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Ma J, Wu M, Wang Z, Yang D, Hou S, Cheng Y, Wang H, Yan Y, Sun J. Pre-exposure to Streptococcus suis improved survival of influenza virus co-infection in mice. Vet Microbiol 2021; 258:109071. [PMID: 33965701 DOI: 10.1016/j.vetmic.2021.109071] [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: 10/21/2020] [Accepted: 04/06/2021] [Indexed: 11/26/2022]
Abstract
The synergism of the influenza virus and respiratory tract pathogens is known to exacerbate diseases in both humans and animals. The mechanism of the co-infection of associated respiratory tract pathogens is explored in this study. Co-infection has a directional effect when influenza virus or other pathogens occur in a different order. In the present study, we used a mouse animal model to study the synergism of influenza virus and Streptococcus suis co-infection in different orders of administration. We found that the group infected with bacteria alone did not show any clinical symptoms, but the group infected with the virus alone showed 100 % mortality and clinical signs typical in infected mice. In the bacteria infected following virus pre-exposure group, the mice died before the virus-infected group and showed severer clinical signs. When the influenza virus was administered after the bacteria, the infected mice showed reduced mortality compared with mice administered the influenza virus alone. The results indicated that the order of infection significantly affected the outcome of the co-infection of these two pathogens in the mice. However, the underlying mechanism was unclear. Therefore, a transcriptome analysis of mouse lungs was conducted to explore the potential mechanism. The results showed that inflammation and cell damage signaling pathways were upregulated, which may have contributed to the increased mortality in the secondary bacterial infection group. Upregulated innate immunity may have been a major cause of reduced mortality when the bacteria were inoculated before the virus infection.
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Affiliation(s)
- Jingjiao Ma
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Mingqing Wu
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhaofei Wang
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Denghui Yang
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Silu Hou
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yuqiang Cheng
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Heng'an Wang
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yaxian Yan
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jianhe Sun
- Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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2
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Obradovic MR, Segura M, Segalés J, Gottschalk M. Review of the speculative role of co-infections in Streptococcus suis-associated diseases in pigs. Vet Res 2021; 52:49. [PMID: 33743838 PMCID: PMC7980725 DOI: 10.1186/s13567-021-00918-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/25/2021] [Indexed: 12/21/2022] Open
Abstract
Streptococcus suis is one of the most important bacterial swine pathogens affecting post-weaned piglets, causing mainly meningitis, arthritis and sudden death. It not only results in severe economic losses but also raises concerns over animal welfare and antimicrobial resistance and remains an important zoonotic agent in some countries. The definition and diagnosis of S. suis-associated diseases can be complex. Should S. suis be considered a primary or secondary pathogen? The situation is further complicated when referring to respiratory disease, since the pathogen has historically been considered as a secondary pathogen within the porcine respiratory disease complex (PRDC). Is S. suis a respiratory or strictly systemic pathogen? S. suis is a normal inhabitant of the upper respiratory tract, and the presence of potentially virulent strains alone does not guarantee the appearance of clinical signs. Within this unclear context, it has been largely proposed that co-infection with some viral and bacterial pathogens can significantly influence the severity of S. suis-associated diseases and may be the key to understanding how the infection behaves in the field. In this review, we critically addressed studies reporting an epidemiological link (mixed infections or presence of more than one pathogen at the same time), as well as in vitro and in vivo studies of co-infection of S. suis with other pathogens and discussed their limitations and possibilities for improvement and proposed recommendations for future studies.
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Affiliation(s)
- Milan R Obradovic
- Groupe de Recherche Sur Les Maladies Infectieuses en Production Animale (GREMIP), Centre de Recherche en Infectiologie Porcine et Aviaire (CRIPA), Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Mariela Segura
- Groupe de Recherche Sur Les Maladies Infectieuses en Production Animale (GREMIP), Centre de Recherche en Infectiologie Porcine et Aviaire (CRIPA), Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Joaquim Segalés
- UAB, CReSA (IRTA-UAB), Campus de la UAB, 08193, Bellaterra (Cerdanyola del Vallès), Spain.,Departament de Sanitat I Anatomia Animals, Facultat de Veterinària, UAB, 08193, Bellaterra (Cerdanyola del Vallès), Spain.,OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193, Bellaterra, Barcelona, Spain
| | - Marcelo Gottschalk
- Groupe de Recherche Sur Les Maladies Infectieuses en Production Animale (GREMIP), Centre de Recherche en Infectiologie Porcine et Aviaire (CRIPA), Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte, Saint-Hyacinthe, QC, J2S 2M2, Canada.
