Symptom Based Models of COVID-19 Infection Using AI

Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV2) has spread around the world in a global pandemic [1-4]. Early and daily detection of suspected COVID-19 patients is the most important approach not only for tracing close contacts to prevent further spread [5], but also providing crucial information for healthcare providers and officials to make resource allocation and policy decisions [6]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Copper Sulfate-Induced Diphenylamine for Rapid Colorimetric Point-of-Care Detection of Contagious Pathogens Combined with Loop-Mediated Isothermal Amplification

Here, we developed a copper sulfate (CuSO4)-initiated diphenylamine (DPA)-based colorimetric strategy coupled with loop-mediated isothermal amplification (LAMP) for rapid detection of two critical contagious pathogens, SARS-CoV-2 and Enterococcus faecium. To detect the DNA, acid hydrolysis of LAMP amplicons was executed, enabling the development of a blue color. In the LAMP amplicons, the bond between the purines and deoxyribose is extremely labile. It can be broken using 70% sulfuric acid followed by phosphate group elimination, which generates a highly active keto aldehyde group. CuSO4 plays an imperative role inducing DPA to rapidly react with the keto aldehyde group, producing an intense blue color within 5 min. Moreover, low quantities such as 103 copies μL-1 of SARS-CoV-2 RNA and 102 CFU mL-1 of E. faecium were successfully detected, revealing the advantages of the introduced method. To confirm practical applicability, multiplex detection of pathogens was performed using a foldable microdevice comprising reaction and detection zones. Various reactions such as DNA extraction, LAMP, and acid hydrolysis occurred in the reaction zone. Then, colorimetric reagents (DPA, CuSO4, and ethylene glycol) contained in the detection zone were mixed with the keto aldehyde group by simply folding the microdevice, which was heated at 65 °C for 5 min for colorimetric detection. An intense blue color was developed where the target DNA was present. These results indicate that the method proposed in this study is highly suitable for point-of-care applications, especially in resource-limited settings for the rapid detection of harmful pathogens. © 2023 American Chemical Society.

Dual-mode visual detection strategies of viable pathogens for point-of-care testing

Here, we introduce a power-free foldable poly(methyl methacrylate) (PMMA) microdevice fully integrating DNA extraction, amplification, and visual detection, realized in novel dual modes – colorimetric and aggregate formation – using 4-Aminoantipyrine (4-AP) for monitoring pathogens. The microdevice contains two parts: reaction and detection zones. A sealing film was utilized to connect the two zones and make the device foldable. The FTA card was deposited in the reaction zone for DNA extraction, followed by loop-mediated isothermal amplification (LAMP) at 65 °C for 45 min. When the detection zone is folded toward the reaction zone, paper discs modified with 4-AP placed in the detection zone are delivered to the reaction zone. Specifically, in the presence of LAMP amplicons, 4-AP is oxidized into antipyrine red or generates aggregates by interacting with copper sulfate, forming copper hybrid nanostructure (Cu-hNs). In the absence of LAMP amplicons, 4-AP is not oxidized and maintains yellow color or fails to form aggregates. Furthermore, we introduced the ethidium homodimer-1 (EthD-1) to identify viable bacteria. EthD-1 penetrated the compromised membranes of nonviable cells and prevented further DNA amplification by intercalating with the DNA. In this way, only samples containing viable cells displayed color change or formed aggregates upon reaction with 4-AP. Using this method, SARS-CoV-2 RNA and Enterococcus faecium were identified by naked eye, with the limit of detection of 103 copies/μL and 102 CFU/mL, respectively, within 60 min. The introduced microdevice can be used for rapidly monitoring viable pathogens and controlling outbreaks of infectious disease in resource-limited settings. © 2022 Elsevier B.V.

