Low-Cost, Real-Time Polymerase Chain Reaction System with Integrated RNA Extraction.

Rapid, easy-to-use, and low-cost systems for biological sample testing are important for point-of-care diagnostics and various other health applications. The recent pandemic of Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) showed an urgent need to rapidly and accurately identify the genetic material of SARS-CoV-2, an enveloped ribonucleic acid (RNA) virus, in upper respiratory specimens from people. In general, sensitive testing methods require genetic material extraction from the specimen. Unfortunately, current commercially available extraction kits are expensive and involve time-consuming and laborious extraction procedures. To overcome the difficulties associated with common extraction methods, we propose a simple enzymatic assay for the nucleic acid extraction step using heat mediation to improve the polymerase chain reaction (PCR) reaction sensitivity. Our protocol was tested on Human Coronavirus 229E (HCoV-229E) as an example, which comes from the large coronaviridae family of viruses that affect birds, amphibians, and mammals, of which SARS-CoV-2 is a member. The proposed assay was performed using a low-cost, custom-made, real-time PCR system that incorporates thermal cycling and fluorescence detection. It had fully customizable reaction settings to allow versatile biological sample testing for various applications, including point-of-care medical diagnosis, food and water quality testing, and emergency health situations. Our results show that heat-mediated RNA extraction is a viable extraction method when compared to commercial extraction kits. Further, our study showed that extraction has a direct impact on purified laboratory samples of HCoV-229E, but no direct impact on infected human cells. This is clinically relevant, as it allows us to circumvent the extraction step on clinical samples when using PCR.

Is Omicron really mild? – Comparative analysis of comorbidities and disease outcomes associated with SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants

Purpose Multiple variants of SARS-CoV-2 from Alpha to Omicron have an estimated 6.1 million deaths globally till date. These variants have been found to vary in transmissibility and severity. The present study deals with comparison of morbidity and mortality with SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants. Materials and method An observational retrospective cohort study was conducted on a cohort of laboratory confirmed patients of SARS-CoV-2 diagnosed by qRT-PCR of nasopharyngeal swabs in periods;April-2021 and January-2022;that were sequenced and variants were recorded. Patients were invited for a telephonic interview after voluntary and informed consent was obtained from each participant wherein, the demographics, co-morbidities, oxygen requirement and mortality outcomes of the patients were enquired about. Results A total of 200 patients, with 100 from each period were included in the study. Major comorbidities in patients included hypertension, diabetes mellitus and pulmonary disease. Patients who succumbed to the Delta variant (26%) were higher as compared to the Omicron variant (10%);with the elderly (68 ​± ​9.7 ​years) having significant mortality during the Omicron variant. The mortality was increased in patients with comorbidities as with hypertension (53.8%, 70%), diabetes mellitus (26.9%, 40%), chronic pulmonary disease (30.8%, 20%), and smoking (15.4%, 40%) in the patients infected with both Delta and Omicron variants, respectively. Conclusion The study concluded that the newer strains of SARS-CoV-2 have potential of high transmissibility and milder disease for the population by large, however, for patients with comorbidities have a higher proportion of adverse outcomes, irrespective of the variant.

Establishment and applications of a duplex quantitative real-time RT-PCR assay for simultaneous detection of bovine rhinitis A virus and bovine rhinitis B virus

