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Evaluation of a real-time mobile PCR device (PCR 1100) for the detection of the rabies gene in field samples. Trop Med Health 2023; 51:17. [PMID: 36932428 PMCID: PMC10020757 DOI: 10.1186/s41182-023-00501-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 01/23/2023] [Indexed: 03/19/2023] Open
Abstract
BACKGROUND The Philippines is ranked among the top countries with 200-300 annual deaths due to rabies. Most human rabies cases have been reported in remote areas, where dog surveillance is inadequate. Therefore, a strategy to effectively improve surveillance in remote areas will increase the number of detections. Detecting pathogens using portable real-time reverse transcription-polymerase chain reaction (RT-PCR) has the potential to be accepted in these areas. Thus, we aimed to develop an assay to detect the rabies virus (RABV) genome by combining the robust primer system LN34 with the PicoGene PCR1100 portable rapid instrument targeting RABV RNA (PCR1100 assay). METHODS Procedures were optimised using an LN34 primer/probe set, KAPA3G Plant PCR Kit (KAPA Biosystems), FastGene Scriptase II (NIPPON Genetics), and an artificial positive control RNA. RESULTS Positive control RNA showed an analytical limit of detection of 10 copies/µL without false positivity, generating results in approximately 32 min. Compared to dFAT or RT-qPCR using field samples, the sensitivity and specificity of the PCR1100 assay were 100%, and even lower copy numbers (approximately 10 copies/µL) were detected. CONCLUSIONS This study demonstrated that the developed assay can detect rabies RNA in field samples. Because dog-mediated rabies is endemic in remote areas, the rapidity, mobility, and practicality of the PCR1100 assay as well as the high sensitivity of the LN34 system make it an ideal tool for the confirmation of rabies in these areas.
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Iqbal BN, Arunasalam S, Divarathna MVM, Jabeer AAOM, Sirisena PDNN, Senaratne T, Muthugala R, Noordeen F. Diagnostic utility and validation of a newly developed real time loop mediated isothermal amplification method for the detection of SARS CoV-2 infection. JOURNAL OF CLINICAL VIROLOGY PLUS 2022; 2:100081. [PMID: 35540180 PMCID: PMC9069985 DOI: 10.1016/j.jcvp.2022.100081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 04/23/2022] [Accepted: 05/04/2022] [Indexed: 01/17/2023] Open
Abstract
Background Detecting SARS-CoV-2 using a simple real time molecular assay will be helpful for the mitigation efforts in low / middle income countries during the pandemic. We have developed and validated a rapid and simple real time loop mediated isothermal amplification assay (LAMP) for screening of SARS-CoV-2 infection in known infected and non-infected individuals. Methods Six sets of primers were designed targeting the N-gene of the SARS-CoV-2 (Accession ID MN994468). LAMP reactions were performed using Warm Start 2X Master Mix and real-time PCR machine at 65 °C for 60 cycles with 15 s for each cycle. Results were read by visualizing turbidity under ultraviolet light and real time fluorescence detection through FAM channel of the real time PCR machine. We tested a total of 320 including 240 SARS CoV-2 positive (Ct values <40) and 80 SARS CoV-2 negative samples as tested by a real time RT-PCR using the newly developed LAMP assay. Results A total of 206 out of 240 SARS CoV-2 positive samples were tested positive by the newly developed LAMP assay with a sensitivity of 86%. All 80 SARS CoV-2 negative samples were tested negative by the newly developed LAMP assay with a specificity of 100%. Conclusion The newly developed real time LAMP assay has a sensitivity of 86% and specificity of 100% compared to the real time RT-PCR for the detection of SARS CoV-2. The new assay will be useful to screen large number of samples if adopted to minimize the time and cost.
