• Biomedical Science Letters
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• v.2 no.2
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• pp.267-274
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• 1996

This study was performed to observe the present status of intestinal parasitic infections among the children in Iksan, Jeonbuk, Korea. During the period from February to June 1996, total 510 fecal samples(male 276, female 234) were collected and examined by formalin-ether sedimentation technique and trichrome stain for intestinal helminths and protozoan cysts. Of 510 samples examined, 62(12.2%) were positive for intestinal parasites. Helminth egg positives were 3(0.6%), and protozoan cyst positives were 59(11.6%). The female group showed higher positive rate(13.2%) than males(11.2%), and the highest positive rates were observed in 7 age group(17.5%), and lowest positive rates were 4 age group(9.5%). 3 species of helminths egg and 6 species of protozoan cyst were detected; Metagonimus yokogawai 0.4%, Enterobius vermicularis 0.2%, Trichuris trichiura 0.2%, Endolimax nana 4.1%, Entamoeba coli 3.9%, Ciardia lamblia 2.0%, Entamoeba histolytica 1.4%, Iodamoeba butschilii 0.8%, and Chilomastix mesnili 0.4%, respectively. In 3 helminth egg positive cases, single infection was 2(66.7%), and double infection 1(33.3%), among 59 protozoan cyst positives, single infection was 54(91.5%), and double infection was 5(8.5%). The highest positive rate of protozoan cyst was 7 age group(14.3), and lowest positive rate was 4 age group(9.5%).

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.575-580
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• 2019

The aim of this study is to determine the species of parasites that affected the inhabitants of the city of Acre on the coast of the eastern Mediterranean during the Ottoman Period. This is the first archaeological study of parasites in the Ottoman Empire. We analysed sediment from a latrine dating to the early 1800s for the presence of helminth eggs and protozoan parasites which caused dysentery. The samples were examined using light microscopy and enzyme-linked immunosorbent assay (ELISA) kits. We found evidence for roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), fish tapeworm (Dibothriocephalus sp.), Taenia tapeworm (Taenia sp.), lancet liver fluke (Dicrocoelium dendriticum), and the protozoa Giardia duodenalis and Entamoeba histolytica. The parasite taxa recovered demonstrate the breadth of species present in this coastal city. We consider the effect of Ottoman Period diet, culture, trade and sanitation upon risk of parasitism in this community living 200 years ago.

• Parasites, Hosts and Diseases
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• v.51 no.5
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• pp.519-524
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• 2013

This study investigated the effect of breast-feeding in protection against protozoan infection in infants with persistent diarrhea. Infants were classified into 2 groups; 161 breast-fed infants and the same number of non-breast-fed infants. Microscopic examinations of stool were done for detection of parasites and measuring the intensity of infection. Moreover, serum levels of IgE and TNF-${\alpha}$ were measured by ELISA. Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Blastocystis sp. were demonstrated in infants with persistent diarrhea. The percentage of protozoan infections was significantly lower in breast-fed infants than that in the non-breast-fed infants. The levels of IgE and TNF-${\alpha}$ were significantly lower in the breast-fed group than in the non-breast-fed group. There were significant positive associations between the serum levels of IgE and TNF-${\alpha}$ and the intensity of parasite infection in the breast-fed group. It is suggested that breast-feeding has an attenuating effect on the rate and intensity of parasite infection.

• Parasites, Hosts and Diseases
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• v.44 no.2 s.138
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• pp.171-174
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• 2006

The status of intestinal parasitic infections and seroprevalence of cystic echinococcosis in the inhabitants In Dornod and Selenge, Mongolia, was observed with stool and serum samples from 165 and 683 residents from August 9 to August 15, 2003. A total of 10 inhabitants (6.1%) were found to be infected with protozoan cysts or oocysts by stool examinations; 7, 1 and 2 cases with Entamoeba coli, Giardia lamblia and Cryptosporidium parvum, respectively. A total of 62 people (9.1 %) revealed significantly high levels of specific antibodies against Echinococcus granulosus by enzyme-linked immunosorbent assay (ELISA). The surveyed areas are rural areas and the sanitized tab water is not available. There is a possibility of endemic transmission of water-borne protozoan diseases in these areas. The clinical echinococcosis is needed to be searched from the seropositive inhabitants.

• Korean Journal of Poultry Science
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• v.26 no.2
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• pp.131-144
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• 1999

Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria seriously impairs the growth and feed utilization of livestock and poultry. Due to complex life cycle of organism and intricate host immune responses to Elmeria, coccidia vaccine development has been difficult. Understanding of basic imunobiology of pertinent host-parasite interactions is necessary for the development of novel control strategy. Although chickens infected with Eimeria spp. produce parasite-specific antibodies in both the circulation and mucosal secretions, antibody mediated responses play a minor role in protection gainst coccidiosis. Rather, increasing evidence show that cell-mediated immunity plays a major role in resistance to coccidiosis. T-lymphocytes appear to respond to coccidiosis both through cytokine production and a direct cytotoxic attack on infected cells. The exact mechanisms by which T-cells eliminate the parasites, however, remain to be investigated. Since it is crucial to understand the intestinal immune system in order to develop an immunological control strategy against any intestinal immune system in order to develop an immunological control strategy against any intestinal diseases, this presentation will summarize our current understanding of the avian intestinal immune system and mucosal immune responses to Eimeria, to provide a conceptual overview of the complex molecular and cellular events involved in intestinal immune responses to enteric pathogens.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.509-513
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• 1991

