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Petro-Turnquist E, Pekarek MJ, Weaver EA. Swine influenza A virus: challenges and novel vaccine strategies. Front Cell Infect Microbiol 2024; 14:1336013. [PMID: 38633745 PMCID: PMC11021629 DOI: 10.3389/fcimb.2024.1336013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 03/21/2024] [Indexed: 04/19/2024] Open
Abstract
Swine Influenza A Virus (IAV-S) imposes a significant impact on the pork industry and has been deemed a significant threat to global public health due to its zoonotic potential. The most effective method of preventing IAV-S is vaccination. While there are tremendous efforts to control and prevent IAV-S in vulnerable swine populations, there are considerable challenges in developing a broadly protective vaccine against IAV-S. These challenges include the consistent diversification of IAV-S, increasing the strength and breadth of adaptive immune responses elicited by vaccination, interfering maternal antibody responses, and the induction of vaccine-associated enhanced respiratory disease after vaccination. Current vaccination strategies are often not updated frequently enough to address the continuously evolving nature of IAV-S, fail to induce broadly cross-reactive responses, are susceptible to interference, may enhance respiratory disease, and can be expensive to produce. Here, we review the challenges and current status of universal IAV-S vaccine research. We also detail the current standard of licensed vaccines and their limitations in the field. Finally, we review recently described novel vaccines and vaccine platforms that may improve upon current methods of IAV-S control.
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Affiliation(s)
- Erika Petro-Turnquist
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, United States
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Matthew J. Pekarek
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, United States
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Eric A. Weaver
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, United States
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
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2
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Abstract
Globally swine influenza is one of the most important diseases of the pig industry, with various subtypes of swine influenza virus co-circulating in the field. Swine influenza can not only cause large economic losses for the pig industry but can also lead to epidemics or pandemics in the human population. We provide an overview of the pathogenic characteristics of the disease, diagnosis, risk factors for the occurrence on pig farms, impact on pigs and humans and methods to control it. This review is designed to promote understanding of the epidemiology of swine influenza which will benefit the control of the disease in both pigs and humans.
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Affiliation(s)
- Yin Li
- School of Veterinary Medicine, Murdoch University, Perth, WA Australia.,Commonwealth Scientific and Industrial Research Organisation, St. Lucia, QLD Australia
| | - Ian Robertson
- School of Veterinary Medicine, Murdoch University, Perth, WA Australia.,College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070 China.,Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, Huazhong Agricultural University, Wuhan, 430070 China
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3
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Chamba Pardo FO, Wayne S, Culhane MR, Perez A, Allerson M, Torremorell M. Effect of strain-specific maternally-derived antibodies on influenza A virus infection dynamics in nursery pigs. PLoS One 2019; 14:e0210700. [PMID: 30640929 PMCID: PMC6331129 DOI: 10.1371/journal.pone.0210700] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 12/31/2018] [Indexed: 12/25/2022] Open
Abstract
Reducing the number of influenza A virus (IAV) infected pigs at weaning is critical to minimize IAV spread to other farms. Sow vaccination is a common measure to reduce influenza levels at weaning. However, the impact of maternally-derived antibodies on IAV infection dynamics in growing pigs is poorly understood. We evaluated the effect of maternally-derived antibodies at weaning on IAV prevalence at weaning, time of influenza infection, number of weeks that pigs tested IAV positive, and estimated quantity of IAV in nursery pigs. We evaluated 301 pigs within 10 cohorts for their influenza serological (seroprevalence estimated by hemagglutination inhibition (HI) test) and virological (prevalence) status. Nasal swabs were collected weekly and pigs were bled 3 times throughout the nursery period. There was significant variability in influenza seroprevalence, HI titers and influenza prevalence after weaning. Increase in influenza seroprevalence at weaning was associated with low influenza prevalence at weaning and delayed time to IAV infection throughout the nursery. Piglets with IAV HI titers of 40 or higher at weaning were also less likely to test IAV positive at weaning, took longer to become infected, tested IAV RT-PCR positive for fewer weeks, and had higher IAV RT-PCR cycle threshold values compared to piglets with HI titers less than 40. Our findings suggest that sow vaccination or infection status that results in high levels of IAV strain-specific maternally-derived antibodies may help to reduce IAV circulation in both suckling and nursery pigs.
