• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.904-908
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• 2007

The protozoan pathogen Giardia lamblia has been major cause of waterborne enteric disease. In this study, we tried to identify G. lamlbia of human infectious species and to detect viable C. lamblia in river water samples including three sites of Han River mainstream and an its creek using PCR and RT-PCR technique. The PCR/RT-PCR methods were performed by using giardin primer based on the giardin gene targeting ventral disk of Giardia. Sensitivity testing in the DNA/RNA extraction and PCR/RT-PCR amplification steps showed that it was possible to detect a single cyst of G. lamblia and viable G. lamblia. The PCR/RT-PCR methods were compared with immunofluorescence(IF) assay by analyzing 48 samples collected from the mainstream water and the creek water. The mean concentration of the total cysts were 6.3 cysts/10 L(arithmetic mean, n = 48) and the positive detection rate were 62.5%(30/48). And the mean concentration of the cysts excluding empty cysts were 4.5 cysts/10 L and the positive detection rate were 52.1%(25/48). It resulted that 24 of 48 samples included Giardia lamblia by PCR assay and 10 of 48 samples included viable G. lamblia by RT-PCR assay. It resulted that the PCR/RT-PCR technique would be available to river water samples with low concentration of Giardia cysts. And it could support the Korean protozoan standard method, which provides useful information for species and viability.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.21-26
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• 2006

A shuttle vector for Escherichia coli and Giardia lamblia was modified to produce a reporter plasmid, which monitors the expression of prescribed gene in G. lamblia by measuring its luciferase activity. Promoter regions of the gap2 gene, one of the genes induced during encystation, were cloned into this plasmid, and the resultant constructs were then transfected into trophozoites of G. lamblia. Transgenic trophozoites containing one of the 3 gap2-luc reporters were induced to encystation, and characterized with respect to gap2 gene expression by measuring their luciferase activities. Giardia containing a gap2-luc fusion of 112-bp upstream region showed full induction of luciferase activity during encystation.

• Parasites, Hosts and Diseases
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• v.52 no.3
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• pp.299-304
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• 2014

This study aimed to identify the assemblages (or subassemblages) of Giardia duodenalis by using normal or nested PCR based on 4 genetic loci: glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), ${\beta}$-giardin (bg), and small subunit ribosomal DNA (18S rRNA) genes. For this work, a total of 216 dogs' fecal samples were collected in Guangdong, China. The phylogenetic trees were constructed with MEGA5.2 by using the neighbor-joining method. Results showed that 9.7% (21/216) samples were found to be positive; moreover, 10 samples were single infection (7 isolates assemblage A, 2 isolates assemblage C, and 1 isolate assemblage D) and 11 samples were mixed infections where assemblage A was predominant, which was potentially zoonotic. These findings showed that most of the dogs in Guangdong were infected or mixed-infected with assemblage A, and multi-locus sequence typing could be the best selection for the genotype analysis of dog-derived Giardia isolates.

• Parasites, Hosts and Diseases
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• v.58 no.6
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• pp.675-679
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• 2020

MYB2 protein was identified as a transcription factor that showed encystation-induced expression in Giardia lamblia. Although nuclear import is essential for the functioning of a transcription factor, an evident nuclear localization signal (NLS) of G. lamblia MYB2 (GlMYB2) has not been defined. Based on putative GlMYB2 NLSs predicted by 2 programs, a series of plasmids expressing hemagglutinin (HA)-tagged GlMYB2 from the promoter of G. lamblia glutamate dehydrogenase were constructed and transfected into Giardia trophozoites. Immunofluorescence assays using anti-HA antibodies indicated that GlMYB2 amino acid sequence #507-#530 was required for the nuclear localization of GlMYB2, and this sequence was named as NLSGlMYB2. We further verified this finding by demonstrating the nuclear location of a protein obtained by the fusion of NLSGlMYB2 and G. lamblia glyceraldehyde 3-phosphate dehydrogenase, a non-nuclear protein. Our data on GlMYB2 will expand our understanding on NLSs functioning in G. lamblia.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.161-165
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• 2008

