• 한국패류학회지
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• 제29권2호
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• pp.147-154
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• 2013

In Incheon bay, mass mortalities of Manila clam associated with winter storms have been reported. In the present study we have monitored pathologic condition of the clams stranded on the tidal flats by the winter storms occurred in late March to early April in 2007. The field surveyed indicated that mortality of the Manila clam in the study areas ranged 10-15%. Condition index, a ratio of tissue weight to the shell weight, of the stranded clams was significantly lower than the non-stranded normal clams collected from the same locations (p < 0.05), indicating that the stranded clams were comparatively in poor physiological condition. Perkinsus olseni, the protozoan parasite was observed most of clams used in the analysis and the infection prevalence ranged 77-90%. The infection intensity of P. olseni determined using Ray's fluid thioglycollate medium (RFTM) cultivation and the 2M NaOH digestion assay indicated that the clams collected during late March and early April in 2007 involved 67,182-1,124,727 P. olseni cells/g tissue. The infection intensity of clams from Gung-Pyeung was significantly higher than the intensities observed from Dae-Bu and Young-Heung (p < 0.05). No clear correlation was found between the infection intensities of P. olseni in the non-stranded normal clams and the stranded clams. The stranded Manila clams were also infected with trematode parasite with the prevalence ranged 5 (Young-Heung) to 12.5% (Dae-Bu). The trematode-infected clams exhibited castrated follicles in the gonad, a typical sign of trematode infection. It was believed that mass mortality of Manila clam observed in this study was associated with the poor physiological condition as indicated by CI, although impacts of the parasite infection cannot be ruled out.

• Parasites, Hosts and Diseases
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• 제52권6호
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• pp.613-619
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• 2014

Neospora caninum (Apicomplexa; Sarcocystidae) is a protozoan that causes abortion in cattle, horses, sheep, and dogs as well as neurological and dermatological diseases in dogs. In the central nervous system of dogs infected with N. caninum, cysts were detected that exhibited gliosis and meningitis. Flavonoids are polyphenolic compounds that exhibit antibacterial, antiparasitic, antifungal, and antiviral properties. In this study, we investigated the effects of flavonoids in a well-established in vitro model of N. caninum infection in glial cell cultures. Glial cells were treated individually with 10 different flavonoids, and a subset of cultures was also infected with the NC-1 strain of N. caninum. All of the flavonoids tested induced an increase in the metabolism of glial cells and many of them increased nitrite levels in cultures infected with NC-1 compared to controls and uninfected cultures. Among the flavonoids tested, 3',4'-dihydroxyflavone, 3',4',5,7-tetrahydroxyflavone (luteolin), and 3,3',4',5,6-pentahydroxyflavone (quercetin), also inhibited parasitophorous vacuole formation. Taken together, our findings show that flavonoids modulate glial cell responses, increase NO secretion, and interfere with N. caninum infection and proliferation.

• Parasites, Hosts and Diseases
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• 제56권4호
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• pp.325-334
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• 2018

Toxoplasma gondii is an apicomplexan zoonotic protozoan parasite that infects most species of warm-blooded animals, including humans. The heavy incidence and severe or lethal damage caused by T. gondii infection clearly indicate a need for the development of an effective vaccine. T. gondii GRA8 is a member of the dense granules protein family and is used as a marker of acute infection. In the present study, we evaluated the protective immunity induced by DNA vaccination based on a recombinant eukaryotic plasmid, pDsRed2-GRA8, against acute toxoplasmosis in mice. BALB/c mice were intramuscularly immunized with the pDsRed2-GRA8 plasmid and then challenged by infection with the highly virulent GFP-RH strain of T. gondii. The specific immune responses and protective efficacy against T. gondii of this vaccine were analyzed by measuring cytokine and serum antibody titers, splenocyte proliferation assays, and the survival times of mice after challenge. Our results showed that mice immunized with pDsRed2-GRA8 demonstrated specific humoral and cellular responses, induced higher IgG antibody titers with predominant IgG2a production; increased levels of IL-10, IL-12 (p70), $IFN-{\gamma}$, $TNF-{\alpha}$, and splenocyte proliferation; and prolonged survival times compared to those of control mice. The present study showed that DNA immunization with pDsRed2-GRA8 induced humoral and cellular immune responses, and all immunized mice showed greater Th1-type immune responses and longer survival times than those of control mice. These results indicated that T. gondii GRA8 DNA immunization induces a partial protective effect against acute toxoplasmosis.

