• Journal of Veterinary Science
• /
• 제25권2호
• /
• pp.28.1-28.11
• /
• 2024

Background: Porcine circovirus type 2 (PCV2) infection is ubiquitous around the world. Diagnosis of the porcine circovirus-associated disease requires clinic-pathological elements together with the quantification of viral loads. Furthermore, given pig farms in regions lacking access to sufficient laboratory equipment, developing diagnostic devices with high accuracy, accessibility, and affordability is a necessity. Objectives: This study aims to investigate two newly developed diagnostic tools that may satisfy these criteria. Methods: We collected 250 specimens, including 170 PCV2-positive and 80 PCV2-negative samples. The standard diagnosis and cycle threshold (Ct) values were determined by quantitative polymerase chain reaction (qPCR). Then, two point-of-care (POC) diagnostic platforms, convective polymerase chain reaction (cPCR, qualitative assay: positive or negative results are shown) and EZtargex (quantitative assay: Ct values are shown), were examined and analyzed. Results: The sensitivity and specificity of cPCR were 88.23% and 100%, respectively; the sensitivity and specificity of EZtargex were 87.65% and 100%, respectively. These assays also showed excellent concordance compared with the qPCR assay (κ = 0.828 for cPCR and κ = 0.820 for EZtargex). The statistical analysis showed a great diagnostic power of the EZtargex assay to discriminate between samples with different levels of positivity. Conclusions: The two point-of-care diagnostic platforms are accurate, rapid, convenient and require little training for PCV2 diagnosis. These POC platforms can discriminate viral loads to predict the clinical status of the animals. The current study provided evidence that these diagnostics were applicable with high sensitivity and specificity in the diagnosis of PCV2 infection in the field.

• Parasites, Hosts and Diseases
• /
• 제56권2호
• /
• pp.113-119
• /
• 2018

Cryptosporidium species is an important cause of gastrointestinal infections globally. This study aimed to shed light on its role in diarrheic immunocompetent patients in Beni-Suef, Egypt and to compare three diagnostic methods. Two hundred diarrheic patients, $37{\pm}16.8year$ old, were enrolled. Stool samples were examined by light microscopy, using modified Ziehl-Neelsen stain (MZN) for Cryptosporidium spp. oocysts. Coproantigens were detected by sandwich ELISA. DNA molecular diagnosis was done by nested PCR. PCR yielded the highest detection rates (21.0%), compared to ELISA (12.5%) and MZN staining method (9.5%). The higher infection rates were in 20-40 year-old group, followed by 40-60 year-old. Association between epidemiologic factors was statistically not significant; positivity and gender, clinical manifestations, residence, source or water, or contact with animals. Cryptosporidiosis is an important enteric parasitic infection in Beni-Suef and PCR remains the gold standard for diagnosis.

• 식물병연구
• /
• 제20권3호
• /
• pp.173-181
• /
• 2014

The early and accurate detection of plant viruses is an essential component to control those. Because the globalization of trade by free trade agreement (FTA) and the rapid climate change promote the country-to-country transfer of viruses and their hosts and vectors, diagnosis of viral diseases is getting more important. Because symptoms of viral diseases are not distinct with great variety and are confused with those of abiotic stresses, symptomatic diagnosis may not be appropriate. From the last three decades, enzyme-linked immunosorbent assays (ELISAs), developed based on serological principle, have been widely used. However, ELISAs to detect plant viruses decrease due to some limitations such as availability of antibody for target virus, cost to produce antibody, requirement of large volume of sample, and time to complete ELISAs. Many advanced techniques allow overcoming demerits of ELISAs. Since the polymerase chain reaction (PCR) developed as a technique to amplify target DNA, PCR evolved to many variants with greater sensitivity than ELISAs. Many systems of plant virus detection are reviewed here, which includes immunological-based detection system, PCR techniques, and hybridization-based methods such as microarray. Some of techniques have been used in practical, while some are still under developing to get the level of confidence for actual use.

• The Plant Pathology Journal
• /
• 제27권4호
• /
• pp.385-389
• /
• 2011

A new reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for the Potato leafroll virus (PLRV) was developed and compared with conventional reverse transcription polymerase chain reaction (RT-PCR) to address its advantages over RTPCR. RT-LAMP primers were designed from the open reading frame 3 (ORF3) sequence of PLRV. The RT-LAMP reactions were conducted without or with a set of loop primers. By real-time monitoring using Turbimeter, the RT-LAMP (with loop primers) detects PLRV in less than 30 min, compared to 120 min of RT-PCR. By adding fluorescent reagent during the reaction, final products of the RT-LAMP were fluorescently visualized under UV light or could be differentiated by naked-eye inspection under normal light. The RT-LAMP was extremely sensitive, about 2000-fold more sensitive than RT-PCR. This study presents great potential of the RT-LAMP for diagnosis and PLRV epidemiology because RT-LAMP method is speedy, sensitive, inexpensive, and convenient.

