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Graaf-Rau A, Schmies K, Breithaupt A, Ciminski K, Zimmer G, Summerfield A, Sehl-Ewert J, Lillie-Jaschniski K, Helmer C, Bielenberg W, Grosse Beilage E, Schwemmle M, Beer M, Harder T. Reassortment incompetent live attenuated and replicon influenza vaccines provide improved protection against influenza in piglets. NPJ Vaccines 2024; 9:127. [PMID: 39003272 PMCID: PMC11246437 DOI: 10.1038/s41541-024-00916-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 06/24/2024] [Indexed: 07/15/2024] Open
Abstract
Swine influenza A viruses (swIAV) cause an economically important respiratory disease in modern pig production. Continuous virus transmission and antigenic drift are difficult to control in enzootically infected pig herds. Here, antibody-positive piglets from a herd enzootically infected with swIAV H1N2 (clade 1 A.3.3.2) were immunized using a homologous prime-boost vaccination strategy with novel live attenuated influenza virus (LAIV) based on a reassortment-incompetent bat influenza-swIAV chimera or a vesicular stomatitis virus-based replicon vaccine. Challenge infection of vaccinated piglets by exposure to H1N2 swIAV-infected unvaccinated seeder pigs showed that both LAIV and replicon vaccine markedly reduced virus replication in the upper and lower respiratory tract, respectively, compared to piglets immunized with commercial heterologous or autologous adjuvanted whole-inactivated virus vaccines. Our novel vaccines may aid in interrupting continuous IAV transmission chains in large enzootically infected pig herds, improve the health status of the animals, and reduce the risk of zoonotic swIAV transmission.
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Affiliation(s)
- Annika Graaf-Rau
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Greifswald, Germany.
| | - Kathrin Schmies
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, Foundation, Bakum, Germany
| | - Angele Breithaupt
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler- Institut, Greifswald, Insel Riems, Germany
| | - Kevin Ciminski
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gert Zimmer
- Institute of Virology and Immunology, Bern & Mittelhaeusern, Switzerland, and Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Artur Summerfield
- Institute of Virology and Immunology, Bern & Mittelhaeusern, Switzerland, and Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Julia Sehl-Ewert
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler- Institut, Greifswald, Insel Riems, Germany
| | | | - Carina Helmer
- SAN Group Biotech Germany GmbH, Hoeltinghausen, Germany
| | | | - Elisabeth Grosse Beilage
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, Foundation, Bakum, Germany
| | - Martin Schwemmle
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Greifswald, Germany
| | - Timm Harder
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Greifswald, Germany
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2
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Dias AS, Baker ALV, Baker RB, Zhang J, Zeller MA, Kitikoon P, Gauger PC. Detection and Characterization of Influenza A Virus Endemic Circulation in Suckling and Nursery Pigs Originating from Vaccinated Farms in the Same Production System. Viruses 2024; 16:626. [PMID: 38675967 PMCID: PMC11054297 DOI: 10.3390/v16040626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Inactivated influenza A virus (IAV) vaccines help reduce clinical disease in suckling piglets, although endemic infections still exist. The objective of this study was to evaluate the detection of IAV in suckling and nursery piglets from IAV-vaccinated sows from farms with endemic IAV infections. Eight nasal swab collections were obtained from 135 two-week-old suckling piglets from four farms every other week from March to September 2013. Oral fluid samples were collected from the same group of nursery piglets. IAV RNA was detected in 1.64% and 31.01% of individual nasal swabs and oral fluids, respectively. H1N2 was detected most often, with sporadic detection of H1N1 and H3N2. Whole-genome sequences of IAV isolated from suckling piglets revealed an H1 hemagglutinin (HA) from the 1B.2.2.2 clade and N2 neuraminidase (NA) from the 2002A clade. The internal gene constellation of the endemic H1N2 was TTTTPT with a pandemic lineage matrix. The HA gene had 97.59% and 97.52% nucleotide and amino acid identities, respectively, to the H1 1B.2.2.2 used in the farm-specific vaccine. A similar H1 1B.2.2.2 was detected in the downstream nursery. These data demonstrate the low frequency of IAV detection in suckling piglets and downstream nurseries from farms with endemic infections in spite of using farm-specific IAV vaccines in sows.
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MESH Headings
- Animals
- Swine
- Swine Diseases/virology
- Swine Diseases/epidemiology
- Swine Diseases/prevention & control
- Orthomyxoviridae Infections/veterinary
- Orthomyxoviridae Infections/virology
- Orthomyxoviridae Infections/epidemiology
- Influenza A virus/genetics
- Influenza A virus/immunology
- Influenza A virus/isolation & purification
- Influenza A virus/classification
- Influenza Vaccines/immunology
- Influenza Vaccines/administration & dosage
- Phylogeny
- Farms
- Animals, Suckling
- Vaccination/veterinary
- Endemic Diseases/veterinary
- Influenza A Virus, H1N1 Subtype/genetics
- Influenza A Virus, H1N1 Subtype/immunology
- Influenza A Virus, H1N1 Subtype/isolation & purification
- RNA, Viral/genetics
- Influenza A Virus, H3N2 Subtype/genetics
- Influenza A Virus, H3N2 Subtype/immunology
- Influenza A Virus, H3N2 Subtype/isolation & purification
- Influenza A Virus, H1N2 Subtype/genetics
- Influenza A Virus, H1N2 Subtype/isolation & purification
- Influenza A Virus, H1N2 Subtype/immunology
- Genome, Viral
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Affiliation(s)
- Alessandra Silva Dias
- Department of Preventive Veterinary Medicine, Minas Gerais State University, 6627 Antonio Carlos Avenue, Belo Horizonte 31620-295, MG, Brazil;
| | - Amy L. Vincent Baker
- Virus and Prion Research Unit, United States Department of Agriculture, National Animal Disease Center, Agricultural Research Service, 1920 Dayton Avenue, Ames, IA 50010, USA; (A.L.V.B.); (P.K.)
| | - Rodney B. Baker
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011, USA; (R.B.B.); (J.Z.); (M.A.Z.)
| | - Jianqiang Zhang
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011, USA; (R.B.B.); (J.Z.); (M.A.Z.)
| | - Michael A. Zeller
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011, USA; (R.B.B.); (J.Z.); (M.A.Z.)
| | - Pravina Kitikoon
- Virus and Prion Research Unit, United States Department of Agriculture, National Animal Disease Center, Agricultural Research Service, 1920 Dayton Avenue, Ames, IA 50010, USA; (A.L.V.B.); (P.K.)
| | - Phillip C. Gauger
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011, USA; (R.B.B.); (J.Z.); (M.A.Z.)
- Phillip Gauger of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011, USA
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3
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Lagan P, Hamil M, Cull S, Hanrahan A, Wregor RM, Lemon K. Swine influenza A virus infection dynamics and evolution in intensive pig production systems. Virus Evol 2024; 10:veae017. [PMID: 38476866 PMCID: PMC10930190 DOI: 10.1093/ve/veae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 02/05/2024] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Swine influenza A virus (swIAV) is one of the main viral pathogens responsible for respiratory disease in farmed pigs. While outbreaks are often epidemic in nature, increasing reports suggest that continuous, endemic infection of herds is now common. The move towards larger herd sizes and increased intensification in the commercial pig industry may promote endemic infection; however, the impact that intensification has on swIAV infection dynamics and evolution is unclear. We carried out a longitudinal surveillance study for over 18 months on two enzootically infected, intensive, indoor, and multi-site pig production flows. Frequent sampling of all production stages using individual and group sampling methods was performed, followed by virological and immunological testing and whole-genome sequencing. We identified weaned pigs between 4 and 12-weeks old as the main reservoir of swIAV in the production flows, with continuous, year-round infection. Despite the continuous nature of viral circulation, infection levels were not uniform, with increasing exposure at the herd level associated with reduced viral prevalence followed by subsequent rebound infection. A single virus subtype was maintained on each farm for the entire duration of the study. Viral evolution was characterised by long periods of stasis punctuated by periods of rapid change coinciding with increasing exposure within the herd. An accumulation of mutations in the surface glycoproteins consistent with antigenic drift was observed, in addition to amino acid substitutions in the internal gene products as well as reassortment exchange of internal gene segments from newly introduced strains. These data demonstrate that long-term, continuous infection of herds with a single subtype is possible and document the evolutionary mechanisms utilised to achieve this.
