scholarly journals Diagnostic Performance of a Magnetic Field-Enhanced Agglutination Readout in Detecting Either Viral Genomes or Host Antibodies in Arbovirus Infection

2021 ◽  
Vol 9 (4) ◽  
pp. 674
Author(s):  
Fanny Leon ◽  
Elena Pinchon ◽  
Nevzat Temurok ◽  
François Morvan ◽  
Jean-Jacques Vasseur ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Diagnostic Performance ◽  
Patient Management ◽  
Epidemiological Surveillance ◽  
Antibody Detection ◽  
Emerging Infections ◽  
Rt Pcr ◽  
Viral Genomes ◽  
Viral Antigens ◽  
Arbovirus Infection

Arbovirus diagnostics on blood from donors and travelers returning from endemic areas is increasingly important for better patient management and epidemiological surveillance. We developed a flexible approach based on a magnetic field-enhanced agglutination (MFEA) readout to detect either genomes or host-derived antibodies. Dengue viruses (DENVs) were selected as models. For genome detection, a pan-flavivirus amplification was performed before capture of biotinylated amplicons between magnetic nanoparticles (MNPs) grafted with DENV probes and anti-biotin antibodies. Magnetization cycles accelerated this chaining process to within 5 min while simple turbidimetry measured the signal. This molecular MFEA readout was evaluated on 43 DENV RNA(+) and 32 DENV RNA(−) samples previously screened by real-time RT-PCR. The sensitivity and the specificity were 88.37% (95% CI, 78.76%–97.95%) and 96.87% (95% CI, 90.84%–100%), respectively. For anti-DENV antibody detection, 103 plasma samples from donors were first screened using ELISA assays. An immunological MFEA readout was then performed by adding MNPs grafted with viral antigens to the samples. Anti-DENV antibodies were detected with a sensitivity and specificity of 90.62% (95% CI, 83.50%–97.76%) and 97.44% (95% CI, 92.48%–100%), respectively. This adaptable approach offers flexibility to platforms dedicated to the screening of emerging infections.

scholarly journals A Novel Multiplex RT-PCR Assay for Simultaneous Detection of Dengue and Chikungunya Viruses

2020 ◽  
Vol 21 (21) ◽  
pp. 8281
Author(s):  
Mohammed Alimul Islam ◽  
Mohamed E. El Zowalaty ◽  
Sumaiya Islam ◽  
Mohiuddin Sharif ◽  
Md. Rajibur Rahman ◽  
...  
Keyword(s):  
Simultaneous Detection ◽  
Cross Reactivity ◽  
Single Step ◽  
Epidemiological Surveillance ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serum Samples ◽  
Viral Genomes ◽  
Specificity And Sensitivity ◽  
Field Samples

The goal of the study was to develop a specific, sensitive, and cost-effective molecular RT-PCR diagnostic assay for the rapid and simultaneous detection of the serotypes of dengue virus (DENV) and Chikungunya virus (CHIKV) from sera of suspected febrile patients. A single-tube, single-step multiplex RT-PCR (mRT-PCR) assay was designed for the detection of viral genomes from clinical and field samples. Specificity and sensitivity of the mRT-PCR assay were evaluated against six different combinations using two reverse transcriptases (AMV-RT and RT-Ace) and three DNA polymerases (LA-Taq, rTaq, and Tth). Among the six combinations, the AMV-RT and LA-Taq combination was more specific and sensitive than other enzyme combinations for detecting viral genomes of DENV-1, DENV-2, DENV-3, and DENV-4 (p < 0.01), and for detecting viral genomes of CHIKV (p < 0.05). The detection limits of the mRT-PCR were 10 focus forming units (FFU) for CHIKV and 1 FFU, 20 FFU, 0.1 FFU, and 10 FFU for DENV-1, DENV-2, DENV-3, and DENV-4, respectively. The primers used for the mRT-PCR did not show any cross-reactivity among the serotypes of DENV or CHIKV. Specificity and sensitivity of the newly developed mRT-PCR were validated using serum samples collected from febrile patients during dengue outbreaks in Bangladesh. The sensitivity for serotype detection of DENV and CHIKV was superior to the virus isolation method and the antigen detection method using the Dengue NS1-Ag assay. This novel mRT-PCR method can be used for molecular epidemiological surveillance of DENV and CHIKV in epidemic and endemic countries.

