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1.
Biosens Bioelectron ; 237: 115456, 2023 Jun 13.
Article in English | MEDLINE | ID: covidwho-20239025

ABSTRACT

Recombinase polymerase amplification (RPA) running at 37-42 °C is fast, efficient and less-implemented; however, the existing technologies of nucleic acid testing based on RPA have some limitations in specificity of single-base recognition and multiplexing capability. Herein, we report a highly specific and multiplex RPA-based nucleic acid detection platform by combining flap endonuclease 1 (FEN1)-catalysed invasive reactions with RPA, termed as FEN1-aided RPA (FARPA). The optimal conditions enable RPA and FEN1-based fluorescence detection to occur automatically and sequentially within a 25-min turnaround time and FARPA exhibits sensitivity to 5 target molecules. Due to the ability of invasive reactions in discriminating single-base variation, this one-pot FARPA is much more specific than the Exo probe-based or CRISPR-based RPA methods. Using a universal primer pair derived from tags in reverse transcription primers, multiplex FARPA was successfully demonstrated by the 3-plex assay for the detection of SARS-CoV-2 pathogen (the ORF1ab, the N gene, and the human RNase P gene as the internal control), the 2-plex assay for the discrimination of SARS-CoV-2 wild-type from variants (Alpha, Beta, Epsilon, Delta, or Omicrons), and the 4-plex assay for the screening of arboviruses (zika virus, tick-borne encephalitis virus, yellow fever virus, and chikungunya virus). We have validated multiplex FARPA with 103 nasopharyngeal swabs for SARS-CoV-2 detection. The results showed a 100% agreement with RT-qPCR assays. Moreover, a hand-held FARPA analyser was constructed for the visualized FARPA due to the switch-like endpoint read-out. This FARPA is very suitable for pathogen screening and discrimination of viral variants, greatly facilitating point-of-care diagnostics.

2.
Trends Analyt Chem ; 165: 117107, 2023 Aug.
Article in English | MEDLINE | ID: covidwho-2324531

ABSTRACT

Molecular detection of SARS-CoV-2 in gargle and saliva complements the standard analysis of nasopharyngeal swabs (NPS) specimens. Although gargle and saliva specimens can be readily obtained non-invasively, appropriate collection and processing of gargle and saliva specimens are critical to the accuracy and sensitivity of the overall analytical method. This review highlights challenges and recent advances in the treatment of gargle and saliva samples for subsequent analysis using reverse transcription polymerase chain reaction (RT-PCR) and isothermal amplification techniques. Important considerations include appropriate collection of gargle and saliva samples, on-site inactivation of viruses in the sample, preservation of viral RNA, extraction and concentration of viral RNA, removal of substances that inhibit nucleic acid amplification reactions, and the compatibility of sample treatment protocols with the subsequent nucleic acid amplification and detection techniques. The principles and approaches discussed in this review are applicable to molecular detection of other microbial pathogens.

3.
Omics Approaches and Technologies in COVID-19 ; : 239-242, 2022.
Article in English | Scopus | ID: covidwho-2297453

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused unparalleled global threat in terms of public health and economic loss. To date, there is no effective way of treating this disease, and the only way to control this disease is the extensive diagnosis of COVID-19 symptomatic patients and isolate them from the healthy population and treat them with appropriate medicine. There is a requirement of a global standard diagnosis method to quickly control this pandemic disease, which should be specific, easy to use, and inexpensive and requires least instrumentation at point-of-care testing (POCT). Serology-based tests are popular, inexpensive, and easy to use to diagnose COVID-19 patients, but they lack sensitivity at lower inoculum concentrations and may indicate false negatives which possess a major threat in spreading this pandemic disease. To avoid this issue, nucleic acid-based tests are more specific and sensitive to diagnose COVID-19 patients. However, it has some limitations such as a low sample throughput, expensive reagents, an extensive time, and requirement of costly quantitative reverse transcription–polymerase chain reaction instruments. To overcome this limitation, the latest CRISPR-based detection methods coupled with allied isothermal nucleic acid amplification methods such as loop-mediated isothermal amplification would provide inexpensive, quick, accurate, and easy ways of diagnosing a large number of populations at POCT. Here, we discuss some of the promising CRISPR-based assays which have the potential to transform COVID-19 diagnosis globally and curb this pandemic disease in the shortest possible time. © 2023 Elsevier Inc. All rights reserved.