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3
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Everett HE, Nash B, Londt BZ, Kelly MD, Coward V, Nunez A, van Diemen PM, Brown IH, Brookes SM. Interspecies Transmission of Reassortant Swine Influenza A Virus Containing Genes from Swine Influenza A(H1N1)pdm09 and A(H1N2) Viruses. Emerg Infect Dis 2021; 26:273-281. [PMID: 31961298 PMCID: PMC6986826 DOI: 10.3201/eid2602.190486] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Influenza A(H1N1)pdm09 (pH1N1) virus has become established in swine in the United Kingdom and currently co-circulates with previously enzootic swine influenza A virus (IAV) strains, including avian-like H1N1 and human-like H1N2 viruses. During 2010, a swine influenza A reassortant virus, H1N2r, which caused mild clinical disease in pigs in the United Kingdom, was isolated. This reassortant virus has a novel gene constellation, incorporating the internal gene cassette of pH1N1-origin viruses and hemagglutinin and neuraminidase genes of swine IAV H1N2 origin. We investigated the pathogenesis and infection dynamics of the H1N2r isolate in pigs (the natural host) and in ferrets, which represent a human model of infection. Clinical and virologic parameters were mild in both species and both intraspecies and interspecies transmission was observed when initiated from either infected pigs or infected ferrets. This novel reassortant virus has zoonotic and reverse zoonotic potential, but no apparent increased virulence or transmissibility, in comparison to pH1N1 viruses.
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4
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Swine influenza virus: Current status and challenge. Virus Res 2020; 288:198118. [PMID: 32798539 DOI: 10.1016/j.virusres.2020.198118] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/19/2022]
Abstract
Since swine influenza virus was first isolated in 1930, it has become endemic in pigs worldwide. Although large amount of swine influenza vaccines has been used in swine industry, swine influenza still cannot be efficiently controlled and has been an important economic disease for swine industry. The high diversity and varied distribution of different subtypes and genotypes of swine influenza viruses circulating in pigs globally is a major challenge to produce broadly effective vaccines and control disease. Importantly, swine influenza virus is able to cross species barrier to infect humans and even caused influenza pandemic in 2009. Herein, current status and challenge of swine influenza viruses is reviewed and discussed.
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Chauhan RP, Gordon ML. A Systematic Review Analyzing the Prevalence and Circulation of Influenza Viruses in Swine Population Worldwide. Pathogens 2020; 9:pathogens9050355. [PMID: 32397138 PMCID: PMC7281378 DOI: 10.3390/pathogens9050355] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/02/2020] [Accepted: 04/09/2020] [Indexed: 01/04/2023] Open
Abstract
The global anxiety and a significant threat to public health due to the current COVID-19 pandemic reiterate the need for active surveillance for the zoonotic virus diseases of pandemic potential. Influenza virus due to its wide host range and zoonotic potential poses such a significant threat to public health. Swine serve as a “mixing vessel” for influenza virus reassortment and evolution which as a result may facilitate the emergence of new strains or subtypes of zoonotic potential. In this context, the currently available scientific data hold a high significance to unravel influenza virus epidemiology and evolution. With this objective, the current systematic review summarizes the original research articles and case reports of all the four types of influenza viruses reported in swine populations worldwide. A total of 281 articles were found eligible through screening of PubMed and Google Scholar databases and hence were included in this systematic review. The highest number of research articles (n = 107) were reported from Asia, followed by Americas (n = 97), Europe (n = 55), Africa (n = 18), and Australia (n = 4). The H1N1, H1N2, H3N2, and A(H1N1)pdm09 viruses were the most common influenza A virus subtypes reported in swine in most countries across the globe, however, few strains of influenza B, C, and D viruses were also reported in certain countries. Multiple reports of the avian influenza virus strains documented in the last two decades in swine in China, the United States, Canada, South Korea, Nigeria, and Egypt provided the evidence of interspecies transmission of influenza viruses from birds to swine. Inter-species transmission of equine influenza virus H3N8 from horse to swine in China expanded the genetic diversity of swine influenza viruses. Additionally, numerous reports of the double and triple-reassortant strains which emerged due to reassortments among avian, human, and swine strains within swine further increased the genetic diversity of swine influenza viruses. These findings are alarming hence active surveillance should be in place to prevent future influenza pandemics.