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Affiliation(s)
- Paula Lagan
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, 12 Stoney Road, Belfast BT4 3SD, Northern Ireland
| | - Michael Hamil
- JMW Farms Ltd., 50 Hamiltonsbawn Road, Armagh BT60 1HW, Northern Ireland
| | - Susan Cull
- Craigavon Area Hospital, 68 Lurgan Road, Craigavon BT63 5QQ, Northern Ireland
| | - Anthony Hanrahan
- School of Biological Sciences, Queen’s University Belfast, 19 Chlorine Gardens, Belfast BT9 5DL, Northern Ireland
| | - Rosanna M Wregor
- JMW Farms Ltd., 50 Hamiltonsbawn Road, Armagh BT60 1HW, Northern Ireland
| | - Ken Lemon
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, 12 Stoney Road, Belfast BT4 3SD, Northern Ireland
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Papatsiros VG, Papakonstantinou GI, Meletis E, Koutoulis K, Athanasakopoulou Z, Maragkakis G, Labronikou G, Terzidis I, Kostoulas P, Billinis C. Seroprevalence of Swine Influenza A Virus (swIAV) Infections in Commercial Farrow-to-Finish Pig Farms in Greece. Vet Sci 2023; 10:599. [PMID: 37888551 PMCID: PMC10610732 DOI: 10.3390/vetsci10100599] [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: 08/11/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
Swine influenza is a highly contagious respiratory disease caused by influenza A virus infection. Pigs play an important role in the overall epidemiology of influenza because of their ability to transmit influenza viruses of avian and human origin, which plays a potential role in the emergence of zoonotic strains with pandemic potential. The aim of our study was to assess the seroprevalence of Swine Influenza Viruses (swIAVs) in commercial pig farms in Greece. A total of 1416 blood samples were collected from breeding animals (gilts and sows) and pigs aged 3 weeks to market age from 40 different swIAV vaccinated and unvaccinated commercial farrow-to-finish pig farms. For the detection of anti-SIV antibodies, sera were analyzed using an indirect ELISA kit CIVTEST SUIS INFLUENZA®, Hipra (Amer, Spain). Of the total 1416 animals tested, 498 were seropositive, indicating that the virus circulates in both vaccinated (54% seroprevalence) and unvaccinated Greek pig farms (23% seroprevalence). In addition, maternally derived antibody (MDA) levels were lower in pigs at 4 and 7 weeks of age in unvaccinated farms than in vaccinated farms. In conclusion, our results underscore the importance of vaccination as an effective tool for the prevention of swIAV infections in commercial farrow-to-finish pig farms.
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Affiliation(s)
- Vasileios G. Papatsiros
- Clinic of Medicine, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece; (G.I.P.); (G.M.)
| | - Georgios I. Papakonstantinou
- Clinic of Medicine, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece; (G.I.P.); (G.M.)
| | - Eleftherios Meletis
- Faculty of Public and One Health, University of Thessaly, 43100 Karditsa, Greece; (E.M.); (P.K.)
| | - Konstantinos Koutoulis
- Department of Poultry Diseases, Faculty of Veterinary Science, School of Health Sciences, University of Thessaly, 43100 Karditsa, Greece;
| | - Zoi Athanasakopoulou
- Department of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece; (Z.A.); (C.B.)
| | - Georgios Maragkakis
- Clinic of Medicine, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece; (G.I.P.); (G.M.)
| | - Georgia Labronikou
- Swine Technical Support, Hipra Hellas SA, 10441 Athens, Greece; (G.L.); (I.T.)
| | - Ilias Terzidis
- Swine Technical Support, Hipra Hellas SA, 10441 Athens, Greece; (G.L.); (I.T.)
| | - Polychronis Kostoulas
- Faculty of Public and One Health, University of Thessaly, 43100 Karditsa, Greece; (E.M.); (P.K.)
| | - Charalambos Billinis
- Department of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece; (Z.A.); (C.B.)
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5
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Graaf A, Hennig C, Jaschniski KL, Koechling M, Stadler J, Boehmer J, Ripp U, Pohlmann A, Schwarz BA, Beer M, Harder T. Emergenceof swine influenza A virus, porcine respirovirus 1 and swine orthopneumovirus in porcine respiratory disease in Germany. Emerg Microbes Infect 2023:2239938. [PMID: 37470510 PMCID: PMC10402848 DOI: 10.1080/22221751.2023.2239938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Respiratory disease is a significant economic issue in pig farming, with a complex aetiology that includes swine influenza A viruses (swIAV), which are common in European domestic pig populations. The most recent human influenza pandemic in 2009 showed swIAV's zoonotic potential. Monitoring pathogens and disease control are critical from a preventive standpoint, and are based on quick, sensitive, and specific diagnostic assays capable of detecting and distinguishing currently circulating swIAV in clinical samples. For passive surveillance, a set of multiplex quantitative reverse transcription real-time PCRs (mRT-qPCR) and MinION-directed sequencing was updated and deployed. Several lineages and genotypes of swIAV were shown to be dynamically developing, including novel reassortants between human pandemic H1N1 and the avian-derived H1 lineage of swIAV. Despite this, nearly 70% (842/1216) of individual samples from pigs with respiratory symptoms were swIAV-negative, hinting to different aetiologies. The complex and synergistic interactions of swIAV infections with other viral and bacterial infectious agents contribute to the aggravation of pig respiratory diseases. Using a newly developed mRT-qPCR for the combined detection of swIAV and the recently described porcine respirovirus 1 (PRV1) and swine orthopneumovirus (SOV) widespread co-circulation of PRV1 (19.6%, 238/1216 samples) and SOV (14.2%, 173/1216 samples) was evident. Because of the high incidence of PRV1 and SOV infections in pigs with respiratory disease, these viruses may emerge as new allies in the porcine respiratory disease syndrome.
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Affiliation(s)
- Annika Graaf
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Christin Hennig
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | | | | | - Julia Stadler
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University Munich, Oberschleissheim, Germany
| | - Jan Boehmer
- IVD Society for Innovative Veterinary Diagnostics mbH, Seelze-Letter, Germany
| | - Ulrike Ripp
- Vaxxinova diagnostics GmbH, Leipzig, Germany
| | - Anne Pohlmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | | | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Timm Harder
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
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6
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Andraud M, Hervé S, Gorin S, Barbier N, Quéguiner S, Paboeuf F, Simon G, Rose N. Evaluation of early single dose vaccination on swine influenza A virus transmission in piglets: From experimental data to mechanistic modelling. Vaccine 2023; 41:3119-3127. [PMID: 37061373 DOI: 10.1016/j.vaccine.2023.04.018] [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: 09/30/2022] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/17/2023]
Abstract
Swine influenza A virus (swIAV) is a major pathogen affecting pigs with a huge economic impact and potentially zoonotic. Epidemiological studies in endemically infected farms permitted to identify critical factors favoring on-farm persistence, among which maternally-derived antibodies (MDAs). Vaccination is commonly practiced in breeding herds and might be used for immunization of growing pigs at weaning. Althoughinterference between MDAs and vaccination was reported in young piglets, its impact on swIAV transmission was not yet quantified. To this aim, this study reports on a transmission experiment in piglets with or without MDAs, vaccinated with a single dose injection at four weeks of age, and challenged 17 days post-vaccination. To transpose small-scale experiments to real-life situation, estimated parameters were used in a simulation tool to assess their influence at the herd level. Based on a thorough follow-up of the infection chain during the experiment, the transmission of the swIAV challenge strain was highly dependent on the MDA status of the pigs when vaccinated. MDA-positive vaccinated animals showed a direct transmission rate 3.6-fold higher than the one obtained in vaccinated animals without MDAs, estimated to 1.2. Vaccination nevertheless reduced significantly the contribution of airborne transmission when compared with previous estimates obtained in unvaccinated animals. The integration of parameter estimates in a large-scale simulation model, representing a typical farrow-to-finish pig herd, evidenced an extended persistence of viral spread when vaccination of sows and single dose vaccination of piglets was hypothesized. When extinction was quasi-systematic at year 5 post-introduction in the absence of sow vaccination but with single dose early vaccination of piglets, the extinction probability fell down to 33% when batch-to-batch vaccination was implemented both in breeding herd and weaned piglets. These results shed light on a potential adverse effect of single dose vaccination in MDA-positive piglets, which might lead to longer persistence of the SwIAV at the herd level.