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Affiliation(s)
- Bushran N Iqbal
- Diagnostic and Research Virology Laboratory, Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka
| | - Shiyamalee Arunasalam
- Diagnostic and Research Virology Laboratory, Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka
| | - Maduja V M Divarathna
- Diagnostic and Research Virology Laboratory, Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka
| | - AAOM Jabeer
- Diagnostic and Research Virology Laboratory, Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka
| | | | - Thamarasi Senaratne
- Department of Multidisciplinary Sciences, Faculty of Allied Health Sciences, General Sir John Kotelawala Defense University, Werahera, Ratmalana 10390, Sri Lanka
| | - Rohitha Muthugala
- Diagnostic and Reference Virology Laboratory, National Hospital, Kandy 20000, Sri Lanka
| | - Faseeha Noordeen
- Diagnostic and Research Virology Laboratory, Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka,Corresponding author
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Wee SK, Sivalingam SP, Yap EPH. Rapid Direct Nucleic Acid Amplification Test without RNA Extraction for SARS-CoV-2 Using a Portable PCR Thermocycler. Genes (Basel) 2020; 11:E664. [PMID: 32570810 PMCID: PMC7349311 DOI: 10.3390/genes11060664] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/02/2020] [Accepted: 06/16/2020] [Indexed: 12/20/2022] Open
Abstract
There is an ongoing worldwide coronavirus disease 2019 (Covid-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At present, confirmatory diagnosis is by reverse transcription polymerase chain reaction (RT-PCR), typically taking several hours and requiring a molecular laboratory to perform. There is an urgent need for rapid, simplified, and cost-effective detection methods. We have developed and analytically validated a protocol for direct rapid extraction-free PCR (DIRECT-PCR) detection of SARS-CoV-2 without the need for nucleic acid purification. As few as six RNA copies per reaction of viral nucleocapsid (N) gene from respiratory samples such as sputum and nasal exudate can be detected directly using our one-step inhibitor-resistant assay. The performance of this assay was validated on a commercially available portable PCR thermocycler. Viral lysis, reverse transcription, amplification, and detection are achieved in a single-tube homogeneous reaction within 36 min. This minimizes hands-on time, reduces turnaround-time for sample-to-result, and obviates the need for RNA purification reagents. It could enable wider use of Covid-19 testing for diagnosis, screening, and research in countries and regions where laboratory capabilities are limiting.
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Affiliation(s)
| | | | - Eric Peng Huat Yap
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore; (S.K.W.); (S.P.S.)
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Li L, He JA, Wang W, Xia Y, Song L, Chen ZH, Zuo HZ, Tan XP, Ho AHP, Kong SK, Loo JFC, Li HW, Gu D. Development of a direct reverse-transcription quantitative PCR (dirRT-qPCR) assay for clinical Zika diagnosis. Int J Infect Dis 2019; 85:167-174. [PMID: 31202908 DOI: 10.1016/j.ijid.2019.06.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/28/2019] [Accepted: 06/09/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE The nucleic acid-based polymerase chain reaction (PCR) assay is commonly applied to detect infection with Zika virus (ZIKV). However, the time- and labor-intensive sample pretreatment required to remove inhibitors that cause false-negative results in clinical samples is impractical for use in resource-limited areas. The aim was to develop a direct reverse-transcription quantitative PCR (dirRT-qPCR) assay for ZIKV diagnosis directly from clinical samples. METHODS The combination of inhibitor-tolerant polymerases, polymerase enhancers, and dirRT-qPCR conditions was optimized for various clinical samples including blood and serum. Sensitivity was evaluated with standard DNA spiked in simulated samples. Specificity was evaluated using clinical specimens of other infections such as dengue virus and chikungunya virus. RESULTS High specificity and sensitivity were achieved, and the limit of detection (LOD) of the assay was 9.5×101 ZIKV RNA copies/reaction. The on-site clinical diagnosis of ZIKV required a 5μl sample and the diagnosis could be completed within 2h. CONCLUSIONS This robust dirRT-qPCR assay shows a high potential for point-of-care diagnosis, and the primer-probe combinations can also be extended for other viral detection. It realizes the goal of large-scale on-site screening for viral infections and could be used for early diagnosis and the prevention and control of viral outbreaks.
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Affiliation(s)
- Lang Li
- School of Public Health, The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, PR China; Shenzhen International Travel Health Care Center and Shenzhen Academy of Inspection and Quarantine, Shenzhen Customs District, Shenzhen, 518033, PR China
| | - Jian-An He
- Shenzhen International Travel Health Care Center and Shenzhen Academy of Inspection and Quarantine, Shenzhen Customs District, Shenzhen, 518033, PR China
| | - Wei Wang
- Department of Laboratory Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Health Science Center, Shenzhen, 518035, PR China
| | - Yun Xia
- Shenzhen International Travel Health Care Center and Shenzhen Academy of Inspection and Quarantine, Shenzhen Customs District, Shenzhen, 518033, PR China
| | - Li Song
- School of Public Health, The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, PR China; Shenzhen International Travel Health Care Center and Shenzhen Academy of Inspection and Quarantine, Shenzhen Customs District, Shenzhen, 518033, PR China
| | - Ze-Han Chen
- School of Public Health, The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, PR China
| | - Hang-Zhi Zuo
- School of Public Health, The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, PR China
| | - Xuan-Ping Tan
- Shenzhen gene-one Biotechnology Co., Ltd., 518000, PR China
| | - Aaron Ho-Pui Ho
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, PR China
| | - Siu-Kai Kong
- Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, PR China
| | - Jacky Fong-Chuen Loo
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, PR China; Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
| | - Hua-Wen Li
- School of Public Health, The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, PR China.
| | - Dayong Gu
- Shenzhen International Travel Health Care Center and Shenzhen Academy of Inspection and Quarantine, Shenzhen Customs District, Shenzhen, 518033, PR China; Department of Laboratory Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Health Science Center, Shenzhen, 518035, PR China.