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Rieckmann K, Pendzialek SM, Vahlenkamp T, Baums CG. A critical review speculating on the protective efficacies of autogenous Streptococcus suis bacterins as used in Europe. Porcine Health Manag 2020; 6:12. [PMID: 32391166 PMCID: PMC7201539 DOI: 10.1186/s40813-020-00150-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/20/2020] [Indexed: 11/10/2022] Open
Abstract
Background Streptococcus (S.) suis is a major porcine pathogen causing high morbidity worldwide. This includes well-managed herds with high hygiene standards. In Europe, no licensed vaccine is available. As practitioners are obliged to reduce the use of antibiotics, autogenous S. suis vaccines have become very popular in Europe. Main body Autogenous vaccines (AV) are generally neither tested for safety, immunogenicity nor protective efficacy, which leads to substantial uncertainties regarding control of disease and return on investment. Here, S. suis publications are reviewed that include important data on epidemiology, pathologies and bacterin vaccination relevant for the use of AV in the field. Differences between herds such as the porcine reproductive and respiratory syndrome virus infection status and the impact of specific S. suis pathotypes are probably highly relevant for the outcome of immunoprophylaxis using autogenous S. suis bacterins. Thus, a profound diagnosis of the herd status is crucial for management of expectations and successful implementation of AV as a tool to control S. suis disease. Induction of opsonizing antibodies is an in vitro correlate of protective immunity elicited by S. suis bacterins. However, opsonophagocytosis assays are difficult to include in the portfolio of diagnostic services. Conclusion Autogenous S. suis bacterins are associated with limitations and risks of failure, which can partly be managed through improvement of diagnostics.
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Affiliation(s)
- Karoline Rieckmann
- 1Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany
| | - Sophia-Mareike Pendzialek
- 1Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany
| | - Thomas Vahlenkamp
- 2Institute of Virology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University Leipzig, Leipzig, Germany
| | - Christoph G Baums
- 1Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany
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7
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Gumbert S, Froehlich S, Rieger A, Stadler J, Ritzmann M, Zoels S. Reproductive performance of pandemic influenza A virus infected sow herds before and after implementation of a vaccine against the influenza A (H1N1)pdm09 virus. Porcine Health Manag 2020; 6:4. [PMID: 31993212 PMCID: PMC6977244 DOI: 10.1186/s40813-019-0141-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 12/23/2019] [Indexed: 01/21/2023] Open
Abstract
Background Reproductive failure in sow herds due to infection with influenza A viruses has been described in the literature, but only a few studies have focused on the pathogenesis and the clinical signs of the infection. Case reports indicate an association between infections with influenza A viruses and reduced reproductive performance, although it has been difficult to experimentally reproduce the clinical outcome of poor reproductive performance. The aim of the present longitudinal field study was to compare the reproductive performance parameters before and after the implementation of vaccination against the influenza A (H1N1)pdm09 virus in sow herds infected with pandemic influenza A virus. Therefore, farm-specific data of 137 sow herds in Germany, including 60,153 sows, as well as the clinical presentation of the infection were surveyed via questionnaire. Furthermore, average performance parameters (return to oestrus rate, abortion rate, stillbirth rate, number of piglets born alive per litter, preweaning mortality rate and number of piglets weaned per sow per year) were recorded for 6 months before vaccination and 6 months after completion of primary vaccination. Results In 79.8% of the farms, the clinical presentation of the infection was characterised by a reduced reproductive performance. These findings were confirmed by analysis of the performance parameters, which revealed a significant decline in the return to oestrus rate (p < 0.001), abortion rate (p < 0.001) and preweaning mortality rate (p = 0.023) and a significant increase of the number in piglets born alive (p = 0.001) and piglets weaned per sow per year (p < 0.001) after immunisation. The stillbirth rate did not change significantly. Conclusion The present study represents the first attempt to demonstrate the association of influenza A virus infection, vaccination and the alteration in reproductive performance parameters, investigating a large number of cases. The results show that by vaccinating against the influenza A (H1N1)pdm09 virus, an improvement in reproductive performance can be achieved in sow herds infected with pandemic influenza A virus. Additionally, the large number of herds that were affected by poor reproductive performance after infection with the aforementioned virus confirms the assumption of an association between pandemic influenza A virus and reproductive losses.