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Affiliation(s)
- M Andraud
- Anses, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare Unit, France.
| | - S Hervé
- Anses, Ploufragan-Plouzané-Niort Laboratory, Swine Virology Immunology Unit, France
| | - S Gorin
- Anses, Ploufragan-Plouzané-Niort Laboratory, Swine Virology Immunology Unit, France
| | - N Barbier
- Anses, Ploufragan-Plouzané-Niort Laboratory, Swine Virology Immunology Unit, France
| | - S Quéguiner
- Anses, Ploufragan-Plouzané-Niort Laboratory, Swine Virology Immunology Unit, France
| | - F Paboeuf
- Anses, Ploufragan-Plouzané-Niort Laboratory, SPF Pig Production and Experimentation, France
| | - G Simon
- Anses, Ploufragan-Plouzané-Niort Laboratory, Swine Virology Immunology Unit, France
| | - N Rose
- Anses, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare Unit, France
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7
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Kontowicz E, Moreno-Madriñan M, Ragland D, Beauvais W. A stochastic compartmental model to simulate intra- and inter-species influenza transmission in an indoor swine farm. PLoS One 2023; 18:e0278495. [PMID: 37141248 PMCID: PMC10159208 DOI: 10.1371/journal.pone.0278495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 04/18/2023] [Indexed: 05/05/2023] Open
Abstract
Common in swine production worldwide, influenza causes significant clinical disease and potential transmission to the workforce. Swine vaccines are not universally used in swine production, due to their limited efficacy because of continuously evolving influenza viruses. We evaluated the effects of vaccination, isolation of infected pigs, and changes to workforce routine (ensuring workers moved from younger pig batches to older pig batches). A Susceptible-Exposed-Infected-Recovered model was used to simulate stochastic influenza transmission during a single production cycle on an indoor hog growing unit containing 4000 pigs and two workers. The absence of control practices resulted in 3,957 pigs [0-3971] being infected and a 0.61 probability of workforce infection. Assuming incoming pigs had maternal-derived antibodies (MDAs), but no control measures were applied, the total number of infected pigs reduced to 1 [0-3958] and the probability of workforce infection was 0.25. Mass vaccination (40% efficacious) of incoming pigs also reduced the total number of infected pigs to 2362 [0-2374] or 0 [0-2364] in pigs assumed to not have MDAs and have MDAs, respectively. Changing the worker routine by starting with younger to older pig batches, reduced the number of infected pigs to 996 [0-1977] and the probability of workforce infection (0.22) in pigs without MDAs. In pigs with MDAs the total number of infected pigs was reduced to 0 [0-994] and the probability of workforce infection was 0.06. All other control practices alone, showed little improvement in reducing total infected pigs and the probability of workforce infection. Combining all control strategies reduced the total number of infected pigs to 0 or 1 with a minimal probability of workforce infection (<0.0002-0.01). These findings suggest that non-pharmaceutical interventions can reduce the impact of influenza on swine production and workers when efficacious vaccines are unavailable.
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Affiliation(s)
- Eric Kontowicz
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, West Lafayette, Indiana
| | - Max Moreno-Madriñan
- Global Health Program, DePauw University, Greencastle, Indiana
- Department of Global Health, Indiana University, Indianapolis, Indiana
| | - Darryl Ragland
- Department of Veterinary Clinical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, Indiana
| | - Wendy Beauvais
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, West Lafayette, Indiana
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Bartlett H, Holmes MA, Petrovan SO, Williams DR, Wood JLN, Balmford A. Understanding the relative risks of zoonosis emergence under contrasting approaches to meeting livestock product demand. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211573. [PMID: 35754996 PMCID: PMC9214290 DOI: 10.1098/rsos.211573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 05/30/2022] [Indexed: 05/03/2023]
Abstract
It has been argued that intensive livestock farming increases the risk of pandemics of zoonotic origin because of long-distance livestock movements, high livestock densities, poor animal health and welfare, low disease resistance and low genetic diversity. However, data on many of these factors are limited, and analyses to date typically ignore how land use affects emerging infectious disease (EID) risks, and how these risks might vary across systems with different yields (production per unit area). Extensive, lower yielding practices typically involve larger livestock populations, poorer biosecurity, more workers and more area under farming, resulting in different, but not necessarily lower, EID risks than higher yielding systems producing the same amount of food. To move this discussion forward, we review the evidence for each of the factors that potentially link livestock production practices to EID risk. We explore how each factor might vary with yield and consider how overall risks might differ across a mix of production systems chosen to reflect in broad terms the current livestock sector at a global level and in hypothetical low- and high-yield systems matched by overall level of production. We identify significant knowledge gaps for all potential risk factors and argue these shortfalls in understanding mean we cannot currently determine whether lower or higher yielding systems would better limit the risk of future pandemics.
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Affiliation(s)
- Harriet Bartlett
- Department of Zoology, University of Cambridge, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Mark A. Holmes
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Silviu O. Petrovan
- Department of Zoology, University of Cambridge, Cambridge, UK
- BioRISC (Biosecurity Research Initiative at St Catharine's), St Catharine's College, Cambridge, UK
| | - David R. Williams
- Sustainability Research Institute, School of Earth and Environment, University of Leeds, Leeds, UK
| | - James L. N. Wood
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Andrew Balmford
- Department of Zoology, University of Cambridge, Cambridge, UK
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Abstract
The twenty-first century has witnessed a wave of severe infectious disease outbreaks, not least the COVID-19 pandemic, which has had a devastating impact on lives and livelihoods around the globe. The 2003 severe acute respiratory syndrome coronavirus outbreak, the 2009 swine flu pandemic, the 2012 Middle East respiratory syndrome coronavirus outbreak, the 2013-2016 Ebola virus disease epidemic in West Africa and the 2015 Zika virus disease epidemic all resulted in substantial morbidity and mortality while spreading across borders to infect people in multiple countries. At the same time, the past few decades have ushered in an unprecedented era of technological, demographic and climatic change: airline flights have doubled since 2000, since 2007 more people live in urban areas than rural areas, population numbers continue to climb and climate change presents an escalating threat to society. In this Review, we consider the extent to which these recent global changes have increased the risk of infectious disease outbreaks, even as improved sanitation and access to health care have resulted in considerable progress worldwide.
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Kessler S, Harder TC, Schwemmle M, Ciminski K. Influenza A Viruses and Zoonotic Events-Are We Creating Our Own Reservoirs? Viruses 2021; 13:v13112250. [PMID: 34835056 PMCID: PMC8624301 DOI: 10.3390/v13112250] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/04/2021] [Accepted: 11/06/2021] [Indexed: 01/16/2023] Open
Abstract
Zoonotic infections of humans with influenza A viruses (IAVs) from animal reservoirs can result in severe disease in individuals and, in rare cases, lead to pandemic outbreaks; this is exemplified by numerous cases of human infection with avian IAVs (AIVs) and the 2009 swine influenza pandemic. In fact, zoonotic transmissions are strongly facilitated by manmade reservoirs that were created through the intensification and industrialization of livestock farming. This can be witnessed by the repeated introduction of IAVs from natural reservoirs of aquatic wild bird metapopulations into swine and poultry, and the accompanied emergence of partially- or fully-adapted human pathogenic viruses. On the other side, human adapted IAV have been (and still are) introduced into livestock by reverse zoonotic transmission. This link to manmade reservoirs was also observed before the 20th century, when horses seemed to have been an important reservoir for IAVs but lost relevance when the populations declined due to increasing industrialization. Therefore, to reduce zoonotic events, it is important to control the spread of IAV within these animal reservoirs, for example with efficient vaccination strategies, but also to critically surveil the different manmade reservoirs to evaluate the emergence of new IAV strains with pandemic potential.
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Affiliation(s)
- Susanne Kessler
- Medical Center, Institute of Virology, University of Freiburg, 79104 Freiburg, Germany; (S.K.); (M.S.)
- Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Timm C. Harder
- Friedrich-Loeffler-Institut (FLI), Institute of Diagnostic Virology, 17493 Greifswald-Insel Riems, Germany;
| | - Martin Schwemmle
- Medical Center, Institute of Virology, University of Freiburg, 79104 Freiburg, Germany; (S.K.); (M.S.)
- Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Kevin Ciminski
- Medical Center, Institute of Virology, University of Freiburg, 79104 Freiburg, Germany; (S.K.); (M.S.)
- Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Correspondence:
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11
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Glud HA, George S, Skovgaard K, Larsen LE. Zoonotic and reverse zoonotic transmission of viruses between humans and pigs. APMIS 2021; 129:675-693. [PMID: 34586648 PMCID: PMC9297979 DOI: 10.1111/apm.13178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/28/2021] [Indexed: 12/30/2022]
Abstract
Humans and pigs share a close contact relationship, similar biological traits, and one of the highest estimated number of viruses compared to other mammalian species. The contribution and directionality of viral exchange between humans and pigs remain unclear for some of these viruses, but their transmission routes are important to characterize in order to prevent outbreaks of disease in both host species. This review collects and assesses the evidence to determine the likely transmission route of 27 viruses between humans and pigs.