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de Oliveira Figueiredo P, de Oliveira DB, Figueiredo LB, Costa GB, Alves PA, Guedes MIMC, Barbosa-Stancioli EF, Drumond BP, Abrahão JS, Kroon EG, de Souza Trindade G. Molecular detection and phylogeny of bovine viral diarrhea virus 1 among cattle herds from Northeast, Southeast, and Midwest regions, Brazil. Braz J Microbiol 2019; 50:571-577. [PMID: 30879262 DOI: 10.1007/s42770-019-00064-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/12/2018] [Indexed: 11/30/2022] Open
Abstract
We examined the circulating BVDV species and genotypes among cattle herds from Northeast, Southeast, and Midwest regions in Brazil. A total of 77 animals tested positive through standard PCR. Phylogenetic analyses revealed the presence of BVDV-1a, highlighting the need for better surveillance strategies to prevent BVDV spread in the country.
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Affiliation(s)
- Poliana de Oliveira Figueiredo
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
| | - Danilo Bretas de Oliveira
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.,Faculdade de Medicina, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil
| | - Leandra Barcelos Figueiredo
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Galileu Barbosa Costa
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Pedro Augusto Alves
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.,Laboratório de Imunologia de Doenças Virais, Fundação Oswaldo Cruz, Centro de Pesquisas René Rachou, Belo Horizonte, MG, Brazil
| | - Maria Isabel Maldonado Coelho Guedes
- Laboratório de Pesquisa em Virologia Animal, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Edel Figueiredo Barbosa-Stancioli
- Laboratório de Virologia Básica e Aplicada, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Betânia Paiva Drumond
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Jônatas Santos Abrahão
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Erna Geessien Kroon
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Giliane de Souza Trindade
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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Barra GB, Santa Rita TH, Jardim DP, Mesquita PG, Nobre CS, Jácomo RH, Abdalla Nery LF. Genotyping of Single Nucleotide Polymorphisms Using Allele-Specific qPCR Producing Amplicons of Small Sizes Directly from Crude Serum Isolated from Capillary Blood by a Hand-Powered Paper Centrifuge. Diagnostics (Basel) 2019; 9:diagnostics9010009. [PMID: 30641881 PMCID: PMC6468353 DOI: 10.3390/diagnostics9010009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/27/2018] [Accepted: 12/29/2018] [Indexed: 12/26/2022] Open
Abstract
The cell-free genomic DNA (gDNA) concentration in serum ranges from 1500 to 7500 copies/mL within 2 h after phlebotomy (6⁻24 times the concentration observed in plasma). Here, we aimed to evaluate the gDNA size distribution in serum with time after coagulation and to test if crude serum can be directly used as a source of gDNA for qPCR. Next, we investigated if single nucleotide polymorphisms (SNPs) could be genotyped directly from the crude serum isolated from capillary blood using a hand-powered paper centrifuge. All tested PCR targets (65, 100, 202 and 688 base pairs) could be successfully amplified from DNA extracted from serum, irrespective of their amplicon size. The observed qPCR quantitation cycles suggested that the genomic DNA yield increased in serum with incubation at room temperature. Additionally, only 65 and 101 base pair qPCR targets could be amplified from crude serum soon after the coagulation. Incubation for 4 days at room temperature was necessary for the amplification of PCR targets of 202 base pairs. The 688 base pair qPCR target could not be amplified from serum directly. Lastly, serum was successfully separated from capillary blood using the proposed paper centrifuge and the genotypes were assigned by testing the crude serum using allele-specific qPCR, producing small amplicon sizes in complete agreement with the genotypes assigned by testing the DNA extracted from whole blood. The serum can be used directly as the template in qPCR for SNP genotyping, especially if small amplicon sizes are applied. This shortcut in the SNP genotyping process could further molecular point-of-care diagnostics due to elimination of the DNA extraction step.
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Affiliation(s)
- Gustavo Barcelos Barra
- Sabin Laboratory, Brasília 70632-300, Brazil.