scholarly journals Diagnostic performance of different sampling approaches for SARS-CoV-2 RT-PCR testing: a systematic review and meta-analysis

2021 ◽  
Author(s):  
Nicole Ngai Yung Tsang ◽  
Hau Chi So ◽  
Ka Yan Ng ◽  
Benjamin J Cowling ◽  
Gabriel M Leung ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Performance ◽  
Meta Analysis ◽  
Rt Pcr

scholarly journals Diagnostic performance of chest CT in differentiating COVID-19 from other causes of ground-glass opacities

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Ali H. Elmokadem ◽  
Dalia Bayoumi ◽  
Sherif A. Abo-Hedibah ◽  
Ahmed El-Morsy
Keyword(s):  
Diagnostic Performance ◽  
Pulmonary Nodules ◽  
Ground Glass Opacity ◽  
Chest Ct ◽  
Ground Glass ◽  
Rt Pcr ◽  
Laboratory Findings ◽  
Halo Sign ◽  
Traction Bronchiectasis ◽  
Chest Ct Scan

Abstract Background To evaluate the diagnostic performance of chest CT in differentiating coronavirus disease 2019 (COVID-19) and non-COVID-19 causes of ground-glass opacities (GGO). Results A total of 80 patients (49 males and 31 females, 46.48 ± 16.09 years) confirmed with COVID-19 by RT-PCR and who underwent chest CT scan within 2 weeks of symptoms, and 100 patients (55 males and 45 females, 48.94 ± 18.97 years) presented with GGO on chest CT were enrolled in the study. Three radiologists reviewed all CT chest exams after removal of all identifying data from the images. They expressed the result as positive or negative for COVID-19 and recorded the other pulmonary CT features with mention of laterality, lobar affection, and distribution pattern. The clinical data and laboratory findings were recorded. Chest CT offered diagnostic accuracy ranging from 59 to 77.2% in differentiating COVID-19- from non-COVID-19-associated GGO with sensitivity from 76.25 to 90% and specificity from 45 to 67%. The specificity was lower when differentiating COVID-19 from non-COVID-19 viral pneumonias (30.5–61.1%) and higher (53.1–70.3%) after exclusion of viral pneumonia from the non-COVID-19 group. Patients with COVID-19 were more likely to have lesions in lower lobes (p = 0.005), peripheral distribution (p < 0.001), isolated ground-glass opacity (p = 0.043), subpleural bands (p = 0.048), reverse halo sign (p = 0.005), and vascular thickening (p = 0.013) but less likely to have pulmonary nodules (p < 0.001), traction bronchiectasis (p = 0.005), pleural effusion (p < 0.001), and lymphadenopathy (p < 0.001). Conclusions Chest CT offered reasonable sensitivity when differentiating COVID-19- from non-COVID-19-associated GGO with low specificity when differentiating COVID-19 from other viral pneumonias and moderate specificity when differentiating COVID-19 from other causes of GGO.

scholarly journals Genomic Epidemiology of SARS-CoV-2 in Madrid, Spain, during the First Wave of the Pandemic: Fast Spread and Early Dominance by D614G Variants

2021 ◽  
Vol 9 (2) ◽  
pp. 454
Author(s):  
Esther Viedma ◽  
Elias Dahdouh ◽  
José González-Alba ◽  
Sara González-Bodi ◽  
Laura Martínez-García ◽  
...  
Keyword(s):  
Air Transportation ◽  
European Population ◽  
Viral Population ◽  
Rt Pcr ◽  
Viral Genomes ◽  
Genomic Epidemiology ◽  
International Transport ◽  
Polymerase Chain ◽  
Phylodynamic Analysis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first detected in Madrid, Spain, on 25 February 2020. It increased in frequency very fast and by the end of May more than 70,000 cases had been confirmed by reverse transcription-polymerase chain reaction (RT-PCR). To study the lineages and the diversity of the viral population during this first epidemic wave in Madrid we sequenced 224 SARS-CoV-2 viral genomes collected from three hospitals from February to May 2020. All the known major lineages were found in this set of samples, though B.1 and B.1.5 were the most frequent ones, accounting for more than 60% of the sequences. In parallel with the B lineages and sublineages, the D614G mutation in the Spike protein sequence was detected soon after the detection of the first coronavirus disease 19 (COVID-19) case in Madrid and in two weeks became dominant, being found in 80% of the samples and remaining at this level during all the study periods. The lineage composition of the viral population found in Madrid was more similar to the European population than to the publicly available Spanish data, underlining the role of Madrid as a national and international transport hub. In agreement with this, phylodynamic analysis suggested multiple independent entries before the national lockdown and air transportation restrictions.