• Parasites, Hosts and Diseases
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• 제29권2호
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• pp.129-138
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• 1991

자유생활 담수 섬모충류의 일종인 Tetrahymenn Pyriformis는 비특이적으로 복강 대식세포를 활성화하여 미생물 살멸효과가 있음이 밝혀졌으나 한국에서 순수분리 배양된 GL주(주)에 대한 평가는 시행된 바 없어 본 섬모충의 추출액을 ICR 마우스 복강 내로 주사하여 복강 대식세포를 활성화한 다음 실험실 내에서 표적 기생 원충인 Toxoplasma gondii (RH 주)를 접촉시켜 시간별로 Togoplasma 살멸 효과를 보아 대식세포의 환성도를 평가하였던 바 다음과 같은 결론을 얻었다. 표적 기생 원충으로서 살아있는 Toxoplasma 영양형을 주입하였을 경우, 대식세포 활성제 처리 실험군은 물론 대조군에서도 모두 처리 1분 이내에 Toxoplasma가 숙주세포내로 침입 내지 탐식되었으며 이때 탐식지수 범위는 15∼51%였다. 대조군에서는 배양 시간에 따라 100개의 대식세포당 총 탐식 표적 기생충 수가 증가하였으나 활성제 처리군에서는 배양 20시간에 그 수가 모두 줄었고 Tetrahymena 처리군에서는 총 표적 기생충 수가 14, 탐식지수 10%로서 가장 왕성한 대식세포 활성도를 나타내었다. 화학 함성 활성제로서는 dimethyldioctadecylammonium bromide (DDA)가 Tetrakymena와 대차 없는 대식세포 활성효과를 보였다. 표적 기생 편충으로서 열처리 Tonxplasma 영양형을 주입하였을 경우, 대조군을 포함한 모든 실험군에서 처리 1분 이내에 역시 Toxoplasma 가 숙주 세포에 의해 탐식되었으며 탐식지수 범위는 8∼25%여서 살아있는 영양형을 처리하였을 때보다 낮은 범위를 보였다. 이때 Tetrakymena 처리군에서는 탐식지수 4%, 대식세포 100개당 표적 세포 총수가 4로서 Texoplasma 추출액 처리군과 함께 가장 우수한 활성제로 평가되었으며 화학합성 활성제로서는 DDA, dextran sulfate, complete Freund's adjutant 순으로 환성 효과가 높았다 이상의 결과로 보아 T. pyriformis (GL 주)는 화학합성 활성제보다 우수한 Toxoplasma 살멸 효과를 나타내었고, 실험실 내에서 대량 무균 배양될 수 있어 앞으로 대식세포 활성제로서, 나아가 Toxopzasma 감염 억제제로서 널리 이용될 가능성이 있을 것으로 생각되었다.

• Parasites, Hosts and Diseases
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• 제35권2호
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• pp.79-86
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• 1997

톡소포자충의 숙주-기생충 상호관계 연구의 일환으로 마우스 비장에서 분리한 T 림프구. B 림프 구 및 과립구(대부분 호중구로 구성)에 톡소포자층의 tachyzoites를 감염시킨 후 감염된 림프구와 호중구의 미세형태 변화를 관찰하는 한편 각 세포의 충체 감염에 대한 감수성을 동위원소 흡수시 험법을 이용하여 정량화하였다. 충체는 병원성이 강한 RH 주를 샤용하였고 각 세포는 BALB/c와 CBA 마우스의 비장에서 분리하여 사용하였다. 감염 후 24시간에 관찰한 결과, T 림프구, B 림프 구 및 호중구는 마우스 주에 상관없이 세포질 내에 tachyzoites가 한 개, 두 개 또는 7-8개까지 관찰되었다. 감염된 T 림프구는 충체 주변에 형성죈 parasitophorous vacuole로 인해 핵이 한 쪽으로 밀리며. 미토콘드리아의 수가 증가하였다 감염된 B 림프구는 조내형질세망(RER)이 대조군에 비해 발달하지 않았으며 감염된 호중구는 과립의 수가 현저히 감소하였다 림프구와 호중구의 톡소포자충 감염에 대한 감수성을 3H-uracil 흡수량으로 정량화한 결과. 마우스 주에 따른 차이는 없었고 모든 종류의 세포 내에서 충체가 활발히 증식함이 확인되었다. 이상의 결과로 볼 때, BALB/c와 CBA 마우스의 비장 T 림프구, B 림프구 및 호중구는 모두 톡소포자충의 tachyzoites 감염에 대해 감수성이 높음을 알 수 있었고, 감염된 면역세포는 그 기능이 저하될 것으로 추측된다.

