1
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Li T, Wong TKF, Ranjard L, Rodrigo AG. pgHMA: Application of the heteroduplex mobility assay analysis in phylogenetics and population genetics. Mol Ecol Resour 2021; 22:653-663. [PMID: 34551204 DOI: 10.1111/1755-0998.13508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 11/26/2022]
Abstract
The heteroduplex mobility assay (HMA) has proven to be a robust tool for the detection of genetic variation. Here, we describe a simple and rapid application of the HMA by microfluidic capillary electrophoresis, for phylogenetics and population genetic analyses (pgHMA). We show how commonly applied techniques in phylogenetics and population genetics have equivalents with pgHMA: phylogenetic reconstruction with bootstrapping, skyline plots, and mismatch distribution analysis. We assess the performance and accuracy of pgHMA by comparing the results obtained against those obtained using standard methods of analyses applied to sequencing data. The resulting comparisons demonstrate that: (a) there is a significant linear relationship (R2 = .992) between heteroduplex mobility and genetic distance, (b) phylogenetic trees obtained by HMA and nucleotide sequences present nearly identical topologies, (c) clades with high pgHMA parametric bootstrap support also have high bootstrap support on nucleotide phylogenies, (d) skyline plots estimated from the UPGMA trees of HMA and Bayesian trees of nucleotide data reveal similar trends, especially for the median trend estimate of effective population size, and (e) optimized mismatch distributions of HMA are closely fitted to the mismatch distributions of nucleotide sequences. In summary, pgHMA is an easily-applied method for approximating phylogenetic diversity and population trends.
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Affiliation(s)
- Teng Li
- Research School of Biology, Australian National University, Canberra, ACT, Australia.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Thomas K F Wong
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Louis Ranjard
- Research School of Biology, Australian National University, Canberra, ACT, Australia.,PlantTech Research Institute, Tauranga, New Zealand
| | - Allen G Rodrigo
- Research School of Biology, Australian National University, Canberra, ACT, Australia.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
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2
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Generation and properties of one strain of H3N2 influenza virus with enhanced replication. Vet Microbiol 2020; 253:108970. [PMID: 33421685 DOI: 10.1016/j.vetmic.2020.108970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/20/2020] [Indexed: 11/23/2022]
Abstract
H3N2 canine influenza virus (CIV) has been circulating in many countries since 2008. The epidemic spread of CIV could be a concern for public health because of the close contact between humans and companion animals. In this study, we used Madin-Darby canine kidney (MDCK) cells as a coinfection model of H3N2 CIV and the pandemic (2009) H1N1 influenza virus to investigate the possibility of genetic mutation or recombination. One of the resultant progeny viruses, designated as CP15, was identified with a significantly increased replication ability. For this viral strain all segments exhibit a homology close to 100 % with its parental strain A/Canine/Jiangsu/06/2010 (JS/10), except for two site mutations K156E and R201 K which occur in the receptor-binding sites of hemagglutinin (HA) and antigen binding sites of neuraminidase (NA), respectively. Virus growth in MDCK cells showed that CP15 had a higher virus titer (more than 10 times) than JS/10. Consistent with this, CP15 exhibited extensive tissue tropism and higher viral RNA loads in the spleen, kidney and lung of mice challenged with this virus compared to JS/10. However, body weight loss and lung injure score due to CP15 infection were greatly reduced. Importantly, anti-CP15 serum antibodies could confer a high neutralization activity against JS/10. These findings indicated that the CP15 strain of high replication ability represents a promising candidate to develop an efficient CIV vaccine.
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3
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Converse A, Thomas P. The zinc transporter ZIP9 (Slc39a9) regulates zinc dynamics essential to egg activation in zebrafish. Sci Rep 2020; 10:15673. [PMID: 32973303 PMCID: PMC7518430 DOI: 10.1038/s41598-020-72515-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 09/02/2020] [Indexed: 01/22/2023] Open
Abstract
The zinc transporter ZIP9 (SLC39A9) was recently characterized as a membrane androgen receptor in various teleost and mammalian cell models. ZIP9 shows the highest expression in ovaries of teleosts, a tissue in which both androgen signaling and zinc dynamics have significant roles. To examine the role of ZIP9 in ovarian physiology, we generated a ZIP9-mutant zebrafish strain using a CRISPR/Cas9 system. zip9-/- females showed significant reductions in fecundity, embryo viability, and growth of their offspring compared to wildtype (WT) fish. Furthermore, a high proportion of zip9-/- eggs failed to undergo normal chorion elevation during activation. In WT eggs, zinc was detected in cortically-localized vesicles which underwent exocytosis upon activation. zip9-/- eggs showed abnormal cortical vesicle development and had a significantly depressed activation-induced zinc release compared to WT eggs. Moreover, pharmacologically sustained elevation of zinc in WT eggs prior to activation resulted in abnormal chorion elevation similar to that observed in zip9-/- eggs. These results indicate that ZIP9 is essential for proper zinc modulation during zebrafish egg activation and presents the first evidence of zinc modulation during egg activation in a non-mammalian species.
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Affiliation(s)
- Aubrey Converse
- Marine Science Institute, The University of Texas at Austin, 750 Channelview Dr., Port Aransas, TX, 78373, USA.
| | - Peter Thomas
- Marine Science Institute, The University of Texas at Austin, 750 Channelview Dr., Port Aransas, TX, 78373, USA
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4
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Development of Nested PCR-Heteroduplex Mobility Assay for Determination of Genetic Diversity in the Block 2 Region of the Plasmodium falciparum Merozoite Surface Protein 1 Gene. J Parasitol Res 2020; 2020:9520326. [PMID: 32328299 PMCID: PMC7168720 DOI: 10.1155/2020/9520326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/22/2020] [Accepted: 03/25/2020] [Indexed: 11/18/2022] Open
Abstract
Genetic diversity of Plasmodium parasite has significantly related to malaria control and vaccine development. The P. falciparum merozoite surface protein 1 (Pfmsp1) gene is a commonly used molecular marker to differentiate genetic diversity. This study is aimed at developing a nested PCR-Heteroduplex Mobility Assay (nPCR-HMA) for determination of the block 2 of the Pfmsp1 gene. The MAD20 family allele of P. falciparum was used as a control for optimization of the annealing and polyacrylamide gel electrophoresis conditions. In order to evaluate the developed nPCR-HMA, 8 clinical P. falciparum isolates were examined for allelic variants. The results revealed 9 allelic variants. Our study indicated that the successful nPCR-HMA with good precision and accuracy offers a more rapid, efficient, and cheap method for large-scale molecular epidemiological studies as compared to nucleotide sequencing.
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5
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Kim JW, Lee CY, Nguyen TT, Kim IH, Kwon HJ, Kim JH. An optimized molecular method for detection of influenza A virus using improved generic primers and concentration of the viral genomic RNA and nucleoprotein complex. J Vet Diagn Invest 2019; 31:175-183. [PMID: 30795722 DOI: 10.1177/1040638719830760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
For reported primer sets used to detect influenza A viruses (IAVs), we verified the nucleotide identities with 9,103 complete sequences of matrix (M) genes. At best, only 93.2% and 85.3% of the sequences had a 100% match with reported forward and reverse primers, respectively. Therefore, we designed new degenerate forward and reverse primers with 100% identity to 94.4% and 96.2% of compared genes, respectively, and the primer set was used with SYBR-based reverse-transcription real-time PCR (SYBR-RT-rtPCR) for lower detection limits. The sensitivity of SYBR-RT-rtPCR with the new primers was 10-fold higher than that with a conventional method in ~2.37% of all M genes in the database used in our study. We successfully increased the sensitivity of SYBR-RT-rtPCR by concentrating the viral ribonucleoprotein (RNP) using immunomagnetic beads and Triton X-100. The improved generic primer set and RNP concentration method may be useful for sensitive detection of IAVs.