- Post-Graduation of Health Science, University of Brasília, Brasilia 70910-900, Brazil.
| | - Ticiane Henriques Santa Rita
- Sabin Laboratory, Brasília 70632-300, Brazil.
- Post-Graduation of Health Science, University of Brasília, Brasilia 70910-900, Brazil.
| | - Daniella Paniago Jardim
- Sabin Laboratory, Brasília 70632-300, Brazil.
- Post-Graduation of Health Science, University of Brasília, Brasilia 70910-900, Brazil.
| | | | - Camila Santos Nobre
- Sabin Laboratory, Brasília 70632-300, Brazil.
- Post-Graduation of Health Science, University of Brasília, Brasilia 70910-900, Brazil.
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Russell GC, Grant DM, Lycett S, Bachofen C, Caldow GL, Burr PD, Davie K, Ambrose N, Gunn GJ, Zadoks RN. Analysis of bovine viral diarrhoea virus: Biobank and sequence database to support eradication in Scotland. Vet Rec 2017; 180:447. [PMID: 28386029 DOI: 10.1136/vr.104072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2017] [Indexed: 12/12/2022]
Abstract
Samples from bovine viral diarrhoea virus (BVDV)-positive cattle were gathered by Scottish diagnostic laboratories and used to produce a Biobank of samples with associated location and identification data in support of the Scottish BVDV eradication scheme. The samples were subject to direct amplification and sequencing of the 5'-untranslated region (5'-UTR) to define the viral types and subtypes present. From 2693 samples collected prior to 2016, approximately 2300 sequences were obtained, representing 8 BVDV type 1 subtypes. No BVDV type 2 samples were detected. The samples came from all regions of the UK but 66 per cent were from Scotland. Analysis of the sequences showed great diversity in the 5'-UTR, with 1206 different sequences. Many samples carried virus with identical 5'-UTR sequences; often from single locations, but there were also examples of the same sequence being obtained from samples at several different locations. This work provides a resource that can be used to analyse the movement of BVDV strains both within Scotland and between Scotland and other nations, particularly in the latter stages of the Scottish eradication programme, and so inform the advice available to both livestock keepers and policymakers.
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Affiliation(s)
- G C Russell
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK
| | - D M Grant
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK
| | - S Lycett
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow
| | - C Bachofen
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK
| | - G L Caldow
- SAC Consulting: Veterinary Services, Allan Watt Building, Bush Estate, Penicuik, Midlothian
| | - P D Burr
- Biobest Laboratories Ltd, Edinburgh Technopole, Penicuik, Midlothian EH26 0PY, UK
| | - K Davie
- Animal Health and Welfare Division, Directorate for Agriculture and Rural Economy, Scottish Government, Saughton House, Edinburgh EH11 3XD, UK
| | - N Ambrose
- Animal Health and Welfare Division, Directorate for Agriculture and Rural Economy, Scottish Government, Saughton House, Edinburgh EH11 3XD, UK
| | - G J Gunn
- SRUC Epidemiology Research Unit, An Lochran, Beechwood Campus, Inverness IV2 5NA, UK
| | - R N Zadoks
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK
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A newly developed BVDV-1 RT-qPCR Taqman assay based on Italian isolates: evaluation as a diagnostic tool. Folia Microbiol (Praha) 2017; 62:279-286. [PMID: 28127668 DOI: 10.1007/s12223-017-0497-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 01/15/2017] [Indexed: 01/01/2023]
Abstract
A single-step TaqMan® RT-qPCR was developed for the detection of bovine viral diarrhea virus type 1 (BVDV-1), an important pathogen of cattle worldwide. The assay was based on conserved 5'UTR sequences of Italian BVDV-1 isolates. In order to establish a diagnostic protocol which simplifies sample collection and processing, the assay was tested on a variety of biological specimens collected from persistently infected calves. The samples analyzed included PBMCs, plasma, dry blood, ear notch and hair bulb. Time and costs required for the analysis of each type of specimen were compared. The RT-qPCR, whose lower limit of detection was 100 copies of viral RNA (1 TCID50), correctly identified all PI animals, irrespective of the type of specimen. The highest copy numbers were obtained from the RNAs extracted from PBMCs, ear notches and hair bulbs. Hair bulb-supernatants directly used as a template allowed identification of all PI animals. In conclusion, based on time and cost evaluation, the most effective and efficient protocol was the one based on the direct analysis of hair bulb-supernatants, avoiding the RNA extraction step.