• Parasites, Hosts and Diseases
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• 제55권5호
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• pp.523-532
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• 2017

A field survey studying intestinal parasites in humans and microbial pathogen contamination at environment was performed in a Laotian rural village to identify potential risks for disease outbreaks. A parasitological investigation was conducted in Ban Lak Sip village, Luang Prabang, Lao PDR involving fecal samples from 305 inhabitants as well as water samples taken from 3 sites of the local stream. Water analysis indicated the presence of several enteric pathogens, i.e., Aeromonas spp., Vibrio spp., E. coli H7, E. coli O157: H7, verocytotoxin-producing E. coli (VTEC), Shigella spp., and enteric adenovirus. The level of microbial pathogens contamination was associated with human activity, with greater levels of contamination found at the downstream site compared to the site at the village and upstream, respectively. Regarding intestinal parasites, the prevalence of helminth and protozoan infections were 68.9% and 27.2%, respectively. Eight helminth taxa were identified in fecal samples, i.e., 2 tapeworm species (Taenia sp. and Hymenolepis diminuta), 1 trematode (Opisthorchis sp.), and 5 nematodes (Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, trichostrongylids, and hookworms). Six species of intestinal protists were identified, i.e., Blastocystis hominis, Cyclospora spp., Endolimax nana, Entamoeba histolytica/E. dispar, Entamoeba coli, and Giardia lamblia. Questionnaires and interviews were also conducted to determine risk factors of infection. These analyses together with a prevailing infection level suggested that most of villagers were exposed to parasites in a similar degree due to limited socio-economic differences and sharing of similar practices. Limited access to effective public health facilities is also a significant contributing factor.

• Parasites, Hosts and Diseases
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• 제51권3호
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• pp.269-277
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• 2013

Amoebic keratitis (AK) caused by Acanthamoeba is one of the most serious corneal infections. AK is frequently misdiagnosed initially as viral, bacterial, or fungal keratitis, thus ensuring treatment delays. Accordingly, the early detection of Acanthamoeba would contribute significantly to disease management and selection of an appropriate anti-amoebic therapy. Recently, the loop-mediated isothermal amplification (LAMP) method has been applied to the clinical diagnosis of a range of infectious diseases. Here, we describe a rapid and efficient LAMP-based method targeting Acanthamoeba 18S rDNA gene for the detection of Acanthamoeba using clinical ocular specimens in the diagnosis of AK. Acanthamoeba LAMP assays detected 11 different strains including all AK-associated species. The copy number detection limit for a positive signal was 10 DNA copies of 18S rDNA per reaction. No cross-reactivity with the DNA of fungi or other protozoa was observed. The sensitivity of LAMP assay was higher than those of Nelson primer PCR and JDP primer PCR. In the present study, LAMP assay based on directly heat-treated samples was found to be as efficient at detecting Acanthamoeba as DNA extracted using a commercial kit, whereas PCR was only effective when commercial kit-extracted DNA was used. This study showed that the devised Acanthamoeba LAMP assay could be used to diagnose AK in a simple, sensitive, and specific manner.

• 대한수의학회지
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• 제37권3호
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• pp.583-593
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• 1997

Indirect fluorescent antibody test(IFAT) and enzyme-linked imuunosorbent assay (IgG-ELISA) as serological diagnostic tools were conducted to evaluate the usefulness for diagnosis of canine babesiosis infected with Babesia gibsoni in domestic various dog breeds, american pit bullterrier, military shepherd, and mongrel dogs. The results obtained from this study were abstracted as follows. The nonionic detergent Triton X-100 and absorbent bio-bead $SM_2$ were useful reagents for the preparation of pure merozoite antigen of B gibsoni to be used in ELISA. The optimum reaction in ELISA was shown when the protein concentration of ELISA antigen was measured as 625ng/ml and the conjugate concentration was diluted into 1/6000 fold. The average OD value of ELISA in sera determined with negative responses in IFAT was measured as $0.255{\pm}0.051$(490nm) and the cut - off value of OD was determined as 0.399(490nm). The serum antibodies in both of IFAT and ELISA were detected on one week after artificially infected with B gibsoni and these high antibody titers, 512X in IFAT and 1024X in ELISA, were long lasted until 15 weeks after infection. The reproducibility of reaction and stability of the antigen absorbed microtitration polystyrene plate preserved in $4^{\circ}C$ refrigerator and $-20^{\circ}C$ freezer, respectively could be lasted until 135 days after storage. The positive rates in IFAT by dog breeds were shown 8.1%(60/744 heads) in mongrel dogs, 81.3%(78/96 heads) in american pit bullterrier and 15.6%(15/96 heads) in military shepherd, while the positive rate in ELISA shown 17.6%(131/744 heads) in mongrel dogs, 83.3%(80/96 heads) in american pit bullterrier and 36.5%(35/96 heads) in military shepherd, respiectively. In the total of 936 heads surveyed with IFAT and ELISA the positive rates in IFAT and ELISA were 16.4%(153/936 heads) and 26.3%(246/936 heads), respectivily. Agreement of reactions between IFAT and ELISA was shown 82.4% in 936 dog sera. The specificity and sensitivity of ELISA reaction were 83.5% and 76.5%, respectively. From the conclusion obtained in this study it was evaluated that IFAT and ELISA were useful as highly specific, sensitive and stable serelogical tools for the diagnosis of canine babesiosis in Korea.

