scholarly journals Is a stable positive rate of <0.1% an indication of a fresh outbreak of SARS-CoV-2 infection?

2021 ◽  
Author(s):  
Alberto Boretti
Keyword(s):  
Polymerase Chain Reaction ◽  
Viral Load ◽  
New Zealand ◽  
Vulnerable Populations ◽  
Healthy Population ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Positive Rate ◽  
Polymerase Chain ◽  
The Government

This letter gives a short analysis of the rate of positive SARS-CoV-2 tests in New Zealand and the restrictions that were implemented in response to these rates changing. Concerned about the growth of the number of positive cases of SARS-CoV-2 infection, the New Zealand government introduced stricter lockdown measures on August 16, 2020, and on August 18, 2020, it postponed elections planned for September. Growth in the number of positive cases was an artifact of the number of tests growing at a higher rate than the number of positive cases. The positive rate on August 16 was 0.05% (13 positive cases from 26,014 tests). On August 2, the positive rate was higher at 0.18% (three positive cases from 1,692 tests), despite the government considering that the virus was eradicated at this time. A better approach to this pandemic would be the development of policies based on the positive rate, not solely on positive case numbers, and to include viral load using reverse transcription polymerase chain reaction (RT-PCR) tests with an appropriate cycle threshold to properly identify infectious cases. It is also advised to protect vulnerable populations and avoid unnecessary limitations to the healthy population. The SARS-CoV-2 pandemic will last longer than several months, and the sooner life gets back to nearly normal, the better.

AN EPIDEMIOLOGY-CLINICAL CORRELATION OF VIRAL LOAD AS MEASURED BY CYCLE THRESHOLD VALUE BY RT-PCR IN COVID-1

2021 ◽  
pp. 1-2
Author(s):  
Atrikumar P. Patel ◽  
Palak Shah ◽  
Pavan Acharya ◽  
Monila N. Patel
Keyword(s):  
Polymerase Chain Reaction ◽  
Viral Load ◽  
Severe Acute Respiratory Syndrome ◽  
Threshold Value ◽  
Clinical Correlation ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Oropharyngeal Swab ◽  
Polymerase Chain ◽  
Novel Coronavirus

The 2019 novel coronavirus [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] was rst documented in December 2019 in Wuhan, China, and spread across the globe resulting in [1]. signicant global morbidity and mortality Diagnosis of COVID-19 is mainly done by nasopharyngeal and oropharyngeal swab RT-PCR (Reverse transcriptase - polymerase chain reaction). Real time RT-PCR is of great interest today for detection of SARS- CoV-2 due to its benets as a specic assay.

scholarly journals Exhaled breath is a significant source of SARS-CoV-2 emission

2020 ◽  
Author(s):  
Jianxin Ma ◽  
Xiao Qi ◽  
Haoxuan Chen ◽  
Xinyue Li ◽  
Zheng Zhang ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Exhaled Breath Condensate ◽  
Exhaled Breath ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Air Samples ◽  
Positive Rate ◽  
Polymerase Chain ◽  
Floor Surfaces ◽  
Breath Condensate

AbstractDespite notable efforts in airborne SARS-CoV-2 detection, no clear evidence has emerged to show how SARS-CoV-2 is emitted into the environments. Here, 35 COVID-19 subjects were recruited; exhaled breath condensate (EBC), air samples and surface swabs were collected and analyzed for SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR). EBC samples had the highest positive rate (16.7%, n = 30), followed by surface swabs(5.4%, n = 242), and air samples (3.8%, n = 26). COVID-19 patients were shown to exhale SARSCoV-2 into the air at an estimated rate of 103-105 RNA copies/min; while toilet and floor surfaces represented two important SARS-CoV-2 reservoirs. Our results imply that airborne transmission of SARS-CoV-2 plays a major role in COVID-19 spread, especially during the early stages of the disease.One Sentence SummaryCOVID-19 patient exhales millions of SARS-CoV-2 particles per hour

scholarly journals maxRatio improves the detection of samples with abnormal amplification profiles on QIAgen’s artus HIV-1 qPCR assay