4.
Smart Innovation, Systems and Technologies ; 335:199-229, 2023.
Article in English | Scopus | ID: covidwho-2251287

ABSTRACT

Over the last year, the evolution in Robotic Process Automation (RPA) has been staggering. The automation it brings to applications has yielded efficiency, reduced operating costs, and decreased the time of research, development, and production. Industries have already integrated RPA into their workflow and are profoundly transforming into an intelligent automated industry with minimum human intervention, calling this the fourth industrial revolution. In this race of transformation, the healthcare industry is quite ahead of many other industries. It stood the test of time when COVID-19 was spreading rapidly and was also resilient against all odds. The system did experience an unprecedented crisis that depicted its weakness, fragility, and unpreparedness. The healthcare system was forced to adapt to a new paradigm. And though there was the loss of life and economy, we learned to evolve as a community to tackle this crisis. This chapter sheds light on the role of RPA and covers how these technologies can assist healthcare workers in their day-to-today activities, reviewing what the fourth industrial revolution would look like in the healthcare sector. The intelligent, automated system would provide a seamless experience of gathering information by various means, processing, and assisting healthcare workers to deliver quality treatment. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

5.
Pathogens ; 10(10)2021 Sep 25.
Article in English | MEDLINE | ID: covidwho-2266812

ABSTRACT

Feline coronavirus (FCoV) is endemic in cat populations worldwide. Persistently, subclinically infected cats play a significant role in spreading the infection. Testing fecal samples of cats may facilitate efforts to decrease the viral burden within a population. Real-time RT-PCR is highly sensitive and specific for the detection of FCoV but must be performed in a fully equipped laboratory. A simple and accurate assay is needed to identify FCoV at the point-of-need. The aim of this study was to develop a rapid FCoV detection assay based on isothermal amplification technology, i.e., reverse transcription-recombinase polymerase amplification (RT-RPA). Primers were designed to target the highly conserved 3' untranslated region of the 7b gene. Running on a constant temperature of 42 °C, reverse transcription as well as DNA amplification and detection was achieved in a maximum of 15 min. A probit analysis revealed a detection limit of 58.5 RNA copies/reaction. For cross-detection, nucleic acids from 19 viruses were tested. Both RT-RPA and real-time RT-PCR showed cross-detection with canine coronavirus and transmissible gastroenteritis virus, but not with other pathogens. To evaluate clinical performance, RNA was extracted from 39 fecal samples from cats. All samples were tested simultaneously with real-time RT-PCR resulting in a RT-RPA sensitivity and specificity of 90.9% and 100%, respectively. RT-RPA can be considered a promising simple method for rapid detection of FCoV.

6.
Lab Med ; 2022 Oct 06.
Article in English | MEDLINE | ID: covidwho-2284100

ABSTRACT

OBJECTIVE: The outbreak of COVID-19 caused by SARS-CoV-2 has led to a serious worldwide pandemic. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR)-based methods were recommended for routine detection of SARS-CoV-2 RNA. Because the reaction time and analytical sensitivity of qRT-PCR limits the diagnosis of SARS-CoV-2, development of a quick process of SARS-CoV-2 detection technology with high analytical sensitivity remains urgent. METHODS: We combined isothermal amplification and fluorescence detection technology to develop a new auto-recombinase polymerase amplification (RPA)-fluorescence platform that could be used in the diagnosis of SARS-CoV-2. RESULTS: By optimization of primers and probes, the RPA platform could detect SARS-CoV-2 nucleotides within 15 min. The limits of detection and specificity of the auto-RPA-fluorescence platform were 5 copies/µL and 100%, respectively. The accuracy of detection of the auto-RPA-fluorescence platform in the 16 positive samples was 100%. CONCLUSION: The RPA platform is a potential technology for the diagnosis of SARS-CoV-2 infection.