Bovine rhinitis virus (BRV) is an important pathogen responsible for the bovine respiratory disease complex (BRDC) and can be divided into two genotypes (BRAV and BRBV). To establish a duplex quantitative real-time RT-PCR assay for simultaneous detection of BRAV and BRBV, specific primers and TaqMan probes targeting the 5'NTR of BRAV and 3'NTR of BRBV were designed. A duplex quantitative real- time RT- PCR assay for simultaneous detecting BRAV and BRBV was preliminarily established by optimizing reaction conditions for each step. The assay specifically detects BRAV and BRBV, and no crossreaction with other common bovine respiratory pathogens, including IDV, BCoV, BVDV-1, BRSV, BPIV-3, BAdV-3, mycoplasma bovis, Pasteurella multocida, Mannheimia haemolytica, Escherichia coli, and Salmonella, was observed. In addition, the sensitivity test showed that the detection limits of this assay were 3.2x101 copies/L for both BRAV and BRBV plasmid standards. Besides, the repeatability test showed that the variation coefficients of this assay were less than 0.05 from both lot-to-lot and intra-lot. These results showed that the assay has high specificity, extreme sensitivity, and good repeatability. Moreover, a total of 43 nasal swabs of BRDC cattle were tested by our assay and four other quantitative real-time RT-PCR assays, including 3 BRAV assays and 4 BRBV assays. The results showed that the detection rates of our assay were 32.56%(14/43) for BRAV and 30.23%(13/43) for BRBV, and the detection rates of other quantitative real-time RT-PCR assays were 0(0/43), 2.33%(1/43), 23.26%(10/43) for BRAV and 27.91% (12/43), 27.91%(12/43), 27.91%(12/43), 27.91%(12/43) for BRBV, indicating that our assay has a more substantial detection capability than other assays. This study firstly established a duplex quantitative real-time RT-PCR assay for simultaneous detection of BRAV and BRBV, and the assay exhibited high specificity, sensitivity, and stability. Moreover, the study firstly confirmed the existence of BRAV in China, contributing to the prevention and control of BRDC.

COVID-19 prediction with Chest X-Ray images using CNN

Coronavirus has outbreak as an epidemic disease, created a pandemic situation for the public health across the Globe. Screening for the large masses is extremely crucial to control disease for the people in a neighborhood. Real-time-PCR[18] is the general diagnostic approach for pathological examination. However, the increasing figure of false results from the test has created a way in choosing alternative procedures. COVID-19 patient's X-rays images of chest has emerged as a significant approach for screening the COVID-19 disease. However, accuracy depends on the knowledge of a radiologist. X-Ray images of lungs may be proper assistive tool for diagnosis in reducing the burden of the doctor. Deep Learning techniques, especially Convolutional Neural Networks (CNN), have been shown to be effective for classification of images in the medical field. Diagnosing the COVID-19 using the four types of Deep-CNN models because they have pre-trained weights. Model needs to pre-trained on the ImageNet database in simplifying the large datasets. CNN-based architectures were found to be ideal in diagnosing the COVID-19 disease. The model having an efficiency of 0.9835 in accuracy, precision of 0.915, sensitivity of 0.963, specificity with 0.972, 0.987 F1 Score and 0.925 ROC AUC. © 2023 IEEE.

Duplex Taq man qPCR for detecting porcine epidemic diarrhea and transmissible gastroenteritis viruses and epidemic study in Fujian

Objective: A Taq Man probe-based duplex real-time PCR for rapid detection of porcine epidemic diarrhea virus(PEDV) and transmissible gastroenteritis virus(TGEV) was developed. A study was conducted using the methodology to analyze the related 2019-2021 epidemic occurred in Fujian. Method: Specific primers and probes labeled with FAM and VIC were designed to amplify the N gene of PEDV and the S gene of TGEV, respectively. A reaction system for the assay was established, optimized, and tested for sensitivity, specificity, and repeatability. The assay was used for the viral detection on297 suspected clinic specimens collected from 2019 to 2021 for an epidemiology study. Result: The newly developed duplex qPCR methodology showed a sensitivity of 10 copies.L-1 on PEDV and TGEV, which was 100 times higher than that of regular PCR. There were no cross reactions with other common viruses. The inter-and intra-assays had variations on Ct values below 1%. On the 297 specimens, the infection rate of PEDV was 88.89%, that of TGEV 1.01%, and that of both PEDV and TGEV 3.37%. Conclusion: The established duplex qPCR had high sensitivity, specificity, repeatability, and reproducibility for detecting PEDV and TGEV. The 2019-2021 epidemic involving the viruses appeared to be mostly PEDV with low incidents of mixed TGEV and PEDV/TGEV infection.

Rapid Detection of Predominant SARS-CoV-2 Variants Using Multiplex High-Resolution Melting Analysis.