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Affiliation(s)
- Helena Aagaard Glud
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sophie George
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kerstin Skovgaard
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lars Erik Larsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Impact of nurse sows on influenza A virus transmission in pigs under field conditions. Prev Vet Med 2021; 188:105257. [PMID: 33472145 DOI: 10.1016/j.prevetmed.2021.105257] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 12/04/2020] [Accepted: 12/30/2020] [Indexed: 12/23/2022]
Abstract
Piglets prior to weaning play a central role in maintaining influenza infections in breeding herds and the use of nurse sows is a common practice to adopt piglets that fall behind and that otherwise would die. Transmission of influenza A virus (IAV) from nurse sows to adopted pigs has been reported experimentally, however, the importance of this route of transmission under field conditions has not yet been elucidated. A cohort study to assess the IAV status in nurse and control sows and their respective litters was carried out in three influenza positive breed-to-wean farms. A total of 94 control and 90 nurse sows were sampled by collecting udder skin wipes and oral swabs at enrollment (∼ 5-7 days after farrowing) and at weaning. Six piglets per litter were sampled randomly at enrollment, 2 days post-enrollment (DPE), 4 DPE, at day 14 of lactation (14DL) and at weaning. At enrollment, 76 % (69/91) of udder wipes and 3 % (3/89) of oral swabs from nurse sows were positive by rRT-PCR compared with 23 % (21/92) of udder wipes and 0 % (0/85) of oral swabs from control sows. Of the 94 control litters sampled, 11.7 %, 14.9 %, 22.9 %, 46.8 % and 63.9 % tested rRT-PCR IAV positive at enrollment, 2DPE, 4DPE, 14 DL and weaning, respectively. Corresponding prevalence for nurse sow litters were 12.2 %, 30.2 %, 37.0 %, 59.4 % and 56.4 %. The odds of IAV positivity were significantly higher (p < 0.05) for litters from nurse sows 2 DPE (odd ratio (OR) = 6.13, 95 % CI = 1.8-21.2), 4 DPE (OR = 5.5, 95 % CI = 1.7-17.8) and 14 DL (OR = 3.7, 95 % CI = 1.1-12.3). However, there were no differences in the proportion of positive samples at weaning. Moreover, approximately 18 % of the control sows and 11 % of nurse sows that tested IAV negative in oral swabs at enrollment, tested IAV positive at weaning. This study indicates that nurse sows can contribute to the transmission and perpetuation of IAV infections in pigs prior to weaning, particularly during the first week after adoption.
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13
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Bhatta TR, Ryt-Hansen P, Nielsen JP, Larsen LE, Larsen I, Chamings A, Goecke NB, Alexandersen S. Infection Dynamics of Swine Influenza Virus in a Danish Pig Herd Reveals Recurrent Infections with Different Variants of the H1N2 Swine Influenza A Virus Subtype. Viruses 2020; 12:v12091013. [PMID: 32927910 PMCID: PMC7551734 DOI: 10.3390/v12091013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 12/15/2022] Open
Abstract
Influenza A virus (IAV) in swine, so-called swine influenza A virus (swIAV), causes respiratory illness in pigs around the globe. In Danish pig herds, a H1N2 subtype named H1N2dk is one of the main circulating swIAV. In this cohort study, the infection dynamic of swIAV was evaluated in a Danish pig herd by sampling and PCR testing of pigs from two weeks of age until slaughter at 22 weeks of age. In addition, next generation sequencing (NGS) was used to identify and characterize the complete genome of swIAV circulating in the herd, and to examine the antigenic variability in the antigenic sites of the virus hemagglutinin (HA) and neuraminidase (NA) proteins. Overall, 76.6% of the pigs became PCR positive for swIAV during the study, with the highest prevalence at four weeks of age. Detailed analysis of the virus sequences obtained showed that the majority of mutations occurred at antigenic sites in the HA and NA proteins of the virus. At least two different H1N2 variants were found to be circulating in the herd; one H1N2 variant was circulating at the sow and nursery sites, while another H1N2 variant was circulating at the finisher site. Furthermore, it was demonstrated that individual pigs had recurrent swIAV infections with the two different H1N2 variants, but re-infection with the same H1N2 variant was also observed. Better understandings of the epidemiology, genetic and antigenic diversity of swIAV may help to design better health interventions for the prevention and control of swIAV infections in the herds.
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Affiliation(s)
- Tarka Raj Bhatta
- Geelong Centre for Emerging Infectious Diseases, Geelong, VIC 3220, Australia;
- School of Medicine, Deakin University, Geelong, VIC 3220, Australia
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
- Correspondence: (T.R.B.); (S.A.); Tel.: +61-0-452199095 (T.R.B.); +61-0-342159635 (S.A.)
| | - Pia Ryt-Hansen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Jens Peter Nielsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Lars Erik Larsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Inge Larsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Anthony Chamings
- Geelong Centre for Emerging Infectious Diseases, Geelong, VIC 3220, Australia;
- School of Medicine, Deakin University, Geelong, VIC 3220, Australia
| | - Nicole B. Goecke
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
- Division for Diagnostics & Scientific Advice, National Veterinary Institute, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Soren Alexandersen
- Geelong Centre for Emerging Infectious Diseases, Geelong, VIC 3220, Australia;
- School of Medicine, Deakin University, Geelong, VIC 3220, Australia
- Barwon Health, University Hospital Geelong, Geelong, VIC 3220, Australia
- Correspondence: (T.R.B.); (S.A.); Tel.: +61-0-452199095 (T.R.B.); +61-0-342159635 (S.A.)
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14
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Zell R, Groth M, Krumbholz A, Lange J, Philipps A, Dürrwald R. Novel reassortant swine H3N2 influenza A viruses in Germany. Sci Rep 2020; 10:14296. [PMID: 32868846 PMCID: PMC7458913 DOI: 10.1038/s41598-020-71275-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 07/16/2020] [Indexed: 11/09/2022] Open
Abstract
Analysis of 228 H3N2 swine influenza A virus isolates collected between 2003 and 2015 in Germany revealed important changes in molecular epidemiology. The data indicate that a novel reassortant, Rietberg/2014-like swine H3N2, emerged in February 2014 in Northern Germany. It is comprised of a hemagglutinin gene of seasonal H3N2 (A/Denmark/129/2005-like), a neuraminidase gene of Emmelsbuell/2009-like swine H1N2 and the internal gene cassette of pandemic H1N1 viruses. Together with Danish swine H3N2 strains of 2013-2015 with identical genome layout, the Rietberg/2014-like viruses represent a second swine H3N2 lineage which cocirculates with a variant of the Gent/1984-like swine H3N2 lineage. This variant, named Gent1984/Diepholz-like swine H3N2, has a Gent/1984-like HA and a Diepholz/2008-like NA; the origin of the internal gene cassette likely derived from avian-like swine H1N1. The first isolate of the Gent1984/Diepholz reassortant emerged in Northern Germany in September 2011 whereas the last German Gent/1984-like isolate was collected in October 2011.
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Affiliation(s)
- Roland Zell
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Friedrich Schiller University Jena, 07745, Jena, Germany.
| | - Marco Groth
- CF DNA Sequencing, Leibniz Institute on Aging, Fritz Lipmann Institute, 07745, Jena, Germany
| | - Andi Krumbholz
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Friedrich Schiller University Jena, 07745, Jena, Germany.,Institute of Infection Medicine, Kiel University and University Medical Center Schleswig-Holstein, 24105, Kiel, Germany
| | - Jeannette Lange
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Friedrich Schiller University Jena, 07745, Jena, Germany.,Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Anja Philipps
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Friedrich Schiller University Jena, 07745, Jena, Germany.,Thermo Fisher Scientific GENEART GmbH, 93059, Regensburg, Germany
| | - Ralf Dürrwald
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Friedrich Schiller University Jena, 07745, Jena, Germany.,Robert Koch Institute, 13353, Berlin, Germany
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15
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Andraud M, Rose N. Modelling infectious viral diseases in swine populations: a state of the art. Porcine Health Manag 2020; 6:22. [PMID: 32843990 PMCID: PMC7439688 DOI: 10.1186/s40813-020-00160-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/25/2020] [Indexed: 02/06/2023] Open
Abstract
Mathematical modelling is nowadays a pivotal tool for infectious diseases studies, completing regular biological investigations. The rapid growth of computer technology allowed for development of computational tools to address biological issues that could not be unravelled in the past. The global understanding of viral disease dynamics requires to account for all interactions at all levels, from within-host to between-herd, to have all the keys for development of control measures. A literature review was performed to disentangle modelling frameworks according to their major objectives and methodologies. One hundred and seventeen articles published between 1994 and 2020 were found to meet our inclusion criteria, which were defined to target papers representative of studies dealing with models of viral infection dynamics in pigs. A first descriptive analysis, using bibliometric indexes, permitted to identify keywords strongly related to the study scopes. Modelling studies were focused on particular infectious agents, with a shared objective: to better understand the viral dynamics for appropriate control measure adaptation. In a second step, selected papers were analysed to disentangle the modelling structures according to the objectives of the studies. The system representation was highly dependent on the nature of the pathogens. Enzootic viruses, such as swine influenza or porcine reproductive and respiratory syndrome, were generally investigated at the herd scale to analyse the impact of husbandry practices and prophylactic measures on infection dynamics. Epizootic agents (classical swine fever, foot-and-mouth disease or African swine fever viruses) were mostly studied using spatio-temporal simulation tools, to investigate the efficiency of surveillance and control protocols, which are predetermined for regulated diseases. A huge effort was made on model parameterization through the development of specific studies and methodologies insuring the robustness of parameter values to feed simulation tools. Integrative modelling frameworks, from within-host to spatio-temporal models, is clearly on the way. This would allow to capture the complexity of individual biological variabilities and to assess their consequences on the whole system at the population level. This would offer the opportunity to test and evaluate in silico the efficiency of possible control measures targeting specific epidemiological units, from hosts to herds, either individually or through their contact networks. Such decision support tools represent a strength for stakeholders to help mitigating infectious diseases dynamics and limiting economic consequences.