7.
Microorganisms ; 11(2)2023 Jan 31.
Article in English | MEDLINE | ID: covidwho-2286055

ABSTRACT

First identified as a new circovirus in Hunan Province in China in 2019, porcine circovirus (PCV4) is now widely detected in other Chinese provinces and South Korea. In recent years, the virus has threatened pig health and operations in the pig industry. Hence, early PCV4 detection and regular surveillance are required to control the spread of infection and prevent collateral damage to the industry. Due to PCV4 being difficult to isolate in vitro, molecular detection methods, such as conventional PCR and real-time PCR, and serological assays are currently the main methods used for the detection of PCV4 infection. However, they are time-consuming, labor-intensive, and complex and require professional personnel. To facilitate rapid pen-side PCV4 diagnoses, we used clustered regularly interspaced short palindromic repeats (CRISPR) and Cas13a technology to develop a quick testing kit. Five recombinase-aided amplification (RPA) primer sets were designed based on the conserved PCV4-Cap gene nucleotide region, which were used to determine several key lateral flow strip (LFD) characteristics (sensitivity, specificity, and accuracy). The results showed that the RPA-Cas13a-LFD reaction could detect PCV4 within 1.5 h in genomic DNA harboring a minimum of a single copy. Furthermore, the assay showed good specificity and absence of cross-reactivity with PCV2, PCV3, or other porcine viruses. When we tested 15 clinical samples, a high accuracy was also recorded. Therefore, we successfully developed a detection assay that was simple, fast, accurate, and suitable for on-site PCV4 testing.

8.
Sens Actuators B Chem ; 383: 133531, 2023 May 15.
Article in English | MEDLINE | ID: covidwho-2240801

ABSTRACT

A fully-enclosed prototype 'pen' for rapid detection of SARS-CoV-2 based on reverse transcriptase isothermal recombinase polymerase amplification (RT-RPA) with dipstick assay was developed. The integrated handheld device, consisting of amplification, detection and sealing modules, was developed to perform rapid nucleic acid amplification and detection under a fully enclosed condition. After RT-RPA amplification with a metal bath or a normal PCR instrument, the amplicons were mixed with dilution buffer prior to being detected on a lateral flow strip. To avoid aerosol contamination causing false-positive, from amplification to final detection, the detection 'pen' had been enclosed to isolate from the environment. With colloidal gold strip-based detection, the detection results could be directly observed by eyes. By cooperating with other inexpensive and rapid methods for POC nucleic acid extraction, the developed 'pen' could detect COVID-19 or other infectious diseases in a convenient, simple and reliable way.

9.
J Med Virol ; 2022 Sep 11.
Article in English | MEDLINE | ID: covidwho-2232515

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused extensive loss of life worldwide. Further, the COVID-19 and influenza mix-infection had caused great distress to the diagnosis of the disease. To control illness progression and limit viral spread within the population, a real-time reverse-transcription PCR (RT-PCR) assay for early diagnosis of COVID-19 was developed, but detection was time-consuming (4-6 h). To improve the diagnosis of COVID-19 and influenza, we herein developed a recombinase polymerase amplification (RPA) method for simple and rapid amplification of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19 and Influenza A (H1N1, H3N2) and B (influenza B). Genes encoding the matrix protein (M) for H1N1, and the hemagglutinin (HA) for H3N2, and the polymerase A (PA) for Influenza B, and the nucleocapsid protein (N), the RNA-dependent-RNA polymerase (RdRP) in the open reading frame 1ab (ORF1ab) region, and the envelope protein (E) for SARS-CoV-2 were selected, and specific primers were designed. We validated our method using SARS-CoV-2, H1N1, H3N2 and influenza B plasmid standards and RNA samples extracted from COVID-19 and Influenza A/B (RT-PCR-verified) positive patients. The method could detect SARS-CoV-2 plasmid standard DNA quantitatively between 102 and 105 copies/ml with a log linearity of 0.99 in 22 min. And this method also be very effective in simultaneous detection of H1N1, H3N2 and influenza B. Clinical validation of 100 cases revealed a sensitivity of 100% for differentiating COVID-19 patients from healthy controls when the specificity was set at 90%. These results demonstrate that this nucleic acid testing method is advantageous compared with traditional PCR and other isothermal nucleic acid amplification methods in terms of time and portability. This method could potentially be used for detection of SARS-CoV-2, H1N1, H3N2 and influenza B, and adapted for point-of-care (POC) detection of a broad range of infectious pathogens in resource-limited settings.