Copper Sulfate-Induced Diphenylamine for Rapid Colorimetric Point-of-Care Detection of Contagious Pathogens Combined with Loop-Mediated Isothermal Amplification

Here, we developed a copper sulfate (CuSO4)-initiated diphenylamine (DPA)-based colorimetric strategy coupled with loop-mediated isothermal amplification (LAMP) for rapid detection of two critical contagious pathogens, SARS-CoV-2 and Enterococcus faecium. To detect the DNA, acid hydrolysis of LAMP amplicons was executed, enabling the development of a blue color. In the LAMP amplicons, the bond between the purines and deoxyribose is extremely labile. It can be broken using 70% sulfuric acid followed by phosphate group elimination, which generates a highly active keto aldehyde group. CuSO4 plays an imperative role inducing DPA to rapidly react with the keto aldehyde group, producing an intense blue color within 5 min. Moreover, low quantities such as 103 copies μL-1 of SARS-CoV-2 RNA and 102 CFU mL-1 of E. faecium were successfully detected, revealing the advantages of the introduced method. To confirm practical applicability, multiplex detection of pathogens was performed using a foldable microdevice comprising reaction and detection zones. Various reactions such as DNA extraction, LAMP, and acid hydrolysis occurred in the reaction zone. Then, colorimetric reagents (DPA, CuSO4, and ethylene glycol) contained in the detection zone were mixed with the keto aldehyde group by simply folding the microdevice, which was heated at 65 °C for 5 min for colorimetric detection. An intense blue color was developed where the target DNA was present. These results indicate that the method proposed in this study is highly suitable for point-of-care applications, especially in resource-limited settings for the rapid detection of harmful pathogens. © 2023 American Chemical Society

Current status of High-risk Smokers Participating in Population-based National Lung Cancer Screening Program in Korea

Introduction: Following assessment of the effectiveness and feasibility based on the results from a two-year population-based nationwide prospective multi-center trial, the Korean government implemented a national lung cancer screening program using low-dose computed tomography (LDCT) for high-risk smokers in 2019. Methods: National Health Insurance Corporation selected high risk targets who are current smokers aged 54 to 74 years with 30 packs per year or more smoking history on the basis of national health-screening database. (Figure 1). Those eligible were offered lung cancer screening by invitation letters in every two years. Screening units provide LDCT using radiation less than 3mGy by at least 16-row multi-detector CT scanners. Screening results were reported by Lung Imaging Reporting and Data System (Lung-RADS). The examinee received results by mail or e-mail;after then, counseling on results and mandatory smoking cessation counselling were provided by certified doctors. National Cancer Center monitored participation rates, post-counseling rates and statistics of screening result for quality control. Screening positive rate is defined as proportion of Lung-RADS category 3 and 4 nodules. Results: The participation rate gradually increased from 24.8% among 332,244 eligible targets in 2019, 25.9% in 2020, to 38.7% among 310,260 targets in 2021, however, the proportion of examinees who participated in post-counseling decreased from 46.3% in 2019 to 32.7% in 2021 due to the COVID-19 pandemic (Figure 2). The positive rates slightly decreased from 9.2% in 2019 to 8.7% in 2021. The variation in positive rates of screening units showed a tendency to decrease (in 2019, the 1st quartile was 4.3%, and the 3rd quartile was 12.9%;and in 2021, 5.2% and 12.5% respectively). Conclusions: National lung cancer screening program has been implemented successfully in Korea with controlling screening positive rates not so high. Controlling false negatives and strengthening post-screening management including smoking cessation counselling needs to improve. [Formula presented] [Formula presented] Keywords: National Lung Cancer Screening, Quality control

A NOVEL STRATEGY FOR POWER-FREE READOUT OF LOOP-MEDIATED ISOTHERMAL AMPLIFICATION USING POLYDOPAMINE INTEGRATED INTO A PAPER DEVICE FOR PATHOGEN DETECTION

The result readouts of loop-mediated isothermal amplification (LAMP) still remain challenging because current techniques require bulky equipment and could not give clear visualization. In this study, we developed a paper device to integrate LAMP and a novel strategy for power-free and naked-eye readout of result relied on polydopamine aggregation. The introduced paper device was used to detect DNA extracted from Escherichia coli O157:H7 (E. coli O157:H7), Enterococcus faecium (E. faecium), and SARS-CoV-2 plasmid. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.