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Affiliation(s)
- Ji-Woon Kim
- Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Farm Animal Medicine (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science (Kwon, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Division of Antimicrobial Resistance, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea (I-H Kim)
| | - Chung-Young Lee
- Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Farm Animal Medicine (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science (Kwon, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Division of Antimicrobial Resistance, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea (I-H Kim)
| | - Thanh Trung Nguyen
- Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Farm Animal Medicine (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science (Kwon, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Division of Antimicrobial Resistance, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea (I-H Kim)
| | - Il-Hwan Kim
- Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Farm Animal Medicine (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science (Kwon, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Division of Antimicrobial Resistance, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea (I-H Kim)
| | - Hyuk-Joon Kwon
- Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Farm Animal Medicine (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science (Kwon, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Division of Antimicrobial Resistance, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea (I-H Kim)
| | - Jae-Hong Kim
- Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Farm Animal Medicine (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology (Kwon), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science (Kwon, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Division of Antimicrobial Resistance, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea (I-H Kim)
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6
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Mitchell JA, Cardwell JM, Leach H, Walker CA, Le Poder S, Decaro N, Rusvai M, Egberink H, Rottier P, Fernandez M, Fragkiadaki E, Shields S, Brownlie J. European surveillance of emerging pathogens associated with canine infectious respiratory disease. Vet Microbiol 2017; 212:31-38. [PMID: 29173585 PMCID: PMC7117498 DOI: 10.1016/j.vetmic.2017.10.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/18/2017] [Accepted: 10/25/2017] [Indexed: 12/31/2022]
Abstract
The largest study of its kind in the field to date, including high-risk kennelled dogs, and for the first time, pet dogs and dogs from other cohorts. A clearly identifiable link between disease and the emerging pathogens: canine respiratory coronavirus and canine pneumovirus. Provides, substantial evidence of CIRD and the circulation of the novel pathogens studied in pet dogs, and dogs from other cohorts. Demonstrates the role and limitations of current vaccine strategies in managing CIRD outbreaks, and the need for including emerging pathogens.
Canine infectious respiratory disease (CIRD) is a major cause of morbidity in dogs worldwide, and is associated with a number of new and emerging pathogens. In a large multi-centre European study the prevalences of four key emerging CIRD pathogens; canine respiratory coronavirus (CRCoV), canine pneumovirus (CnPnV), influenza A, and Mycoplasma cynos (M. cynos); were estimated, and risk factors for exposure, infection and clinical disease were investigated. CIRD affected 66% (381/572) of the dogs studied, including both pet and kennelled dogs. Disease occurrence and severity were significantly reduced in dogs vaccinated against classic CIRD agents, canine distemper virus (CDV), canine adenovirus 2 (CAV-2) and canine parainfluenza virus (CPIV), but substantial proportions (65.7%; 201/306) of vaccinated dogs remained affected. CRCoV and CnPnV were highly prevalent across the different dog populations, with overall seropositivity and detection rates of 47% and 7.7% for CRCoV, and 41.7% and 23.4% for CnPnV, respectively, and their presence was associated with increased occurrence and severity of clinical disease. Antibodies to CRCoV had a protective effect against CRCoV infection and more severe clinical signs of CIRD but antibodies to CnPnV did not. Involvement of M. cynos and influenza A in CIRD was less apparent. Despite 45% of dogs being seropositive for M. cynos, only 0.9% were PCR positive for M. cynos. Only 2.7% of dogs were seropositive for Influenza A, and none were positive by PCR.
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Affiliation(s)
- Judy A Mitchell
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK.
| | - Jacqueline M Cardwell
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK.
| | - Heather Leach
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK.
| | - Caray A Walker
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK.
| | - Sophie Le Poder
- ENVA, University of Paris-Est, UMR 1161 Virologie, 94704 Maisons-Alfort, France; INRA, UMR 1161 Virologie, 94704 Maisons-Alfort, France; ANSES, Laboratoire de santé animale, UMR 1161 Virologie, 94704 Maisons Alfort, France.
| | - Nicola Decaro
- University of Bari, Department of Veterinary Medicine, Strada Provinciale per Casamassima Km 3, 70010 Valenzano (Bari), Italy.
| | - Miklos Rusvai
- University of Veterinary Medicine, Department of Pathology, Istvan u. 2, 1078 Budapest, Hungary.
| | - Herman Egberink
- University of Utrecht, Department of Infectious Diseases and Immunology, Yalelaan 1, 3584 CL, Utrecht, Netherlands.
| | - Peter Rottier
- University of Utrecht, Department of Infectious Diseases and Immunology, Yalelaan 1, 3584 CL, Utrecht, Netherlands.
| | - Mireia Fernandez
- Autonomous University of Barcelona, Hospital Clinic Veterinari, Universitat Automa de Barcelona, 08193 Bellaterra, Cerdanyola del Valles, Spain.
| | - Eirini Fragkiadaki
- Agricultural University of Athens, Faculty of Animal Science and Aquaculture, 75 Iera Odos str., 118 55, Athens, Greece.
| | - Shelly Shields
- Zoetis, Global Biologics Research-Companion Animals/Equine, 333 Portage Street, Kalamazoo, MI 49007, USA.
| | - Joe Brownlie
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK.
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7
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Rashid H, Shafi S, Booy R, Bashir HE, Ali K, Zambon MC, Memish ZA, Ellis J, Coen PG, Haworth E. Influenza and respiratory syncytial virus infections in British Hajj pilgrims. EMERGING HEALTH THREATS JOURNAL 2017. [DOI: 10.3402/ehtj.v1i0.7072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- H Rashid
- Academic Unit of Child Health, Queen Mary University of London, London, UK
| | - S Shafi
- HPA Collaborating Laboratory, Department of Microbiology, Northwick Park Hospital, Middlesex, UK
| | - R Booy
- Academic Unit of Child Health, Queen Mary University of London, London, UK
- National Centre for Immunisation Research and Surveillance of Vaccine Preventable Disease, The Children’s Hospital at Westmead, The University of Sydney, Sydney, New South Wales, Australia
| | - H El Bashir
- Academic Unit of Child Health, Queen Mary University of London, London, UK
| | - K Ali
- Academic Unit of Child Health, Queen Mary University of London, London, UK
| | - MC Zambon
- Respiratory Virus Unit, Centre for Infections, Health Protection Agency, London, UK
| | - ZA Memish
- Department of Medicine, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Saudi Arabia
- Department of Infection Prevention and Control, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh; Saudi Arabia
| | - J Ellis
- Respiratory Virus Unit, Centre for Infections, Health Protection Agency, London, UK
| | - PG Coen
- Infection Control Office, Windeyer Institute of Medical Sciences, University College. London Hospitals NHS Trust, London, UK; and
| | - E Haworth
- Thames Valley Health Protection Unit, Health Protection Agency South East, Oxford, UK
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8
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Das A, Suarez DL. Development and Bench Validation of Real-Time Reverse Transcription Polymerase Chain Reaction Protocols for Rapid Detection of the Subtypes H6, H9, and H11 of Avian Influenza Viruses in Experimental Samples. J Vet Diagn Invest 2016; 19:625-34. [DOI: 10.1177/104063870701900603] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Real-time reverse transcription polymerase chain reaction (RRT-PCR) is commonly used for the rapid detection, as well as to determine the subtype, of avian influenza viruses (AIVs). There are 16 known serologically distinct hemagglutinin (HA) subtypes of AIV described. Currently, determination of the subtypes of AIVs by RRT-PCR tests has been limited to the H5 and H7 subtypes. In this study, RRT-PCR assays were developed in simplex formats for rapid detection of AIV subtypes H6, H9, and H11. The primers and probes for RRT-PCR were designed from nucleotide sequences of the HA genes, which were either downloaded from GenBank (for H6 and H9) or sequenced for this study. The specificity and sensitivity of the RRT-PCR assays were determined based on the detection of the virus from a proficiency panel consisting of 15 different HA subtypes of AIVs and from serial dilutions of target viral RNA. The subtype-specific RRT-PCR assays were used to detect the virus in cloacal and oropharyngeal swabs of experimental chickens inoculated with H6, H9, and H11 AIVs, and the test results were compared with validated RRT-PCR assays based on the amplification of AI matrix (MA) gene. A high correlation of the matrix test and the specific H6, H9, and H11 by the RRT-PCR assays was observed; kappa coefficients for the agreement of test results in cloacal and oropharyngeal swabs combined were 0.927, 0.962, and 0.981, respectively.