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Affiliation(s)
- Sophie Gumbert
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany
| | - Sebastian Froehlich
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany
| | - Anna Rieger
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany
| | - Julia Stadler
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany
| | - Mathias Ritzmann
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany
| | - Susanne Zoels
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany
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Pitzer VE, Aguas R, Riley S, Loeffen WLA, Wood JLN, Grenfell BT. High turnover drives prolonged persistence of influenza in managed pig herds. J R Soc Interface 2017; 13:rsif.2016.0138. [PMID: 27358277 PMCID: PMC4938081 DOI: 10.1098/rsif.2016.0138] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/08/2016] [Indexed: 11/16/2022] Open
Abstract
Pigs have long been hypothesized to play a central role in the emergence of novel human influenza A virus (IAV) strains, by serving as mixing vessels for mammalian and avian variants. However, the key issue of viral persistence in swine populations at different scales is ill understood. We address this gap using epidemiological models calibrated against seroprevalence data from Dutch finishing pigs to estimate the ‘critical herd size’ (CHS) for IAV persistence. We then examine the viral phylogenetic evidence for persistence by comparing human and swine IAV. Models suggest a CHS of approximately 3000 pigs above which influenza was likely to persist, i.e. orders of magnitude lower than persistence thresholds for IAV and other acute viruses in humans. At national and regional scales, we found much stronger empirical signatures of prolonged persistence of IAV in swine compared with human populations. These striking levels of persistence in small populations are driven by the high recruitment rate of susceptible piglets, and have significant implications for management of swine and for overall patterns of genetic diversity of IAV.
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Affiliation(s)
- Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20850, USA
| | - Ricardo Aguas
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London SW7 2AZ, UK
| | - Steven Riley
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London SW7 2AZ, UK
| | - Willie L A Loeffen
- Department of Virology, Central Veterinary Institute, part of Wageningen UR, Lelystad 8200AB, The Netherlands
| | - James L N Wood
- Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Bryan T Grenfell
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20850, USA Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
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Disease surveillance in England and Wales, September 2017. Vet Rec 2017; 181:362-365. [PMID: 28986486 DOI: 10.1136/vr.j4540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Current and emerging issues: Schmallenberg virusHighlights from the scanning surveillance networkon international disease threats Salmonella investigations in ruminants These are among matters discussed in the Animal and Plant Health Agency's (APHA's) disease surveillance report for September 2017.
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11
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Gerber PF, Dawson L, Strugnell B, Burgess R, Brown H, Opriessnig T. Using oral fluids samples for indirect influenza A virus surveillance in farmed UK pigs. Vet Med Sci 2016; 3:3-12. [PMID: 29067204 PMCID: PMC5645835 DOI: 10.1002/vms3.51] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 10/06/2016] [Accepted: 11/01/2016] [Indexed: 12/03/2022] Open
Abstract
Influenza A virus (IAV) is economically important in pig production and has broad public health implications. In Europe, active IAV surveillance includes demonstration of antigen in nasal swabs and/or demonstration of antibodies in serum (SER) samples; however, collecting appropriate numbers of individual pig samples can be costly and labour‐intensive. The objective of this study was to compare the probability of detecting IAV antibody positive populations using SER versus oral fluid (OF) samples. Paired pen samples, one OF and 5–14 SER samples, were collected cross‐sectional or longitudinally. A commercial nucleoprotein (NP)‐based blocking ELISA was used to test 244 OF and 1004 SER samples from 123 pens each containing 20–540 pigs located in 27 UK herds. Overall, the IAV antibody detection rate was higher in SER samples compared to OFs under the study conditions. Pig age had a significant effect on the probability of detecting positive pens. For 3–9‐week‐old pigs the probability of detecting IAV antibody positive samples in a pen with 95% confidence intervals was 40% (23–60) for OF and 61% (0.37–0.80) for SER (P = 0.04), for 10–14‐week‐old pigs it was 19% (8–40) for OF and 93% (0.71–0.99) for SER (P < 0.01), and for 18–20‐week‐old pigs it was 67% (41–85) for OF and 81% (0.63–0.91) for SER (P = 0.05). Collecting more than one OF sample in pens with more than 25 less than 18‐week‐old pigs should be further investigated in the future to elucidate the suitability of OF for IAV surveillance in herds with large pen sizes.