Coronavirus disease 2019, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a considerable threat to global public health. This study developed and evaluated a rapid, low-cost, expandable, and sequencing-free high-resolution melting (HRM) assay for the direct detection of SARS-CoV-2 variants. A panel of 64 common bacterial and viral pathogens that can cause respiratory tract infections was employed to evaluate our method's specificity. Serial dilutions of viral isolates determined the sensitivity of the method. Finally, the assay's clinical performance was assessed using 324 clinical samples with potential SARS-CoV-2 infection. Multiplex HRM analysis accurately identified SARS-CoV-2 (as confirmed with parallel reverse transcription-quantitative PCR [qRT-PCR] tests), differentiating between mutations at each marker site within approximately 2 h. For each target, the limit of detection (LOD) was lower than 10 copies/reaction (the LOD of N, G142D, R158G, Y505H, V213G, G446S, S413R, F486V, and S704L was 7.38, 9.72, 9.96, 9.96, 9.50, 7.80, 9.33, 8.25, and 8.25 copies/reaction, respectively). No cross-reactivity occurred with organisms of the specificity testing panel. In terms of variant detection, our results had a 97.9% (47/48) rate of agreement with standard Sanger sequencing. The multiplex HRM assay therefore offers a rapid and simple procedure for detecting SARS-CoV-2 variants. IMPORTANCE In the face of the current severe situation of increasing SARS-CoV-2 variants, we developed an upgraded multiplex HRM method for the predominant SARS-CoV-2 variants based on our original research. This method not only could identify the variants but also could be utilized in subsequent detection of novel variants since the assay has great performance in terms of flexibility. In summary, the upgraded multiplex HRM assay is a rapid, reliable, and economical detection method, which could better screen prevalent virus strains, monitor the epidemic situation, and help to develop measures for the prevention and control of SARS-CoV-2.

Development of a colloidal gold immunochromatographic assay strip using monoclonal antibody for rapid detection of porcine deltacoronavirus.

Porcine deltacoronavirus (PDCoV) cause diarrhea and dehydration in newborn piglets and has the potential for cross-species transmission. Rapid and early diagnosis is important for preventing and controlling infectious disease. In this study, two monoclonal antibodies (mAbs) were generated, which could specifically recognize recombinant PDCoV nucleocapsid (rPDCoV-N) protein. A colloidal gold immunochromatographic assay (GICA) strip using these mAbs was developed to detect PDCoV antigens within 15 min. Results showed that the detection limit of the GICA strip developed in this study was 103 TCID50/ml for the suspension of virus-infected cell culture and 0.125 µg/ml for rPDCoV-N protein, respectively. Besides, the GICA strip showed high specificity with no cross-reactivity with other porcine pathogenic viruses. Three hundred and twenty-five fecal samples were detected for PDCoV using the GICA strip and reverse transcription-quantitative real-time PCR (RT-qPCR). The coincidence rate of the GICA strip and RT-qPCR was 96.9%. The GICA strip had a diagnostic sensitivity of 88.9% and diagnostic specificity of 98.5%. The specific and efficient detection by the strip provides a convenient, rapid, easy to use and valuable diagnostic tool for PDCoV under laboratory and field conditions.

A Silicon-Based PDMS-PEG Copolymer Microfluidic Chip for Real-Time Polymerase Chain Reaction Diagnosis.

Polydimethylsiloxane (PDMS) has been widely used to make lab-on-a-chip devices, such as reactors and sensors, for biological research. Real-time nucleic acid testing is one of the main applications of PDMS microfluidic chips due to their high biocompatibility and transparency. However, the inherent hydrophobicity and excessive gas permeability of PDMS hinder its applications in many fields. This study developed a silicon-based polydimethylsiloxane-polyethylene-glycol (PDMS-PEG) copolymer microfluidic chip, the PDMS-PEG copolymer silicon chip (PPc-Si chip), for biomolecular diagnosis. By adjusting the modifier formula for PDMS, the hydrophilic switch occurred within 15 s after contact with water, resulting in only a 0.8% reduction in transmittance after modification. In addition, we evaluated the transmittance at a wide range of wavelengths from 200 nm to 1000 nm to provide a reference for its optical property study and application in optical-related devices. The improved hydrophilicity was achieved by introducing a large number of hydroxyl groups, which also resulted in excellent bonding strength of PPc-Si chips. The bonding condition was easy to achieve and time-saving. Real-time PCR tests were successfully conducted with higher efficiency and lower non-specific absorption. This chip has a high potential for a wide range of applications in point-of-care tests (POCT) and rapid disease diagnosis.