• 한국어병학회지
• /
• 제21권3호
• /
• pp.181-188
• /
• 2008

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to detect and identify four fish viruses, fish iridovirus, viral hemorrhagic septicaemia virus (VHSV), viral nervous necrosis virus (VNNV), hirame rhabdovirus (HRV). Four viruses were detected by PCR with each specific primers. Identification of iridovirus was achieved by digesting the PCR amplified fragment with a restriction enzyme ApaⅠ. It was possible to distinguish positive from false positive PCR amplicons of VHSV by RFLP of PstⅠ or HindⅢ restriction enzymes. VNNV was identified using RFLP of BamHⅠrestriction enzyme and HRV was identified by XbaⅠ restriction enzyme. This approach can be used for more rapid, simple and specific diagnosis of fish viral diseases.

• Parasites, Hosts and Diseases
• /
• 제55권6호
• /
• pp.601-606
• /
• 2017

Cystoisospora is responsible for morbidity in immunocompromised patients. PCR is sensitive for diagnosing Cystoisospora; however, it needs reevaluation for differential molecular diagnosis of cystoisosporiasis. We aimed at evaluating melting curve analysis (MCA) after real-time PCR (qPCR) in diagnosis and genotyping of Cystoisospora as an alternative to conventional PCR. We included 293 diarrheic stool samples of patients attending the Department of Clinical Oncology and Nuclear Medicine of Cairo University Hospitals, Egypt. Samples were subjected to microscopy, nested PCR (nPCR), and qPCR targeting the internal transcribed spacer 2 region (ITS2) of the ribosomal RNA (r RNA) gene followed by melting temperatures ($T_ms$) analysis and comparing the results to PCR-RFLP banding patterns. Using microscopy and ITS2-nPCR, 3.1% and 5.8% of cases were Cystoisospora positive, respectively, while 10.9% were positive using qPCR. Genotyping of Cystoisospora by qPCR-MCA revealed 2 genotypes. These genotypes matched with 2 distinct melting peaks with specified $T_ms$ at $85.8^{\circ}C$ and $88.6^{\circ}C$, which indicated genetic variation among Cystoisospora isolates in Egypt. Genotype II proved to be more prevalent (65.6%). HIV-related Kaposi sarcoma and leukemic patients harbored both genotypes with a tendency to genotype II. Genotype I was more prevalent in lymphomas and mammary gland tumors while colorectal and hepatocellular tumors harbored genotype II suggesting that this genotype might be responsible for the development of cystoisosporiasis in immunocompromised patients. Direct reliable identification and differentiation of Cystoisospora species could be established using $qPCR-T_ms$ analysis which is useful for rapid detection and screening of Cystoisospora genotypes principally in high risk groups.

• 대한수의학회지
• /
• 제41권4호
• /
• pp.535-542
• /
• 2001

A multiplex PCR technique was developed for detecting specifically each Mycobacterium bovis, M. tuberculosis, M. avium and M. avium subsp, paratuberculosis, respectively, using clinical samples of field cattle. To apply this novel technique to clinical specimens, blood sample was obtained from live cows comprising 11 intradermal tuberculin test (ITT)-positive and 17 ITT-negative and tested by multiplex PCR. Positive results were obtained from 15 cows by the multiplex PCR, showing that 4 (23.5%) of the 17 ITT-negative cows were multiplex PCR positive. The multiplex PCR results also showed that among the 15 positive cows, 7 (46.7%) were infected with M. bovis, 1 (6.7%) with M. tuberculosis and 7 (46.7%) with M. avium. The sensitivity and specificity of multiplex PCR in comparison with those of ITT were 100% and 76.5%. The correlation between the multiplex PCR and ITT assays with blood samples was considered excellent, 85.7% agreement and ${\kappa}=0.72$. The results obtained, using reference mycobacterial strains and typed clinical samples, show that the multiplex PCR method may be a rapid, sensitive, and specific tool for the differential identification of various mycobacterial strains in a single-step assay. Therefore, multiplex PCR assay is a useful tool for early diagnosis of tuberculosis in live cattle and to identify the species or complex of mycobacterium from clinical samples.