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Affiliation(s)
- Amaresh Das
- From the Southeast Poultry Research Laboratory, Agricultural Research Service, USDA, Athens, GA
| | - David L. Suarez
- From the Southeast Poultry Research Laboratory, Agricultural Research Service, USDA, Athens, GA
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9
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Lee E, Kim EJ, Shin YK, Song JY. Design and testing of multiplex RT-PCR primers for the rapid detection of influenza A virus genomic segments: Application to equine influenza virus. J Virol Methods 2015; 228:114-22. [PMID: 26655588 DOI: 10.1016/j.jviromet.2015.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 11/12/2015] [Accepted: 11/16/2015] [Indexed: 02/07/2023]
Abstract
The avian influenza A virus causes respiratory infections in animal species. It can undergo genomic recombination with newly obtained genetic material through an interspecies transmission. However, the process is an unpredictable event, making it difficult to predict the emergence of a new pandemic virus and distinguish its origin, especially when the virus is the result of multiple infections. Therefore, identifying a novel influenza is entirely dependent on sequencing its whole genome. Occasionally, however, it can be time-consuming, costly, and labor-intensive when sequencing many influenza viruses. To compensate for the difficulty, we developed a rapid, cost-effective, and simple multiplex RT-PCR to identify the viral genomic segments. As an example to evaluate its performance, H3N8 equine influenza virus (EIV) was studied for the purpose. In developing this protocol to amplify the EIV eight-segments, a series of processes, including phylogenetic analysis based on different influenza hosts, in silico analyses to estimate primer specificity, coverage, and variation scores, and investigation of host-specific amino acids, were progressively conducted to reduce or eliminate the negative factors that might affect PCR amplification. Selectively, EIV specific primers were synthesized with dual priming oligonucleotides (DPO) system to increase primer specificity. As a result, 16 primer pairs were selected to screen the dominantly circulating H3N8 EIV 8 genome segments: PA (3), PB2 (1), PA (3), NP (3), NA8 (2), HA3 (1), NS (1), and M (2). The diagnostic performance of the primers was evaluated with eight sets composing of four segment combinations using viral samples from various influenza hosts. The PCR results suggest that the multiplex RT-PCR has a wide range of applications in detection and diagnosis of newly emerging EIVs. Further, the proposed procedures of designing multiplex primers are expected to be used for detecting other animal influenza A viruses.
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Affiliation(s)
- EunJung Lee
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyang-ro, Manan-gu, Anyang-si, Gyeonggi-do, Republic of Korea
| | - Eun-Ju Kim
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyang-ro, Manan-gu, Anyang-si, Gyeonggi-do, Republic of Korea
| | - Yeun-Kyung Shin
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyang-ro, Manan-gu, Anyang-si, Gyeonggi-do, Republic of Korea
| | - Jae-Young Song
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyang-ro, Manan-gu, Anyang-si, Gyeonggi-do, Republic of Korea.
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10
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Amorim AR, Fornells LAMG, Reis FDC, Rezende DJ, Mendes GDS, Couceiro JNDSS, Santos NSDO. Influenza A virus infection of healthy piglets in an abattoir in Brazil: animal-human interface and risk for interspecies transmission. Mem Inst Oswaldo Cruz 2014; 108:548-53. [PMID: 23903968 PMCID: PMC3970599 DOI: 10.1590/0074-0276108052013003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/30/2013] [Indexed: 02/02/2023] Open
Abstract
Asymptomatic influenza virus infections in pigs are frequent and the
lack of measures for controlling viral spread facilitates the circulation of
different virus strains between pigs. The goal of this study was to demonstrate
the circulation of influenza A virus strains among asymptomatic piglets in an
abattoir in Brazil and discuss the potential public health impacts. Tracheal
samples (n = 330) were collected from asymptomatic animals by a veterinarian
that also performed visual lung tissue examinations. No slaughtered animals
presented with any noticeable macroscopic signs of influenza infection following
examination of lung tissues. Samples were then analysed by reverse
transcription-polymerase chain reaction that resulted in the identification of
30 (9%) influenza A positive samples. The presence of asymptomatic pig
infections suggested that these animals could facilitate virus dissemination and
act as a source of infection for the herd, thereby enabling the emergence of
influenza outbreaks associated with significant economic losses. Furthermore,
the continuous exposure of the farm and abattoir workers to the virus increases
the risk for interspecies transmission. Monitoring measures of swine influenza
virus infections and vaccination and monitoring of employees for influenza
infection should also be considered. In addition regulatory agencies should
consider the public health ramifications regarding the potential zoonotic viral
transmission between humans and pigs.
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Affiliation(s)
- Ariane Ribeiro Amorim
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
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11
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Fornells LAMG, Travassos CEPF, Costa CM, Novelli R, Petrucci MP, Soffiati FL, Bianchi I, de Souza LFL, Veiga VF, Liberal MHT, Couceiro JNSS. Detection of avian paramyxoviruses in migratory and resident birds in the state of Rio de Janeiro, Brazil. Avian Dis 2014; 57:780-4. [PMID: 24597121 DOI: 10.1637/10548-040813-resnote.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Paramyxoviruses and avian influenza viruses are present worldwide, and wild birds are known natural reservoirs of these viruses. This study monitored the circulation of these viruses in migratory and resident coastal birds captured in the state of Rio de Janeiro, Brazil. In total, 494 birds were trapped, and their fecal samples were collected and inoculated into embryonated chicken eggs. The allantoic fluids were evaluated using a hemagglutination test and PCR amplification of the genes of the M and L proteins of influenza A virus and paramyxovirus, respectively. Avian paramyxovirus was detected in 5 (1.01%) of the birds. The majority of these viruses were isolated from migratory birds classified into the order Charadriiformes (families Scolopacidae and Charadriidae). Four samples were characterized as avian paramyxovirus serotype-2 (APMV-2) by a hemagglutination inhibition test. These results reinforce the importance of continuous surveillance of wild species in Brazil.
