The study was designed and conducted from April 2004 to November 2005 to assess the infection of intestinal protozoa in school children. A total of 652 stool samples of school children in three schools from different geographical places of Ninh Binh (Red River Delta), Phu Tho (foot hill area) and Ha Giang (northern mountainous) was examined by etherformalin (WHO recommended technique). A general prevalence of protozoa of 19.01%, of which the individual infection rates of 22.96%, 13,18%, and 21.07% were found in Ninh Binh, Phu Tho and Ha Giang, respectively. The protozoa species such as E.histolytica; E.coli; E.nana; E.hartmanni (belonging Amoeba) were more commonly found (11.8%) while G.lambia (Flagellata) was less (5.9%). Oocyst was rare (2.1%) and no case of Cryptosporidium was found.
Protozoa ; Child

The importance of Toxoplasma gondii in human disease stimulated a number of electron microscope studies on the structure of this protozoan parasite. Gustafson et al. first studied the fine structure by means of thin sections in 1954. Many other papers havs subsequantly appeared. It is well known that Toxoplasma gondii has two stages in its life cycle-the proliferative forms and the cyst. The purpose of the electron microscopical work reported here was to study the fine structure of Toxoplasma gondii with recent techniques clarifying the correlation between the proliferative forms and cyst. RH strain and KM strain as proliferative forms on the one hand and Beverley strain as a cyst form of Toxoplasma gondii on the other hand were used throughout this study. The conoid, toxoneme, nucleus, nucleolus, osmiophilic granules, mitochondria and vacuoles were found in RH strain as wsll as in KM strain and Beverley strain. The endoplasmic reticulum was found in the cytoplasm of RH strain and KM strain. It was better developed in KM strain than in RH strain. The outside contour of the organism of Beverley strain was somewhat irregular and toxoneme of this organism was better developed than in the other two strains. Vacuoles were found in RH strain, KM strain and Beverley strain. Furthermore, tube-like bodies were observed in the vacuoles of the organism of RH strain. In KM strain, two organisms of the same size were demonstrated in the leucocytes. It was presumed that they were products of longitudinal division.
parasitology-protozoa- Toxoplasma gondii ; electron microscopy

A total of 377 pregnant women, 43 pelvic tumor patients and 80 of multiphysic health center persons as controls were examined by indirect latex agglutination test in order to evaluate Toxoplasma antibody titers at Kang-Nam St. Mary's Hospital in Seoul. Throughout this survey, 1:32 or more titers of diluted sera were regarded as positive. The 337 samples of test sera in pregnant women showed negatives in 319 cases (84.6 percent), 1:2 in 44 cases (11.7 percent), 1:4 in 9 cases (2.4 percent), 1:8 in 2 cases (0.5 percent), 1:16 in 1 case (0.3 percent) and 1:32 in 2 cases (0.5 percent) respectively. The 43 samples of test sera in pelvic tumor patients showed negatives in 29 cases (67.4 percent), 1:2 in 8 cases (18.6 percent), 1:4 in 1 case (2.3 percent), 1:16 in 2 cases (4.7 percent), 1:32 in 1 case (2.3 percent) and 1:128 in 2 cases (4.7 percent). The 80 samples of test sera in multiphysic health center persons as controls negatives in 56 cases (70.0 percent), 1:2 in 19 cases (23.8 percent), 1:4 in 3 cases (3.8 percent), 1:8 in 1 case (1.3 percent) and 1:128 in 1 case (1.3 percent). Among total 420 study cases, 5 cases (1.2 percent) showed positives , and they were 2 cases (0.5 percent) of pregnant women and 3 cases (7.0 percent) of pelvic tumor patients. One case (1.3 percent) out of 80 control sera showed positive result.
parasitology-protozoa ; Toxoplasma gondii ; diagnosis ; immunology

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

A total of 421 patients hospitalized in St. Mary's Hospital were examined by indirect latex agglutination test in order to evaluate the Toxoplasma antibody in Korean from June to August 1981. The test sera of the patients were obtained from each age group by random sampling. The 421 samples of test sera showed negative in 153, 1:2 in 157, 1:4 in 59, 1:8 in 27, 1:16 in 7, 1:32 in 9, 1:64 in 2, 1:128 in 4 and 1:256 in 3 cases, respectively. The positive rate of Toxoplasma antibody was 4.3 percent in this sample when indirect latex antibodies of 1:32 or higher were regarded as positive. The titers of positive Toxoplasma antibodies were increased by age.
parasitology-protozoa ; Toxoplasma gondii ; toxoplasmosis ; immunology ; diagnosis