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1030
Author(s):  
Luigi Marongiu ◽  
Eric B. Shain ◽  
Marianna Martinelli ◽  
Matteo Pagliari ◽  
Heike Allgayer
Keyword(s):  
Polymerase Chain Reaction ◽  
Viral Load ◽  
Predictive Value ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Alternative Approach ◽  
External Standard ◽  
Polymerase Chain ◽  
Anti Hiv ◽  
Hiv 1

Background: Accurate viral load (VL) determination is paramount to determine the efficacy of anti-HIV-1 therapy. The conventional method used, fit-point (FP), assumes an equal efficiency in the polymerase chain reaction (PCR) among samples that might not hold for low-input templates. An alternative approach, maxRatio, was introduced to compensate for inhibition in PCR. Methods: Herein, we assessed whether maxRatio could improve VL quantification using 2,544 QIAgen artus HI virus-1 RT-PCR reactions. The assay’s standard dilutions were used to build external standard curves with either FP or maxRatio that re-calculated the VLs. Results: FP and maxRatio were highly comparable (Pearson’s ρ=0.994, Cohen’s  κ=0.885), and the combination of the two methods identified samples (n=41) with aberrant amplification profiles. Conclusions: The combination of maxRatio and FP could improve the predictive value of the assay.

scholarly journals Production of Newcastle Disease Polyclonal Antibody as the Alternative of Immunohistochemistry Primary Antibody against Newcastle Disease in Poultry

2021 ◽  
Vol 11 (2) ◽  
pp. 187-192
Author(s):  
Muhammad Kholish Naf’an ◽  
Kurniasih Kurniasih ◽  
Tri Untari ◽  
Yos Adi Prakoso
Keyword(s):  
Polymerase Chain Reaction ◽  
New Zealand ◽  
Polyclonal Antibody ◽  
Newcastle Disease ◽  
Primary Antibody ◽  
Rt Pcr ◽  
Chain Reaction ◽  
New Zealand White Rabbits ◽  
Polymerase Chain ◽  
Similar Accuracy

Newcastle disease (ND) is the most pathogenic viral infection in poultry. Furthermore, the availability of laboratories that support the molecular diagnosis of ND is still limited in Indonesia. The present study aimed to produce ND polyclonal antibody as the alternative of immunohistochemistry primary antibody against ND in poultry. Two adult male New Zealand White rabbits weighed 2.5 kg were vaccinated seven days after the adaptation using intraperitoneal injection of the ND live vaccine at multilevel doses weekly. The serum was collected inactivated, and purified in the sixth week. A total number of 31 chicken samples were collected and their samples of brain, lung, spleen, and intestine were tested using immunohistochemistry and Reverse Transcription Polymerase Chain reaction (RT-PCR). The result showed that 19/31 (61%) were positive against immunohistochemistry and RT-PCR and a total of 12/31 (39%) were negative. Based on the obtained results, immunohistochemistry using ND polyclonal antibody had a similar accuracy with RT-PCR. It can be concluded that ND polyclonal antibody produced by vaccination in the rabbit could be used as the alternative immunohistochemistry primary antibody for diagnosing ND in poultry.

scholarly journals DETERMINATION OF VARIOUS CLINICAL STAGES OF CHRONIC HEPATITIS B THROUGH MEASURING VIRUS LOAD DNA BY REAL-TIME POLYMERASE CHAIN REACTION (RT-PCR)

2020 ◽  
pp. 1-2
Author(s):  
Subhash Kumar Saw ◽  
MD. Mohammad Sohail ◽  
Jainendra Kumar
Keyword(s):  
Polymerase Chain Reaction ◽  
Chronic Hepatitis ◽  
Viral Load ◽  
Hepatitis B ◽  
Real Time ◽  
Chronic Hepatitis B ◽  
Hbv Dna ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Polymerase Chain

