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

This study was performed to observe the present status of intestinal parasitic infections in a remote island, Yondo, located in southern part of Jeonranam-do(province), Korea. In February and May 1988, total 1,011 individual stool samples were collected and examined for intestinal helminths and protozoa using formalin-ether centrifugal sedimentation technique. The results are summarized as follows: Of 1,011 ingabitants examined, 398(39.4%) were positive for intestinal parasites. Helminth positives were 372(36.8%), and protozoan cyst positives were 56(5.5%). Ten species of parasites were found. Trichuris trichiura revealed the highest infection rate of 27.5%, Ascaris lumbricoides 17.4%, Taenia sp. 5.8%, Entamoeba coli 3.3%, Giardia lamblia 1.5%, Endolimax nana 0.8%, Hymenolepis nana 0.4%, hookworm 0.2%, Trichostrongylus orientalis 0.2%, and Entamoeba histolytica 0.2%, respectively. The female group showed higher positive rate (44.0%) than males (34.7%). Also, higher positive rates were observed among adults as compared with the group younger than 10 years old. Average value of E.P.G. was 1,876(range 200-17,800) in A. lumbricoides positives, and 327(range 200-1,600) in T. trichiura positive cases. In helminth egg positive cases, single infection was 63.4%, double infection 34.7%, and triple infection 1.9%, respectively. Among protozoan cyst positives, single infection was 94.6%, and double infection was 5.4%. The present study revealed that the prevalence of intestinal parasites among inhabitants in Yondo island is still so high that special control measures should be performed.
parasitology-helminth-trematoda ; cestoda-nematoda-protozoa ; epidemiology ; Ascaris lumbricoides ; Taenia sp. ; Entamoeba coli ; Giardia lamblia ; Endolimax nana ; hookworm ; Trichostrongylus orientalis ; Entamoeba histolytica

Total of 2,643 Korean soldiers were examined of their stool for parasitic infections by both cellophane thick smear and formalin-ether concentration techniques from August 1983 to December 1985. Out of them, 73.6% were free from any parasite, 22.6% were ova positive and 4.0% cyst positive. The ova positive rates by species were Ascaris lumbricoides 2.0%, Trichuris trichiura 13.0%, hookworm and Trichostrongylus orientalis 0.08% respectively, Clonorchis sinensis 7.6%, Metagonimus yokogawai 1.1%, Paragonimus westermani 0.08%, Echinostoma hortense 0.04%, Fibricola seoulensis 0.9%, Taenia sp. 0.3%, Hymenolepis nana 0.2% and H. diminuta 0.04%. Most of them (87.3%) were positive by a species, 11.9% by two and 0.8% by 3 species. The cyst positive rates were Entamoeba histolytica 0.6%, E. coli 1.4%, Endolimax nana 1.7%, Iodoameba butschlii 0.04% and Giardia lambla 0.9%. Among the cyst positives, 89.5% were positive by a species, 7.6% by two and 0.5% by 3 species. The intestinal parasite infections among the Korean soldiers decreased distinctly compared with previous data.
parasitology-helminth-nematoda ; trematoda ; cestoda ; protozoa ; epidemiology ; Clonorchis sinensis ; Trichuris trichiura ; Metagonimus yokogawai ; hookworm ; Ascaris lumbricoides ; Diphyllobothrium latum ; Hymenolepis nana ; Entamoeba histolytica ; Giardia lamblia ; Entamoeba coli ; Endolimax nana ; Trichostrongylus orientalis ; Paragonimus westermani ; Echinostoma hortense ; Fibricola seoulensis ; Taenia sp. ; Hymenolepis diminuta

The present study was undertaken to evaluate the present status of intestinal parasitic infection in Seoul area, Korea. During the period from June 1985 to July 1986, a total of 5,251 stool samples were collected in Department of Clinical Pathology, Hanyang University Hospital and examined by formalin-ether sedimentation technique once for helminth ova and protozoan cysts. The results were summerized as follows: The overall egg positive rate of intestinal helminthes was 2.53 per cent ; and 1.43 per cent for Clonorchis sinensis, 0.7 per cent for Trichuris trichiura, 0.13 per cent for Metagonimus yokogawai, 0.06 per cent for hookworm, and 0.02 per cent for Ascaris lumbricoides, Diphyllobothrium latum and Hymenolepis nana, respectively. The overall cyst positive rate of intestinal protozoa was 1.07 per cent. Cyst positive rate was 0.06 per cent for Entamoeba histolytica and 0.13 per cent for Giardia lamblia, respectively. Higher prevalence of intestinal parasitic infection was observed in male and in 21-50 year-old groups. The highest prevalence of Clonorchis sinensis infection was observed in 40th age group(3.4 per cent), and male (2.3 per cent) was more infected than female (0.7 per cent) in general.
parasitology-helminth-nematoda ; trematoda ; cestoda ; protozoa ; epidemiology ; Clonorchis sinensis ; Trichuris trichiura ; Metagonimus yokogawai ; hookworm ; Ascaris lumbricoides ; Diphyllobothrium latum ; Hymenolepis nana ; Entamoeba histolytica ; Giardia lamblia ; Entamoeba coli ; Endolimax nana

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 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

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 review dealt with biology, host-parasite relationship, symptomatology, epidemiology, diagnosis, treatment of Entamoeba histolytica infection and free livng amoeba.
parasitology-protozoa ; Entamoeba histolytica ; Entabmoeba gingivalis ; Trichomonas tenax ; Naegleria sp. ; Naegleria fowleri ; Acanthamoeba lenticulata ; Acanthamoeba sp. ; biology ; epidemiology ; diagnosis ; chemotherapy ; metronidazole ; onidazole ; tinidazole

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