DIAGNOSTIC ROLE OF CHEST CT USING CO-RADS CATEGORIZATION IN SARS-COV-2 INFECTION WITH EMPHASIS ON IMPACT OF CT IN PATIENTS WITH DELAYED OR NEGATIVE INITIAL RTPCR TEST

2021 ◽  
pp. 51-52
Author(s):  
Tharani Putta ◽  
Kaushik Deconda
Keyword(s):  
Diagnostic Performance ◽  
Virus Disease ◽  
Vital Role ◽  
Chest Ct ◽  
Lung Involvement ◽  
Test Results ◽  
Rt Pcr ◽  
Diagnostic Role ◽  
Pcr Test

BACKGROUND AND OBJECTIVE: Role of chest CT in diagnosis of corona virus disease 2019 (COVID-19) has been controversial. The purpose of this study is to evaluate the diagnostic performance of chest CT when utilizing COVID-19 Reporting and Data System (CO-RADS). METHODOLOGY: Retrospective study including consecutive patients with positive SARS-CoV-2 RT-PCR test (initial or repeat test) and chest CT done in our institute between June and September 2020. Spectrum of CT ndings, CO-RADS score and 25 point CT severity score (CTSS) were recorded. RESULTS: A total of 300 consecutive patients with SARS-CoV-2 infection were included in the analysis. Out of the 168 patients who underwent CT prior to positive RT-PCR result, 125 (74.4%) had CO-RADS 3, 4 or 5 score on chest CT. 32 study patients (10.6%) had initial negative RT-PCR of which 24 (75%) had CO-RADS 4 or 5 score. Of the total patients with CO-RADS 3 to 5 score (227), 20 (8.8%) had severe lung involvement (CTSS 18-25), 83 (36.6%) had moderate lung involvement (CTSS 8-17) and 124 (54.6%) had mild lung involvement (CTSS 1-7). The mean CTSS was 7.9 with mean lobar score being higher in lower lobes (RLL=1.82, LLL=1.78) compared to the upper and middle lobes (RUL=1.61, RML=1.19, LUL=1.53). CONCLUSION:CT using CO-RADS scoring system has good diagnostic performance. In addition to assessing disease severity, it plays a vital role in triage of patients with suspected COVID-19 especially when there is limited availability of SARS-CoV-2 RT-PCR tests, delay in RT-PCR test results or in negative RT-PCR cases when there is high index of clinical suspicion.

scholarly journals Automated Low Cost Method of Quantification of Hepatitis C Virus

2015 ◽  
Vol 14 (3) ◽  
pp. 247-253
Author(s):  
Faiz MMT Marikar ◽  
Dammika Senevirathna ◽  
Neil Fernandopulle
Keyword(s):  
Viral Load ◽  
Hepatitis C ◽  
Blood Donors ◽  
Low Cost ◽  
Medical Science ◽  
Simultaneous Detection ◽  
Plasma Samples ◽  
Rt Pcr ◽  
Viral Genomes ◽  
Post Therapy

This paper describes the development of a Dig-dUTP based multiplex real time RT-PCR for the simultaneous detection of HCV viral amount in plasma samples. Viral genomes were identified in the same sample by Dig-dUTP PCR 216 bp region. Analysis of known scalar concentrations of reference plasma indicated that the multiplex procedure detects at least 500 copies/ml of HCV. In addition, we also assayed HCV viral load in eighty co-infected patients and in fifteen blood donors, confirming the sensitivity and specificity of the assay. This method may represent a useful alternative method for the detection of HCV co-infection, reliable for a rapid and relatively inexpensive screening of blood donors. The assay may be used to determine post-therapy viral clearance.Bangladesh Journal of Medical Science Vol.14(3) 2015 p.247-253

scholarly journals Use of immunodot blot and multiplex reverse transcriptase-polymerase chain reaction in dengue virus detection in macerates of Aedes aegypti larvae

2012 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
Aline T.A. Chagas ◽  
Michelle D. Oliveira ◽  
Jose M.S. Mezencio ◽  
Eduardo A.M. Silva ◽  
Leandro L. Oliveira ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Reverse Transcriptase ◽  
Epidemiological Surveillance ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Denv Serotypes ◽  
Polymerase Chain ◽  
Pcr Techniques