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Affiliation(s)
| | - Spencer Wayne
- Health Services, Pipestone Veterinary Services, Pipestone, MN, United States of America
| | - Marie Rene Culhane
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, United States of America
| | - Andres Perez
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, United States of America
| | - Matthew Allerson
- Health and Research Division, Holden Farms Inc., Northfield, MN, United States of America
| | - Montserrat Torremorell
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, United States of America
- * E-mail:
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4
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Takemae N, Tsunekuni R, Uchida Y, Ito T, Saito T. Experimental infection of pigs with H1 and H3 influenza A viruses of swine by using intranasal nebulization. BMC Vet Res 2018; 14:115. [PMID: 29587842 PMCID: PMC5870511 DOI: 10.1186/s12917-018-1434-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 03/16/2018] [Indexed: 02/19/2023] Open
Abstract
BACKGROUND Experimental infection of pigs via direct intranasal or intratracheal inoculation has been mainly used to study the infectious process of influenza A viruses of swine (IAVs-S). Nebulization is known to be an alternative method for inoculating pigs with IAVs-S, because larger quantities of virus potentially can be delivered throughout the respiratory tract. However, there is very little data on the experimental infection of pigs by inhalation using nebulizer. In the current study, we used intranasal nebulization to inoculate pigs with 9 different IAVs-S-3 H1N1, 2 H1N2, and 4 H3N2 strains. We then assessed the process of infection by evaluating the clinical signs, nasal and oral viral shedding, and seroconversion rates of the pigs inoculated. RESULTS Lethargy and sneezing were the predominant clinical signs among pigs inoculated with 7 of the 9 strains evaluated; the remaining 2 strains (1 H1N1 and 1 H1N2 isolate) failed to induce any clinical signs throughout the experiments. Significantly increased rectal temperatures were observed with an H1N1 or H3N2 strains between 1 and 3 days post-inoculation (dpi). In addition, patterns of nasal viral shedding differed among the strains: nasal viral shedding began on 1 dpi for 6 strains, with all 9 viruses being shed from 2 to 5 dpi. The detection of viral shedding was less sensitive from oral samples than nasal secretions. Viral shedding was not detected in either nasal or oral swabs after 10 dpi. According to hemagglutination-inhibition assays, all inoculated pigs had seroconverted to the inoculating virus by 14 dpi, with titers ranging from 10 to 320. CONCLUSIONS Our current findings show that intranasal nebulization successfully established IAV-S infections in pigs and demonstrate that clinical signs, viral shedding, and host immune responses varied among the strains inoculated.
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Affiliation(s)
- Nobuhiro Takemae
- Division of Transboundary Animal Disease, National Institute of Animal Health, NARO, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.,Thailand-Japan Zoonotic Diseases Collaboration Center, Kasetklang, Chatuchak, Bangkok, 10900, Thailand
| | - Ryota Tsunekuni
- Division of Transboundary Animal Disease, National Institute of Animal Health, NARO, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.,Thailand-Japan Zoonotic Diseases Collaboration Center, Kasetklang, Chatuchak, Bangkok, 10900, Thailand
| | - Yuko Uchida
- Division of Transboundary Animal Disease, National Institute of Animal Health, NARO, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.,Thailand-Japan Zoonotic Diseases Collaboration Center, Kasetklang, Chatuchak, Bangkok, 10900, Thailand
| | - Toshihiro Ito
- The Avian Zoonosis Research Center, Faculty of Agriculture, Tottori University, 4-101 Koyama-cho Minami, Tottori, Tottori, 680-8550, Japan
| | - Takehiko Saito
- Division of Transboundary Animal Disease, National Institute of Animal Health, NARO, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan. .,Thailand-Japan Zoonotic Diseases Collaboration Center, Kasetklang, Chatuchak, Bangkok, 10900, Thailand. .,United Graduate School of Veterinary Sciences, Gifu University, 1-1, Yanagito, Gifu, Gifu, 501-1112, Japan.
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5
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Pitzer VE, Aguas R, Riley S, Loeffen WLA, Wood JLN, Grenfell BT. High turnover drives prolonged persistence of influenza in managed pig herds. J R Soc Interface 2017; 13:rsif.2016.0138. [PMID: 27358277 PMCID: PMC4938081 DOI: 10.1098/rsif.2016.0138] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/08/2016] [Indexed: 11/16/2022] Open
Abstract
Pigs have long been hypothesized to play a central role in the emergence of novel human influenza A virus (IAV) strains, by serving as mixing vessels for mammalian and avian variants. However, the key issue of viral persistence in swine populations at different scales is ill understood. We address this gap using epidemiological models calibrated against seroprevalence data from Dutch finishing pigs to estimate the ‘critical herd size’ (CHS) for IAV persistence. We then examine the viral phylogenetic evidence for persistence by comparing human and swine IAV. Models suggest a CHS of approximately 3000 pigs above which influenza was likely to persist, i.e. orders of magnitude lower than persistence thresholds for IAV and other acute viruses in humans. At national and regional scales, we found much stronger empirical signatures of prolonged persistence of IAV in swine compared with human populations. These striking levels of persistence in small populations are driven by the high recruitment rate of susceptible piglets, and have significant implications for management of swine and for overall patterns of genetic diversity of IAV.
