scholarly journals The Outcome of Porcine Foetal Infection with Bungowannah Virus Is Dependent on the Stage of Gestation at Which Infection Occurs. Part 1: Serology and Virology

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 691 ◽  
Author(s):  
Deborah S. Finlaison ◽  
Peter D. Kirkland
Keyword(s):  
Polymerase Chain Reaction ◽  
Disease Outbreak ◽  
Late Gestation ◽  
Chain Reaction ◽  
Viral Shedding ◽  
Persistent Infections ◽  
Qrt Pcr ◽  
Polymerase Chain ◽  
Foetal Infection ◽  
Antibody Levels

Bungowannah virus is a novel porcine pestivirus identified in a disease outbreak in Australia in 2003. The aim of this study was to determine the outcome of infection of the pregnant pig with this virus. Twenty-four pregnant pigs were infected at days 35, 55, 75 or 90 of gestation. Blood, tonsillar and rectal swabs were collected from each pig at birth and then weekly until euthanasia or death. Tissues were sampled at necropsy. Viral load was measured by real-time reverse-transcription polymerase chain reaction (qRT-PCR) and antibody levels in serum by peroxidase-linked immunoassay. Bungowannah virus was detected in the serum and excretions of all infected pigs at birth regardless of the stage of gestation at which infection occurred. Persistent infections occurred following infection prior to the development of foetal immunocompetence. Unexpectedly some animals infected at day 55 of gestation later cleared the virus and seroconverted. Viraemia and viral shedding resolved quickest following infection in late gestation.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

scholarly journals Longest reported case of symptomatic COVID-19 reporting positive for over 230 days in an immunocompromised patient in the United States

2021 ◽  
Vol 9 ◽  
pp. 2050313X2110400
Author(s):  
Bilal Chaudhry ◽  
Lidiya Didenko ◽  
Maaria Chaudhry ◽  
Andrew Malek ◽  
Kirill Alekseyev
Keyword(s):  
Risk Factors ◽  
Polymerase Chain Reaction ◽  
Immunocompromised Patient ◽  
The United States ◽  
Immunocompromised Patients ◽  
Chain Reaction ◽  
Viral Shedding ◽  
Time Period ◽  
Increased Risk ◽  
Polymerase Chain

Coronavirus 2019 (COVID-19) pneumonia was first noted in Wuhan, China. Since the start of the pandemic, there have been millions of cases diagnosed. The average time from onset of symptoms to testing negative SARS-CoV-2 via reverse transcription polymerase chain reaction is roughly 25 days. In patients who continually test positive for COVID-19, it is essential to determine precisely which risk factors contribute to the increase in viral shedding duration. We present a case about a 62-year-old man who has persistently tested positive for COVID-19 for more than 230 days. We followed his treatment course, in which he had been hospitalized multiple times since the onset of symptoms back in April 2020. We have determined that patients with immunosuppression, especially those taking corticosteroids, are at increased risk of prolonged viral shedding. It is essential to continually monitor these immunocompromised patients as they required a greater time period in order to have an appropriate immune response in which antibodies are created.

scholarly journals Covid-19 Re-infection vs Prolonged Viral Shedding

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Richard J. Barohn ◽  
Mary Hindle ◽  
Lauren Peck ◽  
Syed Hasan Raza Naqvi
Keyword(s):  
Polymerase Chain Reaction ◽  
Acquired Immunity ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Initial Infection ◽  
Viral Shedding ◽  
Number Of Patients ◽  
The World ◽  
Polymerase Chain ◽  
Spread Of Infection

  Since December 2019, COVID 19 pandemic has devastated communities across the world. As number of patients recovered from COVID 19 continue to rise, question of acquired immunity versus chances of re-infection becomes critical to understand the future spread of infection. Here, we present a case of a patient previously recovered from COVID-19, develops new symptoms concerning for possible re-infection with positive reverse transcriptase-polymerase chain reaction (RT-PCR) after few months of initial infection.  

scholarly journals Quantitation of 35S Promoter in Maize DNA Extracts from Genetically Modified Organisms Using Real-Time Polymerase Chain Reaction, Part 2: Interlaboratory Study

2005 ◽  
Vol 88 (2) ◽  
pp. 558-573 ◽  
Author(s):  
Max Feinberg ◽  
Sophie Fernandez ◽  
Sylvanie Cassard ◽  
Chrystèle Charles-Delobel ◽  
Yves Bertheau ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Interlaboratory Study ◽  
Performance Criteria ◽  
Tolerance Interval ◽  
Chain Reaction ◽  
Qrt Pcr ◽  
Polymerase Chain