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Affiliation(s)
- Luz Alba M G Fornells
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Cidade Universitaria, Avenida Carlos Chagas Filho, 373, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Carlos E P F Travassos
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Claudia M Costa
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Ronaldo Novelli
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Melissa P Petrucci
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Flavio L Soffiati
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Iliani Bianchi
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Luiz F Lino de Souza
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, 28015-620, Campos dos Goytacazes, RJ, Brazil
| | - Venício F Veiga
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Cidade Universitaria, Avenida Carlos Chagas Filho, 373, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Maíra H T Liberal
- Laboratório de Biologia Animal-Setor de Biotecnologia, Empresa de Pesquisa do Estado do Rio de Janeiro, Alameda São Boaventura, 770, Pesagro, Fonseca, 24120-191, Niterói, RJ, Brazil
| | - José Nelson S S Couceiro
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Cidade Universitaria, Avenida Carlos Chagas Filho, 373, 21941-902, Rio de Janeiro, RJ, Brazil
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Hillen S, von Berg S, Köhler K, Reinacher M, Willems H, Reiner G. Occurrence and severity of lung lesions in slaughter pigs vaccinated against Mycoplasma hyopneumoniae with different strategies. Prev Vet Med 2014; 113:580-8. [DOI: 10.1016/j.prevetmed.2013.12.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 10/25/2022]
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13
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ZENG XJ, LIN Y, ZHAO YB, LU CP, LIU YJ. Experimental infection of dogs with H3N2 canine influenza virus from China. Epidemiol Infect 2013; 141:2595-603. [PMID: 23510585 PMCID: PMC9151373 DOI: 10.1017/s0950268813000472] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 01/10/2013] [Accepted: 02/08/2013] [Indexed: 11/07/2022] Open
Abstract
Canine influenza virus (CIV) is an emerging pathogen that causes acute respiratory disease in dogs. The aim of this study was to investigate the pathogenicity of A/canine/Jiangsu/06/2010 (H3N2) virus isolated in China. Nine dogs were inoculated intranasally with 107.95 of 50% egg infectious dose (EID50) of the virus. The onset of clinical signs and virus shedding was observed on day 1 post-infection (p.i.). The peak clinical score occurred between days 4 and 6 p.i. The experimentally infected dogs were found to shed virus not only via the respiratory tract but also via the digestive tract. Viral RNA could be detected in multiple organs including the trachea, lung, liver, spleen, kidney, brain and duodenum. All the sampled organs from infected dogs showed significant lesions and viral antigen staining. The results differed from those reporting using previous CIV strains; the Chinese isolate could induce extrapulmonary infection and cause extensive lesions in dogs.
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Affiliation(s)
- X. J. ZENG
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Y. LIN
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Y. B. ZHAO
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - C. P. LU
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Y. J. LIU
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
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Genetic and pathobiologic characterization of H3N2 canine influenza viruses isolated in the Jiangsu Province of China in 2009–2010. Vet Microbiol 2012; 158:247-58. [DOI: 10.1016/j.vetmic.2012.02.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 02/05/2012] [Accepted: 02/09/2012] [Indexed: 01/06/2023]
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15
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Microbiologic Diagnosis of Respiratory Illness. KENDIG & CHERNICKÂS DISORDERS OF THE RESPIRATORY TRACT IN CHILDREN 2012. [PMCID: PMC7151856 DOI: 10.1016/b978-1-4377-1984-0.00024-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Fornells LAMG, Silva TF, Bianchi I, Travassos CEPF, Liberal MHT, Andrade CM, Petrucci MP, Veiga VF, Vaslin MFS, Couceiro JNSS. Detection of paramyxoviruses in Magellanic penguins (Spheniscus magellanicus) on the Brazilian tropical coast. Vet Microbiol 2011; 156:429-33. [PMID: 22189432 DOI: 10.1016/j.vetmic.2011.11.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/23/2011] [Accepted: 11/25/2011] [Indexed: 01/16/2023]
Abstract
Aquatic migratory birds are a major vectors by which influenza viruses and paramyxoviruses are spread in nature. Magellanic penguins (Spheniscus magellanicus) are usually present on the southern shores of South America and can swim as far as the southern coast of Brazil in winter. In 2008, however, several Magellanic penguins were observed on the northeastern coast of Brazil. Paramyxoviruses were isolated from Magellanic penguins on the Espírito Santo state coast, approximately 4000 km from their breeding colonies, although influenza viruses were not detected. Among the paramyxoviruses, five Avulavirus isolates belonging to serotype APMV-2 and the serotype APMV-10, which was proposed by Miller et al. (2010), were identified. These results highlight the risks associated with the spread of paramyxoviruses between natural to non-natural habitats by birds exhibiting unusual migration patterns, and they document for the first time the presence of the APMV-2 and APMV-10 serotypes on penguins in Brazil. The local avifauna may become infected with these viruses through close contact between migratory and resident birds. Continued surveillance of virus incidence in these migratory populations of penguins is necessary to detect and prevent the potential risks associated with these unusual migration patterns.
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17
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Abdel-Moneim AS, Afifi MA, El-Kady MF. Genetic drift evolution under vaccination pressure among H5N1 Egyptian isolates. Virol J 2011; 8:283. [PMID: 21651796 PMCID: PMC3146449 DOI: 10.1186/1743-422x-8-283] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 06/08/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The highly pathogenic H5N1 is a major avian pathogen that intensively affects the poultry industry in Egypt even in spite of the adoption of vaccination strategy. Antigenic drift is among the strategies the influenza virus uses to escape the immune system that might develop due to the pressure of extensive vaccination. H5N1 mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences such an eventuality will entail. METHODS H5N1 was isolated from the pooled organ samples of four different affected flocks in specific pathogen free embryonated chicken eggs (SPF-ECE). A reverse transcriptase polymerase chain reaction (RT-PCR) was performed to the haemagglutingin and neuraminidase. Sequencing of the full length haemagglutingin was performed. Sequence analyses of the isolated strains were performed and compared to all available H5N1 from Egyptian human and avian strains in the flu database. Changes in the different amino acid that may be related to virus virulence, receptor affinity and epitope configuration were assigned and matched with all available Egyptian strains in the flu database. RESULTS One out of the four strains was found to be related to the B2 Egyptian lineage, 2 were related to A1 lineage and the 4th was related to A2 lineage. Comparing data obtained from the current study by other available Egyptian H5N1 sequences remarkably demonstrates that amino acid changes in the immune escape variants are remarkably restricted to a limited number of locations on the HA molecule during antigenic drift. Molecular diversity in the HA gene, in relevance to different epitopes, were not found to follow a regular trend, suggesting abrupt cumulative sequence mutations. However a number of amino acids were found to be subjected to high mutation pressure. CONCLUSION The current data provides a comprehensive view of HA gene evolution among H5N1 subtype viruses in Egypt. Egyptian H5N1-AIVs are constantly undergoing genetic changes and reveal a complex pattern of drifts. These findings raise the concerns about the value of using influenza vaccines in correlation with the development of antigenic drift in influenza epidemics.
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Affiliation(s)
- Ahmed S Abdel-Moneim
- Department of Virology, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt.