10.
Trends Biotechnol ; 2022 Oct 19.
Article in English | MEDLINE | ID: covidwho-2231283

ABSTRACT

The coupling of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas RNA-programmable nucleases with nucleic acid detection platforms has brought radical changes to the field of disease diagnosis. Recently, Sánchez et al. developed a simple, rapid, highly sensitive, precise, and in-field deployable point-of-care (POC) and point-of-need (PON) molecular disease detection tool that can be used in diverse agricultural applications.

11.
Microbiol Spectr ; 11(1): e0296622, 2023 02 14.
Article in English | MEDLINE | ID: covidwho-2193562

ABSTRACT

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was initially identified in 2019, after which it spread rapidly throughout the world. With the progression of the epidemic, new variants of SARS-CoV-2 with faster transmission speeds and higher infectivity have constantly emerged. The proportions of people asymptomatically infected or reinfected after vaccination have increased correspondingly, making the prevention and control of COVID-19 extremely difficult. There is therefore an urgent need for rapid, convenient, and inexpensive detection methods. In this paper, we established a nucleic acid visualization assay targeting the SARS-CoV-2 nucleoprotein (N) gene by combining reverse transcription-recombinase polymerase amplification with closed vertical flow visualization strip (RT-RPA-VF). This method had high sensitivity, comparable to that of reverse transcription-quantitative PCR (RT-qPCR), and the concordance between RT-RPA-VF and RT-qPCR methods was 100%. This detection method is highly specific and is not compatible with bat coronavirus HKU4, human coronaviruses 229E, OC43, and HKU1-CoV, Middle East respiratory syndrome coronavirus (MERS-CoV), or other respiratory pathogens. However, multiple SARS-CoV-2 variants are detectable within 25 min at 42°C using this visual method, including RNA transcripts of the Wuhan-Hu-1 strain at levels as low as 1 copy/µL, the Delta strain at 1 copy/µL, and the Omicron strain at 0.77 copies/µL. The RT-RPA-VF method is a simple operation for the rapid diagnosis of COVID-19 that is safe and free from aerosol contamination and could be an affordable and attractive choice for governments seeking to promote their emergency preparedness and better their responses to the continuing COVID-19 epidemic. In addition, this method also has great potential for early monitoring and warning of the epidemic situation at on-site-nursing points. IMPORTANCE The global COVID-19 epidemic, ongoing since the initial outbreak in 2019, has caused panic and huge economic losses worldwide. Due to the continuous emergence of new variants, COVID-19 has been responsible for a higher proportion of asymptomatic patients than the previously identified SARS and MERS, which makes early diagnosis and prevention more difficult. In this manuscript, we describe a rapid, sensitive, and specific detection tool, RT-RPA-VF. This tool provides a new alternative for the detection of SARS-CoV-2 variants in a range as low as 1 to 0.77 copies/µL RNA transcripts. RT-RPA-VF has great potential to ease the pressure of medical diagnosis and the accurate identification of patients with suspected COVID-19 at point-of-care.


Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , SARS-CoV-2/genetics , Reverse Transcription , RNA, Viral/genetics , Recombinases/genetics , Sensitivity and Specificity
12.
European Journal of Molecular and Clinical Medicine ; 9(7):8388-8394, 2022.
Article in English | EMBASE | ID: covidwho-2168680

ABSTRACT

Artificial intelligence (AI)/digital employees, or metaphorical software robots (bots), are the foundation of the business process automation technology known as robotic process automation (RPA). The term "software robotics" has been used sometimes (not to be confused with robot software). Using internal application programming interfaces (APIs) or specialized scripting languages, a software developer creates a set of steps to automate a job and interface to the back-end system in conventional workflow automation technologies. RPA systems, on the other hand, create the action list by seeing the user carry out the job in the graphical user interface (GUI) of the programme, and then carry out the automation by repeating those actions directly in the GUI. In products that may not normally have APIs for this purpose, this can lessen the barrier to the usage of automation. Nowadays, monitoring every day covid status is not possible for an individual. So, the plan is to send an updated covid status through email automatically to the end users by using Robotic Process Automation (RPA). The main goal of this paper is to send corona information to the end users who are in need of covid details. For this, the end user wants to provide their email id and country name which they want to know about. The rest of the RPA process will be done by the bot using data scraping. Then email automation will be done to send email automatically. It is easy to check the required particular data from the cluster of data. It is easy to read and understand for all end users. Copyright © 2022 Ubiquity Press. All rights reserved.

13.
SSM Popul Health ; 21: 101329, 2023 Mar.
Article in English | MEDLINE | ID: covidwho-2165871

ABSTRACT

Objectives: In response to the COVID-19 pandemic, Australia implemented mandatory hotel quarantine for returned international travellers from March 2020-November 2021. Healthcare was rapidly transformed and scaled up to facilitate delivery of face-to-face and virtual healthcare within quarantine facilities. We sought to understand, from the patient perspective, what a virtual model of healthcare may need to be aware of to respond to, protect, and mitigate people's mental health within a 'public health protection' context of quarantine. Design: Qualitative study design using in-depth semi-structured interviews exploring experiences of the virtual model of healthcare in quarantine. Setting: Special Health Accommodation (SHA) quarantine facilities following Australian Federal and New South Wales (NSW) State quarantine policy, NSW, Australia. Participants: 25 returned international travellers aged 18 years or older of any COVID-19 status who quarantined within SHA between October 2020-March 2021. Results: Participants identified three broad areas of concern. Firstly, their potential to transmit COVID-19, that created anxiety for all participants. Secondly, the effects of losing personal freedoms in quarantine to protect the wider Australian community. Thirdly, many participants entered quarantine during intense biographical moments in their lives, compounding the stress of their experience. Participants felt lost within the 'faceless' quarantine administrative system they navigated prior to their actual arrival in Australia and during their mandated quarantine period. This cumulative experience compromised their expectations and experiences of person-centred care once in quarantine. Conclusions: Quarantine has been a critical public health measure for managing COVID-19 in Australia. The pandemic provides opportunities to learn from quarantine implementation. Participants struggled to separate healthcare provision from the broader quarantine systems and processes. Due to this confusion, blame was directed at healthcare providers for many, and in some cases all difficulties, including those encountered getting into and once within quarantine. Valuable lessons can be learnt from engaging with patients' perspectives to adapt and strengthen future quarantine to deliver responsive, person-centred healthcare.

14.
Bioengineering (Basel) ; 9(10)2022 10 18.
Article in English | MEDLINE | ID: covidwho-2081979

ABSTRACT

The outbreak of the monkeypox virus (MPXV) in non-endemic countries is an emerging global health threat and may have an economic impact if proactive actions are not taken. As shown by the COVID-19 pandemic, rapid, accurate, and cost-effective virus detection techniques play a pivotal role in disease diagnosis and control. Considering the sudden multicountry MPXV outbreak, a critical evaluation of the MPXV detection approaches would be a timely addition to the endeavors in progress for MPXV control and prevention. Herein, we evaluate the current MPXV detection methods, discuss their pros and cons, and provide recommended solutions to the problems. We review the traditional and emerging nucleic acid detection approaches, immunodiagnostics, whole-particle detection, and imaging-based MPXV detection techniques. The insights provided in this article will help researchers to develop novel techniques for the diagnosis of MPXV.