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Affiliation(s)
- Priscilla F Gerber
- The Roslin Institute and The Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianScotlandUK
| | - Lorna Dawson
- School of AgricultureFood and Rural DevelopmentNewcastle UniversityNewcastle upon TyneUK
| | - Ben Strugnell
- Evidence-based Veterinary Consultancy (EBVC) Ltd.Rural Enterprise CentreRedhillsPenrithCumbriaUK
| | - Robert Burgess
- Evidence-based Veterinary Consultancy (EBVC) Ltd.Rural Enterprise CentreRedhillsPenrithCumbriaUK
| | - Helen Brown
- The Roslin Institute and The Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianScotlandUK
| | - Tanja Opriessnig
- The Roslin Institute and The Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianScotlandUK.,Department of Veterinary Diagnostic and Production Animal MedicineIowa State UniversityAmesIowaUSA
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12
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Fragaszy E, Ishola DA, Brown IH, Enstone J, Nguyen‐Van‐Tam JS, Simons R, Tucker AW, Wieland B, Williamson SM, Hayward AC, Wood JLN. Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort. Influenza Other Respir Viruses 2016; 10:291-300. [PMID: 26611769 PMCID: PMC4910179 DOI: 10.1111/irv.12364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2015] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Pigs are mixing vessels for influenza viral reassortment, but the extent of influenza transmission between swine and humans is not well understood. OBJECTIVES To assess whether occupational exposure to pigs is a risk factor for human infection with human and swine-adapted influenza viruses. METHODS UK pig industry workers were frequency-matched on age, region, sampling month, and gender with a community-based comparison group from the Flu Watch study. HI assays quantified antibodies for swine and human A(H1) and A(H3) influenza viruses (titres ≥ 40 considered seropositive and indicative of infection). Virus-specific associations between seropositivity and occupational pig exposure were examined using multivariable regression models adjusted for vaccination. Pigs on the same farms were also tested for seropositivity. RESULTS Forty-two percent of pigs were seropositive to A(H1N1)pdm09. Pig industry workers showed evidence of increased odds of A(H1N1)pdm09 seropositivity compared to the comparison group, albeit with wide confidence intervals (CIs), adjusted odds ratio after accounting for possible cross-reactivity with other swine A(H1) viruses (aOR) 25·3, 95% CI (1·4-536·3), P = 0·028. CONCLUSION The results indicate that A(H1N1)pdm09 virus was common in UK pigs during the pandemic and subsequent period of human A(H1N1)pdm09 circulation, and occupational exposure to pigs was a risk factor for human infection. Influenza immunisation of pig industry workers may reduce transmission and the potential for virus reassortment.
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Affiliation(s)
- Ellen Fragaszy
- Department of Infectious Disease InformaticsFarr Institute of Health Informatics ResearchUniversity College LondonLondonUK
- Department of Infectious Disease EpidemiologyLondon School of Hygiene and Tropical MedicineLondonUK
| | - David A. Ishola
- Department of Infectious Disease InformaticsFarr Institute of Health Informatics ResearchUniversity College LondonLondonUK
- Immunisation DepartmentPublic Health EnglandLondonUK
| | - Ian H. Brown
- Animal and Plant Health Agency (formerly Animal Health and Veterinary Laboratories Agency)WeybridgeUK
| | - Joanne Enstone
- Health Protection and Influenza Research GroupDivision of Epidemiology and Public HealthUniversity of NottinghamNottinghamUK
| | - Jonathan S. Nguyen‐Van‐Tam
- Health Protection and Influenza Research GroupDivision of Epidemiology and Public HealthUniversity of NottinghamNottinghamUK
| | - Robin Simons
- Animal and Plant Health Agency (formerly Animal Health and Veterinary Laboratories Agency)WeybridgeUK
| | - Alexander W. Tucker
- Disease Dynamics UnitDepartment of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - Barbara Wieland
- Royal Veterinary CollegeNorth MymmsUK
- ILRI: International Livestock Research InstituteAddis AbabaEthiopia
| | - Susanna M. Williamson
- Animal and Plant Health Agency (formerly Animal Health and Veterinary Laboratories Agency)WeybridgeUK
| | - Andrew C. Hayward
- Department of Infectious Disease InformaticsFarr Institute of Health Informatics ResearchUniversity College LondonLondonUK
| | | | - James L. N. Wood
- Disease Dynamics UnitDepartment of Veterinary MedicineUniversity of CambridgeCambridgeUK
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Comparison of Respiratory Disease Prevalence among Voluntary Monitoring Systems for Pig Health and Welfare in the UK. PLoS One 2015; 10:e0128137. [PMID: 26020635 PMCID: PMC4447343 DOI: 10.1371/journal.pone.0128137] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 04/22/2015] [Indexed: 12/05/2022] Open
Abstract
Surveillance of animal diseases provides information essential for the protection of animal health and ultimately public health. The voluntary pig health schemes, implemented in the United Kingdom, are integrated systems which capture information on different macroscopic disease conditions detected in slaughtered pigs. Many of these conditions have been associated with a reduction in performance traits and consequent increases in production costs. The schemes are the Wholesome Pigs Scotland in Scotland, the BPEX Pig Health Scheme in England and Wales and the Pig Regen Ltd. health and welfare checks done in Northern Ireland. This report set out to compare the prevalence of four respiratory conditions (enzootic pneumonia-like lesions, pleurisy, pleuropneumonia lesions and abscesses in the lung) assessed by these three Pig Health Schemes. The seasonal variations and year trends associated with the conditions in each scheme are presented. The paper also highlights the differences in prevalence for each condition across these schemes and areas where further research is needed. A general increase in the prevalence of enzootic pneumonia like lesions was observed in Scotland, England and Wales since 2009, while a general decrease was observed in Northern Ireland over the years of the scheme. Pleurisy prevalence has increased since 2010 in all three schemes, whilst pleuropneumonia has been decreasing. Prevalence of abscesses in the lung has decreased in England, Wales and Northern Ireland but has increased in Scotland. This analysis highlights the value of surveillance schemes based on abattoir pathology monitoring of four respiratory lesions. The outputs at scheme level have significant value as indicators of endemic and emerging disease, and for producers and herd veterinarians in planning and evaluating herd health control programs when comparing individual farm results with national averages.