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Affiliation(s)
- Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20850, USA
| | - Ricardo Aguas
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London SW7 2AZ, UK
| | - Steven Riley
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London SW7 2AZ, UK
| | - Willie L A Loeffen
- Department of Virology, Central Veterinary Institute, part of Wageningen UR, Lelystad 8200AB, The Netherlands
| | - James L N Wood
- Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Bryan T Grenfell
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20850, USA Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
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6
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Chamba Pardo FO, Alba-Casals A, Nerem J, Morrison RB, Puig P, Torremorell M. Influenza Herd-Level Prevalence and Seasonality in Breed-to-Wean Pig Farms in the Midwestern United States. Front Vet Sci 2017; 4:167. [PMID: 29075636 PMCID: PMC5641542 DOI: 10.3389/fvets.2017.00167] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/25/2017] [Indexed: 01/30/2023] Open
Abstract
Influenza is a costly disease for pig producers and understanding its epidemiology is critical to control it. In this study, we aimed to estimate the herd-level prevalence and seasonality of influenza in breed-to-wean pig farms, evaluate the correlation between influenza herd-level prevalence and meteorological conditions, and characterize influenza genetic diversity over time. A cohort of 34 breed-to-wean farms with monthly influenza status obtained over a 5-year period in piglets prior to wean was selected. A farm was considered positive in a given month if at least one oral fluid tested influenza positive by reverse transcriptase polymerase chain reaction. Influenza seasonality was assessed combining autoregressive integrated moving average (ARIMA) models with trigonometric functions as covariates. Meteorological conditions were gathered from local land-based weather stations, monthly aggregated and correlated with influenza herd-level prevalence. Influenza herd-level prevalence had a median of 28% with a range from 7 to 57% and followed a cyclical pattern with levels increasing during fall, peaking in both early winter (December) and late spring (May), and decreasing in summer. Influenza herd-level prevalence was correlated with mean outdoor air absolute humidity (AH) and temperature. Influenza genetic diversity was substantial over time with influenza isolates belonging to 10 distinct clades from which H1 delta 1 and H1 gamma 1 were the most common. Twenty-one percent of farms had three different clades co-circulating over time, 18% of farms had two clades, and 41% of farms had one clade. In summary, our study showed that influenza had a cyclical pattern explained in part by air AH and temperature changes over time, and highlighted the importance of active surveillance to identify high-risk periods when strategic control measures for influenza could be implemented.
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Affiliation(s)
| | - Ana Alba-Casals
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, United States
| | - Joel Nerem
- Pipestone Veterinary Services, Pipestone, MN, United States
| | - Robert B Morrison
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, United States
| | - Pedro Puig
- Departament de Matemàtiques, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Montserrat Torremorell
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, United States
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7
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Raghunath S, Pudupakam RS, Deventhiran J, Tevatia R, Leroith T. Pathogenicity and transmission of triple reassortant H3N2 swine influenza A viruses is attenuated following Turkey embryo propagation. Vet Microbiol 2017; 201:208-215. [PMID: 28284612 DOI: 10.1016/j.vetmic.2017.01.030] [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: 12/15/2016] [Revised: 01/25/2017] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
Abstract
Genetic lineages of swine influenza A viruses (SIVs) have recently been established in Turkeys in the United States. To identify molecular determinants that are involved in virulence and transmission of SIVs to Turkeys, we sequentially passaged two triple reassortant H3N2 SIV isolates from Minnesota in ten day old specific-pathogen free (SPF) Turkey embryos and tested them in seven-day old Turkey poults. We found that SIV replication in Turkey embryos led to minimal mutations in and around the receptor binding and antigenic sites of the HA molecule, while other gene segments were unchanged. The predominant changes associated with Turkey embryo passage were A223V, V226A and T248I mutations in the receptor-binding and glycosylation sites of the HA molecule. Furthermore, Turkey embryo propagation altered receptor specificity in SIV strain 07-1145. Embryo passaged 07-1145 virus showed a decrease in α2, 6 sialic acid receptor binding compared to the wild type virus. Intranasal infection of wild type SIVs in one-week-old Turkey poults resulted in persistent diarrhea and all the infected birds seroconverted at ten days post infection. The 07-1145 wild type virus also transmitted to age matched in-contact birds introduced one-day post infection. Turkeys infected with embryo passaged viruses displayed no clinical signs and were not transmitted to in-contact poults. Our results suggest that Turkey embryo propagation attenuates recent TR SIVs for infectivity and transmission in one week old Turkeys. Our findings will have important implications in identifying molecular determinants that control the transmission and virulence of TR SIVs in Turkeys and other species.
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Affiliation(s)
- Shobana Raghunath
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States; Vajra Instruments Inc., Lincoln, NE, United States.
| | - Raghavendra Sumanth Pudupakam
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Jagadeeswaran Deventhiran
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Rahul Tevatia
- Dept of Chemical and Bioengineering, University of Nebraska, Lincoln, NE, United States
| | - Tanya Leroith
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.