Advances in Nucleic Acid Amplification-Based Microfluidic Devices for Clinical Microbial Detection

Accurate and timely detection of infectious pathogens is urgently needed for disease treatment and control of possible outbreaks worldwide. Conventional methods for pathogen detection are usually time-consuming and labor-intensive. Novel strategies for the identification of pathogenic nucleic acids are necessary for practical application. The advent of microfluidic technology and microfluidic devices has offered advanced and miniaturized tools to rapidly screen microorganisms, improving many drawbacks of conventional nucleic acid amplification-based methods. In this review, we summarize advances in the microfluidic approach to detect pathogens based on nucleic acid amplification. We survey microfluidic platforms performing two major types of nucleic acid amplification strategies, namely, polymerase chain reaction (PCR) and isothermal nucleic acid amplification. We also provide an overview of nucleic acid amplification-based platforms including studies and commercialized products for SARS-CoV-2 detection. Technologically, we focus on the design of the microfluidic devices, the selected methods for sample preparation, nucleic acid amplification techniques, and endpoint analysis. We also compare features such as analysis time, sensitivity, and specificity of different platforms. The first section of the review discusses methods used in microfluidic devices for upstream clinical sample preparation. The second section covers the design, operation, and applications of PCR-based microfluidic devices. The third section reviews two common types of isothermal nucleic acid amplification methods (loop-mediated isothermal amplification and recombinase polymerase amplification) performed in microfluidic systems. The fourth section introduces microfluidic applications for nucleic acid amplification-based detection of SARS-CoV-2. Finally, the review concludes with the importance of full integration and quantitative analysis for clinical microbial identification.

Changes in the Distribution of Respiratory Microorganisms before and during the COVID-19 Pandemic, Daegu, Korea

Background: Acute respiratory infection (ARI) is the most common infectious disease in all ages and genders worldwide. Respiratory microorganisms such as respiratory viruses, are commonly responsible for causing ARI. COVID-19 is still prevalent in Korea. The implementation of lockdown and strict control measures, the mandatory wearing of masks, and social distancing are critical steps for controlling the risk of COVID-19 spread. This study was conducted to find out how these changes in daily lives impacted the distribution of respiratory microorganisms. Methods: A retrospective study was conducted to identify the incidence and distribution patterns of ARI-causing respiratory microorganisms before (Period.) and during the COVID-19 pandemic (Period.) in terms of detection method, age, month, and season. In particular, data in Periods. and. were compared for eight major kinds of respiratory microorganisms: adenovirus (AdV), human metapneumovirus (HMPV), human rhinovirus/enterovirus (Rhino/Entero), influenza virus (Flu) A, Flu B, human parainfluenza virus (HPIV) 3, respiratory syncytial virus, and Mycoplasma pneumoniae. Results: A total of 27,191 respiratory specimens were tested, of which 5,513 were obtained from children and adolescents (age groups 1. 5) and 21,678 from adults (age group 6). The overall positive rates for at least one respiratory microorganism in Periods. and. were 23.1% (1,199/5,193) and 4.9% (1,070/21,998), respectively (p < 0.001). The overall positive rates in male and female patients were significantly different (8.7% vs. 7.9%;p = 0.016). On the FilmArray (TM) RP assay, positive rates in all age groups decreased significantly in Period. compared with Period.. AdV, Rhino/Entero, and Flu A were detected in all four seasons, but HMPV and HPIV3 were not detected. The overall positive rates on FilmArray and the Flu antigen test in Period. were significantly decreased. In the COVID-19 test, the positive rates were high in March and April 2020, and decreased thereafter, but these increased again in the winter of 2020/2021. Conclusions: Life changes due to COVID-19 pandemic have had a significant impact on the distribution of respiratory microorganisms;our study results might provide useful information on respiratory virus epidemiology.