• 한국어병학회지
• /
• 제37권1호
• /
• pp.147-153
• /
• 2024

The World Organization for Animal Health (WOAH) recommends two protocols (ITS and COI) for conventional PCR of G. salaris diagnosis. However, ITS PCR protocol may yield false-positive results, leading to unnecessary countermeasures. It's difficult to distinguish between G. salaris and false-positive by similar amplicon size of PCR, since the amplicon size of ITS PCR in G. salaris and false-positive was 1,300 and 1,187 bp, respectively. The nucleotide sequences of ITS false-positive in rainbow trout is 99.7% identical to previously reported host genome sequences of rainbow trout (Oncorhynchus mykiss) and 95.3 to 89.1% identical to those of other salmonid fish species. To reduce false-positive PCR band, PCR was performed by the different annealing temperature, but PCR bands were still detected. In RFLP analysis by HaeIII, the PCR product of G. salaris was digested into four bands of 512, 399, 234 and 154 bp, while the false-positive was digested into seven bands of 297, 263, 242, 144, 93, 80 and 68 bp. In the RFLP patterns digested by HindIII, G. salaris showed two bands of 659 and 640 bp, while false-positive had one fragment of 1,187 bp without any digestion. Therefore, the RFLP method of ITS PCR with HaeIII and HindIII can be used for differentiation between G. salaris and false-positive. These results might provide important information on the improvement of PCR diagnostic method of G. salaris.

• 대한의생명과학회지
• /
• 제5권2호
• /
• pp.191-200
• /
• 1999

최근 다약제 내성균주의 출현과 후천성 면역결핍증으로 인한 결핵발병률의 증가는 전세계적으로 중요한 보건문제가 되었다. 따라서 보다 빠르고 신뢰할 만한 진단법은 결핵 박멸을 위한 가장 중요한 필요조건 중의 하나일 것이다. 본 연구는 171명의 환자를 대상으로 폐결핵 진단의 전통적 방법들 (X-선, 항산성 염색, 배양)과 PCR법간의 진단적 가치와 효율성을 비교 검토하기 위해 시행하였다. 흉부 X-선 소견 및 검사 결과 그리고 다른 임상 소견들을 통해 결핵으로 확진된 예는 전체 171건의 검체 중 39예 (22.8%)였다. 이러한 확진을 근거로 할 때 각 검사별 민감도, 특이도, 효율성, 위양성률, 위음성률을 살펴보면 흉부 X-선의 경우 각각 69.2%, 87.1%, 83.0%, 12.9%, 30.8%； 항산성 염색의 경우 79.9%,95.5%,91.8%,4.6%, 20.5%； 배양의 경우 56.4%,99.2%,89.5%,0.8%,43.6%； PCR의 경우 82.1%, 96.2%, 93.0%,3.8%, 17.9%였다. PCR의 경우 가장 높은 민감도 및 효율성과 가장 낮은 위음성률을 보였다. 배양법은 가장 높은 특이도와 가장 낮은 위양성률을 보였다. 결론적으로 PCR은 결핵 진단을 위한 신속하고 효율적인 우수한 검사 방법이므로 일상적 임상 검사로의 활용가치가 매우 높다고 하겠다. 그러나 전통적인 여러 방법들 역시 임상상황에 따라 그 나름대로의 특별한 가치를 지니고 있으므로 철저한 정도관리를 통해 PCR과 병행 한다면 결핵균 검출율을 보다 높일 수 있으리라 판단된다.

• Tuberculosis and Respiratory Diseases
• /
• 제78권3호
• /
• pp.203-209
• /
• 2015

Background: Induced sputum (IS) has been used to collect airway secretions in subjects who have inadequate sputum production. The aim of this study was to investigate the efficacy of IS for the diagnosis of pulmonary tuberculosis (PTB) in adults unable to expectorate sputum. Methods: Medical records of 39 PTB patients who underwent IS due to absence of spontaneous sputum production between January 2011 and March 2014 at a tertiary hospital in South Korea were reviewed. Results of acid fast bacilli smear, Mycobacterium tuberculosis culture and polymerase chain reaction assay for M. tuberculosis (TB-PCR) of IS specimens from these patients were analyzed. Clinical and high-resolution computed tomography (HRCT) characteristics were also analyzed to find characteristics associated with IS culture positivity. Results: Of the 39 IS specimens from PTB patients, 7 (17.9%) were smear positive and 31 (79.5%) were culture positive. Twenty-four IS specimens were tested for TB-PCR and 13 (54.2%) were positive on TB-PCR. Multivariate analysis showed that younger age (p=0.04) and presence of tree-in-bud appearance on HRCT (p=0.03) were independent predictors of IS culture positivity. Conclusion: IS is useful for the diagnosis of PTB in adults unable to expectorate sputum. Younger age and tree-in-bud appearance on HRCT were associated with IS culture positivity in these patients.