The <em>Dengue virus</em> is the main arbovirus that affects man in terms of morbidity and mortality. The detection of the virus is very important for epidemiological surveillance, so here we propose to standardize and compare the immunodot blot (IDB) and multiplex reverse transcriptase-polymerase chain reaction (M-RT-PCR) techniques to detect and characterize the dengue virus (DENV) serotypes in samples of <em>Aedes aegypti</em> larvae. Thus, the IDB and M-RT-PCR techniques were standardized using macerated samples of larvae collected in nature. The use of monoclonal antibodies in IDB has not shown great results, but DENV detection through this method was possible using polyclonal antibodies. The distinction of serotypes 1, 2 and 3 was carried out by M-RT-PCR.

scholarly journals Duration of viral detection in throat and rectum of a patient with COVID-19

2020 ◽  
Author(s):  
Le Van Tan ◽  
Nghiem My Ngoc ◽  
Bui Thi Ton That ◽  
Le Thi Tam Uyen ◽  
Nguyen Thi Thu Hong ◽  
...  
Keyword(s):  
Infection Control ◽  
Patient Management ◽  
Ho Chi Minh City ◽  
Rt Pcr ◽  
Viral Detection ◽  
Oral Transmission ◽  
Viral Shedding ◽  
Clinical Recovery ◽  
Global Pandemic ◽  
Rapid Spread

AbstractThe rapid spread of coronavirus disease 2019 (COVID-19) raises concern about a global pandemic. Knowledge about the duration of viral shedding remains important for patient management and infection control. We report the duration of viral detection in throat and rectum of a COVID-19 patient treated at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam. Despite clinical recovery, SARS-CoV-2 RNA remained detectable by real time RT-PCR in throat and rectal swabs until day 11 and 18 of hospitalization, respectively. Because live SARS-CoV-2 has been successfully isolated from a stool sample from a COVID-19 patient in China, the results demonstrate that COVID-19 patients may remain infectious for long periods, and fecal-oral transmission may be possible. Therefore, our finding has important implications for infection control.

scholarly journals Performance evaluation of the Simtomax® CoronaCheck rapid diagnostic test

2020 ◽  
Author(s):  
P. J. Ducrest ◽  
A. Freymond ◽  
J.-M. Segura
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Diagnostic Performance ◽  
High Sensitivity ◽  
High Specificity ◽  
Negative Control ◽  
List Type ◽  
Plasma Samples ◽  
Rt Pcr ◽  
Two Samples

AbstractThe aim of this study was to evaluate the diagnostic performance of Simtomax® CoronaCheck, a serology rapid diagnostic test (RDT) for the detection of IgG and IgM against SARS-CoV-2. 48 plasma samples positive for SARS-CoV-2 based on RT-PCR and 98 negative control samples were studied. Diagnostic performance of the IgG/IgM RDT was assessed against RT-PCR and the electro-chemiluminescence immunoassay (ECLIA) Elecsys® Anti-SARS-CoV-2 total Ig. Overall, the RDT sensitivity was 92% (95% confidence interval [95%CI]: 79-97), specificity 97% (95% CI: 91-99%), PPV 94% (95% CI: 81-98) and the NPV 96% (95% CI: 89-99). When considering only samples collected ≥ 15 days post-symptoms (DPS), the sensitivity increased to 98% (95%CI: 86-100) and the specificity was 97% (95% CI: 91-99%). Two samples with 180 DPS were still positive for IgG. Globally, this IgG/IgM RDT displayed a high diagnostic accuracy for SARS-CoV-2 IgG/IgM detection in plasma samples in high COVID-19 prevalence settings. It could be effectively used, in absence of facilities for routine diagnostic serology, for samples with a DPS between 15 and 180 days.Highlights–The rapid diagnostic test Simtomax CoronaCheck displays a high sensitivity of 98% and a high specificity of 97% for SARS-CoV-2 IgG/IgM detection in plasma samples after 15 days post-symptoms.–The rapid diagnostic test Simtomax CoronaCheck can detect SARS-CoV-2 antibodies in plasma up to 180 days after symptom onset.–The rapid diagnostic test Simtomax CoronaCheck could be effectively used as an alternative to serological analysis using laboratory facilities.

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