15.
BMC Vet Res ; 18(1): 369, 2022 Oct 11.
Article in English | MEDLINE | ID: covidwho-2064800

ABSTRACT

BACKGROUND: Swine acute diarrhea syndrome coronavirus (SADS-CoV) causes acute vomiting and diarrhea in piglets, leading to significant financial losses for the pig industry. Recombinase polymerase amplification (RPA) is a rapid nucleic acid amplification technology used under constant temperature conditions. The study established a real-time reverse transcription (RT)-RPA assay for early diagnosis of SADS-CoV.  RESULTS: The detection limit of the real-time RT-RPA was 74 copies/µL of SADS-CoV genomic standard recombinant plasmid in 95% of cases. The assay was performed in less than 30 min and no cross-reactions were observed with eight other common viruses that affect swine, including classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), pseudo rabies virus (PRV), swine influenza virus (SIV), seneca valley virus (SVA), transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV). The coefficient of variation (C.V.) values of the two standards dilutions and three positive clinical sample ranged from 2.95% to 4.71%. A total of 72 clinical fecal samples from swine with diarrheal symptoms were analyzed with the developed RT-RPA and quantitative RT-PCR. There was 98.61% agreement between the RT-RPA and the quantitative real-time PCR results. CONCLUSIONS: These results indicated that the developed RT-RPA assay had good specificity, sensitivity, stability and repeatability. The study successfully established a broadly reactive RT-RPA assay for SADS-CoV detection.


Subject(s)
Alphacoronavirus , Coronavirus Infections , Nucleic Acids , Swine Diseases , Alphacoronavirus/genetics , Animals , Coronavirus Infections/diagnosis , Coronavirus Infections/veterinary , Diarrhea/diagnosis , Diarrhea/veterinary , Real-Time Polymerase Chain Reaction/veterinary , Recombinases , Sensitivity and Specificity , Swine , Swine Diseases/diagnosis
17.
Biosensors (Basel) ; 12(8)2022 Aug 13.
Article in English | MEDLINE | ID: covidwho-2023160

ABSTRACT

Dermatophytosis, an infectious disease caused by several fungi, can affect the hair, nails, and/or superficial layers of the skin and is of global significance. The most common dermatophytes in cats and dogs are Microsporum canis and Trichophyton mentagrophytes. Wood's lamp examination, microscopic identification, and fungal culture are the conventional clinical diagnostic methods, while PCR (Polymerase Chain Reaction) and qPCR (Quantitative PCR) are playing an increasingly important role in the identification of dermatophytes. However, none of these methods could be applied to point-of-care testing (POCT). The recent development of the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) based diagnostic platform promises a rapid, accurate, and portable diagnostic tool. In this paper, we present a Cas12a-fluorescence assay to detect and differentiate the main dermatophytes in clinical samples with high specificity and sensitivity. The Cas12a-based assay was performed with a combination of recombinase polymerase amplification (RPA). The results could be directly visualized by naked eyes under blue light, and all tested samples were consistent with fungal culture and sequencing results. Compared with traditional methods, the RPA-Cas12a-fluorescence assay requires less time (about 30 min) and less complicated equipment, and the visual changes can be clearly observed with naked eyes, which is suitable for on-site clinical diagnosis.


Subject(s)
Arthrodermataceae , Dermatomycoses , Animals , CRISPR-Cas Systems , Cats , Dermatomycoses/diagnosis , Dermatomycoses/microbiology , Dermatomycoses/veterinary , Dogs , Hair/microbiology , Recombinases
18.
Talanta ; 252: 123835, 2023 Jan 15.
Article in English | MEDLINE | ID: covidwho-1984108