Abstract The European Committee for Standardization (CEN) and the European Network of GMO Working Laboratories have proposed development of a modular strategy for stepwise validation of complex analytical techniques. When applied to the quantitation of genetically modified organisms (GMOs) in food products, the instrumental quantitation step of the technique is separately validated from the DNA extraction step to better control the sources of uncertainty and facilitate the validation of GMO-specific polymerase chain reaction (PCR) tests. This paper presents the results of an interlaboratory study on the quantitation step of the method standardized by CEN for the detection of a regulatory element commonly inserted in GMO maize-based foods. This is focused on the quantitation of P35S promoter through using the quantitative real-time PCR (QRT-PCR). Fifteen French laboratories participated in the interlaboratory study of the P35S quantitation operating procedure on DNA extract samples using either the thermal cycler ABI Prism® 7700 (Applied Biosystems, Foster City, CA) or Light Cycler® (Roche Diagnostics, Indianapolis, IN). Attention was focused on DNA extract samples used to calibrate the method and unknown extract samples. Data were processed according to the recommendations of ISO 5725 standard. Performance criteria, obtained using the robust algorithm, were compared to the classic data processing after rejection of outliers by the Cochran and Grubbs tests. Two laboratories were detected as outliers by the Grubbs test. The robust precision criteria gave values between the classical values estimated before and after rejection of the outliers. Using the robust method, the relative expanded uncertainty by the quantitation method is about 20% for a 1% Bt176 content, whereas it can reach 40% for a 0.1% Bt176. The performances of the quantitation assay are relevant to the application of the European regulation, which has an accepted tolerance interval of about ±50%. These data were fitted to a power model (r2 = 0.96). Thanks to this model, it is possible to propose an estimation of uncertainty of the QRT-PCR quantitation step and an uncertainty budget depending on the analytical conditions.

scholarly journals Evaluation of the Reverse Transcription-Polymerase Chain Reaction/Probe Test of Serum Samples and Immunohistochemistry of Skin Sections for Detection of Acute Bovine Viral Diarrhea Infections

2002 ◽  
Vol 14 (4) ◽  
pp. 303-307 ◽  
Author(s):  
Julia F. Ridpath ◽  
Sharon K. Hietala ◽  
Steve Sorden ◽  
John D. Neill
Keyword(s):  
Polymerase Chain Reaction ◽  
Polymerase Chain Reaction Amplification ◽  
Clinical Signs ◽  
Bovine Viral Diarrhea ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Serum Samples ◽  
Viral Diarrhea ◽  
Persistent Infections ◽  
Polymerase Chain

Bovine viral diarrhea viruses (BVDV) cause both acute and persistent infections. While diagnostic tests have been designed to detect animals persistently infected (PI) with BVDV, the reliability of these tests in detecting acute BVDV infections is not known. It is also possible that acute BVDV infections may be confused with persistent infections in surveys for PI animals. In this study, 2 tests presently in use in diagnostic laboratories to test for PI animals, polymerase chain reaction amplification followed by probe hybridization (RT-PCR/probe) of serum samples and immunohistochemical detection of viral antigen in skin biopsies (IHC), were evaluated for their ability to detect acute BVDV infections. Sixteen colostrum-deprived, BVDV-free, and BVDV-antibody-free calves were infected with 6 different BVDV strains. Clinical signs, seroconversion, and virus isolation indicated that inoculated animals did replicate virus. Virus could be detected in 19% (3/16) of acutely infected animals by the RT-PCR/probe technique. No acutely infected animals were positive by IHC.

Quantitative expression analysis of Bodhesin genes in the buck (Capra hircus) reproductive tract by real-time polymerase chain reaction (qRT-PCR)

2009 ◽  
Vol 110 (3-4) ◽  
pp. 245-255 ◽  
Author(s):  
Luciana M. Melo ◽  
Antônia S.F. Nascimento ◽  
Felipe G. Silveira ◽  
Rodrigo M.S. Cunha ◽  
Nathália A.C. Tavares ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Expression Analysis ◽  
Reproductive Tract ◽  
Capra Hircus ◽  
Chain Reaction ◽  
Quantitative Expression ◽  
Qrt Pcr ◽  
Polymerase Chain
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