Multiplex RT Real-Time PCR Based on Target Failure to Detect and Identify Different Variants of SARS-CoV-2: A Feasible Method That Can Be Applied in Clinical Laboratories.

Shortly after its emergence, Omicron and its sub-variants have quickly replaced the Delta variant during the current COVID-19 outbreaks in Vietnam and around the world. To enable the rapid and timely detection of existing and future variants for epidemiological surveillance and diagnostic applications, a robust, economical real-time PCR method that can specifically and sensitively detect and identify multiple different circulating variants is needed. The principle of target- failure (TF) real-time PCR is simple. If a target contains a deletion mutation, then there is a mismatch with the primer or probe, and the real-time PCR will fail to amplify the target. In this study, we designed and evaluated a novel multiplex RT real-time PCR (MPL RT-rPCR) based on the principle of target failure to detect and identify different variants of SARS-CoV-2 directly from the nasopharyngeal swabs collected from COVID-19 suspected cases. The primers and probes were designed based on the specific deletion mutations of current circulating variants. To evaluate the results from the MPL RT-rPCR, this study also designed nine pairs of primers for amplifying and sequencing of nine fragments from the S gene containing mutations of known variants. We demonstrated that (i) our MPL RT-rPCR was able to accurately detect multiple variants that existed in a single sample; (ii) the limit of detection of the MPL RT-rPCR in the detection of the variants ranged from 1 to 10 copies for Omicron BA.2 and BA.5, and from 10 to 100 copies for Delta, Omicron BA.1, recombination of BA.1 and BA.2, and BA.4; (iii) between January and September 2022, Omicron BA.1 emerged and co-existed with the Delta variant during the early period, both of which were rapidly replaced by Omicron BA.2, and this was followed by Omicron BA.5 as the dominant variant toward the later period. Our results showed that SARS-CoV-2 variants rapidly evolved within a short period of time, proving the importance of a robust, economical, and easy-to-access method not just for epidemiological surveillance but also for diagnoses around the world where SARS-CoV-2 variants remain the WHO's highest health concern. Our highly sensitive and specific MPL RT-rPCR is considered suitable for further implementation in many laboratories, especially in developing countries.

Evaluation of the artus® Prep&Amp UM RT-PCR for detection of SARS-CoV-2 from nasopharyngeal swabs without prior nucleic acid eluate extraction.

Here we describe a retrospective clinical evaluation of the QIAGEN artus® SARS-CoV-2 Prep&Amp UM RT-PCR assay that detects SARS-CoV-2 RNA without the need for a nucleic acid eluate extraction procedure. Using Roche SARS-CoV-2 RT-PCR on the cobas® 8800 platform as a reference standard, a total of 225 confirmed SARS-CoV-2 positive and 320 negative nasopharyngeal swabs in viral transport media, were used to evaluate the artus® assay. Using the RT-PCR cycle threshold as a semi-quantitative marker of viral load, an assessment of over 370,000 SARS-CoV-2 RT-PCR positive results was used in the design of the reference positive specimen cohort. The viral load of all reference positive specimens used in the evaluation was a unique and accurate representation of the range and levels of SARS-CoV-2 positivity observed over a 13-month period of the COVID-19 pandemic. The artus® RT-PCR detects the presence of SARS-CoV-2 RNA, an internal control, and the human RNase P gene to ensure specimen quality. The diagnostic sensitivity of artus® was 92.89% with a specificity of 100%. To assess the analytical sensitivity, a limit of detection was performed using the 1st WHO NIBSC SARS-CoV-2 international standard, recording a 95% LOD of 1.1 × 103 IU/ml. The total invalid rate of specimens was 7.34% due to a lack of detectable RNase P (Ct >35). The artus® SARS-CoV-2 Prep&Amp UM RT-PCR assay is a new rapid RT-PCR assay, which may be considered to produce acceptable levels of diagnostic sensitivity and specificity whilst potentially halving the laboratory processing time.