Objective and Aim: There was a paradigm shift of hepatitis B (CHB) diagnosis as clinicians are shifted to molecular diagnostic methods from serological one. Specially in molecular system to determine response of treatment as well as different stages of infection as well as recovery by quantification of viral DNA load through real time polymerase chain reaction (RT-PCR). The main objective of the study is to determine the various clinical stages of chronic hepatitis B through measuring virus load DNA by real-time polymerase chain reaction (RT-PCR) Material and Methods: This is a retrospective study of those patients whose ALT (elevated) and HBeAg (positive) status is known. Serum fraction were initially obtained after 4 hour centrifugation of blood sample and nucleic acid was extracted at -80 °C. Qiagen DNA extraction kit were used to extract DNA. 48-well MiniOpticon by Bio-red machine and with the help of Geno-sense HBV quantitative PCR kit, real-time polymerase chain reaction (RT-PCR) was conducted. Result: The study was conducted in 64 patients. It has been found that among this patients inactive carriers that is ALT normal and HBeAg-negative were 27 (42.2%) and rest of the patients had HBeAg-positive or HBeAg-negative with ALT elevated that is they were chronic active hepatitis B patients. HBeAg was negative in 42 (65.6%) and positive in 22 (33.4%) subjects. 15 (23%) patients were infected with Chronic hepatitis B among the patients who were HBeAg-negative. Among 64 subjects, detectable viral load was found in 55 (86%) CHB patients. A significantly lower (median 5.6 × 105) serum HBV DNA load were found in HBeAg-negative16 patients as compare to 26 patients with higher viral load (median 2.5 × 108) and were HBeAg-positive. It has also found that viral load was quite higher (median 1.5 × 103) in 27 inactive carriers. Antiviral therapy was started in HBeAg-negative 6 patients and HBeAg-positive 13 patients based on the viral load. Conclusion: Stages of CHB can be determined by Quantitation of HBV DNA based on ALT (elevated or not) and HBeAg (positive or negative) status. For those patients who are inactive carriers and HBeAg-negative with respect to viral load it could play an important role in assessment and to decide on antiviral therapy.

scholarly journals Assessment of COVID-19 Pandemic in Nepal: A Lockdown Scenario Analysis

2020 ◽  
Author(s):  
Kusum Sharma ◽  
Amrit Banstola ◽  
Rishi Ram Parajuli
Keyword(s):  
Health Care ◽  
Polymerase Chain Reaction ◽  
Spatial Distribution ◽  
Economic Education ◽  
Entry And Exit ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Education And Health ◽  
Polymerase Chain ◽  
The Government

AbstractThe Government of Nepal issued a nationwide lockdown from 24 March to 21 July 2020. Here we present the overall scenario of COVID-19, government efforts, impact on socio-economic, education, and health care, and prevailing challenges when the lockdown was lifted. We collated and analysed data provided by the Nepalese Ministry of Health and Population. There were only two confirmed cases from 610 Reverse Transcription Polymerase Chain Reaction (RT-PCR) tests and no fatalities when the government introduced nationwide lockdown. Nepal had performed 7791 RT-PCR tests for COVID-19, the highest number of tests during the lockdown. It has recorded its highest daily rise in coronavirus infections with a total of 740 new cases from the total of 4483 RT-PCR tests performed on a single day. Nepal had reported a total of 17994 positive cases and 40 deaths at the end of lockdown. The spatial distribution clearly shows that the cases were rapidly spreading from the southern part of the country where most points of entry and exit from India are located. The government needs to allocate more resources, increase its capacity to test and trace, establish dedicated isolation and quarantine facilities, and impose local restrictions to manage potential COVID-19 outbreaks after easing lockdown.

scholarly journals maxRatio improves the detection of samples with abnormal amplification profiles on QIAgen’s artus HIV-1 qPCR assay

F1000Research ◽  
2021 ◽  
Vol 9 ◽  
pp. 1030
Author(s):  
Luigi Marongiu ◽  
Eric B. Shain ◽  
Marianna Martinelli ◽  
Matteo Pagliari ◽  
Heike Allgayer
Keyword(s):  
Polymerase Chain Reaction ◽  
Viral Load ◽  
Predictive Value ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Alternative Approach ◽  
External Standard ◽  
Polymerase Chain ◽  
Anti Hiv ◽  
Hiv 1

