• 한국가금학회지
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• 제19권3호
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• pp.151-160
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• 1992

현재 콕시듐 병의 방제는 약제 투여, 사육관리, 백신을 이용하거나 혹은 이들 방법을 적당히 혼합하여 실시하고 있다. 약제 투여 방법은 약의 내성이라는 문제점을 내재하고 있지만 아직도 콕시듐 방제에 최우선 방법으로 쓰고 있으며 이러한 약제 내성을 조금이나마 지연시키기 위하여 shuttle, 혹은 rotation program을 쓰고 있다. 따라서 약제 내성 검사는 각 농장에 어떠한 약제가 효과가 있는지를 알아보는데 가장 중요한 방법이 되어 왔던 것이다. 콕시듐 방제에 있어서 사육관리에 의한 방법은 아직은 완전한 효과적인 방법으로 정착되지 않았는데 그 이우는 소독제만으로는 콕시듐의 원충을 죽일 수 없기 때문이다. 백신에 의한 방법은 현재까지 살아있는 콕시듐 원충을 제한적으로 쓰고 있는 단계이다. 새로운 형태의 백신개발이 요즈음 연구가 되고 있는데 이 백신은 순화시킨 콕시듐 원충을 사용하거나 유전공학적 방법 혹은 원충의 일부분에 대한 항원을 추출하여 백신으로 이용하는 것이다.

• 한국가금학회지
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• 제26권2호
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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.

• 대한의생명과학회지
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• 제17권3호
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• pp.173-176
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• 2011

Free-living Acanthamoeba are eukaryotic protozoan organisms that are widely distributed in the air, water, etc such as environment. Acanthamoeba ingest the Escherichia coli which will replicate in cytoplasm of Acanthamoeba. Bacterial pathogenicity or virulence is one of important determinant factors to survive in free-living Acanthamoeba and otherwise Acanthamoebic pathogenicity is also an important factor for their interactions. Bacterial association with pathogenic strain of Acanthamoeba T1 and T4 was lower about two times than non-pathogenic T7. Bacterial invasion percentages into T1 were higher about three times than T7 but bacterial survival in T7 was increased as T1. The capsule-deletion mutant exhibited limited ability for invasion/uptake by and survival inside pathogenic Acanthamoeba T4. E. coli-outer membrane protein A (OmpA) decreased bacterial association with A. castellanii by about three times and it had higher effects than lipopolysaccharides (LPS). Under favorable conditions, the mutants were not survived in Acanthamoeba up to 24 h incubation. Therefore, this review will report pathogenic and non-pathogenic Acanthamoeba strains interactions with E. coli and its several mutants, i.e., capsule, OmpA and LPS.

• Parasites, Hosts and Diseases
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• 제55권2호
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• pp.129-135
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• 2017

A total of 60 samples were collected from 35 swimming pools in Beijing, China, and the presence of Cryptosporidium and Giardia were investigated. The results showed that 16.7% and 15.0% of samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively, with a mean concentration of 0.30 oocysts/10 L and 0.27 cysts/10 L. The oocysts and cysts were found to have higher rates of occurrence in August than in May. Genotyping confirmed the presence of Cryptosporidium hominis, C. parvum, and Giardia assemblages A and B, all of which were associated with human infections. The predominant species/assemblages were C. hominis and Giardia assemblage A. Analyses of the relationships between parasite oocysts/cysts, indicator bacteria, and physical-chemical parameters revealed that there was no correlation between 2 parasites and fecal bacterial indicators, whilst there was a significant correlation between protozoa and urea concentration, which indicates that urea concentration rather than fecal bacterial indicators might be an appropriate index for chlorine-resistant protozoa in swimming pools. This study provides useful information to improve the safety of swimming pool water and deduce the risk of protozoan infections.

• 한국미생물·생명공학회지
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• 제14권2호
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• pp.133-137
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• 1986

원생동물인 Tetrahymena thermophila의 17S-rDNA구조 및 hygromycin 내성 기구에 대한 연구의 일부로서 hygromycin 내성변이주 hmr3의 17S-rDNA를 대장균의 vector pBR 322에 cloning하였다. 우선 rDNA는 hot phenol-cresol 용액으로 추출하여 제한효소 Hind III 처리로서 약 2.2kbp의 17S-rDNA를 agarose 전기영동상에서 분리하였다. 이를 pBR 322에 cloning하여 wild type의 17S-rDNA probe와 colony hybridization시켜 선별하였다. 그중 5-19 균주의 recombinant plasmid로부터 17S-rDNA 의 전사 orientation위치가 pBR322의 tetracyline내성 유전자 쪽으로 삽입되어 있는 것을 확인하였다.

• 한국식품위생안전성학회지
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• 제7권2호
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• pp.107.2-119
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• 1992

Fish pathology is one of the main scientific bases upon which this expansion in aquaculture has been dependent and requires a wide knowledge of the environmental constraints, the physiology and characteristic of the various pathogens, the responses of the host, and the methods by which they may be controlled. The primary disease and parasite problems in aquaculture animals related to viral, bacteria, fungal and protozoan epizootics. Parasitic nematodes, trematodes and cestodes are commonly found in aquaculture animals, but seldom are they present in concentrations sufficient to cause significant problems, When an epizootic does occur and chemical treatment is indicated, the appropriate chemical must be selected an properly applied. We have antibiotics, sulfa, nitrofuran and other chemicals for treatment of fish diseases, Some may be mixed with the feed during formulation, added to the pellets of feed as a surface coating, given in the form of an injection or used as a bath. Even though a drug or chemical has been officially approved for use in aquaculture, the substance should never be used unless there is a clear need, Some of the reasions for this view are as follows: (1) the constant use of antibiotics can leak to the development of resistant strains of bacteria, (2) biofilter efficiency may be impaired or destroyed by chemicals added to closed recirculating water systems, and(3) the injudicious use of chemical can have a damaging effect on the environment as well as on human.