Identification of feline corona- virus in breeding catteries by molecular biological methods and shedding persistency

Infectious peritonitis virus (FIPV) causes a fatal disease in cats. This virus occurs both in cats bred in households with optimal welfare and outdoor cats. Feline patients with the effusive form of disease usually survive a few days to weeks from the appearance of the first clinical signs. Cats with the non- effusive form survive for weeks to months. FIPV is caused by a mutation from feline enteric coronavirus (FECV). In our study, we diagnosed feline coronavirus from the feces of 82% of the tested cats. The persistence of the feline coronavirus in the organism is influenced by environmental factors, the genome of the host and the causative agent. Negative environmental conditions that increase the likelihood of FIPV disease are long-term stress, mainly more labile individuals and a high concentration of domesticated cats in one place. In the host, there are important factors such as immune system performance, age, breed and genetic background. In our study, we primarily verified the real time RT-PCR method for identifying the virus from the feces of 71 cats and subsequently gaine the valuable data on the dynamics of feline coronavirus excretion, primarily for epizootological purposes and for the purposes of genetic analyzes of susceptibility to infection.

Assessment of different laboratory tests for the diagnosis of novel coronavirus infections

Rapid diagnosis of coronavirus disease 2019 (COVID-19)-infected patients is urgent in making decisions on public health measures. There are different types of diagnostic tests, such as quantitative PCR assay, antibody, and antigen-based and CRISPR-based tests, which detect genetic materials, viral proteins, or human antibodies in clinical samples. However, the proper test should be highly sensitive, quick, and affordable to address this life-threatening situation. This review article highlights the advantages and disadvantages of each test and compares its different features, such as sensitivity, specificity, and limit of detection to reach a reliable conclusion. Moreover, the FDA- authorized kits and studies' approaches toward these have been compared to provide a better perspective to the researchers.Copyright © 2022 Lippincott Williams and Wilkins. All rights reserved.

Multicenter post-marketing clinical evaluation on the clinical performance of the five domestic fast nucleic acid detection reagents for 2019-nCoV.

Objective This multicenter clinical evaluation analyzed the clinical performance of five fast nucleic acid detection systems for 2019-nCoV. Methods Clinical performance of the five fast nucleic acid detection reagents approved in China was evaluated in the present study. Fifty-seven throat swabs samples from COVID-19 patients and fifteen throat swabs samples from healthy people were collected from the First Affiliated Hospital of Zhejiang University school of Medicine, Tongji Hospital of Tongji Medical College of HUST, and National Institute of Viral Disease Control and Prevention of CDC to evaluate the positive coincidence rate, negative coincidence rate, total coincidence rate, the detection time and retest rate as well as the relation between positive intensity and positive coincidence rate of the five fast nucleic acid detection systems in November 2020. Results The positive coincidence rates of the five kits were 92.59% (50/54), 83.64% (46/55), 98.25% (56/57), 94.44% (51/54) and 98.18% (54/55);and the negative coincidence rates were 93.33% (14/15), 93.33% (14/15), 86.67% (13/15), 100% (14/14) and 93.33% (14/15);and the total coincidence rates were 92.75% (64/69), 85.71% (60/70), 95.83% (69/72), 94.20% (65/69) and 97.14% (68/70), respectively. The positive coincidence rate of the five kits reached 100% for the strong-positive (90/90) and medium-positive samples (84/84), but only 82.18% (83/101) for weak-positive samples (cycle threshold value>33), and the retest rate of two kits were 15.28% (11/72) and 12.50% (9/72), which were both higher than 10%. Total time from sample extraction to amplification was between 32.33-65.33 minutes for these five kits. Conclusion The five fast nucleic acid detection reagents have good performance and can be used as a supplement to routine nucleic acid detection reagents.Copyright © 2022 Chinese Journal of Laboratory Medicine. All rights reserved.

One-step multiple TaqMan real-time RT-PCR for simultaneous detection of swine diarrhea viruses