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Affiliation(s)
- M. Andraud
- Anses, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, F22440 Ploufragan, France
| | - N. Rose
- Anses, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, F22440 Ploufragan, France
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16
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Cocirculation of Swine H1N1 Influenza A Virus Lineages in Germany. Viruses 2020; 12:v12070762. [PMID: 32679903 PMCID: PMC7411773 DOI: 10.3390/v12070762] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/16/2022] Open
Abstract
The genome analysis of 328 H1N1 swine influenza virus isolates collected in a 13-year long-term swine influenza surveillance in Germany is reported. Viral genomes were sequenced with the Illumina next-generation sequencing technique and conventional Sanger methods. Phylogenetic analyses were conducted with Bayesian tree inference. The results indicate continued prevalence of Eurasian avian swine H1N1 but also emergence of a novel H1N1 reassortant, named Schneiderkrug/2013-like swine H1N1, with human-like hemagglutinin and avian-like neuraminidase and internal genes. Additionally, the evolution of an antigenic drift variant of A (H1N1) pdm09 was observed, named Wachtum/2014-like swine H1N1. Both variants were first isolated in northwest Germany, spread to neighboring German states and reached greater proportions of the H1N1 isolates of 2014 and 2015. The upsurge of Wachtum/2014-like swine H1N1 is of interest as this is the first documented persistent swine-to-swine spread of A (H1N1) pdm09 in Germany associated with antigenic variation. Present enzootic swine influenza viruses in Germany now include two or more co-circulating, antigenically variant viruses of each of the subtypes, H1N1 and H1N2.
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17
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Nirmala J, Perez A, Culhane MR, Allerson MW, Sreevatsan S, Torremorell M. Genetic variability of influenza A virus in pigs at weaning in Midwestern United States swine farms. Transbound Emerg Dis 2020; 68:62-75. [PMID: 32187882 DOI: 10.1111/tbed.13529] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 02/04/2020] [Accepted: 02/13/2020] [Indexed: 01/15/2023]
Abstract
Suckling piglets play an important role at maintaining influenza A virus (IAV) infections in breeding herds and disseminating them to other farms at weaning. However, the role they play at weaning to support and promote genetic variability of IAV is not fully understood. The objective here was to evaluate the genetic diversity of IAV in pigs at weaning in farms located in the Midwestern USA. Nasal swabs (n = 9,090) collected from piglets in breed-to-wean farms (n = 52) over a six-month period across seasons were evaluated for the presence of IAV. Nasal swabs (n = 391) from 23 IAV-positive farms were whole-genome sequenced. Multiple lineages of HA (n = 7) and NA (n = 3) were identified in 96% (22/23) and 61% (237/391) of the investigated farms and individual piglets, respectively. Co-circulation of multiple types of functional HA and NA was identified in most (83%) farms. Whole IAV genomes were completed for 126 individual piglet samples and 25 distinct and 23 mixed genotypes were identified, highlighting significant genetic variability of IAV in piglets. Co-circulation of IAV in the farms and co-infection of individual piglets at weaning was observed at multiple time points over the investigation period and appears to be common in the investigated farms. Statistically significant genetic variability was estimated within and between farms by AMOVA, and varying levels of diversity between farms were detected using the Shannon-Weiner Index. Results reported here demonstrate previously unreported levels of molecular complexity and genetic variability among IAV at the farm and piglet levels at weaning. Movement of such piglets infected at weaning may result in emergence of new strains and maintenance of endemic IAV infection in the US swine herds. Results presented here highlight the need for developing and implementing novel, effective strategies to prevent or control the introduction and transmission of IAV within and between farms in the country.
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Affiliation(s)
| | - Andres Perez
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
| | - Marie R Culhane
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
| | - Matthew W Allerson
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
| | - Srinand Sreevatsan
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI, USA
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18
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Giang E, Hetman BM, Sargeant JM, Poljak Z, Greer AL. Examining the Effect of Host Recruitment Rates on the Transmission of Streptococcus suis in Nursery Swine Populations. Pathogens 2020; 9:pathogens9030174. [PMID: 32121513 PMCID: PMC7157574 DOI: 10.3390/pathogens9030174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/08/2020] [Accepted: 02/27/2020] [Indexed: 11/16/2022] Open
Abstract
Streptococcus suis is a swine pathogen that is capable of causing severe outbreaks of disease in the nursery. Demographic parameters such as host recruitment rates can have profound effects on the transmission dynamics of infectious diseases and, thus, are critically important in high-turnover populations such as farmed swine. However, knowledge concerning the implications that such parameters have on S. suis disease control remains unknown. A stochastic mathematical model incorporating sub-clinically infected pigs was developed to capture the effects of changes in host recruitment rate on disease incidence. Compared to our base model scenario, our results show that monthly introduction of pigs into the nursery (instead of weekly introduction) reduced cumulative cases of S. suis by up to 59%, while increasing disease-removal rates alone averted up to 64% of cases. Sensitivity analysis demonstrated that the course of infection in sub-clinically infected pigs was highly influential and generated significant variability in the model outcomes. Our model findings suggest that modifications to host recruitment rates could be leveraged as a tool for S. suis disease control, however improving our understanding of additional factors that influence the risk of transmission would improve the precision of the model estimates.
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Affiliation(s)
- Elissa Giang
- Department of Population Medicine, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada; (B.M.H.); (J.M.S.); (Z.P.)
- Correspondence: (E.G.); (A.L.G.)
| | - Benjamin M. Hetman
- Department of Population Medicine, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada; (B.M.H.); (J.M.S.); (Z.P.)
| | - Jan M. Sargeant
- Department of Population Medicine, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada; (B.M.H.); (J.M.S.); (Z.P.)
- Center for Public Health and Zoonoses, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
| | - Zvonimir Poljak
- Department of Population Medicine, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada; (B.M.H.); (J.M.S.); (Z.P.)
- Center for Public Health and Zoonoses, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
| | - Amy L. Greer
- Department of Population Medicine, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada; (B.M.H.); (J.M.S.); (Z.P.)
- Center for Public Health and Zoonoses, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
- Correspondence: (E.G.); (A.L.G.)
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19
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Ryt-Hansen P, Pedersen AG, Larsen I, Kristensen CS, Krog JS, Wacheck S, Larsen LE. Substantial Antigenic Drift in the Hemagglutinin Protein of Swine Influenza A Viruses. Viruses 2020; 12:E248. [PMID: 32102230 PMCID: PMC7077184 DOI: 10.3390/v12020248] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/16/2022] Open
Abstract
The degree of antigenic drift in swine influenza A viruses (swIAV) has historically been regarded as minimal compared to that of human influenza A virus strains. However, as surveillance activities on swIAV have increased, more isolates have been characterized, revealing a high level of genetic and antigenic differences even within the same swIAV lineage. The objective of this study was to investigate the level of genetic drift in one enzootically infected swine herd over one year. Nasal swabs were collected monthly from sows (n = 4) and piglets (n = 40) in the farrowing unit, and from weaners (n = 20) in the nursery. Virus from 1-4 animals were sequenced per month. Analyses of the sequences revealed that the hemagglutinin (HA) gene was the main target for genetic drift with a substitution rate of 7.6 × 10-3 substitutions/site/year and evidence of positive selection. The majority of the mutations occurred in the globular head of the HA protein and in antigenic sites. The phylogenetic tree of the HA sequences displayed a pectinate typology, where only a single lineage persists and forms the ancestor for subsequent lineages. This was most likely caused by repeated selection of a single immune-escape variant, which subsequently became the founder of the next wave of infections.
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Affiliation(s)
- Pia Ryt-Hansen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, DK-2800 Kongens Lyngby, Denmark
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, DK-1870 Frederiksberg C, Denmark; (I.L.); (L.E.L.)
| | - Anders Gorm Pedersen
- Department of Health Technology, Section for Bioinformatics, Technical University of Denmark, Kemitorvet Building 208, DK-2800 Kongens Lyngby, Denmark;
| | - Inge Larsen
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, DK-1870 Frederiksberg C, Denmark; (I.L.); (L.E.L.)
| | | | - Jesper Schak Krog
- Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark;
| | - Silke Wacheck
- Ceva Santé Animale 10 Avenue de la Ballastière, 33500 Libourne, France;
| | - Lars Erik Larsen
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, DK-1870 Frederiksberg C, Denmark; (I.L.); (L.E.L.)