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8
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Rajao DS, Sandbulte MR, Gauger PC, Kitikoon P, Platt R, Roth JA, Perez DR, Loving CL, Vincent AL. Heterologous challenge in the presence of maternally-derived antibodies results in vaccine-associated enhanced respiratory disease in weaned piglets. Virology 2016; 491:79-88. [PMID: 26874588 DOI: 10.1016/j.virol.2016.01.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 12/17/2015] [Accepted: 01/22/2016] [Indexed: 12/19/2022]
Abstract
Control of influenza A virus (IAV) in pigs is done by vaccination of females to provide maternally-derived antibodies (MDA) through colostrum. Our aim was to evaluate if MDA interfere with IAV infection, clinical disease, and transmission in non-vaccinated piglets. In the first study, naïve sows were vaccinated with H1N2-δ1 whole inactivated virus (WIV) vaccine. In a follow-up study seropositive sows to 2009 pandemic H1N1 (H1N1pdm09) were boosted with H1N1pdm09 WIV or secondary experimental infection (EXP). MDA-positive pigs were challenged with homologous or heterologous virus, and MDA-negative control groups were included. WIV-MDA piglets were protected from homologous infection. However, piglets with WIV-derived MDA subsequently challenged with heterologous virus developed vaccine associated enhanced respiratory disease (VAERD), regardless of history of natural exposure in the sows. Our data indicates that although high titers of vaccine-derived MDA reduced homologous virus infection, transmission, and disease, MDA alone was sufficient to induce VAERD upon heterologous infection.
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Affiliation(s)
- Daniela S Rajao
- Virus and Prion Research Unit, National Animal Disease Center, USDA, ARS, 1920 Dayton Ave, Ames, IA 50010, United States
| | - Matthew R Sandbulte
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, 2180 Veterinary Medicine, Ames, IA 50011, United States
| | - Phillip C Gauger
- Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 2630 Veterinary Medicine, Ames, IA 50011, United States
| | - Pravina Kitikoon
- Virus and Prion Research Unit, National Animal Disease Center, USDA, ARS, 1920 Dayton Ave, Ames, IA 50010, United States
| | - Ratree Platt
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, 2180 Veterinary Medicine, Ames, IA 50011, United States
| | - James A Roth
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, 2180 Veterinary Medicine, Ames, IA 50011, United States
| | - Daniel R Perez
- Poultry Diagnostic and Research Center, University of Georgia, 953 College Station Rd, Athens, GA 30602, United States
| | - Crystal L Loving
- Virus and Prion Research Unit, National Animal Disease Center, USDA, ARS, 1920 Dayton Ave, Ames, IA 50010, United States
| | - Amy L Vincent
- Virus and Prion Research Unit, National Animal Disease Center, USDA, ARS, 1920 Dayton Ave, Ames, IA 50010, United States.
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9
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Sandbulte MR, Spickler AR, Zaabel PK, Roth JA. Optimal Use of Vaccines for Control of Influenza A Virus in Swine. Vaccines (Basel) 2015; 3:22-73. [PMID: 26344946 PMCID: PMC4494241 DOI: 10.3390/vaccines3010022] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/09/2015] [Accepted: 01/19/2015] [Indexed: 12/29/2022] Open
Abstract
Influenza A virus in swine (IAV-S) is one of the most important infectious disease agents of swine in North America. In addition to the economic burden of IAV-S to the swine industry, the zoonotic potential of IAV-S sometimes leads to serious public health concerns. Adjuvanted, inactivated vaccines have been licensed in the United States for over 20 years, and there is also widespread usage of autogenous/custom IAV-S vaccines. Vaccination induces neutralizing antibodies and protection against infection with very similar strains. However, IAV-S strains are so diverse and prone to mutation that these vaccines often have disappointing efficacy in the field. This scientific review was developed to help veterinarians and others to identify the best available IAV-S vaccine for a particular infected herd. We describe key principles of IAV-S structure and replication, protective immunity, currently available vaccines, and vaccine technologies that show promise for the future. We discuss strategies to optimize the use of available IAV-S vaccines, based on information gathered from modern diagnostics and surveillance programs. Improvements in IAV-S immunization strategies, in both the short term and long term, will benefit swine health and productivity and potentially reduce risks to public health.