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14
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Lin X, Huang C, Shi J, Wang R, Sun X, Liu X, Zhao L, Jin M. Investigation of Pathogenesis of H1N1 Influenza Virus and Swine Streptococcus suis Serotype 2 Co-Infection in Pigs by Microarray Analysis. PLoS One 2015; 10:e0124086. [PMID: 25906258 PMCID: PMC4407888 DOI: 10.1371/journal.pone.0124086] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 02/27/2015] [Indexed: 12/11/2022] Open
Abstract
Swine influenza virus and Streptococcus suis are two important contributors to the porcine respiratory disease complex, and both have significant economic impacts. Clinically, influenza virus and Streptococcus suis co-infections in pigs are very common, which often contribute to severe pneumonia and can increase the mortality. However, the co-infection pathogenesis in pigs is unclear. In the present study, co-infection experiments were performed using swine H1N1 influenza virus and Streptococcus suis serotype 2 (SS2). The H1N1-SS2 co-infected pigs exhibited more severe clinical symptoms, serious pathological changes, and robust apoptosis of lungs at 6 days post-infection compared with separate H1N1 and SS2 infections. A comprehensive gene expression profiling using a microarray approach was performed to investigate the global host responses of swine lungs against the swine H1N1 infection, SS2 infection, co-infection, and phosphate-buffered saline control. Results showed 457, 411, and 844 differentially expressed genes in the H1N1, SS2, and H1N1-SS2 groups, respectively, compared with the control. Noticeably, genes associated with the immune, inflammatory, and apoptosis responses were highly overexpressed in the co-infected group. Pathway analysis indicated that the cytokine–cytokine receptor interactions, MAPK, toll-like receptor, complement and coagulation cascades, antigen processing and presentation, and apoptosis pathway were significantly regulated in the co-infected group. However, the genes related to these were less regulated in the separate H1N1 and SS2 infection groups. This observation suggested that a certain level of synergy was induced by H1N1 and SS2 co-infection with significantly stronger inflammatory and apoptosis responses, which may lead to more serious respiratory disease syndrome and pulmonary pathological lesion.
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Affiliation(s)
- Xian Lin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Canhui Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Jian Shi
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Ruifang Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Xin Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Xiaokun Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Lianzhong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China
- * E-mail:
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15
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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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16
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Dang Y, Lachance C, Wang Y, Gagnon CA, Savard C, Segura M, Grenier D, Gottschalk M. Transcriptional approach to study porcine tracheal epithelial cells individually or dually infected with swine influenza virus and Streptococcus suis. BMC Vet Res 2014; 10:86. [PMID: 24708855 PMCID: PMC4022123 DOI: 10.1186/1746-6148-10-86] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/31/2014] [Indexed: 11/16/2022] Open
Abstract
Background Swine influenza is a highly contagious viral infection in pigs affecting the respiratory tract that can have significant economic impacts. Streptococcus suis serotype 2 is one of the most important post-weaning bacterial pathogens in swine causing different infections, including pneumonia. Both pathogens are important contributors to the porcine respiratory disease complex. Outbreaks of swine influenza virus with a significant level of co-infections due to S. suis have lately been reported. In order to analyze, for the first time, the transcriptional host response of swine tracheal epithelial (NPTr) cells to H1N1 swine influenza virus (swH1N1) infection, S. suis serotype 2 infection and a dual infection, we carried out a comprehensive gene expression profiling using a microarray approach. Results Gene clustering showed that the swH1N1 and swH1N1/S. suis infections modified the expression of genes in a similar manner. Additionally, infection of NPTr cells by S. suis alone resulted in fewer differentially expressed genes compared to mock-infected cells. However, some important genes coding for inflammatory mediators such as chemokines, interleukins, cell adhesion molecules, and eicosanoids were significantly upregulated in the presence of both pathogens compared to infection with each pathogen individually. This synergy may be the consequence, at least in part, of an increased bacterial adhesion/invasion of epithelial cells previously infected by swH1N1, as recently reported. Conclusion Influenza virus would replicate in the respiratory epithelium and induce an inflammatory infiltrate comprised of mononuclear cells and neutrophils. In a co-infection situation, although these cells would be unable to phagocyte and kill S. suis, they are highly activated by this pathogen. S. suis is not considered a primary pulmonary pathogen, but an exacerbated production of proinflammatory mediators during a co-infection with influenza virus may be important in the pathogenesis and clinical outcome of S. suis-induced respiratory diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Marcelo Gottschalk
- Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, St-Hyacinthe, J2S 2M2 Québec, Canada.