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20
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Ryt-Hansen P, Larsen I, Kristensen CS, Krog JS, Larsen LE. Limited impact of influenza A virus vaccination of piglets in an enzootic infected sow herd. Res Vet Sci 2019; 127:47-56. [PMID: 31677416 DOI: 10.1016/j.rvsc.2019.10.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 01/15/2023]
Abstract
Recent studies have questioned the effect of maternal derived antibodies (MDAs) to protect piglets against infection with influenza A virus (IAV). The lack of protection against IAV infections provided by MDAs has encouraged alternative vaccination strategies targeting young piglets in an attempt to stimulate an early antibody response. There is a lack of studies documenting the efficacy of piglet vaccination. In the present study, we monitored a group of vaccinated and non-vaccinated piglets in a Danish sow herd that initiated piglet vaccination with ¼ dose of an inactivated swine influenza vaccine at the time of castration (day 3-4). A total of 160 piglets from 11 sows were included and either vaccinated with 0.5 mL inactivated swine influenza vaccine or sham-vaccinated. From week 0 until week 6, all included piglets were clinically examined and nasal swapped once per week and weighed at weeks 0, 3 and 6. Blood samples were collected from sows at week 0 and from piglets at week 3. Vaccination of piglets had limited effect on clinical signs, body weight, antibody development and viral shedding, within the first 6 weeks of life. At least 50% of all pigs of each treatment group tested positive for IAV at week 2, and very early onset of IAV shedding was observed. In total, 18 pigs were IAV positive in nasal swabs for more than one consecutive sampling time indicating prolonged shedding and 14 pigs were IAV positive with negative samplings in between indicating re-infection with the same IAV strain.
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Affiliation(s)
- Pia Ryt-Hansen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, DK-2800 Kongens Lyngby, Denmark.
| | - Inge Larsen
- Dpt. of Veterinary and Animal Sciences Grønnegårdsvej 2, University of Copenhagen, DK-1870 Frederiksberg C, Denmark.
| | | | - Jesper Schak Krog
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, DK-2800 Kongens Lyngby, Denmark.
| | - Lars Erik Larsen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, DK-2800 Kongens Lyngby, Denmark; Dpt. of Veterinary and Animal Sciences Grønnegårdsvej 2, University of Copenhagen, DK-1870 Frederiksberg C, Denmark.
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21
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van Eijk M, Hillaire MLB, Rimmelzwaan GF, Rynkiewicz MJ, White MR, Hartshorn KL, Hessing M, Koolmees PA, Tersteeg MH, van Es MH, Meijerhof T, Huckriede A, Haagsman HP. Enhanced Antiviral Activity of Human Surfactant Protein D by Site-Specific Engineering of the Carbohydrate Recognition Domain. Front Immunol 2019; 10:2476. [PMID: 31749796 PMCID: PMC6842947 DOI: 10.3389/fimmu.2019.02476] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/03/2019] [Indexed: 12/11/2022] Open
Abstract
Innate immunity is critical in the early containment of influenza A virus (IAV) infection and surfactant protein D (SP-D) plays a crucial role in innate defense against IAV in the lungs. Multivalent lectin-mediated interactions of SP-D with IAVs result in viral aggregation, reduced epithelial infection, and enhanced IAV clearance by phagocytic cells. Previous studies showed that porcine SP-D (pSP-D) exhibits distinct antiviral activity against IAV as compared to human SP-D (hSP-D), mainly due to key residues in the lectin domain of pSP-D that contribute to its profound neutralizing activity. These observations provided the basis for the design of a full-length recombinant mutant form of hSP-D, designated as “improved SP-D” (iSP-D). Inspired by pSP-D, the lectin domain of iSP-D has 5 amino acids replaced (Asp324Asn, Asp330Asn, Val251Glu, Lys287Gln, Glu289Lys) and 3 amino acids inserted (326Gly-Ser-Ser). Characterization of iSP-D revealed no major differences in protein assembly and saccharide binding selectivity as compared to hSP-D. However, hemagglutination inhibition measurements showed that iSP-D expressed strongly enhanced activity compared to hSP-D against 31 different IAV strains tested, including (pandemic) IAVs that were resistant for neutralization by hSP-D. Furthermore, iSP-D showed increased viral aggregation and enhanced protection of MDCK cells against infection by IAV. Importantly, prophylactic or therapeutic application of iSP-D decreased weight loss and reduced viral lung titers in a murine model of IAV infection using a clinical isolate of H1N1pdm09 virus. These studies demonstrate the potential of iSP-D as a novel human-based antiviral inhalation drug that may provide immediate protection against or recovery from respiratory (pandemic) IAV infections in humans.
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Affiliation(s)
- Martin van Eijk
- Division of Molecular Host Defence, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | | | - Guus F Rimmelzwaan
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Hanover, Germany
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA, United States
| | - Mitchell R White
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States
| | - Kevan L Hartshorn
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States
| | - Martin Hessing
- U-Protein Express B.V., Life Science Incubator, Utrecht, Netherlands
| | - Peter A Koolmees
- Division of Veterinary Public Health, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
| | - Monique H Tersteeg
- Division of Veterinary Public Health, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
| | | | - Tjarko Meijerhof
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Anke Huckriede
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Henk P Haagsman
- Division of Molecular Host Defence, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
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22
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Ryt-Hansen P, Larsen I, Kristensen CS, Krog JS, Wacheck S, Larsen LE. Longitudinal field studies reveal early infection and persistence of influenza A virus in piglets despite the presence of maternally derived antibodies. Vet Res 2019; 50:36. [PMID: 31113477 PMCID: PMC6530179 DOI: 10.1186/s13567-019-0655-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/24/2019] [Indexed: 12/14/2022] Open
Abstract
A longitudinal study was performed in three Danish farrow to grower (30 kilos) herds over a 4-month period to investigate the dynamics and clinical impacts of influenza A virus (IAV) infections. In each herd, four batches consisting of four sows each with five ear-tagged piglets were included. Nasal swabs and/or blood were sampled from the sows and/or the piglets prior to farrowing and at weeks 1, 3, and 5 and at the end of the nursery period. Clinical examinations were performed at each sampling time. The sows and piglets were tested for IAV and IAV antibodies in nasal swabs and blood samples, respectively. The results revealed three enzootically infected herds, where the majority of the pigs were infected during the first 5 weeks after birth. Infected piglets of only 3 days of age were detected in the farrowing unit, where the sows were also shedding virus. In all herds, low to moderate numbers of infected pigs (ranging from 3.6 to 20.7%) were found to be virus positive in nasal swabs at two consecutive sampling times. Furthermore, clinical signs of respiratory disease were associated with IAV detection. The findings of this study documented that IAV can persist in herds and that piglets as young as 3 days can be infected despite the presence of maternally derived antibodies.
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Affiliation(s)
- Pia Ryt-Hansen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, 2800 Kongens Lyngby, Denmark
| | - Inge Larsen
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, 1870 Frederiksberg C, Denmark
| | | | - Jesper Schak Krog
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, 2800 Kongens Lyngby, Denmark
| | - Silke Wacheck
- IDT Biologika GmbH, Am Pharmapark, 06861 Dessau-Rosslau, Germany
| | - Lars Erik Larsen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, 2800 Kongens Lyngby, Denmark
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23
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Kaiser TJ, Smiley RA, Fergen B, Eichmeyer M, Genzow M. Influenza A virus shedding reduction observed at 12 weeks post-vaccination when newborn pigs are administered live-attenuated influenza virus vaccine. Influenza Other Respir Viruses 2019; 13:274-278. [PMID: 30843324 PMCID: PMC6468078 DOI: 10.1111/irv.12630] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 01/09/2023] Open
Abstract
Background Influenza A virus in swine (IAV‐S) causes an acute respiratory disease of swine which results in great economic losses. A bivalent H1N1 and H3N2, NS1‐truncated live‐attenuated IAV‐S vaccine (LAIV, Ingelvac Provenza™) has recently become available. Objective Reduction of shedding during an outbreak in the nursery or finisher is an important parameter from an epidemiological control strategy; therefore, a laboratory efficacy study was conducted to evaluate nasal virus shedding when vaccinated pigs were challenged with either heterologous H1N2 or H3N2 strains 12 weeks post‐vaccination. Methods Between 1 and 5 days of age, pigs born to IAV‐S seronegative dams were intranasally administered 1 mL of vaccine or saline. At 30 days post‐vaccination, pigs were weaned and randomized into two different challenge groups consisting of vaccinated pigs and control pigs commingled within pens for the two challenge groups. At 85 days post‐vaccination, pigs in the first group were challenged with A/Swine/North Carolina/001169/2006 H1N2 challenge strain, and the second group was challenged with A/Swine/Nebraska/97901‐10/2008 H3N2. Nasal swabs were collected daily for five days and tested by virus isolation. Results and conclusion This study showed significant reduction in nasal virus shedding with regard to both frequency and duration. A 1 mL intranasal dose of Ingelvac Provenza™ given as early as 1 day of age showed protection for at least 12 weeks later as evidenced by the reduction of shedding live, viable virus after challenge with either a heterologous H1N2 strain or a heterologous H3N2 strain.