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Affiliation(s)
- Matthew R Sandbulte
- Center for Food Security and Public Health, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
| | - Anna R Spickler
- Center for Food Security and Public Health, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
| | - Pamela K Zaabel
- Center for Food Security and Public Health, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
| | - James A Roth
- Center for Food Security and Public Health, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
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10
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Finelli L, Swerdlow DL. The emergence of influenza A (H3N2)v virus: what we learned from the first wave. Clin Infect Dis 2013; 57 Suppl 1:S1-3. [PMID: 23794725 DOI: 10.1093/cid/cit324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Lyn Finelli
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, NE, Atlanta, GA 30333, USA
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11
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Allerson MW, Davies PR, Gramer MR, Torremorell M. Infection dynamics of pandemic 2009 H1N1 influenza virus in a two-site swine herd. Transbound Emerg Dis 2013; 61:490-9. [PMID: 23294593 DOI: 10.1111/tbed.12053] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Indexed: 11/28/2022]
Abstract
Influenza A viruses are common causes of respiratory disease in pigs and can be transmitted among multiple host species, including humans. The current lack of published information on infection dynamics of influenza viruses within swine herds hinders the ability to make informed animal health, biosecurity and surveillance programme decisions. The objectives of this serial cross-sectional study were to describe the infection dynamics of influenza virus in a two-site swine system by estimating the prevalence of influenza virus in animal subpopulations at the swine breeding herd and describing the temporal pattern of infection in a selected cohort of growing pigs weaned from the breeding herd. Nasal swab and blood samples were collected at approximately 30-day intervals from the swine breeding herd (Site 1) known to be infected with pandemic 2009 H1N1 influenza virus. Sows, gilts and neonatal pigs were sampled at each sampling event, and samples were tested for influenza virus genome using matrix gene RRT-PCR. Influenza virus was detected in neonatal pigs, but was not detected in sow or gilt populations via RRT-PCR. A virus genetically similar to that detected in the neonatal pig population at Site 1 was also detected at the wean-to-finish site (Site 2), presumably following transportation of infected weaned pigs. Longitudinal sampling of nasal swabs and oral fluids revealed that influenza virus persisted in the growing pigs at Site 2 for at least 69 days. The occurrence of influenza virus in neonatal pigs, but not breeding females, at Site 1 emphasizes the potential for virus maintenance in this dynamic subpopulation, the importance of including this subpopulation in surveillance programmes and the potential transport of influenza virus between sites via the movement of weaned pigs.
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Affiliation(s)
- M W Allerson
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
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12
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Allerson M, Deen J, Detmer SE, Gramer MR, Joo HS, Romagosa A, Torremorell M. The impact of maternally derived immunity on influenza A virus transmission in neonatal pig populations. Vaccine 2013; 31:500-5. [PMID: 23174202 PMCID: PMC3534892 DOI: 10.1016/j.vaccine.2012.11.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 11/02/2012] [Accepted: 11/08/2012] [Indexed: 11/22/2022]
Abstract
The commonality of influenza A virus (IAV) exposure and vaccination on swine farms in the United States ensures that the majority of neonatal pigs will have some degree of maternal immunity to IAV. The influence of maternal immunity on IAV transmission in neonatal pig populations will impact virus prevalence and infection dynamics across pig populations. The main objective of this study was to assess the impact of maternally derived immunity on IAV transmission in an experimental setting. Neonatal pigs suckled colostrum and derived maternal (passive) immunity from sows in one of three treatment groups: (a) non-vaccinated control (CTRL) or vaccinated with (b) homologous (PASSV-HOM) or (c) heterologous (PASSV-HET) inactivated experimental IAV vaccines. Sentinel neonatal pigs derived from the groups above were challenged with IAV via direct contact with an experimentally infected pig (seeder pig) and monitored for IAV infection daily via nasal swab sampling. A susceptible-infectious-recovered (SIR) experimental model was used to obtain and estimate transmission parameters in each treatment group via a generalized linear model. All sentinel pigs in the CTRL (30/30) and PASSV-HET (30/30) groups were infected with IAV following contact with the seeder pigs and the reproduction ratio estimates (95% confidence interval) were 10.4 (6.6-15.8) and 7.1 (4.2-11.3), respectively. In contrast, 1/20 sentinel pigs in the PASSV-HOM group was infected following contact with the seeder pigs and the reproduction ratio estimate was significantly lower compared to the CTRL and PASSV-HET groups at 0.8 (0.1-3.7). Under the conditions of this study, IAV transmission was reduced in neonatal pigs with homologous maternal immunity compared to seronegative neonatal pigs and pigs with heterologous maternal immunity as defined in this study. This study provides estimates for IAV transmission in pigs with differing types of maternal immunity which may describe the influence of maternal immunity on IAV prevalence and infection dynamics in pig populations.
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Affiliation(s)
- Matt Allerson
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
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13
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Live attenuated influenza vaccine provides superior protection from heterologous infection in pigs with maternal antibodies without inducing vaccine-associated enhanced respiratory disease. J Virol 2012; 86:10597-605. [PMID: 22811541 DOI: 10.1128/jvi.01439-12] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Control of swine influenza A virus (IAV) in the United States is hindered because inactivated vaccines do not provide robust cross-protection against the multiple antigenic variants cocirculating in the field. Vaccine efficacy can be limited further for vaccines administered to young pigs that possess maternally derived immunity. We previously demonstrated that a recombinant A/sw/Texas/4199-2/1998 (TX98) (H3N2) virus expressing a truncated NS1 protein is attenuated in swine and has potential for use as an intranasal live attenuated influenza virus (LAIV) vaccine. In the present study, we compared 1 dose of intranasal LAIV with 2 intramuscular doses of TX98 whole inactivated virus (WIV) with adjuvant in weanling pigs with and without TX98-specific maternally derived antibodies (MDA). Pigs were subsequently challenged with wild-type homologous TX98 H3N2 virus or with an antigenic variant, A/sw/Colorado/23619/1999 (CO99) (H3N2). In the absence of MDA, both vaccines protected against homologous TX98 and heterologous CO99 shedding, although the LAIV elicited lower hemagglutination inhibition (HI) antibody titers in serum. The efficacy of both vaccines was reduced by the presence of MDA; however, WIV vaccination of MDA-positive pigs led to dramatically enhanced pneumonia following heterologous challenge, a phenomenon known as vaccine-associated enhanced respiratory disease (VAERD). A single dose of LAIV administered to MDA-positive pigs still provided partial protection from CO99 and may be a safer vaccine for young pigs under field conditions, where dams are routinely vaccinated and diverse IAV strains are in circulation. These results have implications not only for pigs but also for other influenza virus host species.