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Dibárbora M, Cappuccio J, Olivera V, Quiroga M, Machuca M, Perfumo C, Pérez D, Pereda A. Swine influenza: clinical, serological, pathological, and virological cross-sectional studies in nine farms in Argentina. Influenza Other Respir Viruses 2013; 7 Suppl 4:10-5. [PMID: 24224814 PMCID: PMC4942990 DOI: 10.1111/irv.12200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Influenza A viruses (IAV) are important pathogens responsible for economic losses in the swine industry and represent a threat to public health. In Argentina, clinical, pathological, and virological findings suggest that IAV infection is widespread among pig farms. In addition, several subtypes of IAV, such as pH1N1, H3N2, δ1H1N1, and δ2H1N2, have been reported. OBJECTIVES To evaluate the infection patterns of influenza virus in nine pig farms in Argentina. METHODS Clinical, serological, pathological, and virological cross-sectional studies were conducted. RESULTS Clinical and pathological results were characteristic of endemic influenza infection in eight of the nine farms studied. By rRT-PCR, six of the nine farms were positive to influenza. Five IAV were obtained. Genome analysis determined that four of the isolations were pH1N1 and that the remaining one was a reassortant human origin H3N2 virus containing pandemic internal genes. Serological results showed that all farms were positive to influenza A antibodies. Moreover, the hemagglutination inhibition test showed that infection with viruses containing HA's from different subtypes (pH1, δ1H1, δ2H1, and H3) is present among the farms studied and that coinfections with two or more subtypes were present in 80.5% of positive pigs. CONCLUSIONS Because vaccines against IAV are not licensed in Argentina, these results reflect the situation of IAV infection in non-vaccinated herds. This study provides more information about the circulation and characteristics of IAV in a poorly surveyed region. This study provides more data that will be used to evaluate the tools necessary to control this disease.
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Affiliation(s)
- Marina Dibárbora
- Laboratorio Aves y PorcinosInstituto de Virología CICVyA – Instituto Nacional de Tecnología Agropecuaria (INTA)Buenos AiresArgentina
| | - Javier Cappuccio
- Cátedra de Patología Especial, Facultad de Cs. VeterinariasUniversidad Nacional de La PlataBuenos AiresArgentina
| | - Valeria Olivera
- Laboratorio Aves y PorcinosInstituto de Virología CICVyA – Instituto Nacional de Tecnología Agropecuaria (INTA)Buenos AiresArgentina
| | - Maria Quiroga
- Cátedra de Patología Especial, Facultad de Cs. VeterinariasUniversidad Nacional de La PlataBuenos AiresArgentina
| | - Mariana Machuca
- Cátedra de Patología Especial, Facultad de Cs. VeterinariasUniversidad Nacional de La PlataBuenos AiresArgentina
| | - Carlos Perfumo
- Cátedra de Patología Especial, Facultad de Cs. VeterinariasUniversidad Nacional de La PlataBuenos AiresArgentina
| | - Daniel Pérez
- Virginia‐Maryland Regional College of Veterinary Medicine and Department of Veterinary MedicineUniversity of MarylandCollege ParkMDUSA
| | - Ariel Pereda
- Laboratorio Aves y PorcinosInstituto de Virología CICVyA – Instituto Nacional de Tecnología Agropecuaria (INTA)Buenos AiresArgentina
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18
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Capsular sialic acid of Streptococcus suis serotype 2 binds to swine influenza virus and enhances bacterial interactions with virus-infected tracheal epithelial cells. Infect Immun 2013; 81:4498-508. [PMID: 24082069 DOI: 10.1128/iai.00818-13] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model.