This study was performed for the purpose of monitoring monthly levels of two pathogenic microorganisms, Cryptosporidium and Giardia, from November 2005 to August 2007 in Sangsa Lake. Water temperatures, pH and DO fluctuated seasonally at the study site. Annual mean values of BOD, COD and SS were $0.8\;mg\;L^{-1}$, $2.3\;mg\;L^{-1}$ and $1.9\;mg\;L^{-1}$ respectively. Although there was distinct seasonal variation in water chemistry and chlorophyll $\underline{a}$ concentration, the lake generally contains low concentrations of nutrients and chlorophyll $\underline{a}$. The relative abundance of coliform bacteria was always greater than that of fecal coliform. The fecal coliform bacteria comprised $8.5{\sim}22.1%$ of total coliform bacteria. Seasonal analysis of Cryptosporidium and Giardia levels in the study site showed that in winter (November through February), Cryptosporidium oocysts and Giardia cysts were most abundant ($1.1{\sim}1.8\;{\times}\;10\;cells\;L^{-1}$ and $3.8{\sim}5.1\;{\times}\;10\;cells\;L^{-1}$, respectively), while in summer (July through September) the abundance was lowest ($0.0{\sim}0.3\;{\times}\;10\;cells\;L^{-1}$ and $0.9{\sim}2.9\;{\times}\;10\;cells\;L^{-1}$, respectively). Molecular identification revealed two subtypes of Cyrptosporidium parvum in Sangsa Lake.

• Parasites, Hosts and Diseases
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• v.54 no.1
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• pp.1-8
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• 2016

Laboratory workers, in resource-poor countries, still consider PCR detection of Giardia lamblia more costly and more time-consuming than the classical parasitological techniques. Based on 2 published primers, an in-house one-round touchdown PCR-RFLP assay was developed. The assay was validated with an internal amplification control included in reactions. Performance of the assay was assessed with DNA samples of various purities, 91 control fecal samples with various parasite load, and 472 samples of unknown results. Two cysts per reaction were enough for PCR detection by the assay with exhibited specificity (Sp) and sensitivity (Se) of 100% and 93%, respectively. Taking a published small subunit rRNA reference PCR test results (6%; 29/472) as a nominated gold standard, G. lamblia was identified in 5.9% (28/472), 5.2%, (25/472), and 3.6% (17/472) by PCR assay, $RIDA^{(R)}$ Quick Giardia antigen detection test (R-Biopharm, Darmstadt, Germany), and iodine-stained smear microscopy, respectively. The percent agreements (kappa values) of 99.7% (0.745), 98.9% (0.900), and 97.7% (0.981) were exhibited between the assay results and that of the reference PCR, immunoassay, and microscopy, respectively. Restriction digestion of the 28 Giardia-positive samples revealed genotype A pattern in 12 and genotype B profile in 16 samples. The PCR assay with the described format and exhibited performance has a great potential to be adopted in basic clinical laboratories as a detection tool for G. lamblia especially in asymptomatic infections. This potential is increased more in particular situations where identification of the parasite genotype represents a major requirement as in epidemiological studies and infection outbreaks.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.445-446
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• 2000

Disinfection of pathogenic protozoa Giardia has been done by using $TiO_2$ prepared by hydrothermal process. $TiO_2$ suspended in a photoreactor or immobilized on the optical-fiber surface immersed in a photoreactor has been applied with the ultraviolet light. It has been shown that disinfection effect with $TiO_2/UV$ system 2 times as that with only the UV light and disinfection capability of Giardia increased with an increased $TiO_2$ concentration up to 0.1g/L in a $suspended-TiO_2$ reactor.