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14
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Simon-Grifé M, Martín-Valls GE, Vilar MJ, Busquets N, Mora-Salvatierra M, Bestebroer TM, Fouchier RA, Martín M, Mateu E, Casal J. Swine influenza virus infection dynamics in two pig farms; results of a longitudinal assessment. Vet Res 2012; 43:24. [PMID: 22452923 PMCID: PMC3353254 DOI: 10.1186/1297-9716-43-24] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 03/27/2012] [Indexed: 12/05/2022] Open
Abstract
In order to assess the dynamics of influenza virus infection in pigs, serological and virological follow-ups were conducted in two whole batches of pigs from two different farms (F1 and F2), from 3 weeks of age until market age. Anti-swine influenza virus (SIV) antibodies (measured by ELISA and hemagglutination inhibition) and nasal virus shedding (measured by RRT-PCR and isolation in embryonated chicken eggs and MDCK cells) were carried out periodically. SIV isolates were subtyped and hemagglutinin and neuraminidase genes were partially sequenced and analyzed phylogenetically. In F1, four waves of viral circulation were detected, and globally, 62/121 pigs (51.2%) were positive by RRT-PCR at least once. All F1 isolates corresponded to H1N1 subtype although hemagglutination inhibition results also revealed the presence of antibodies against H3N2. The first viral wave took place in the presence of colostral-derived antibodies. Nine pigs were positive in two non-consecutive sampling weeks, with two of the animals being positive with the same isolate. Phylogenetic analyses showed that different H1N1 variants circulated in that farm. In F2, only one isolate, H1N2, was detected and all infections were concentrated in a very short period of time, as assumed for a classic influenza outbreak. These findings led us to propose that influenza virus infection in pigs might present different patterns, from an epidemic outbreak to an endemic form with different waves of infections with a lower incidence.
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Affiliation(s)
- Meritxell Simon-Grifé
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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15
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Torremorell M, Allerson M, Corzo C, Diaz A, Gramer M. Transmission of influenza A virus in pigs. Transbound Emerg Dis 2012; 59 Suppl 1:68-84. [PMID: 22226050 DOI: 10.1111/j.1865-1682.2011.01300.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Influenza A virus infections cause respiratory disease in pigs and are a risk to public health. The pig plays an important role in influenza ecology because of its ability to support replication of influenza viruses from avian, swine and human species. Influenza A virus is widespread in pigs worldwide, and influenza A virus interspecies transmission has been documented in many events. Influenza A virus is mostly transmitted through direct pig-to-pig contact and aerosols although other indirect routes of transmission may also exist. Several factors contribute to differences in the transmission dynamics within populations including among others vaccination, pig flow, animal movement and animal introduction which highlights the complexity of influenza A transmission in pigs. In addition, pigs can serve as a reservoir of influenza A viruses for other pigs and other species and understanding mechanisms of transmission within pigs and from pigs to other species and vice versa is crucial. In this paper, we review the current understanding of influenza virus transmission in pigs. We highlight the ubiquity of influenza A virus in the pig population and the widespread distribution of pandemic H1N1 virus worldwide while emphasizing an understanding of the routes of transmission and factors that contribute to virus spread and dissemination within and between pig populations. In addition, we describe transmission events between pigs and other species including people. Understanding transmission is crucial for designing effective control strategies and for making well-informed recommendations for surveillance.
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Affiliation(s)
- M Torremorell
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA.
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16
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Holyoake PK, Kirkland PD, Davis RJ, Arzey KE, Watson J, Lunt RA, Wang J, Wong F, Moloney BJ, Dunn SE. The first identified case of pandemic H1N1 influenza in pigs in Australia. Aust Vet J 2011; 89:427-31. [PMID: 22008120 DOI: 10.1111/j.1751-0813.2011.00844.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 300-sow farrow-to-finish herd in New South Wales was infected with influenza pandemic (H1N1) 2009 (H1N1/09) virus in July 2009 and became the first recorded case of influenza in pigs in Australia. The outbreak resulted from human-to-pig transmission. Clinical signs in affected pigs were mild compared with overseas reports of 'classical' swine influenza virus and included coughing and decreased appetite in a small proportion of non-lactating breeding stock, weaners, growers and finishers. A diagnosis of H1N1/09 influenza virus infection was confirmed using a combination of serology (haemagglutination inhibition, blocking enzyme-linked immunosorbent assay) and real-time reverse transcription polymerase chain reaction. Attempts at virus isolation were unsuccessful. Results of a longitudinal study of pigs on this farm suggested that the virus continued to circulate for 9 weeks after the onset of infection, but was not present 6 months later. This report highlights the difficulties in preventing transmission of H1N1/09 influenza virus from infected humans to pigs during a human pandemic.