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Affiliation(s)
- Troy J Kaiser
- Boehringer Ingelheim Vetmedica Inc, St. Joseph, Missouri
| | - Rex A Smiley
- Boehringer Ingelheim Vetmedica Inc, St. Joseph, Missouri
| | | | | | - Marika Genzow
- Boehringer Ingelheim Vetmedica GmbH, Ingelheim, Germany
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24
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Chamba Pardo FO, Schelkopf A, Allerson M, Morrison R, Culhane M, Perez A, Torremorell M. Breed-to-wean farm factors associated with influenza A virus infection in piglets at weaning. Prev Vet Med 2018; 161:33-40. [PMID: 30466656 DOI: 10.1016/j.prevetmed.2018.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 09/10/2018] [Accepted: 10/11/2018] [Indexed: 12/12/2022]
Abstract
Breed-to-wean pig farms play an important role in spreading influenza A virus (IAV) because suckling piglets maintain, diversify and transmit IAV at weaning to other farms. Understanding the nature and extent of which farm factors drive IAV infection in piglets is a prerequisite to reduce the burden of influenza in swine. We evaluated the association between IAV infection in piglets at weaning and farm factors including farm features, herd management practices and gilt- and piglet-specific management procedures performed at the farm. Voluntarily enrolled breed-to-wean farms (n = 83) agreed to share IAV diagnostic testing and farm data from July 2011 through March 2017 including data obtained via the administration of a survey. There were 23% IAV RT-PCR positive samples of the 12,814 samples submitted for IAV testing within 2989 diagnostic submissions with 30% positive submissions. Among all the factors evaluated (n = 24), and considering the season-adjusted multivariable analysis, only sow IAV vaccination and gilt IAV status at entry significantly reduced (p-value<0.05) IAV infections in piglets at weaning. Results from this study indicate that veterinarians and producers could manage these identified factors to reduce the burden of influenza in piglets prior to wean and perhaps, reduce the spread of IAV to other farms and people.
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Affiliation(s)
- Fabian Orlando Chamba Pardo
- Veterinary Population Medicine Department, University of Minnesota, 335 AS/VM, 1988 Fitch Ave., St. Paul, MN 55108, USA.
| | - Adam Schelkopf
- Health Department, Pipestone Veterinary Services, 1300 South Highway 75, PO Box 188, Pipestone, MN 56164, USA.
| | - Matthew Allerson
- Health and Research Department, Holden Farms Inc., 457 375th street, Dennison, MN 55018, USA.
| | - Robert Morrison
- Veterinary Population Medicine Department, University of Minnesota, 335 AS/VM, 1988 Fitch Ave., St. Paul, MN 55108, USA.
| | - Marie Culhane
- Veterinary Population Medicine Department, University of Minnesota, 335 AS/VM, 1988 Fitch Ave., St. Paul, MN 55108, USA.
| | - Andres Perez
- Veterinary Population Medicine Department, University of Minnesota, 335 AS/VM, 1988 Fitch Ave., St. Paul, MN 55108, USA.
| | - Montserrat Torremorell
- Veterinary Population Medicine Department, University of Minnesota, 335 AS/VM, 1988 Fitch Ave., St. Paul, MN 55108, USA.
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25
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Bolton MJ, Abente EJ, Venkatesh D, Stratton JA, Zeller M, Anderson TK, Lewis NS, Vincent AL. Antigenic evolution of H3N2 influenza A viruses in swine in the United States from 2012 to 2016. Influenza Other Respir Viruses 2018; 13:83-90. [PMID: 30216671 PMCID: PMC6304321 DOI: 10.1111/irv.12610] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/31/2018] [Accepted: 09/05/2018] [Indexed: 12/27/2022] Open
Abstract
Background Six amino acid positions (145, 155, 156, 158, 159, and 189, referred to as the antigenic motif; H3 numbering) in the globular head region of hemagglutinin (HA1 domain) play an important role in defining the antigenic phenotype of swine Clade IV (C‐IV) H3N2 IAV, containing an H3 from a late 1990s human‐to‐swine introduction. We hypothesized that antigenicity of a swine C‐IV H3 virus could be inferred based upon the antigenic motif if it matched a previously characterized antigen with the same motif. An increasing number of C‐IV H3 genes encoding antigenic motifs that had not been previously characterized were observed in the U.S. pig population between 2012 and 2016. Objectives A broad panel of contemporary H3 viruses with uncharacterized antigenic motifs was selected across multiple clades within C‐IV to assess the impact of HA1 genetic diversity on the antigenic phenotype. Methods Hemagglutination inhibition (HI) assays were performed with isolates selected based on antigenic motif, tested against a panel of swine antisera, and visualized by antigenic cartography. Results A previously uncharacterized motif with low but sustained circulation in the swine population demonstrated a distinct phenotype from those previously characterized. Antigenic variation increased for viruses with similar antigenic motifs, likely due to amino acid substitutions outside the motif. Conclusions Although antigenic motifs were largely associated with antigenic distances, substantial diversity among co‐circulating viruses poses a significant challenge for effective vaccine development. Continued surveillance and antigenic characterization of circulating strains is critical for improving vaccine efforts to control C‐IV H3 IAV in U.S. swine.
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Affiliation(s)
- Marcus J Bolton
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa
| | - Eugenio J Abente
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa
| | - Divya Venkatesh
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Jered A Stratton
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa
| | - Michael Zeller
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa.,Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Tavis K Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa
| | - Nicola S Lewis
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Amy L Vincent
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa
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26
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Etbaigha F, R Willms A, Poljak Z. An SEIR model of influenza A virus infection and reinfection within a farrow-to-finish swine farm. PLoS One 2018; 13:e0202493. [PMID: 30248106 PMCID: PMC6152865 DOI: 10.1371/journal.pone.0202493] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 08/03/2018] [Indexed: 11/23/2022] Open
Abstract
Influenza A virus (IAV) in swine is a pathogen that causes a threat to the health as well as to the production of swine. Moreover, swine can spread this virus to other species including humans. The virus persists in different types of swine farms as evident in a number of studies. The core objectives of this study are (i) to analyze the dynamics of influenza infection of a farrow-to-finish swine farm, (ii) to explore the reinfection at the farm level, and finally (iii) to examine the effectiveness of two control strategies: vaccination and reduction of indirect contact. The analyses are conducted using a deterministic Susceptible-Exposed-Infectious-Recovered (SEIR) model. Simulation results show that the disease is maintained in gilts and piglets because of new susceptible pigs entering the population on a weekly basis. A sensitivity analysis shows that the results are not sensitive to variation in the parameters. The results of the reinfection simulation indicate that the virus persists in the entire farm. The control strategies studied in this work are not successful in eliminating the virus within the farm.
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Affiliation(s)
- Fatima Etbaigha
- Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario N1G 2W1 Canada
| | - Allan R Willms
- Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario N1G 2W1 Canada
| | - Zvonimir Poljak
- Department of Population Medicine, University of Guelph, Guelph, Ontario N1G 2W1 Canada
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27
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Herd-level infectious disease surveillance of livestock populations using aggregate samples. Anim Health Res Rev 2018; 19:53-64. [PMID: 29779505 DOI: 10.1017/s1466252318000038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
All sectors of livestock production are in the process of shifting from small populations on many farms to large populations on fewer farms. A concurrent shift has occurred in the number of livestock moved across political boundaries. The unintended consequence of these changes has been the appearance of multifactorial diseases that are resistant to traditional methods of prevention and control. The need to understand complex animal health conditions mandates a shift toward the collection of longitudinal animal health data. Historically, collection of such data has frustrated and challenged animal health specialists. A promising trend in the evolution toward more efficient and effective livestock disease surveillance is the increased use of aggregate samples, e.g. bulk tank milk and oral fluid specimens. These sample types provide the means to monitor disease, estimate herd prevalence, and evaluate spatiotemporal trends in disease distribution. Thus, this article provides an overview of the use of bulk tank milk and pen-based oral fluids in the surveillance of livestock populations for infectious diseases.
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28
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Andraud M, Fablet C, Renson P, Eono F, Mahé S, Bourry O, Rose N. Estimating Parameters Related to the Lifespan of Passively Transferred and Vaccine-Induced Porcine Reproductive and Respiratory Syndrome Virus Type I Antibodies by Modeling Field Data. Front Vet Sci 2018; 5:9. [PMID: 29435455 PMCID: PMC5796902 DOI: 10.3389/fvets.2018.00009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/12/2018] [Indexed: 12/23/2022] Open
Abstract
The outputs of epidemiological models are strongly related to the structure of the model and input parameters. The latter are defined by fitting theoretical concepts to actual data derived from field or experimental studies. However, some parameters may remain difficult to estimate and are subject to uncertainty or sensitivity analyses to determine their variation range and their global impact on model outcomes. As such, the evaluation of immunity duration is often a puzzling issue requiring long-term follow-up data that are, most of time, not available. The present analysis aims at characterizing the kinetics of antibodies against Porcine Reproductive and Respiratory Syndrome virus (PRRSv) from longitudinal data sets. The first data set consisted in the serological follow-up of 22 vaccinated gilts during 21 weeks post-vaccination (PV). The second one gathered the maternally derived antibodies (MDAs) kinetics in piglets from three different farms up to 14 weeks of age. The peak of the PV serological response against PRRSv was reached 6.9 weeks PV on average with an average duration of antibodies persistence of 26.5 weeks. In the monitored cohort of piglets, the duration of passive immunity was found relatively short, with an average duration of 4.8 weeks. The level of PRRSv-MDAs was found correlated with the dams' antibody titer at birth, and the antibody persistence was strongly related to the initial MDAs titers in piglets. These results evidenced the importance of PRRSv vaccination schedule in sows, to optimize the delivery of antibodies to suckling piglets. These estimates of the duration of active and passive immunity could be further used as input parameters of epidemiological models to analyze their impact on the persistence of PRRSv within farms.