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19
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Expanded cocirculation of stable subtypes, emerging lineages, and new sporadic reassortants of porcine influenza viruses in swine populations in Northwest Germany. J Virol 2013; 87:10460-76. [PMID: 23824819 DOI: 10.1128/jvi.00381-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The emergence of the human 2009 pandemic H1N1 (H1N1pdm) virus from swine populations refocused public and scientific attention on swine as an important source of influenza A viruses bearing zoonotic potential. Widespread and year-round circulation of at least four stable lineages of porcine influenza viruses between 2009 and 2012 in a region of Germany with a high-density swine population is documented here. European avian influenza virus-derived H1N1 (H1N1av) viruses dominated the epidemiology, followed by human-derived subtypes H1N2 and H3N2. H1N1pdm viruses and, in particular, recently emerging reassortants between H1N1pdm and porcine HxN2 viruses (H1pdmN2) were detected in about 8% of cases. Further reassortants between these main lineages were diagnosed sporadically. Ongoing diversification both at the phylogenetic and at the antigenic level was evident for the H1N1av lineage and for some of its reassortants. The H1avN2 reassortant R1931/11 displayed conspicuously distinct genetic and antigenic features and was easily transmitted from pig to pig in an experimental infection. Continuing diverging evolution was also observed in the H1pdmN2 lineage. These viruses carry seven genome segments of the H1N1pdm virus, including a hemagglutinin gene that encodes a markedly antigenically altered protein. The zoonotic potential of this lineage remains to be determined. The results highlight the relevance of surveillance and control of porcine influenza virus infections. This is important for the health status of swine herds. In addition, a more exhaustive tracing of the formation, transmission, and spread of new reassortant influenza A viruses with unknown zoonotic potential is urgently required.
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20
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Lycett SJ, Baillie G, Coulter E, Bhatt S, Kellam P, McCauley JW, Wood JLN, Brown IH, Pybus OG, Leigh Brown AJ. Estimating reassortment rates in co-circulating Eurasian swine influenza viruses. J Gen Virol 2012; 93:2326-2336. [PMID: 22971819 PMCID: PMC3542128 DOI: 10.1099/vir.0.044503-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/24/2012] [Indexed: 12/22/2022] Open
Abstract
Swine have often been considered as a mixing vessel for different influenza strains. In order to assess their role in more detail, we undertook a retrospective sequencing study to detect and characterize the reassortants present in European swine and to estimate the rate of reassortment between H1N1, H1N2 and H3N2 subtypes with Eurasian (avian-like) internal protein-coding segments. We analysed 69 newly obtained whole genome sequences of subtypes H1N1-H3N2 from swine influenza viruses sampled between 1982 and 2008, using Illumina and 454 platforms. Analyses of these genomes, together with previously published genomes, revealed a large monophyletic clade of Eurasian swine-lineage polymerase segments containing H1N1, H1N2 and H3N2 subtypes. We subsequently examined reassortments between the haemagglutinin and neuraminidase segments and estimated the reassortment rates between lineages using a recently developed evolutionary analysis method. High rates of reassortment between H1N2 and H1N1 Eurasian swine lineages were detected in European strains, with an average of one reassortment every 2-3 years. This rapid reassortment results from co-circulating lineages in swine, and in consequence we should expect further reassortments between currently circulating swine strains and the recent swine-origin H1N1v pandemic strain.
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Affiliation(s)
- S. J. Lycett
- Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - G. Baillie
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - E. Coulter
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - S. Bhatt
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - P. Kellam
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - J. W. McCauley
- Division of Virology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - J. L. N. Wood
- Cambridge Infectious Diseases Consortium, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - I. H. Brown
- Animal Health and Veterinary Laboratories Agency – Weybridge, Addlestone, Surrey, KT15 3NB, UK
| | - O. G. Pybus
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - A. J. Leigh Brown
- Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - for the Combating Swine Influenza Initiative (COSI) Consortium
- Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
- Division of Virology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
- Cambridge Infectious Diseases Consortium, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
- Animal Health and Veterinary Laboratories Agency – Weybridge, Addlestone, Surrey, KT15 3NB, UK
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21
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Sims L. Keeping track of swine influenza viruses. Vet Rec 2012; 171:269-70. [DOI: 10.1136/vr.e6111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Les Sims
- Asia Pacific Veterinary Information Services; PO Box 55 Montmorency Victoria 3094 Australia
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