Objective: The aim of this study was to establish a one-step multiplex real-time RT-PCR method to simultaneously detect and quantify five swine diarrhea related viruses, PEDV, GARV, PDCoV, SADS-CoV and PTV, so as to provide an efficient and sensitive tool for rapid diagnosis and epidemiological investigation of porcine diarrhea. Method: The ORF3 gene sequences of several genotypes of PEDV were analyzed, and then the primers and probes were designed for detection of PEDV field strains by referring to the ORF3 genes, which contained deletion mutations in attenuated strains. The 5'-end conserved region of NSP5 genes of GARV G3, G4, G5 and G9 strains were analyzed for design of probes and primers. The specific primers and probes targeting to the conserved regions of PDCoV M, PTV 5'UTR and SADS-CoV N genes were designed for detection of the pathogens. The ROC curves were completed by referring to parameters that were set in RStudio. The specificity value, sensitivity value, and areas under the curves (AUC) and Youden value were calculated according to ROC curves to determine the cut-off CT value. The amplified fragments were cloned into pEASY-T1 vector. The standards prepared through in vitro transcription were named as cRNA-PEDV, cRNA-GARV, cRNA-PDCoV, cRNA-PTV and cRNA-SADS-CoV. The sensitivity, specificity and repeatability of one-step multiplex real-time RT-PCR were evaluated. Coincidence rate between this and another similar method were compared in the detection of clinical samples. Result: Both the annealing temperature and optimal concentrations of primers and probes were obtained for detection of the five pathogens. According to the ROC curve, the CT cut off values for detection of PEDV, GARV, PDCoV, PTV, and SADS-CoV were set as 35.78, 34.25, 34.98, 34.60, and 35.70, respectively. The detection sensitivity of this method for the five pathogens could reach 1..102 copies/L. The standard curves had a good linear relationship and the amplification efficiency was between 96.3% and 104%. The established method could not detect the PEDV vaccine strains and other swine infecting viruses and bacteria including TGEV, CSFV, PRV, PRRSV, S.choleraesuis, P.multocida, E.coli, S.suis and S.aureus. The repeatability test showed the range of intra-assay and inter-assay coefficients of variability: 0.22% to 3.08% and 0.89% to 4.0%, respectively. The detection coincidence rates of the established detection method and another similar method for the five pathogens in 242 clinical samples were 97.9%, 98.8%, 100%, 98.3% and 100% for PEDV, GARV, PDCoV, PTV and SADS-CoV, respectively. The Kappa values were all higher than 0.9. The method had advantage over a commercial diagnostic kit for detection of PEDV wild strains in accuracy. Detection results with clinical samples showed that positive rates of PEDV, GARV, PDCoV and PTV was 10.7% (26/242), 13.6% (33/242), 18.2% (44/242) and 14.5% (35/242), respectively, demonstrating the prevalence state of the four pathogens in Sichuan province in the years. SADS-CoV was not detectable in any areas, but the phenomenon of coinfection with different diarrhea causing viruses was common. Therefore, it was necessary to strengthen the surveillance of several porcine diarrhea viruses in Sichuan province for preventive control. Conclusion: In this study, a one-step multiplex real-time RT-PCR was established for simultaneous detection of PEDV wild strains, PDCoV, SADS-COV and GARV, PTV multiple genotypes, which provided an efficient and sensitive tool for the differential diagnosis and epidemiological investigation of swine diarrhea disease.

Association of blood groups with the clinical presentation of COVID-19 infection

Background: Blood groups' antigens, represent polymorphic traits inherited among populations, their expression differences, can increase or decrease the host susceptibility to infections. We aimed here to correlate the relation between the different blood groups and hosts' susceptibility towards COVID-19 infection. Methods: 355 samples, were analyzed for SARS-CoV-2 and blood groups typing. The candidates were then divided according to their results into;210 positive-PCR (viral persistent, clearance and ICU admitted), and 145 negative-PCR contacts and then results were compared. Results: The highest frequency in control and viral clearance group was O-phenotype, followed by A-phenotype and the least was AB-phenotype. The highest frequency in the viral persistent group, was A-group, showed followed by B-group and the least was O-group. Lastly in ICU group, A-group was the highest frequency, followed by O-group and the least was B-group. Using Chi-square method, a statistically significant result was observed (p-value= 0.034). Conclusions: The blood group-O was the protective phenotype, controversy to the O-group, A-group was the risky phenotype, also AB-group was risky, as it showed the lowest frequency in both control and viral clearance group. Interestingly, the B-group was the least group susceptible to have bad prognosis and be admitted to the ICU. This can be a safety guideline for classifying healthcare workers, according to their ABO, to work with suspected cases with COVID-19 and also may help in developing specific anti-histo-blood group antibodies as an effective co-therapy for COVID-19. © 2020 The author (s).