• Parasites, Hosts and Diseases
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• 제26권4호
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• pp.229-238
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• 1988

HL-60세포에서 Toxoplasma gondii의 in vitro배양과 HL-60세포를 DMSO로 처리하여 과립세포로 분화시킨 세포에서 Toxoplasma에 대한 세포매개성 면역 기능을 검토하였다. 먼저, HL-60 세포를 여러 농도의 DMSO로 처리하였는데, 1.3%(V/V)로 3일간 처리하였을 때, HL-60 세포 의 적정 분화가 이루어졌다. 분화의 정도는 형태적, 생리적, 및 기능적 관점에서 검사되었는데, DMSO를 처리한 경우, 3H-thymidine의 흡입이 감소하는 것으로 보아 DNA 합성이 억제됨을 알 수 있었으며, 기능적으로는 주화성 물질인 FMLP에 대해 이동하는 성질을 보였으며, 형태적으로는 핵1세포질의 비가 큰 promyelocyte에서 작은 비를 갖는 과립 세포로 변화하여 분화를 입증하였다. 이후, HL-60 세포나 DMSO로 분화를 유도한 HL-60 세포와 Toxoplasma를 같이 배양하면서 이들의 관계를 관찰하였다. Lysosome에 선택적으로 흡입되는 형광 물질(acridine orange)로 전처리한 표본은 형광현미경하에 서 관찰하였으며, 다른 표본은 Giemsa로 염색하여 광학 현미경하에서 관찰하여 비교하였다. HL-60 세포에서는 72시간의 배양으로 Toxoplasma가 세포질내에서 증식하여 rosette를 형성하였으며, DMSO로 분화시킨 HL-60 세 포에서는 배양 초기 1시간째에 phagocytosis가 일어났으며 이후 세포내 소화가 이루어져 72시간째에는 lysosome이 원상태로 되돌아오는 것이 관찰되었다. 이상의 결과들로 볼 때, Toxoplnsma의 숙주 세포내에서의 기생 혹은 면역 세포에 의한 감수성에 phagosome 과 Iysosome의 융합이 결정적인 인자임을 알 수 있었으며, 아울러 HL-60 세포에서의 Toxoplasma의 증식 가능성과 DMSO로 분화시킨 HL-60 세포의 Toxoplasma 파괴 효과가 원충 기생충과 숙주의 상호 관계를 규명하는 좋은 모델임을 제시하였다.

• Parasites, Hosts and Diseases
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• 제52권3호
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• pp.305-310
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• 2014

Ascidian soft tunic syndrome (AsSTS) caused by Azumiobodo hoyamushi (A. hoyamushi) is a serious aquaculture problem that results in mass mortality of ascidians. Accordingly, the early and accurate detection of A. hoyamushi would contribute substantially to disease management and prevention of transmission. Recently, the loop-mediated isothermal amplification (LAMP) method was adopted for clinical diagnosis of a range of infectious diseases. Here, the authors describe a rapid and efficient LAMP-based method targeting the 18S rDNA gene for detection of A. hoyamushi using ascidian DNA for the diagnosis of AsSTS. A. hoyamushi LAMP assay amplified the DNA of 0.01 parasites per reaction and detected A. hoyamushi in 10 ng of ascidian DNA. To validate A. hoyamushi 18S rDNA LAMP assays, AsSTS-suspected and non-diseased ascidians were examined by microscopy, PCR, and by using the LAMP assay. When PCR was used as a gold standard, the LAMP assay showed good agreement in terms of sensitivity, positive predictive value (PPV), and negative predictive value (NPV). In the present study, a LAMP assay based on directly heat-treated samples was found to be as efficient as DNA extraction using a commercial kit for detecting A. hoyamushi. Taken together, this study shows the devised A. hoyamushi LAMP assay could be used to diagnose AsSTS in a straightforward, sensitive, and specific manner, that it could be used for forecasting, surveillance, and quarantine of AsSTS.