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18
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Genotyping and screening of reassortant live-attenuated influenza B vaccine strain. J Virol Methods 2009; 165:133-8. [PMID: 19883691 DOI: 10.1016/j.jviromet.2009.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 10/16/2009] [Accepted: 10/22/2009] [Indexed: 12/20/2022]
Abstract
Live-attenuated influenza virus vaccines can be generated by reassortment of gene segments between an attenuated donor strain and a virulent wild-type virus. The annual production schedule for the seasonal influenza vaccine necessitates rapid and efficient genotyping of the reassorted progeny to identify the desired vaccine strains. This study describes a multiplex RT-PCR system capable of identifying each gene segment from the cold-adapted attenuated donor virus, B/Lee/40ca. The specificity of the amplification system was optimized by testing various wild-type influenza B viruses. The resulting RT-PCR method is sensitive and efficient enough for routine identification of reassortant clones to identify the desired gene constellation, consisting of six segments from the attenuated donor virus and the H and N genes from the wild-type virus. By providing a more rapid and efficient means of genotyping the candidate reassortant strains, this method could be implemented to expedite the generation of each component strain and allow more time to culture and process the final seasonal influenza vaccine.
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19
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Chiapponi C, Zanni I, Garbarino C, Barigazzi G, Foni E. Comparison of the usefulness of the CACO-2 cell line with standard substrates for isolation of swine influenza A viruses. J Virol Methods 2009; 163:162-5. [PMID: 19781571 DOI: 10.1016/j.jviromet.2009.09.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 09/11/2009] [Accepted: 09/15/2009] [Indexed: 10/20/2022]
Abstract
Influenza A virus isolation is undertaken routinely in embryonated chicken eggs, but to improve virus detection various cell lines can be used. The CACO-2 cell line was compared to the MDCK cell line and embryonated chicken eggs for the isolation of H1N1, H1N2, H3N2 swine influenza A virus subtypes from clinical specimens. From 2006 to 2008, 104 influenza A samples found positive by PCR from 42 respiratory outbreaks in Italian swine farms were examined by virus isolation. Sixty swine influenza A viruses were isolated (16 H1N1, 28 H1N2 and 16 H3N2) and their growth behaviour on the different substrates was examined. 16/16 H1N1, 28/28 H1N2 and 8/16 of H3N2 viruses were isolated from the CACO-2 cell line, while 7/16 H1N1, 3/28 H1N2 and 16/16 H3N2 viruses were isolated using embryonated chicken eggs. Only 9/16 H1N1, 1/28 H1N2 and 6/16 H3N2 viruses replicated in MDCK cells. A link was found between viral hemagglutinin and the isolation rate on the various substrates. The CACO-2 line was statistically more sensitive (Fisher's exact test, p<0.01) compared to the MDCK cells and embryonated chicken eggs for the isolation of H1N1 and H1N2 subtypes. In contrast influenza A H3N2 virus was isolated more readily in embryonated chicken eggs than in cultured cells (Fisher's exact test, p<0.01).
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Affiliation(s)
- Chiara Chiapponi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna Bruno Ubertini, Sezione Diagnostica di Parma, via dei Mercati 13/A, 43100 Parma, Italy.
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20
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Sarli G, Ostanello F, Morandi F, Fusaro L, Gnudi M, Bacci B, Nigrelli A, Alborali L, Dottori M, Vezzoli F, Barigazzi G, Fiorentini L, Sala V, Leotti G, Joisel F. Application of a protocol for the diagnosis of postweaning multisystemic wasting syndrome in Italy. Vet Rec 2009; 164:519-23. [DOI: 10.1136/vr.164.17.519] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- G. Sarli
- Department of Veterinary Public Health and Animal Pathology; School of Veterinary Medicine; Università di Bologna; Via Tolara di Sopra 50, 40064, Ozzano Emilia Bologna Italy
| | - F. Ostanello
- Department of Veterinary Public Health and Animal Pathology; School of Veterinary Medicine; Università di Bologna; Via Tolara di Sopra 50, 40064, Ozzano Emilia Bologna Italy
| | - F. Morandi
- Department of Veterinary Public Health and Animal Pathology; School of Veterinary Medicine; Università di Bologna; Via Tolara di Sopra 50, 40064, Ozzano Emilia Bologna Italy
| | - L. Fusaro
- Department of Veterinary Public Health and Animal Pathology; School of Veterinary Medicine; Università di Bologna; Via Tolara di Sopra 50, 40064, Ozzano Emilia Bologna Italy
| | - M. Gnudi
- Department of Veterinary Public Health and Animal Pathology; School of Veterinary Medicine; Università di Bologna; Via Tolara di Sopra 50, 40064, Ozzano Emilia Bologna Italy
| | - B. Bacci
- Department of Veterinary Public Health and Animal Pathology; School of Veterinary Medicine; Università di Bologna; Via Tolara di Sopra 50, 40064, Ozzano Emilia Bologna Italy
| | - A. Nigrelli
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna ‘Bruno Libertini’ (IZSLER) - Section of Mantova; Strada Circonvallazione Sud 21/A 46100 Mantova Italy
| | - L. Alborali
- IZSLER - Section of Brescia; Via A. Bianchi 9 25124 Brescia Italy
| | - M. Dottori
- IZSLER - Section of Reggio Emilia; Via Pitagora 2 42100 Reggio Emilia Italy
| | - F. Vezzoli
- IZSLER - Section of Lodi; Via Einstein Loc. C. na Codazza 26900 Lodi Italy
| | - G. Barigazzi
- IZSLER - Section of Parma; Via dei Mercati 13/A 43100 Parma Italy
| | - L. Fiorentini
- IZSLER - Section of Forlì; Via Marchini 1 47100 Forlì-Cesena Italy
| | - V. Sala
- Department of Animal Pathology; Hygiene and Veterinary Public Health; School of Veterinary Medicine; Università di Milano; Via CEloria 10 20133 Milano Italy
| | - G. Leotti
- Merial Italia Spa; Strada 6, Palazzo E/5, 200090 Milanofiori, Assago Milano Italy
| | - F. Joisel
- Merial International; 29 av Tony Garnier 69007 Lyon France
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21
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Qiu BF, Liu WJ, Peng DX, Hu SL, Tang YH, Liu XF. A reverse transcription-PCR for subtyping of the neuraminidase of avian influenza viruses. J Virol Methods 2008; 155:193-8. [PMID: 18984006 DOI: 10.1016/j.jviromet.2008.10.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Revised: 09/27/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
Abstract
To date, nine neuraminidase (NA) subtypes of avian influenza viruses have been identified. In order to differentiate the NA of avian influenza viruses rapidly, a reverse transcription PCR (RT-PCR) was developed. Nine pairs of NA-specific primers for the RT-PCR were designed based on the analysis of 509 complete NA sequences in GenBank. The primers were designed to amplify partial NA genes and each pair is unique to a single NA subtype (N1-N9). By nine RT-PCRs simultaneously in a set of separate tubes, the subtype of NA was determined by subsequent agarose gel electrophoresis and ethidium bromide staining, since only one of the nine RT-PCRs would give a product of expected size for each virus strain. In comparison with the established method of sequence analysis of 101 reference strains or isolates of avian influenza viruses, the RT-PCR method had a sensitivity of 97.3% and a specificity of 91.1% in subtyping avian influenza viruses. These results indicate that the RT-PCR method described below provides a specific and sensitive alternative to conventional NA-subtyping methods.