• Journal of Yeungnam Medical Science
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• 제34권1호
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• pp.96-100
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• 2017

Amebic liver abscess (ALA) is the most common extraintestinal manifestation of amebiasis. Amebiasis, a parasitic infection caused by Entamoeba histolytica, used to be a prevalent protozoan disease in Korea, however, with an improving sanitary system, it has been among very uncommon etiology of liver abscess. A recent report suggested that ALA is an emerging parasitic infection in human immunodeficiency virus (HIV)-infected patients even in areas where the disease is not endemic and recommended HIV screening in patients in areas where ALA is not endemic, particularly those without history of travel to a disease-endemic area. We report on two patients who were admitted for treatment of ALA and then diagnosed as HIV infection. We also reviewed the etiology and characteristics of ALA in our hospital during the last 5 years.

• 한국동물위생학회지
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• 제39권1호
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• pp.21-28
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• 2016

Protozoan parasite, the genus Eimeria, causes an intestinal disease, coccidiosis, in young broilers. Coccidiosis induces significant economic loss in poultry production. This study was designed to identify the prevalence of Eimeria spp. in broilers in Gyeonggi province, Korea. Fecal samples from broilers at 94 farms were collected in two chicken slaughterhouses between March and June 2015. Eimeria infection was determined by microscopic examination and PCR using ITS-1 region. The prevalence of Eimeria was 58.5% (55 of 94). E. acervulina was identified in 96.4% of samples, E. tenella in 81.8%, E. maxima in 12.7%, E. praecox in 12.7%, E. brunetti in 5.5%, E. necatrix in 1.8%, and E. mitis in 1.8%. Body weight (BW) of broilers infected with both E. tenella and E. acervulina ($mean=1.53{\pm}0.19^Bkg$) was significantly lower than broilers with E. acervulina positive/E. tenalla negative ($mean=1.74{\pm}0.07^Akg$) or Eimeria negative ($mean=1.65{\pm}0.15^Akg$) (Duncan's multiple range test, P<0.01). High prevalence of Eimeria tenella and the impact on the broiler body weight shows the importance of this protozoa in broiler industry. Development of the periodic monitoring strategy and systemic management for the purpose of the prevention/eradication of Eimeria infection among broilers is required.

• Parasites, Hosts and Diseases
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• 제52권6호
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• pp.581-593
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• 2014

Toxoplasmosis is an opportunistic infection caused by the protozoan parasite Toxoplasma gondii. T. gondii is widespread globally and causes severe diseases in individuals with impaired immune defences as well as congenitally infected infants. The high prevalence rate in some parts of the world such as South America and Africa, coupled with the current drug treatments that trigger hypersensitivity reactions, makes the development of immunotherapeutics intervention a highly important research priority. Immunotherapeutics strategies could either be a vaccine which would confer a pre-emptive immunity to infection, or passive immunization in cases of disease recrudescence or recurrent clinical diseases. As the severity of clinical manifestations is often greater in developing nations, the development of well-tolerated and safe immunotherapeutics becomes not only a scientific pursuit, but a humanitarian enterprise. In the last few years, much progress has been made in vaccine research with new antigens, novel adjuvants, and innovative vaccine delivery such as nanoparticles and antigen encapsulations. A literature search over the past 5 years showed that most experimental studies were focused on DNA vaccination at 52%, followed by protein vaccination which formed 36% of the studies, live attenuated vaccinations at 9%, and heterologous vaccination at 3%; while there were few on passive immunization. Recent progress in studies on vaccination, passive immunization, as well as insights gained from these immunotherapeutics is highlighted in this review.

• Parasites, Hosts and Diseases
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• 제54권4호
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• pp.461-469
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• 2016

Giardia lamblia is a protozoan that causes diarrheal diseases in humans. Cytoskeletal structures of Giardia trophozoites must be finely reorganized during cell division. To identify Giardia proteins which interact with microtubules (MTs), Giardia lysates were incubated with in vitro-polymerized MTs and then precipitated by ultracentifugation. A hypothetical protein (GL50803_8405) was identified in the precipitated fraction with polymerized MTs and was named GlMBP1 (G. lamblia microtubule-binding protein 1). Interaction of GlMBP1 with MTs was confirmed by MT binding assays using recombinant GlMBP1 (rGlMBP1). In vivo expression of GlMBP1 was shown by a real-time PCR and western blot analysis using anti-rGlMBP1 antibodies. Transgenic G. lamblia trophozoites were constructed by integrating a chimeric gene encoding hemagglutinin (HA)-tagged GlMBP1 into a Giardia chromosome. Immunofluorescence assays of this transgenic G. lamblia, using anti-HA antibodies, revealed that GlMBP1 mainly localized at the basal bodies, axonemes, and median bodies of G. lamblia trophozoites. This result indicates that GlMBP1 is a component of the G. lamblia cytoskeleton.