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

Eight 2-day-old SPF chickens were each inoculated orally with a single dose of 5+O105 oocysts of Cryptosporidium baileyi, and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. baileyi IgG antibody levels remained high(1:106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1+O107 oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation(PCI), at 1:1,024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles, but did not exhibit any oocyst shedding before or after experimental reinfection.
parasitology-protozoa ; Cryptosporidium baileyi ; chicken ; IgG ; immunology

The role of passive cell-mediated transfer of immunity against primary amoebic meningoencephalitis(PAME) in mice was studied. Naegleria fowleri, ITMAP 359, were cultured in CGVS medium. The ICR mice used were six week-old males of average weight of 15 g. Immunization was done by three intraperitoneal injections of l x 10(6) N. fowleri trophozoites at the interval of one week. Splenocytes were obtained from normal and immune mice spleens, and 1 x 10(7) cells were administered intraperitoneally into mice 3 days before challenge infection. Mice were infected intranasally with 7 x 10(4) N. fowleri trophozoites in a 3 microliter suspension under secobarbiturate anesthesia. Transplants of normal or immune splenocytes seem to alter the pattern of the PAME development. The splenocytes transferred from immune mice reduced the mortality rate in the N. fowleri infected mice, as compared with the mice transferred with the same number of normal splenocytes or without splenocyte. The blastogenic response of the splenocytes to both lipopolysaccharide and concanavalin A was elevated on day 7 after infection the mice transinoculated with immune splenocytes. The serum antibody titers in the mice transferred with immune splenocytes were increased gradually from day 7 up to day 20 after infections by mean of ELISA. It is suggested that the transfer of splenocytes from immunized mice conferred immunity against N. fowleri infection.
parasitology-protozoa ; Naegleria fowleri ; meningoencephalitis ; brain ; immunology

Present study aimed to elucidate the immunosuppressive effect of prednisolone on Naegleria fowleri infection in mice. N. fowleri was cultured in CGVS medium (Willert and Le Ray, 1973). White female mice, weighing about 18 g, used for experiments were divided into five groups; untreated control group, prednisolone treated groups (before, during and after infection), and only prednisolone treated group. In the prednisolone treated group, the hormone was injected intramuscularly 5 doses of 10 mg/kg every other day. According to designated time of treatment, each mouse was challenged with 1 x 10(5) N. fowleri intranasally. Changes of body weights, clinical manifestations and number of dead mouse were observed. Brain and lung tissues of dead mice were cultured in the non-nutrient agar (Kasprzak and Mazur, 1972), or stained with hematoxylin-eosin for the examination of histopathological changes. Results of the experiment are summarized as follows: Mortality among the prednisolone treated groups was higher than that in untreated control group, and among the treated groups, the pretreated group showed shorter survival time. Body weights among untreated control mice showed no significant increase, however, treated groups of mice showed the decrease during the administration and recovery of the weights were observed at 2 to 3 days after the completion of treatment. In the treated control groups, the infected mice began to show the pathologic findings 5 days after infection while the untreated mice began to show the findings 8 days after infection. Tissue damages in brain and lung occurred due to virulence of amoeba were more severe among treated mice than that in untreated control group. The above mentioned results suggest that the treatment with prednisolone weaken the resistance of mice against N. fowleri infection, and probably induce more severe primary amoebic meningoencephalitis. Especially severe pathological findings were shown in pre-treated group, compared with untreated group.
parasitology-protozoa ; Naegleria fowleri ; meningoencephalitis ; brain ; prednisolone

Under the current epidemiological conditions as found in Korea, and considering the limited funds available for the malaria project, passive case detection proved to be the only practical mechanism to obtain reliable data required for the delimitation of malarious areas. The malaria map of the country was completed at the end of 1965. The high SPRs found among the blood smears reported by the PCD undts are due to the fact that the Korean farmer is able to recognize the clinical symptoms of the disease. The "fever case" reports are therefore actually "suspect malaria case" reports. The consistently high SPR has resulted in the detection of a large number of parasite carriers with the number of smears to be examined being reduced to a minimum. Although the medical group gave an important contribution to the success of the PCD service in Korea, the number of medical and public health facilities in the rural areas are still too small. This made it necessary to obtain the collaboration of laymen groups like school teachers, village chiefs etc., and their participation largely contributed to the success of the present programme. The degree of collaboration by the PCD units is higher in the more malarious areas. As no form of encouragement e.g., a reporting fee, has been given to these laymen during the past few years it becomes increasingly more difficult to maintain their active co-operation. It is felt that through passive case detection alone it will not be possible to collect adequate information to provide the proof for the complete interruption of transmission.
parasitology-protozoa ; Plasmodium vivax ; malaria ; diagnosis ; epidemiology