitants of 11 areas in Gyeong-gi Do (province) near by Seoul City, and 6 areas in Jeonra Bug Do, southwestern part of Korea. The samples were fixed with SAF solution and were examined by formalin-ether sedimentation technique. The results are summarized as follows: Overall positive rate of intestinal protozoa was 11.1 percent: Gyeong-gi Do, 10.7 percent; Jeonra Bug Do, 11.7 percent. Five species of intestinal protozoa were detected: Entamoeba histolytica 0.69 percent, Entamoeba coli 5.52 percent, Endolimax nana 2.71 percent, Giardia lamblia 2.23 percent, Iodamoeba butschlii 0.l8 percent. Highest positive rates among the examined areas were recognized: Incheon City of Gyeong-gi Do, 26.7 percent; Im-sil Gun(county) of Jeonra Bug Do, 19.9 percent. By species, E. nana showed the highest prevalence rate (13.74 percent) in Incheon City, and E. histolytica (2.37 percent) and E. coli (9.95 percent) in Im-sil Gun. Prevalence of E. histolytica in rural areas was higher than in urban areas. No significant difference in the prevalence rate by sex and age was recognized, although the group under 10 years and over 60 years were lower than in other age groups. The highest positive rate of E. histolytica was observed in pauper group and significant linearity of prevalence rate of E. histolytica by monthly income was observed. The inhabitants who used conventional latrine showed higher prevalence, 11.5 percent, than the group of inhabitants who used modified privy. Although no significant difference of positive rate was recognized by academic career, but the lowest prevalence rate was observed in college graduates. Over half of the surveyed population, 64.8 percent has no experience on anthelmintic practice. Number of anthelmintic application resulted no difference in prevalence. In conclusion, prevalences of intestinal protozoa in Gyeong-gi Do and Jeonra Bug Do decreased remarkably in comparison with those of one decade before. However, economic level, academic career and anthelmintic administration seemed no essential reasons for such declination.
parasitology-protozoa ; epidemiology ; Entamoeba histolytica ; Entamoeba coli ; Endolimax nana ; Giardia lamblia ; Iodamoeba butschlii