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Affiliation(s)
- Bao-Feng Qiu
- Animal Infectious Disease Laboratory, School of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, China
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22
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Mannering SA, McAuliffe L, Lawes JR, Erles K, Brownlie J. Strain typing of Mycoplasma cynos isolates from dogs with respiratory disease. Vet Microbiol 2008; 135:292-6. [PMID: 18977617 PMCID: PMC7126931 DOI: 10.1016/j.vetmic.2008.09.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 09/01/2008] [Accepted: 09/15/2008] [Indexed: 12/03/2022]
Abstract
The association of Mycoplasma cynos with canine infectious respiratory disease is increasingly being recognised. This study describes the strain typing of 14 M. cynos isolates cultured from trachea and bronchoalveolar lavage samples of six dogs with respiratory disease, from two separate kennels in the United Kingdom. The genetic similarity of the isolates was investigated using pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD). Most of the isolates from four dogs housed at a re-homing kennel were genetically similar and some isolates from different dogs were indistinguishable by both PFGE and RAPD. These isolates were cultured from dogs with non-overlapping stays in the kennel, which may indicate maintenance of some strains within kennels. A small number of isolates showed much greater genetic heterogeneity and were genetically distinct from the main group of M. cynos strains. There was also a high degree of similarity of the M. cynos type strain (isolated from a dog with respiratory disease in Denmark in 1971) to at least one of the United Kingdom isolates using PFGE analysis, which may suggest possible conservation of pathogenic strains of M. cynos.
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Rashid H, Shafi S, Booy R, El Bashir H, Ali K, Zambon M, Memish Z, Ellis J, Coen P, Haworth E. Influenza and respiratory syncytial virus infections in British Hajj pilgrims. EMERGING HEALTH THREATS JOURNAL 2008; 1:e2. [PMID: 22460211 PMCID: PMC3167590 DOI: 10.3134/ehtj.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2006] [Revised: 09/03/2007] [Accepted: 09/27/2007] [Indexed: 11/18/2022]
Abstract
Viral respiratory infections including influenza and respiratory syncytial virus (RSV) have been reported during the Hajj among international pilgrims. To help establish the burden of these infections at the Hajj, we set up a study to confirm these diagnoses in symptomatic British pilgrims who attended the 2005 Hajj. UK pilgrims with symptoms of upper respiratory tract infection (URTI) were invited to participate; after taking medical history, nasal swabs were collected for point-of-care testing (PoCT) of influenza and for subsequent PCR analysis for influenza and RSV. Of the 205 patients recruited, 37 (18%) were positive for either influenza or RSV. Influenza A (H3) accounted for 54% (20/37) of the virus-positive samples, followed by RSV 24% (9/37), influenza B 19% (7/37), and influenza A (H1) 3% (1/37). Of the influenza-positive cases, 29% (8/28) had recently had a flu immunisation. Influenza was more common in those who gave a history of contact with a pilgrim with a respiratory illness than those who did not (17 versus 9%). The overall rate of RSV was 4% (9/202). This study confirms that influenza and RSV cause acute respiratory infections in British Hajj pilgrims. Continuing surveillance and a programme of interventions to contain the spread of infection are needed at the Hajj, particularly when the world is preparing for an influenza pandemic.
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Affiliation(s)
- H Rashid
- Academic Unit of Child Health, Queen Mary University of London, London, UK
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24
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Escorcia M, Vázquez L, Méndez ST, Rodríguez-Ropón A, Lucio E, Nava GM. Avian influenza: genetic evolution under vaccination pressure. Virol J 2008; 5:15. [PMID: 18218105 PMCID: PMC2259324 DOI: 10.1186/1743-422x-5-15] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 01/24/2008] [Indexed: 11/10/2022] Open
Abstract
Antigenic drift of avian influenza viruses (AIVs) has been observed in chickens after extended vaccination program, similar to those observed with human influenza viruses. To evaluate the evolutionary properties of endemic AIV under high vaccination pressure (around 2 billion doses used in the last 12 years), we performed a pilot phylogenic analysis of the hemagglutinin (HA) gene of AIVs isolated from 1994 to 2006. This study demonstrates that Mexican low pathogenicity (LP) H5N2-AIVs are constantly undergoing genetic drifts. Recent AIV isolates (2002-2006) show significant molecular drifts when compared with the H5N2 vaccine-strain or other field isolates (1994-2000). This study also demonstrates that molecular drifts in the HA gene lineages follow a yearly trend, suggesting gradually cumulative sequence mutations. These findings might explain the increasing incidence of LP H5N2 AIV isolated from commercial avian farms. These findings support recent concerns about the challenge of AIV antigenic drift and influenza epidemics.
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Affiliation(s)
- Magdalena Escorcia
- Departamento de Producción Animal Aves, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, DF 04510, México.
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25
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Rapid differentiation of influenza A virus subtypes and genetic screening for virus variants by high-resolution melting analysis. J Clin Microbiol 2008; 46:1090-7. [PMID: 18174299 DOI: 10.1128/jcm.02015-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We assessed the use of high-resolution melting (HRM) analysis for the rapid identification of influenza A virus subtypes and the detection of newly emerging virus variants. The viral matrix gene was amplified by LightCycler real-time reverse transcription-PCR (RT-PCR) in the presence of the LCGreen I fluorescent dye. Upon optimization of the assay conditions, all the major influenza A virus subtypes, including H1N1, H3N2, H5N1, H7N3, and H9N2, were amplifiable by this method and had a PCR product length of 179 bp. Real-time RT-PCR of in vitro-transcribed H3N2 RNA revealed a standard curve for quantification with a linear range (correlation coefficient = 0.9935) across at least 8 log units of RNA concentrations and a detection limit of 10(3) copies of viral RNA. We performed HRM analysis of the PCR products with the HR-1 instrument and used the melting profiles as molecular fingerprints for virus subtyping. The virus subtypes were identified from the high-resolution derivative plot obtained by heteroduplex formation between the PCR products of the viral isolates tested and those of the reference viral isolates. The melting profiles were consistent with minimal interassay variability. Hence, an HRM database and a working protocol were established for the identification of these five influenza A virus subtypes. When this protocol was used to test 21 clinical influenza A virus isolates, the results were comparable to those obtained by RT-PCR with hemagglutinin-specific primer sets. Sequence variants of the clinical isolates (n = 4) were also revealed by our HRM analytical scheme. This assay requires no multiplexing or hybridization probes and provides a new approach for influenza A virus subtyping and genetic screening of virus variants in a clinical virology laboratory.
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26
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Rashid H, Shafi S, Haworth E, El Bashir H, Ali KA, Memish ZA, Booy R. Value of rapid testing for influenza among Hajj pilgrims. Travel Med Infect Dis 2007; 5:310-3. [PMID: 17870637 DOI: 10.1016/j.tmaid.2007.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 07/18/2007] [Accepted: 07/24/2007] [Indexed: 10/22/2022]
Abstract
BACKGROUND Muslim pilgrims going on the Hajj are at risk of influenza. The treatment and prevention of influenza with antiviral drugs depends on rapid diagnosis using a near-patient test such as the QuickVue influenza test. The suitability of this test among pilgrims has not been studied in the past and this study assesses the usefulness of the test for diagnosing influenza among those attending the Hajj. METHODS The sensitivity and specificity of the QuickVue test were measured against reverse transcriptase polymerase chain reaction by undertaking the tests on nasal swab samples from pilgrims. RESULTS The sensitivity and specificity of the QuickVue test were 22% and 99%, respectively, and its likelihood ratio for a positive and a negative test were 22 and 0.79 in that order. CONCLUSION The QuickVue influenza test using nasal swabs is poorly sensitive for diagnosing influenza among Hajj pilgrims. Given its high specificity and an even higher likelihood ratio for a positive test it may still be a very useful tool for influenza surveillance at the Hajj.