Background: Accurate viral load (VL) determination is paramount to determine the efficacy of anti-HIV-1 therapy. The conventional method used, fit-point (FP), assumes an equal efficiency in the polymerase chain reaction (PCR) among samples that might not hold for low-input templates. An alternative approach, maxRatio, was introduced to compensate for inhibition in PCR. Methods: Herein, we assessed whether maxRatio could improve VL quantification using 2,544 QIAgen artus HI virus-1 RT-PCR reactions. The assay’s standard dilutions were used to build external standard curves with either FP or maxRatio that re-calculated the VLs. Results: FP and maxRatio were highly comparable (Pearson’s ρ=0.994, Cohen’s  κ=0.885), and the combination of the two methods identified samples (n=41) with aberrant amplification profiles. Conclusions: The combination of maxRatio and FP could improve the predictive value of the assay.

scholarly journals Comparison of SARS-CoV-2 viral load in saliva samples in symptomatic and asymptomatic cases

2021 ◽  
Author(s):  
Anuja Bhatta ◽  
Rebecca Henkhaus ◽  
Heather L. Fehling
Keyword(s):  
Polymerase Chain Reaction ◽  
Viral Load ◽  
Reverse Transcription ◽  
Specific Gene ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Gene Target ◽  
Viral Loads ◽  
Ct Value ◽  
Polymerase Chain

AbstractSARS-CoV-2 infections can be symptomatic as well as asymptomatic. In this study, we analyzed 460,814 saliva samples collected from July 2020 to January 2021 for a SARS-CoV-2-specific gene target using the FDA EUA test, CRL Rapid Response™, based on reverse transcription polymerase chain reaction (RT-PCR). We measured SARS-CoV-2 viral loads using cycle threshold (Ct) values. A total of 17,813 samples tested positive for COVID-19 using self-collected saliva samples. The Ct values ranged from 11 to 40, 91.3% distributed between 22 to 38 Ct. We then compared Ct values for symptomatic and asymptomatic cases for all positive saliva samples. A total of 8,706 cases were symptomatic with an average Ct value of 29.24, and 9,107 cases were asymptomatic with an average Ct value of 30.99. Hence, SARS-CoV-2 viral loads (Ct) in saliva samples for both symptomatic and asymptomatic cases are similar.

scholarly journals maxRatio improves the detection of samples with abnormal amplification profiles on QIAgen’s artus HIV-1 qPCR assay

F1000Research ◽  
2021 ◽  
Vol 9 ◽  
pp. 1030
Author(s):  
Luigi Marongiu ◽  
Eric B. Shain ◽  
Marianna Martinelli ◽  
Matteo Pagliari ◽  
Heike Allgayer
Keyword(s):  
Polymerase Chain Reaction ◽  
Viral Load ◽  
Predictive Value ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Alternative Approach ◽  
External Standard ◽  
Polymerase Chain ◽  
Anti Hiv ◽  
Hiv 1

Background: Accurate viral load (VL) determination is paramount to determine the efficacy of anti-HIV-1 therapy. The conventional method used, fit-point (FP), assumes an equal efficiency in the polymerase chain reaction (PCR) among samples that might not hold for low-input templates. An alternative approach, maxRatio, was introduced to compensate for inhibition in PCR. Methods: Herein, we assessed whether maxRatio could improve VL quantification using 2,544 QIAgen artus HI virus-1 RT-PCR reactions. The assay’s standard dilutions were used to build external standard curves with either FP or maxRatio that re-calculated the VLs. Results: FP and maxRatio were highly comparable (Pearson’s ρ=0.994, Cohen’s  κ=0.885), and the combination of the two methods identified samples (n=41) with aberrant amplification profiles. Conclusions: The combination of maxRatio and FP could improve the predictive value of the assay.

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