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Affiliation(s)
- P K Holyoake
- Industry and Investment, Wagga Wagga Agricultural Institute, New South Wales, Australia.
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17
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Dawood FS, Dong L, Liu F, Blau DM, Peebles PJ, Lu X, Wagers L, Oakland B, Zielenski M, Daly R, Horan V, Swenson SL, Schmitt BJ, Hancock K, Katz JM, Bridges C, Kightlinger L, Finelli L. A Pre-Pandemic Outbreak of Triple-Reassortant Swine Influenza Virus Infection Among University Students, South Dakota, 2008. J Infect Dis 2011; 204:1165-71. [DOI: 10.1093/infdis/jir502] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Beaudoin A, Johnson S, Davies P, Bender J, Gramer M. Characterization of influenza a outbreaks in Minnesota swine herds and measures taken to reduce the risk of zoonotic transmission. Zoonoses Public Health 2011; 59:96-106. [PMID: 21824375 DOI: 10.1111/j.1863-2378.2011.01423.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Influenza A virus infections commonly cause respiratory disease in swine and can be transmitted between people and pigs, with potentially novel strains introduced into herds and spilling back into the human population. The goals of this study were to characterize influenza infections in Minnesota pigs and assess biosecurity measures used by swine workers. Veterinarians submitting influenza-positive swine samples to the University of Minnesota Veterinary Diagnostic Laboratory between October 2007 and April 2009 were surveyed regarding disease-related information and biosecurity procedures at each farm. Influenza-positive samples were submitted year-round, peaking in spring and fall. H1N1 was the most commonly detected subtype (56%), followed by H3N2 (14%) and H1N2 (12%). Most positive submissions were associated with illness in growing pigs (median age 8.8 weeks, IQR 5-15). Median morbidity and mortality were 25% (IQR 10-48) and 2% (IQR 0.5-3.5), respectively. Vaccination of sows and growing pigs was conducted at 71% and 7.9% of the swine farms, respectively. Specialized footwear was reported as the most common form of protective equipment used by workers. Employee vaccination for seasonal influenza was 19%. The sow vaccination rate in this study is consistent with national data, although growing pig vaccination is lower than the national average. Seasonal and age trends identified here may provide diagnostic guidance when growing pigs experience respiratory disease. Inconsistent use of protective equipment and employee vaccination at swine farms indicates the need for further discussion and research of approaches to minimize interspecies influenza transmission on swine farms.
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Affiliation(s)
- A Beaudoin
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA
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19
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Zilberman D, Otte J, Roland-Holst D, Pfeiffer D. Epidemiology of Highly Pathogenic Avian Influenza Virus Strain Type H5N1. HEALTH AND ANIMAL AGRICULTURE IN DEVELOPING COUNTRIES 2011; 36. [PMCID: PMC7122524 DOI: 10.1007/978-1-4419-7077-0_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Highly pathogenic avian influenza (HPAI) is a severe disease of poultry. It is highly transmissible with a flock mortality rate approaching 100% in vulnerable species (Capua et al. 2007a). Due to the potentially disastrous impact the disease can have on affected poultry sectors, HPAI has received huge attention and is classified as a notifiable disease by the World Organisation for Animal Health (OIE).
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Affiliation(s)
- David Zilberman
- College of Natural Resources, Dept. Agricultural & Resource Economics, University of California, Berkeley, Giannini Hall 206, Berkeley, 94720-3310 California USA
| | - Joachim Otte
- Food and Agriculture Organization of the, Viale delle Terme di Caracalla, Rome, 00100 Italy
| | - David Roland-Holst
- , Department of Agricultural and Resource, University of California, Giannini Hall 207, Berkeley, 94720-3310 USA
| | - Dirk Pfeiffer
- , Veterinary Clinical Sciences, The Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA United Kingdom
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20
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Lloyd LE, Jonczyk M, Jervis CM, Flack DJ, Lyall J, Foote A, Mumford JA, Brown IH, Wood JL, Elton DM. Experimental transmission of avian-like swine H1N1 influenza virus between immunologically naïve and vaccinated pigs. Influenza Other Respir Viruses 2011; 5:357-64. [PMID: 21668691 PMCID: PMC4942048 DOI: 10.1111/j.1750-2659.2011.00233.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Please cite this paper as: Lloyd et al. (2011) Experimental transmission of avian‐like swine H1N1 influenza virus between immunologically naïve and vaccinated pigs. Influenza and Other Respiratory Viruses 5(5), 357–364. Background Infection of pigs with swine influenza has been studied experimentally and in the field; however, little information is available on the natural transmission of this virus in pigs. Two studies in an experimental transmission model are presented here, one in immunologically naïve and one in a combination of vaccinated and naïve pigs. Objectives To investigate the transmission of a recent ‘avian‐like’ swine H1N1 influenza virus in naive piglets, to assess the antibody response to a commercially available vaccine and to determine the efficiency of transmission in pigs after vaccination. Methods Transmission chains were initiated by intranasal challenge of two immunologically naïve pigs. Animals were monitored daily for clinical signs and virus shedding. Pairs of pigs were sequentially co‐housed, and once virus was detected in recipients, prior donors were removed. In the vaccination study, piglets were vaccinated and circulating antibody levels were monitored by haemagglutination inhibition assay. To study transmission in vaccinates, a pair of infected immunologically naïve animals was co‐housed with vaccinated recipient pigs and further pairs of vaccinates were added sequentially as above. The chain was completed by the addition of naive pigs. Results and conclusions Transmission of the H1N1 virus was achieved through a chain of six pairs of naïve piglets and through four pairs of vaccinated animals. Transmission occurred with minimal clinical signs and, in vaccinates, at antibody levels higher than previously reported to protect against infection.