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Affiliation(s)
- Harunor Rashid
- Academic Unit of Child Health, Queen Mary University of London, UK.
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27
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Ellis JS, Smith JW, Braham S, Lock M, Barlow K, Zambon MC. Design and validation of an H5 TaqMan real-time one-step reverse transcription-PCR and confirmatory assays for diagnosis and verification of influenza A virus H5 infections in humans. J Clin Microbiol 2007; 45:1535-43. [PMID: 17473050 PMCID: PMC1865909 DOI: 10.1128/jcm.02007-06] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Increasing diversity among influenza H5N1 viruses has resulted in the need for sensitive and specific diagnostic assays, fully validated for the detection of H5 viruses belonging to all hemagglutinin (HA) clades, particularly the recently circulating H5N1 viruses of clade 2. In this report, the development and validation of a real-time, one-step TaqMan reverse transcription-PCR (RT-PCR) assay specific for the detection of influenza A H5 viruses from clades 1, 1', 2, and 3 is described. The real-time assay for H5 virus was shown to be highly sensitive, detecting H5 virus levels of <1 PFU from each of the HA clades. Specificity of the H5 RT-PCR for influenza A H5 viruses was demonstrated by using influenza A viruses of different subtypes, clinical samples containing influenza A viruses H1N1, H3N2, and H5N1, influenza B viruses, and other respiratory viruses. The usefulness of the inclusion of a distinguishable assay positive control and of confirmatory assays for the laboratory diagnosis and verification of H5 virus infections was demonstrated. A real-time RT-PCR pyrosequencing assay, a restriction enzyme digestion assay, and direct sequencing of the H5 real-time RT-PCR amplicon were validated for the confirmation of H5 detection by the diagnostic real-time assay. The H5 real-time assay was applied to diagnostic testing for suspected cases of influenza A virus H5 infection in the United Kingdom. Influenza A H5 viruses were not detected in the cases analyzed; however, influenza A H3N2 virus was detected in 57% of the suspected cases of H5. The H5 TaqMan real-time RT-PCR and confirmatory assays will be useful tools for the laboratory surveillance and rapid diagnosis of H5 infections in humans.
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Affiliation(s)
- Joanna S Ellis
- Centre for Infections, Health Protection Agency, 61 Colindale Avenue, Colindale, London NW9 5HT, United Kingdom.
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Abstract
Molecular diagnostic tests are commonly used to diagnose avian influenza virus because they are sensitive and can be performed rapidly, with high throughput, and at a moderate cost. Molecular diagnostic tests recently have proven themselves to be invaluable in controlling disease outbreaks around the world. Several different methods, including traditional reverse transcription-polymerase chain reaction (PCR), real-time reverse transcription-polymerase chain reaction, and nucleic acid sequence-based amplification among others, have been described for the diagnosis of avian influenza in poultry with many different variations of primers, probes, enzymes, etc. Few of these tests have been validated, with the understanding that validation should be described as a level of comparison testing to show "fitness for purpose." None of the molecular diagnostic tests are validated for all species or specimen types that might be presented to a diagnostic laboratory. The sensitivity and specificity for all the molecular tests are governed by three critical control points, including RNA extraction, enzymes used for amplification, and the sequence of primers and probes. The RNA extraction step is of particular concern, since high-quality RNA is needed for any of the molecular tests. Some sample types, including cloacal (fecal) swabs and tissues, are difficult to process, with issues of poor RNA extraction or PCR inhibitors being common. The development of internal controls, robotics, and bead reagents are providing improved performance of existing tests, and new technologies will likely provide better tests for the future. With any molecular test, assay assurance must be performed on an ongoing basis, which includes the use of proficiency panels to measure test performance.
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Affiliation(s)
- David L Suarez
- Southeast Poultry Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA
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Chan CH, Lin KL, Chan Y, Wang YL, Chi YT, Tu HL, Shieh HK, Liu WT. Amplification of the entire genome of influenza A virus H1N1 and H3N2 subtypes by reverse-transcription polymerase chain reaction. J Virol Methods 2006; 136:38-43. [PMID: 16687177 DOI: 10.1016/j.jviromet.2006.03.027] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Revised: 03/29/2006] [Accepted: 03/30/2006] [Indexed: 10/24/2022]
Abstract
This study describes the development of a simple RT-PCR method to amplify the whole genome of the influenza A virus based on the amplification of full-length gene segments. Primers were designed based on the conserved regions of both the 5'-end and the 3'-end of each gene segment. After optimizing the duration and temperature of denaturing, annealing, and extension, these primers could amplify all of the full-length gene segments. To test the accuracy of the method, all amplicons were subjected to DNA sequencing with an autosequencer. Eighteen strains of influenza A virus which belonged to H1N1 or H3N2 subtypes were tested. All eight segments of both subtypes were successfully amplified in all tested strains. Using a newly developed reverse-transcriptase (RT), primers and PCR running conditions, this study established a protocol to amplify the entire genome of the influenza A virus. This method provides a tool which can be used for the amplification of all genes of the H1N1 and H3N2 subtypes of influenza A virus prior to analysis of their sequences, and to construct expression plasmids for further study.
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Affiliation(s)
- Chi-Ho Chan
- Department of Microbiology and Immunology, Chung Shan Medical University (CSMU), 110, Sec. No. 1, Chien-Kuo N. Road, Taichung 402, Taiwan, Republic of China.
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Landolt GA, Karasin AI, Hofer C, Mahaney J, Svaren J, Olsen CW. Use of real-time reverse transcriptase polymerase chain reaction assay and cell culture methods for detection of swine influenza A viruses. Am J Vet Res 2005; 66:119-24. [PMID: 15691046 DOI: 10.2460/ajvr.2005.66.119] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate sensitivity and specificity of a real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay performed on pooled nasal swab specimens, compared with virus isolation performed on individual nasal swab specimens by use of 2 cell culture lines for detection of swine influenza A viruses. SAMPLE POPULATION 900 nasal swab specimens obtained from pigs at an abattoir and 62 nasal swab specimens submitted for diagnostic testing. PROCEDURES Primers were chosen to amplify a conserved portion of the influenza virus matrix gene. Assay sensitivity was initially determined by testing serial dilutions of various subtypes of swine influenza viruses. Sensitivity and specificity were confirmed by use of nasal swab specimens with or without addition of known concentrations of influenza virus and further validated by testing nasal swab specimens obtained through an abattoir surveillance program or submitted for diagnostic testing. Aliquots of specimens were pooled in sets of 10, and results of real-time RT-PCR assays were compared with results of virus isolation of individual specimens in Madin Darby canine kidney (MDCK) and mink lung (Mv1Lu) cells. RESULTS Real-time RT-PCR assay was highly specific (100%) and sensitive (88% to 100%). Among the 16 viruses isolated, 3 grew only in Mv1Lu cells and 3 grew only in MDCK cells. CONCLUSIONS AND CLINICAL RELEVANCE Results indicate that real-time RT-PCR assay is a fast and accurate test for screening numerous nasal swab specimens for swine influenza virus. Some viruses were isolated in only MDCK or Mv1Lu cells, indicating that use of >1 cell line may be required to isolate a broad range of influenza A viruses.