• Journal of Microbiology
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• v.44 no.3
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• pp.360-362
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• 2006

Cyclospora cayetanensis is an agent of emerging infectious disease, and a recognized cause of diarrhea in some patients. Also, the flagellated protozoan, Giardia intestinalis, induces a diarrheal illness of the small intestine. Cases of cyclosporiasis are frequently missed, primarily due to the fact that the parasite can be quite difficult to detect in human fecal samples, despite an increasing amount of data regarding this parasite. On the other hand, G. intestinalis can be readily recognized via the microscopic visualization of its trophozoite or cyst forms in stained preparations or unstained wet mounts. In this report, we describe an uncommon case of co-infection with G. intestinalis and C. cayetanensis in an immunocompetent patient with prolonged diarrhea, living in a non-tropical region of Turkey.

• Korean Journal of Veterinary Service
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• v.40 no.1
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• pp.61-66
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• 2017

Calf diarrhea is a disease experienced by almost all of calves after birth and is one of the representative causes of damage to farmers due to mass mortality and of economic losses to them by inhibiting normal growth. In this study, we conducted quick detection of etiologic agents of diarrhea by using a rapid diagnostic kit to multiply diagnose antigens of five etiologic agents of calf diarrhea (rotavirus, coronavirus, Escherichia coli, Cryptosporidium, Giardia) in Hanwoo (Korean native cattle) calves. When the positive antigen proportion of the calf diarrheal feces for each farm was analyzed, rotavirus, coronavirus, Escherichia coli, Cryptosporidium, and Giardia showed antigen positive rates of 0~67%, 0~20%, 0~60%, 0~20%, and 0~67%, respectively. With regard to the antigen positive rate by age in days after birth, 1-week-old calves showed the antigen positive rate of 20% in rotavirus and 20% in Giardia, and 2-week-old calves showed that of 50% in rotavirus. In addition, 4-week-old calves showed the antigen positive rate of 10% in rotavirus, 10% in coronavirus, 10% in Escherichia coli, and 30% in Giardia, and 8-week-old calves showed the antigen positive rate of 17% in coronavirus, 50% in Escherichia coli, 17% in Cryptosporidium, and 33% in Giardia. Based on the results of this study, the etiologic agents of diarrhea in Hanwoo calves for each farm are widely distributed. Although younger than 2-week-old calves were strongly positive for rotavirus, older than 4-week-old calves were highly positive for Giardia and Escherichia coli. In conclusion, we considered that a rapid diagnostic kit is an effective method for quick detection of etiologic agents and would be helpful for cattle farmers and veterinarians to select appropriate therapeutic method.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.321-327
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• 2006

This interlaboratory study was designed to evaluate protozoan test methods in water and to predict the major causes of deviation of the methods. Each of four laboratories with previous experience of protozoa analysis in water participated, and met the initial performance criteria of EPA 1623 method provided. The protozoan analysis procedure consists of filtrations, concentration, immunomagnetic separation, dyeing (staining) and counting with observation. We tested three different filtration equipments: capsule filter for 10 L of surface water, and high volume (HV) capsule filter and membrane filter for 100 L of finished water. When the recovery of each step of the procedure was evaluated with EasySeed, the commercial stock of each 100 Cryptosporidium and Giardia, immunomagnetic separation and filtration step were the most crucial steps affecting the stability of the recovery, especially for Cryptosporidium. There was no significant difference of recovery among the filtration methods. Recovery of protozoa from source water were evaluated with spiked EasySeed as matrix tests. The recoveries of Giardia increased significantly in the matrix tests compared those in the deionized water. We also applied red stained mixture stocks of Cryptosporidium and Giardia called ColorSeed as internal standards of water sample tests. The recoveries of both EasySeed and ColorSeed in samples tested were within the range of the criteria, however, the Giardia recoveries using ColorSeed decreased significantly. Further optimization study with ColorSeed will be necessary, considering the convenience of using the internal standard without additional sample analysis. The significant factors of the recovery variation were identified as the differences of laboratories as well as water quality and type of the stock for spiking. The results of this study emphasize the importance of the quality assurance program for protozoan analysis lab in water.