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Affiliation(s)
- Lucy E Lloyd
- Animal Health Trust, Kentford, Newmarket, Suffolk, UK
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21
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Torremorell M, Juarez A, Chavez E, Yescas J, Doporto JM, Gramer M. Procedures to eliminate H3N2 swine influenza virus from a pig herd. Vet Rec 2009; 165:74-7. [DOI: 10.1136/vetrec.165.3.74] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M. Torremorell
- Genus/PIC; Suite 2200, 100 Bluegrass Commons Boulevard Hendersonville TN 37075 USA
| | - A. Juarez
- PIC Mexico; Wenseslao de la Barquera 7, Queretaro Queretaro 76040 México
| | - E. Chavez
- PIC Mexico; Wenseslao de la Barquera 7, Queretaro Queretaro 76040 México
| | - J. Yescas
- Presqueria Norte SN-6 Residencial El Álamo; Colonia Reforma, Navojoa Sonora CP 85800 Mexico
| | - J. M. Doporto
- Departamento de Producción Animal; Facultad de Medicina Veterinaria y Zootecnia; Universidad Nacional Autónoma de México; Avenida Universidad 3000 Delegacion Coyoacan CP 04510 Mexico
| | - M. Gramer
- University of Minnesota Veterinary Diagnostic Laboratory; 1333 Gortner Avenue St Paul MN 55108 USA
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22
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Kitikoon P, Nilubol D, Erickson BJ, Janke BH, Hoover TC, Sornsen SA, Thacker EL. The immune response and maternal antibody interference to a heterologous H1N1 swine influenza virus infection following vaccination. Vet Immunol Immunopathol 2006; 112:117-28. [PMID: 16621020 DOI: 10.1016/j.vetimm.2006.02.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 01/30/2006] [Accepted: 02/13/2006] [Indexed: 10/24/2022]
Abstract
This study investigated the efficacy of a bivalent swine influenza virus (SIV) vaccine in piglets challenged with a heterologous H1N1 SIV isolate. The ability of maternally derived antibodies (MDA) to provide protection against a heterologous challenge and the impact MDA have on vaccine efficacy were also evaluated. Forty-eight MDA(+) pigs and 48 MDA(-) pigs were assigned to 8 different groups. Vaccinated pigs received two doses of a bivalent SIV vaccine at 3 and 5 weeks of age. The infected pigs were challenged at 7 weeks of age with an H1N1 SIV strain heterologous to the H1N1 vaccine strain. Clinical signs, rectal temperature, macroscopic and microscopic lesions, virus excretion, serum and local antibody responses, and influenza-specific T-cell responses were measured. The bivalent SIV vaccine induced a high serum hemagglutination-inhibition (HI) antibody titer against the vaccine virus, but antibodies cross-reacted at a lower level to the challenge virus. This study determined that low serum HI antibodies to a challenge virus induced by vaccination with a heterologous virus provided protection demonstrated by clinical protection and reduced pneumonia and viral excretion. The vaccine was able to prime the local SIV-specific antibody response in the lower respiratory tract as well as inducing a systemic SIV-specific memory T-cell response. MDA alone were capable of suppressing fever subsequent to infection, but other parameters showed reduced protection against infection compared to vaccination. The presence of MDA at vaccination negatively impacted vaccine efficacy as fever and clinical signs were prolonged, and unexpectedly, SIV-induced pneumonia was increased compared to pigs vaccinated in the absence of MDA. MDA also suppressed the serum antibody response and the induction of SIV-specific memory T-cells following vaccination. The results of this study question the effectiveness of the current practice of generating increased MDA levels through sow vaccination in protecting piglets against disease.
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Affiliation(s)
- Pravina Kitikoon
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
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