Antibody responses to acute COVID-19 infection;assessment via multiplex LABScreen COVID Plus Assay

Background: Understanding the profile of antibody responses following acute COVID-19 infection is required. Aim: to describe the pattern of IgG anti-COVID-19 antibody production in patients with acute infection using the LABScreen COVID Plus assay. Results: The overall seropositivity was 69/73(94.5%). Anti-Spike, Spike 1 and spike S2 subunits were positive in 78.1%, while anti spike receptor binding domain (RBD) was detected in 68.4% and anti nucleocapsid protein in 61.6%. The overall positivity of the assay reached 100.0% during the second week post symptoms. The mean fluorescent intensities (MFI) of anti-Spike S1 was higher in the second week than the first week, p=0.03. MFI of anti-Spike S2 was significantly higher in PCR positive patients in comparison with the negative ones, p=0.006. When compared to the RT-PCR results;the overall antibodies positivity, anti-Spike, and anti-Spike2 antibodies had sensitivities (100% and 84.7%) and specificities (28.6% and 50.0%) and accuracies (86.3% and 78.1%). Patients' outcome correlated significantly with the time of hospital admission, p=0.001. Conclusion: COVID-19 IgG antibodies are detectable with considerable frequencies during the first two weeks post infection. Anti S2 antibodies correlates well with the RT-PCR results. The LABScreen COVID Plus is a sensitive assay for the detection of post-acute COVID-19 infection antibody responses. © 2020 The author (s).

Interpretation of chest CT scan of patients with COVID-19 in imam Khomeini Hospital of Jiroft University of Medical Sciences from December to March 2019

Background & Aims: Along with laboratory testing, chest CT scans may be helpful to diagnose COVID-19 in individuals with a high clinical suspicion of infection. Due to their availability and rapid turnaround time, the role of chest computed tomography (CT) scan is growing for early diagnosis of patients with COVID-19. However, due to the low efficiency of viral nucleic acid detection as well as low specificity of chest CT scan for detecting COVID-19 pneumonia, this method shows incomplete clinical performance for proper COVID-19 disease diagnosis. Due to the highly contagious nature of the Coronavirus 2019 and the importance of early detection of the disease, a limited number of nucleic acid test kits, such as rRT-PCR and the possibility of false-negative rRT-PCR results, chest CT scan as a non-invasive method, it can be a highly accurate tool for early detection of suspected COVID-19 cases. The purpose of this study was the Interpretation of chest CT scan of patints with COVID-19 in Imam Khomeini Hospital of Jiroft University of Medical Sciences from December to March 2019 Methods: This research is a retrospective study that was conducted with the aim of interpreting CT scans of the chest in patients with covid-19 in Imam Khomeini Hospital, Jiroft University of Medical Sciences from March 2018 to June 2019. After obtaining permission from the ethics committee of the university, the researcher appeared in the research environment according to the pre-determined schedule for sampling. The desired data were extracted from the patients' files and recorded in a questionnaire form that was designed for this purpose. The criteria for entering the study included cases whose demographic information, clinical and laboratory data were complete and the positive PCR test along with chest CT imaging findings were available in the file, the exclusion criterion was the presence of low quality chest images. The data were extracted from the hospital information system based on clinical electronic medical records. including demographic information including age, sex, level of education and data related to the underlying disease, disease symptoms (cough, fever, phlegm, shortness of breath, chest pain, etc.) and the frequency of imaging findings in the chest CT scan that They were examined and evaluated according to age, gender, level of education, clinical symptoms, underlying disease and based on lymphopenia and lymphocytosis. and chest CT scan report of patients with COVID-19, which was available in the PACS system of this hospital, were evaluated. In this way, all the CT images of the chest by a radiologist as well as a lung specialist who were not aware of the clinical and laboratory data of the patients, in terms of the types of findings include, Patchy ground glass opcification, diffuse ground glass opacification, Air space opacity, Consolidation, pleural effusion, Atelectasis, Bronchiectasis, Fibrotic change, Cavitation, Lymphadenopathy. And the distribution of conflict was investigated as peripheral, central, bilateral, and unilateral. Results: The highest number of people with Covid-19 were in the age range of 30 to 59 years and men. In CT scan findings, the highest CT scan imaging findings as well as the highest mortality rate in patients were PGGO view (63.3%) and peripheral and bilateral involvement and the lowest frequency was related to Cavitation findings. In the examination of CT scan findings, PGGO and peripheral and bilateral involvement were the most frequent and Cavitation was the least frequent. Also, the findings of PGGO, Peripheral and Bilateral in the CT scan of the people who died had the highest frequency. In none of the imaging findings of the chest scan, there was no statistically significant relationship with the level of education, the level of education and death of patients due to COVID-19. There was no significant difference between gender and the findings of PGGO and Cavitation and peripheral involvement and Bilateral, but between the findings of DGGO and gender and there was a significant relationsh