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Affiliation(s)
- Mathieu Andraud
- Unité épidémiologie et bien-être du porc, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France.,Université Bretagne-Loire, Rennes, France
| | - Christelle Fablet
- Unité épidémiologie et bien-être du porc, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France.,Université Bretagne-Loire, Rennes, France
| | - Patricia Renson
- Université Bretagne-Loire, Rennes, France.,Unité Virologie Immunologie Porcines, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France.,Union des Groupements de Producteurs de Viande de Bretagne (UGPVB), Rennes, France
| | - Florent Eono
- Unité épidémiologie et bien-être du porc, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France.,Université Bretagne-Loire, Rennes, France
| | - Sophie Mahé
- Université Bretagne-Loire, Rennes, France.,Unité Virologie Immunologie Porcines, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France
| | - Olivier Bourry
- Université Bretagne-Loire, Rennes, France.,Unité Virologie Immunologie Porcines, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France
| | - Nicolas Rose
- Unité épidémiologie et bien-être du porc, Anses Laboratoire de Ploufragan-Plouzané, Ploufragan, France.,Université Bretagne-Loire, Rennes, France
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29
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Cador C, Andraud M, Willem L, Rose N. Control of endemic swine flu persistence in farrow-to-finish pig farms: a stochastic metapopulation modeling assessment. Vet Res 2017; 48:58. [PMID: 28974251 PMCID: PMC5627436 DOI: 10.1186/s13567-017-0462-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 09/12/2017] [Indexed: 12/26/2022] Open
Abstract
Swine influenza viruses (swIAVs) are known to persist endemically in farrow-to-finish pig farms, leading to repeated swine flu outbreaks in successive batches of pigs at a similar age (mostly around 8 weeks of age). This persistence in European swine herds involves swIAVs from European lineages including H1avN1, H1huN2, H3N2, the 2009 H1N1 pandemic virus and their reassortants. The specific population dynamics of farrow-to-finish pig farms, the immune status of the animals at infection-time, the co-circulation of distinct subtypes leading to consecutive or concomitant infections have been evidenced as factors favouring swIAV persistence within herds. We developed a stochastic metapopulation model representing the co-circulation of two distinct swIAVs within a typical farrow-to-finish pig herd to evaluate the risk of reassortant viruses generation due to co-infection events. Control strategies related to herd management and/or vaccination schemes (batch-to-batch or mass vaccination of the sow herd and vaccination of growing pigs) were implemented to assess their relative efficacy regarding viral persistence. The overall probability of a co-infection event for France, possibly leading to reassortment, was evaluated to 16.8%. The export of consecutive piglets batches was identified as the most efficient measure facilitating swIAV infection fade-out. Although some vaccination schemes (batch-to-batch vaccination) had a beneficial effect in breeding sows by reducing the persistence of swIAVs within this subpopulation, none of vaccination strategies achieved swIAVs fade-out within the entire farrow-to-finish pig herd.
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Affiliation(s)
- Charlie Cador
- Swine Epidemiology and Welfare Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France. .,Université Bretagne Loire, Rennes, France.
| | - Mathieu Andraud
- Swine Epidemiology and Welfare Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.,Université Bretagne Loire, Rennes, France
| | - Lander Willem
- Centre for Health Economics & Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp Research, Antwerp, Belgium
| | - Nicolas Rose
- Swine Epidemiology and Welfare Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.,Université Bretagne Loire, Rennes, France
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30
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White LA, Torremorell M, Craft ME. Influenza A virus in swine breeding herds: Combination of vaccination and biosecurity practices can reduce likelihood of endemic piglet reservoir. Prev Vet Med 2016; 138:55-69. [PMID: 28237236 DOI: 10.1016/j.prevetmed.2016.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/26/2016] [Accepted: 12/16/2016] [Indexed: 01/29/2023]
Abstract
Recent modelling and empirical work on influenza A virus (IAV) suggests that piglets play an important role as an endemic reservoir. The objective of this study is to test intervention strategies aimed at reducing the incidence of IAV in piglets and ideally, preventing piglets from becoming exposed in the first place. These interventions include biosecurity measures, vaccination, and management options that swine producers may employ individually or jointly to control IAV in their herds. We have developed a stochastic Susceptible-Exposed-Infectious-Recovered-Vaccinated (SEIRV) model that reflects the spatial organization of a standard breeding herd and accounts for the different production classes of pigs therein. Notably, this model allows for loss of immunity for vaccinated and recovered animals, and for vaccinated animals to have different latency and infectious periods from unvaccinated animals as suggested by the literature. The interventions tested include: (1) varied timing of gilt introductions to the breeding herd, (2) gilt separation (no indirect transmission to or from the gilt development unit), (3) gilt vaccination upon arrival to the farm, (4) early weaning, and (5) vaccination strategies of sows with different timing (mass and pre-farrow) and efficacy (homologous vs. heterologous). We conducted a Latin Hypercube Sampling and Partial Rank Correlation Coefficient (LHS-PRCC) analysis combined with a random forest analysis to assess the relative importance of each epidemiological parameter in determining epidemic outcomes. In concert, mass vaccination, early weaning of piglets (removal 0-7days after birth), gilt separation, gilt vaccination, and longer periods between introductions of gilts (6 months) were the most effective at reducing prevalence. Endemic prevalence overall was reduced by 51% relative to the null case; endemic prevalence in piglets was reduced by 74%; and IAV was eliminated completely from the herd in 23% of all simulations. Importantly, elimination of IAV was most likely to occur within the first few days of an epidemic. The latency period, infectious period, duration of immunity, and transmission rate for piglets with maternal immunity had the highest correlation with three separate measures of IAV prevalence; therefore, these are parameters that warrant increased attention for obtaining empirical estimates. Our findings support other studies suggesting that piglets play a key role in maintaining IAV in breeding herds. We recommend biosecurity measures in combination with targeted homologous vaccination or vaccines that provide wider cross-protective immunity to prevent incursions of virus to the farm and subsequent establishment of an infected piglet reservoir.
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Affiliation(s)
- L A White
- Department of Ecology, Evolution & Behavior, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Avenue, St. Paul, MN 55108, USA.
| | - M Torremorell
- Department of Veterinary Population Medicine, University of Minnesota, 385 Animal Science/Veterinary Medicine Building, 1988 Fitch Avenue, St. Paul, MN 55108, USA
| | - M E Craft
- Department of Veterinary Population Medicine, University of Minnesota, 385 Animal Science/Veterinary Medicine Building, 1988 Fitch Avenue, St. Paul, MN 55108, USA
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31
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Cador C, Rose N, Willem L, Andraud M. Maternally Derived Immunity Extends Swine Influenza A Virus Persistence within Farrow-to-Finish Pig Farms: Insights from a Stochastic Event-Driven Metapopulation Model. PLoS One 2016; 11:e0163672. [PMID: 27662592 PMCID: PMC5035019 DOI: 10.1371/journal.pone.0163672] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/12/2016] [Indexed: 12/28/2022] Open
Abstract
Swine Influenza A Viruses (swIAVs) have been shown to persist in farrow-to-finish pig herds with repeated outbreaks in successive batches, increasing the risk for respiratory disorders in affected animals and being a threat for public health. Although the general routes of swIAV transmission (i.e. direct contact and exposure to aerosols) were clearly identified, the transmission process between batches is still not fully understood. Maternally derived antibodies (MDAs) were stressed as a possible factor favoring within-herd swIAV persistence. However, the relationship between MDAs and the global spread among the different subpopulations in the herds is still lacking. The aim of this study was therefore to understand the mechanisms induced by MDAs in relation with swIAV spread and persistence in farrow-to-finish pig herds. A metapopulation model has been developed representing the population dynamics considering two subpopulations—breeding sows and growing pigs—managed according to batch-rearing system. This model was coupled with a swIAV-specific epidemiological model, accounting for partial passive immunity protection in neonatal piglets and an immunity boost in re-infected animals. Airborne transmission was included by a between-room transmission rate related to the current prevalence of shedding pigs. Maternally derived partial immunity in piglets was found to extend the duration of the epidemics within their batch, allowing for efficient between-batch transmission and resulting in longer swIAV persistence at the herd level. These results should be taken into account in the design of control programmes for the spread and persistence of swIAV in swine herds.
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Affiliation(s)
- Charlie Cador
- Swine epidemiology and welfare research unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
- Université Bretagne Loire, Rennes, France
- * E-mail:
| | - Nicolas Rose
- Swine epidemiology and welfare research unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
- Université Bretagne Loire, Rennes, France
| | - Lander Willem
- Centre for Health Economics Research & Modeling of Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium
| | - Mathieu Andraud
- Swine epidemiology and welfare research unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
- Université Bretagne Loire, Rennes, France
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