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Affiliation(s)
- Gabriele A Landolt
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
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Banda A, Villegas P, El-Attrache J. Heteroduplex Mobility Assay for Genotyping Infectious Bursal Disease Virus. Avian Dis 2004; 48:851-62. [PMID: 15666866 DOI: 10.1637/7189-040204r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A heteroduplex mobility assay (HMA) was developed to genotype infectious bursal disease virus (IBDV). This method analyzed 390-base pair (bp) polymerase chain reaction (PCR) products, encompassing the hypervariable region of the VP2 gene. IBDV strains from the United States and other countries were analyzed. The HMA was able to differentiate standard, antigenic variants and very virulent strains of IBDV. Minor differences between different strains from the same subtype were also detected. Close relationships between field IBDV with vaccines prepared with Delaware E strain were determined by HMA. The results obtained by HMA were confirmed by restriction fragment length polymorphism (RFLP) and phylogenetic analysis of nucleotide sequences. The HMA proved to be a useful technique to rapidly genotype different field strains of IBDV and should prove to be a useful tool in epidemiologic studies.
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Affiliation(s)
- Alejandro Banda
- Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-4875, USA
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Kuroiwa Y, Nagai K, Okita L, Tsutsumi H. Genetic variability and molecular epidemiology of respiratory syncytial virus subgroup a strains in Japan determined by heteroduplex mobility assay. J Clin Microbiol 2004; 42:2048-53. [PMID: 15131169 PMCID: PMC404669 DOI: 10.1128/jcm.42.5.2048-2053.2004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used heteroduplex mobility assay (HMA) to determine the genetic variability of 118 respiratory syncytial virus (RSV) field isolates from 19 epidemics occurring in a Japanese urban area between 1980 and 2000. Nucleotides 1 to 584 of the attachment G glycoprotein gene were amplified by reverse transcription-PCR, and the PCR amplicons were analyzed by HMA by using the earliest isolate from 1980 as the reference throughout. We also performed PCR-restriction fragment length polymorphism (RFLP) analysis and phylogenetic analysis on the same nucleotide sequence. PCR-RFLP revealed 9 patterns, whereas HMA produced 31 distinct patterns. The RFLP patterns were divided into two to seven distinct HMA genotypes. Field strains with similar degrees of G gene nucleotide differences from the reference strain often showed distinct HMA types. The RSV genetic heterogeneity detected by direct sequencing of the PCR amplicon was usually identical to HMA analysis. Analysis of the molecular epidemiology of RSV subgroup A isolates obtained by HMA showed that new RSV variants emerged with each epidemic and that previously dominant variants seldom recurred in subsequent epidemics. HMA is useful in detecting genetic variants of RSV subgroup A and has some advantages over other conventional methods.
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Affiliation(s)
- Yuki Kuroiwa
- Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Hokkaido 060-8543, Japan.
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Green J, Gallimore CI, Shore J, Sellwood J, Brown DWG. Application of the heteroduplex mobility assay (HMA) for the investigation of the genomic diversity among noroviruses in environmental samples. J Virol Methods 2004; 120:59-67. [PMID: 15234810 DOI: 10.1016/j.jviromet.2004.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Revised: 04/13/2004] [Accepted: 04/21/2004] [Indexed: 11/29/2022]
Abstract
Recent studies have demonstrated the widespread contamination of river and seawater with noroviruses (NV), often with more than one strain. The heteroduplex mobility assay (HMA) in which amplicons from study samples are hybridised (by denaturing and reannealing) to amplicons from reference strains and resolved by electrophoresis, has the potential to provide a simple and rapid means to identify samples containing multiple NV strains and to establish the diversity of strains within that sample. PCR amplicons from environmental samples that were tested directly in the HMA assay were shown to contain more than one strain. In order to evaluate HMA for investigations of NV diversity in environmental samples, amplicons from three representative samples were cloned and, for each, 20 amplicons derived from individual clones were analysed by HMA. Between two and six different HMA profiles were demonstrated among clones from a single sample indicating the extent of NV diversity in the sample. Sequence analysis confirmed the relationship of HMA profile and NV 'genotype'. Far greater diversity was seen among Genogroup (G) II (Ni/E3) amplicons than Genogroup (G) I (Ando/E3) amplicons (generated from the RNA dependent RNA polymerase region of the ORF1 of noroviruses), which often contained only a single strain, which is reflective of the greater prevalence of GII NVs over GI NVs. Overall, four GII and four GI strains were identified in these environmental water/sewage samples.
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Affiliation(s)
- Jonathan Green
- Enteric, Respiratory and Neurological Virus Laboratory, Specialist and Reference Microbiology Division, Health Protection Agency, Colindale, London, UK
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Ellis JS, Alvarez-Aguero A, Gregory V, Lin YP, Hay A, Zambon MC. Influenza AH1N2 viruses, United Kingdom, 2001-02 influenza season. Emerg Infect Dis 2003; 9:304-10. [PMID: 12643824 PMCID: PMC2958547 DOI: 10.3201/eid0903.020404] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
During the winter of 2001-02, influenza AH1N2 viruses were detected for the first time in humans in the U.K. The H1N2 viruses co-circulated with H3N2 viruses and a very small number of H1N1 viruses and were isolated in the community and hospitalized patients, predominantly from children <15 years of age. Characterization of H1N2 viruses indicated that they were antigenically and genetically homogeneous, deriving the hemagglutinin (HA) gene from recently circulating A/New Caledonia/20/99-like H1N1 viruses, whereas the other seven genes originated from recently circulating H3N2 viruses. Retrospective reverse transcription-polymerase chain reaction analysis of influenza A H1 viruses isolated in the U.K. during the previous winter identified a single H1N2 virus, isolated in March 2001, indicating that H1N2 viruses did not widely circulate in the U.K. before September 2001. The reassortment event is estimated to have occurred between 1999 and early 2001, and the emergence of H1N2 viruses in humans reinforces the need for frequent surveillance of circulating viruses.
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Affiliation(s)
- Joanna S Ellis
- Central Public Health Laboratory, Colindale, London, United Kingdom.
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Abstract
The past decade has seen tremendous developments in molecular diagnostic techniques. In particular, the development of PCR technology has enabled rapid and sensitive viral diagnostic tests to influence patient management. Molecular methods used directly on clinical material have an important role to play in the diagnosis and surveillance of influenza viruses. Molecular diagnostic tests that allow timely and accurate detection of influenza are already implemented in many laboratories. The combination of automated purification of nucleic acids with real-time PCR should enable even more rapid identification of viral pathogens such as influenza viruses in clinical material. The recent development of DNA microarrays to identify either multiple gene targets from a single pathogen, or multiple pathogens in a single sample has the capacity to transform influenza diagnosis. While molecular methods will not replace cell culture for the provision of virus isolates for antigenic characterisation, they remain invaluable in assisting our understanding of the epidemiology of influenza viruses.
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Affiliation(s)
- Joanna S Ellis
- Respiratory Virus Unit, Enteric, Respiratory and Neurological Virus Laboratory, Public Health Laboratory Service, Central Public Health Laboratory, 61 Colindale Avenue, Colindale, London NW9 5HT, UK.
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