Preliminary survey on the prevalence of swine internal parasites was carried out at 91 pens of 4 piggeries being operated by the sawdust fermentation floor system in Kyunggi province. To investigate the effects of viability of eggs., larva and cysts, temperatures at the underlayer of the sawdust floor and rooms of pens were taken three times a day for 8 days. In a pig farm which has been operated by the sawdust fermentation floor system for G years, eggs and larva of Ascaris suum, Trichuris suis, Oesophagostomum sp., Hyostrongylus sp. and Strongyloides ransomi were detected from 42(70.0%) among 60 pens. Cysts and oocysts of coccidia, Balantidium coli, Entamoeba sp. were also detected from 50(83.3%) among 60 pens. In three pig farms which have been operated by the sawdust fermentation floor system for one year, eggs and larva of nematoda were not detected at all, and the contamination rates of protozoan cysts and oocysts was relatively low situation. The change of the temperature in the pig room was variable according to outside condition, whereas that in underfloor was consistently stable between $28^{\circ}C$ to $30^{\circ}C$ which was strictly suitable for the development of eggs, larva and cysts.

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.275-284
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• 1988

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: 1. Of 1,011 inhabitants examined, 398(39.4%) were positive for intestinal parasites. Helminth positives were 372(36.8%) , and protozoan cyst positives were 56(5.5%) . 2. 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%, Ciardia Zamblia 1.5%, Endelimax nasa 0.8%, Hymenolepis nana 0.4%, Hookworm 0.2%, Trichostrongylus orientalis 0,2%, and Entamoeba histolytica 0.2%, respectively. 3. 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. 4. 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. 5. In helminth egg Positive cases, single in(traction 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.

• Korean Journal of Poultry Science
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• v.19 no.3
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• pp.161-176
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• 1992

Coccidiosis is caused by Eimeria infecting primarily the intestine of the susceptible host, thereby seriously impairing the growth and feed utilization of livestock and poultry. The genus Eimeria contains a number of obligate intracellular protozoan parasites with a complicated life-cycle involving both asexual and sexual stages of development. The desire to develop a vaccine against Eimeria has Promoted active research to elucidate the mechanisms of protective immunity and identification of candidate vaccine antigens. Protozoa are unique in their modes of transmission and nature of disease manifestations, the significance of which should be considered in the development of a control strategy. An intricate and complex interplay of different cell populations and cytokines is involved not only in the pathogenesis of coccidiosis but also in the development of protective immunity Thus, comprehensive understanding of the events leading to protection following Eimeria infection will be crucial for the development of an effective vaccine.

• Parasites, Hosts and Diseases
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• v.51 no.5
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• pp.497-502
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• 2013

Autophagy-related protein 8 (Atg8) is an essential component of autophagy formation and encystment of cystforming parasites, and some protozoa, such as, Acanthamoeba, Entamoeba, and Dictyostelium, have been reported to possess a type of Atg8. In this study, an isoform of Atg8 was identified and characterized in Acanthamoeba castellanii (AcAtg8b). AcAtg8b protein was found to encode 132 amino acids and to be longer than AcAtg8 protein, which encoded 117 amino acids. Real-time PCR analysis showed high expression levels of AcAtg8b and AcAtg8 during encystation. Fluorescence microscopy demonstrated that AcAtg8b is involved in the formation of the autophagosomal membrane. Chemically synthesized siRNA against AcAtg8b reduced the encystation efficiency of Acanthamoeba, confirming that AcAtg8b, like AcAtg8, is an essential component of cyst formation in Acanthamoeba. Our findings suggest that Acanthamoeba has doubled the number of Atg8 gene copies to ensure the successful encystation for survival when 1 copy is lost. These 2 types of Atg8 identified in Acanthamoeba provide important information regarding autophagy formation, encystation mechanism, and survival of primitive, cyst-forming protozoan parasites.

• Parasites, Hosts and Diseases
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• v.53 no.5
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• pp.583-595
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• 2015

DEAD/DExH-box RNA helicases catalyze the folding and remodeling of RNA molecules in prokaryotic and eukaryotic cells, as well as in many viruses. They are characterized by the presence of the helicase domain with conserved motifs that are essential for ATP binding and hydrolysis, RNA interaction, and unwinding activities. Large families of DEAD/DExH-box proteins have been described in different organisms, and their role in all molecular processes involving RNA, from transcriptional regulation to mRNA decay, have been described. This review aims to summarize the current knowledge about DEAD/DExH-box proteins in selected protozoan and nematode parasites of medical importance worldwide, such as Plasmodium falciparum, Leishmania spp., Trypanosoma spp., Giardia lamblia, Entamoeba histolytica, and Brugia malayi. We discuss the functional characterization of several proteins in an attempt to understand better the molecular mechanisms involving RNA in these pathogens. The current data also highlight that DEAD/DExH-box RNA helicases might represent feasible drug targets due to their vital role in parasite growth and development.