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Grant DM, Dagleish MP, Bachofen C, Boag B, Deane D, Percival A, Zadoks RN, Russell GC. Assessment of the rabbit as a wildlife reservoir of bovine viral diarrhea virus: serological analysis and generation of trans-placentally infected offspring. Front Microbiol 2015; 6:1000. [PMID: 26441927 PMCID: PMC4585287 DOI: 10.3389/fmicb.2015.01000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/07/2015] [Indexed: 11/13/2022] Open
Abstract
Eradication of bovine viral diarrhea virus (BVDV) is ongoing in many European countries and is based on removal of persistently infected (PI) cattle. In this context, low-level risks, including alternative reservoirs of infection, may become more important as the number of BVDV-free herds increases. Alternative reservoirs include livestock, such as sheep and goats, as well as wildlife, including deer and rabbits. Due to the extensive nature of the beef industry in Scotland, where an eradication program started in 2010, contact between cattle and alternative reservoir hosts is common. Seroprevalence to BVDV in rabbit populations can be high. In addition, rabbits can be infected with BVDV by natural routes, indicating that they could be a wildlife reservoir of infection. We analyzed the potential risk to livestock from rabbit populations in the UK by two approaches. First, ∼260 serum samples from free-ranging wild rabbits in Scotland and northern England were tested for BVDV-specific antibodies by ELISA. Only three samples exhibited low level BVDV-specific reactivity, suggesting that BVDV infection of rabbits was not frequent. Second, rabbits were challenged with BVDV at day 7 or 12 of pregnancy. This did not lead to any clinical signs in the infected animals or obvious increases in abortion or stillbirth in the infected dams. Samples from the dams, placental material and ∼130 offspring were tested by BVDV-specific RT-PCR and antibody ELISA. Positive PCR results in the placentas and in the tissues and body fluids of rabbits up to 10 days old showed that trans-placental infection of rabbits with BVDV had occurred. Many of the offspring had BVDV-specific antibodies. These data support the view that a wildlife reservoir of BVDV in rabbit poses a small but non-zero risk of re-infection for BVDV-free cattle herds. Rabbits are susceptible to infection with BVDV but only a small proportion of free-living rabbits in the UK appear to have been infected.
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Affiliation(s)
- Dawn M Grant
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK
| | - Mark P Dagleish
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK
| | - Claudia Bachofen
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK
| | | | - David Deane
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK
| | - Ann Percival
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK
| | - Ruth N Zadoks
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK ; Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, UK
| | - George C Russell
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park Midlothian, UK
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Kang K, Yang K, Zhong J, Tian Y, Zhang L, Zhai J, Zhang L, Song C, Gou CY, Luo J, Gou D. A direct real-time polymerase chain reaction assay for rapid high-throughput detection of highly pathogenic North American porcine reproductive and respiratory syndrome virus in China without RNA purification. J Anim Sci Biotechnol 2014; 5:45. [PMID: 25324970 PMCID: PMC4198619 DOI: 10.1186/2049-1891-5-45] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/25/2014] [Indexed: 01/16/2023] Open
Abstract
Background Porcine reproductive and respiratory syndrome virus (PRRSV), and particularly its highly pathogenic genotype (HP-PRRSV), have caused massive economic losses to the global swine industry. Results To rapidly identify HP-PRRSV, we developed a direct real-time reverse transcription polymerase chain reaction method (dRT-PCR) that could detect the virus from serum specimen without the need of RNA purification. Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result. Additionally, the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR (cRT-PCR) that used purified RNA. The lowest detection limit of HP-PRRSV was 6.3 TCID50 using dRT-PCR. We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR. Moreover, the dRT-PCR method was able to tolerate 5-20% (v/v) serum. Conclusions Our dRT-PCR assay allows for easier, faster, more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods. To the best of our knowledge, this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA. We believe our approach has a great potential for application to other RNA viruses. Electronic supplementary material The online version of this article (doi:10.1186/2049-1891-5-45) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kang Kang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100 China ; College of Life Sciences, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, 518060 China
| | - Keli Yang
- Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, 430064 China
| | - Jiasheng Zhong
- College of Life Sciences, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, 518060 China
| | - Yongxiang Tian
- Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, 430064 China
| | - Limin Zhang
- College of Life Sciences, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, 518060 China
| | - Jianxin Zhai
- Shenzhen Ao Dong Inspection and Testing Technology Co,. Ltd, Shenzhen, 518000 China
| | - Li Zhang
- Shenzhen Ao Dong Inspection and Testing Technology Co,. Ltd, Shenzhen, 518000 China
| | - Changxu Song
- Veterinary Medicine Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640 China
| | | | - Jun Luo
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100 China
| | - Deming Gou
- College of Life Sciences, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, Shenzhen, 518060 China
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