ABSTRACT

In this paper we present a new method for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), targeting a specific region "N gene." Under isothermal reaction conditions, we integrated ligation (Lig; high selectivity) and recombinase polymerase amplification (RPA; high sensitivity) processes, obtaining a robust method of detection. For point-of-care testing, we incorporated our laboratory-produced pyrophosphate ion (PPi)-sensing probe (PK-probe) for colorimetric analysis of the reaction. The total detection system was efficient and effective at diagnosing this RNA virus-mediated disease rapidly (30 min). In a full-genome SARS-CoV-2 study, our PK-probe/Lig-RPA system functioned with a limit of detection of 1160 copies/ml, with a single-mismatch level of selectively, and it was highly selective even in the presence of bacterial genomes commonly found in the human mouth and nose. This robust, straightforward, selective, efficient, and ultrasensitive colorimetric detection method, with potential for point-of-care analysis, should also be effective in detecting a diverse range of other RNA-based diseases.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Recombinases , Colorimetry , Nucleic Acid Amplification Techniques/methods , COVID-19/diagnosis , Sensitivity and Specificity , RNA, Viral
19.
Front Vet Sci ; 9: 962438, 2022.
Article in English | MEDLINE | ID: covidwho-1979080

ABSTRACT

African swine fever virus (ASFV) is a leading cause of worldwide agricultural loss. ASFV is a highly contagious and lethal disease for both domestic and wild pigs, which has brought enormous economic losses to a number of countries. Conventional methods, such as general polymerase chain reaction and isothermal amplification, are time-consuming, instrument-dependent, and unsatisfactorily accurate. Therefore, rapid, sensitive, and field-deployable detection of ASFV is important for disease surveillance and control. Herein, we created a one-pot visual detection system for ASFV with CRISPR/Cas12a technology combined with LAMP or RPA. A mineral oil sealing strategy was adopted to mitigate sample cross-contamination between parallel vials during high-throughput testing. Furthermore, the blue fluorescence signal produced by ssDNA reporter could be observed by the naked eye without any dedicated instrument. For CRISPR-RPA system, detection could be completed within 40 min with advantageous sensitivity. While CRISPR-LAMP system could complete it within 60 min with a high sensitivity of 5.8 × 102 copies/µl. Furthermore, we verified such detection platforms display no cross-reactivity with other porcine DNA or RNA viruses. Both CRISPR-RPA and CRISPR-LAMP systems permit highly rapid, sensitive, specific, and low-cost Cas12a-mediated visual diagnostic of ASFV for point-of-care testing (POCT) applications.

20.
Biology (Basel) ; 11(7)2022 Jul 06.
Article in English | MEDLINE | ID: covidwho-1963700

ABSTRACT

Porcine epidemic diarrhea virus (PEDV) infection is an important acute diarrheal disease of swine that results in economic and industrial losses worldwide. The clinical manifestations in infected piglets are severe diarrhea, dehydration with milk curd indigestion, leading to death. The diagnosis of PEDV is essential for monitoring and managing the disease. PEDV can be detected and identified by serology and the nucleic acid of the virus in clinical samples. Therefore, a novel isothermal amplification and detection technique, reverse transcription-recombinase polymerase amplification couple nucleic acid lateral flow (RT-RPA-NALF) was developed for the rapid detection of PEDV. Qualitative reverse transcription-polymerase chain reaction (RT-qPCR) was established as the gold standard assay to compare results. Specific primer pairs and probes were designed, and RT-RPA conditions were optimized to amplify the M gene of PEDV. The established RT-RPA-NALF assay could finish in 25 min at a temperature of 42 °C and the amplicon interpreted by visual detection. The developed RT-RPA-NALF assay was specific to the M gene of PEDV, did not detect other common swine diarrhea pathogens, and showed minimal detection at 102 TCID50/mL PEDV. The RT-RPA-NALF assay can detect PEDV in 5 simulated fecal samples. Furthermore, in 60 clinical fecal samples, the results of RT-RPA-NALF correlated with RT-qPCR assay, which provides sensitivity of 95.65% and specificity of 100%, with a coincident rate of 98.33%. The rapid RT-RPA-NALF is simple and rapid, increases high sensitivity, and can be used in the field.

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