Testing and diagnosis for COVID-19

Nucleic acid amplification tests for coronavirus diseases (COVID-19) were nearly established by the end of January 2020, mainly at regional Public Health Laboratories (PHLs) nationwide. Initially, the nucleic acid amplification test was a combination of conventional PCR and sequencing, in accordance with the pathogen detection manual of the National Institute of Infectious Diseases (NIID). However, this was soon changed to a real-time PCR method (NIID method), and test reagents were distributed by the NIID. In order to cope with the further increase in the number of tests, private laboratories began testing for novel coronaviruses in March, and PHLs cooperated with the launch of testing by private laboratories. Subsequently, a large variety of test reagents that replaced the NIID method were approved by the Ministry of Health, Labour and Welfare as in Vitro diagnostic products.

A Novel Universal Primer Multiplex Real-Time PCR (UP-M-rtPCR) Approach for Specific Identification and Quantitation of Cat, Dog, Fox, and Mink Fractions Using Nuclear DNA Sequences.

Adulteration of meat with carnivorous animals (such as cats, dogs, foxes, and minks) can cause ethical problems and lead to disease transmission; however, DNA quantitative methods for four carnivorous species in one tube reaction are still rare. In this study, a carnivore-specific nuclear DNA sequence that is conserved in carnivorous animals but has base differences within the sequence was used to design universal primers for its conserved region and corresponding species-specific probes for the hypervariable region. A novel universal primer multiplex real-time PCR (UP-M-rtPCR) approach was developed for the specific identification and quantitation of cat, dog, fox, and mink fractions in a single reaction, with a 0.05 ng absolute limit of detection (LOD) and 0.05% relative LOD. This approach simplifies the PCR system and improves the efficiency of simultaneous identification of multiple animal-derived ingredients in meat. UP-M-rtPCR showed good accuracy (0.48-7.04% relative deviation) and precision (1.42-13.78% relative standard deviation) for quantitative analysis of cat, dog, fox, and mink DNA as well as excellent applicability for the evaluation of meat samples.

Ultrafast Plasmonic Nucleic Acid Amplification and Real-Time Quantification for Decentralized Molecular Diagnostics.

Point-of-care real-time reverse-transcription polymerase chain reaction (RT-PCR) facilitates the widespread use of rapid, accurate, and cost-effective near-patient testing that is available to the public. Here, we report ultrafast plasmonic nucleic acid amplification and real-time quantification for decentralized molecular diagnostics. The plasmonic real-time RT-PCR system features an ultrafast plasmonic thermocycler (PTC), a disposable plastic-on-metal (PoM) cartridge, and an ultrathin microlens array fluorescence (MAF) microscope. The PTC provides ultrafast photothermal cycling under white-light-emitting diode illumination and precise temperature monitoring with an integrated resistance temperature detector. The PoM thin film cartridge allows rapid heat transfer as well as complete light blocking from the photothermal excitation source, resulting in real-time and highly efficient PCR quantification. Besides, the MAF microscope exhibits close-up and high-contrast fluorescence microscopic imaging. All of the systems were fully packaged in a palm size for point-of-care testing. The real-time RT-PCR system demonstrates the rapid diagnosis of coronavirus disease-19 RNA virus within 10 min and yields 95.6% of amplification efficiency, 96.6% of classification accuracy for preoperational test, and 91% of total percent agreement for clinical diagnostic test. The ultrafast and compact PCR system can decentralize point-of-care molecular diagnostic testing in primary care and developing countries.