Chapter 3 Swine Influenza Viruses: A North American Perspective

https://doi.org/10.1016/S0065-3527(08)00403-XGet rights and content

Abstract

Influenza is a zoonotic viral disease that represents a health and economic threat to both humans and animals worldwide. Swine influenza (SI) was first recognized clinically in pigs in the Midwestern U.S., in 1918, coinciding with the human influenza pandemic known as the Spanish flu. Since that time SI has remained of importance to the swine industry throughout the world. In this review, the epidemiology of swine influenza virus (SIV) infection in North American pigs is described in detail. The first 80 years of SI remained relatively static, whereas the last decade has become dynamic with the establishment of many emerging subtypes. With the increasing number of novel subtypes and genetic variants, the control of SI has become increasingly difficult and innovative strategies to combat this economically important zoonotic disease are critical. Therefore, protective immune responses against influenza virus infections as well as new paradigms of vaccine development in pigs are discussed in the review. It is expected that the dynamic evolutionary changes of SIVs in North American pigs will continue, making currently available prophylactic approaches of limited use to control the spread and economic losses associated with this important swine pathogen.

Section snippets

Introduction to Influenza A Viruses

Influenza is a zoonotic viral disease that represents a health and economic threat to both humans and animals worldwide. Influenza A viruses infect a wide variety of species and exhibit only a partial restriction of their host range, that is, there is occasional transmission from one species to another. Annual epidemics/epizootics in humans and animals and occasional influenza pandemics in humans depend on the continued molecular evolution of influenza viruses giving rise to new antigenic

Evolution of North American SI Viruses of the H1 and H3 Subtype

Historically, SI in the United States had a predictable pattern with an epizootic in the late fall and early winter months similar to that in humans. Prior to 1998, this acute respiratory disease was almost exclusively caused by viruses of the classical‐swine H1N1 lineage (cH1N1; Easterday and van Reeth, 1999). The cH1N1 virus, first isolated and identified in North America in 1930 (Shope, 1931), is believed to have been introduced into the U.S. pig population during the 1918 Spanish influenza

Cross‐Species Transmission of Influenza A Viruses and Novel Subtypes in North American Swine

Influenza A viruses of all 16 HA and 9 NA subtypes have been recovered from wild waterfowl and seabirds (Fouchier et al., 2005, Webster et al., 1992). From these studies it was concluded that waterfowl provide a vast global reservoir of influenza viruses in nature from which novel viruses can emerge and infect mammalian species (Webby and Webster, 2001). Prominent examples of cross‐species transmission of influenza viruses from avian to mammalian species or vice versa are the recent infections

Vaccination of Pigs Against SI

Vaccinating pigs against influenza A virus has become a common practice in the U.S. swine industry over the last 10 years. Inactivated influenza vaccines became commercially available in 1994. In 1995, influenza vaccine usage was not reported in the National Animal Health Monitoring System survey of the U.S. swine operations (USDA, 1995). However, by 2000, over 40% of large producers reported that they vaccinated breeding females and approximately 20% vaccinated weaned pigs (USDA, 2003). In the

Conclusions and Outlook

The impact of influenza A in humans and animals, whether measured by morbidity, mortality, or economic losses, is significant. It is, therefore, essential to understand the mechanisms that allow these viruses to jump species barriers and establish themselves in new animal populations. The emergence of new subtypes of SIVs (hu‐H1, H3N2, H4N6, and H2N3) in North American pigs has implications not only for pigs but also for the people who care for them. These newly emerging viruses are capable of

Acknowledgments

The authors thank the team of technical and animal care staff that has significantly contributed to the many studies described in this review. We thank Mike Marti for illustrations and Drs A. Garcia‐Sastre, M. R. Gramer, and R.J. Webby for their continued support. Projects described in this review were funded by the USDA‐Agricultural Research Service and in part with Federal funds from the National Institute Allergy and Infectious Diseases, National Institutes of Health, Department of Health

References (108)

  • R. Klopfleisch et al.

    Encephalitis in a stone marten (Martes foina) after natural infection with highly pathogenic avian influenza virus subtype H5N1

    J. Comp. Pathol.

    (2007)
  • D.L. Larsen et al.

    Systemic and mucosal immune responses to H1N1 influenza virus infection in pigs

    Vet. Microbiol.

    (2000)
  • W.L. Loeffen et al.

    Effect of maternally derived antibodies on the clinical signs and immune response in pigs after primary and secondary infection with an influenza H1N1 virus

    Vet. Immunol. Immunopathol.

    (2003)
  • G.A. Mayr et al.

    Immune responses and protection against foot‐and‐mouth disease virus (FMDV) challenge in swine vaccinated with adenovirus‐FMDV constructs

    Vaccine

    (2001)
  • H.H. Nguyen et al.

    Heterosubtypic immunity to lethal influenza A virus infection is associated with virus‐specific CD8(+) cytotoxic T lymphocyte responses induced in mucosa‐associated tissues

    Virology

    (1999)
  • C.W. Olsen

    The emergence of novel swine influenza viruses in North America

    Virus Res.

    (2002)
  • J.M. Pacheco et al.

    Rapid protection of cattle from direct challenge with foot‐and‐mouth disease virus (FMDV) by a single inoculation with an adenovirus‐vectored FMDV subunit vaccine

    Virology

    (2005)
  • P. Palese et al.

    Inhibition of influenza and parainfluenza virus replication in tissue culture by 2‐deoxy‐2,3‐dehydro‐N‐trifluoroacetylneuraminic acid (FANA)

    Virology

    (1974)
  • K.V. Reeth et al.

    Genetic relationships, serological cross‐reaction and cross‐protection between H1N2 and other influenza A virus subtypes endemic in European pigs

    Virus Res.

    (2004)
  • G.N. Rogers et al.

    Receptor determinants of human and animal influenza virus isolates: Differences in receptor specificity of the H3 hemagglutinin based on species of origin

    Virology

    (1983)
  • C. Scholtissek et al.

    The nucleoprotein as a possible major factor in determining host specificity of influenza H3N2 viruses

    Virology

    (1985)
  • K.F. Shortridge et al.

    An influenza epicentre?

    Lancet

    (1982)
  • K. Van Reeth et al.

    Protection against a European H1N2 swine influenza virus in pigs previously infected with H1N1 and/or H3N2 subtypes

    Vaccine

    (2003)
  • A.L. Vincent et al.

    Evaluation of hemagglutinin subtype 1 swine influenza viruses from the United States

    Vet. Microbiol.

    (2006)
  • A.L. Vincent et al.

    Efficacy of intranasal administration of a truncated NS1 modified live influenza virus vaccine in swine

    Vaccine

    (2007)
  • A.L. Vincent et al.

    Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

    Vet. Microbiol.

    (2008)
  • R.J. Webby et al.

    Multiple lineages of antigenically and genetically diverse influenza A virus co‐circulate in the United States swine population

    Virus Res.

    (2004)
  • R.G. Webster

    The importance of animal influenza for human disease

    Vaccine

    (2002)
  • D.J. Alexander et al.

    Recent zoonoses caused by influenza A viruses

    Rev. Sci. Tech.

    (2000)
  • M.E. Baca‐Estrada et al.

    Induction of mucosal immunity in cotton rats to haemagglutinin‐esterase glycoprotein of bovine coronavirus by recombinant adenovirus

    Immunology

    (1995)
  • M.H. Bikour et al.

    Evaluation of a protective immunity induced by an inactivated influenza H3N2 vaccine after an intratracheal challenge of pigs

    Can. J. Vet. Res.

    (1996)
  • D.A. Buonagurio et al.

    Evolution of human influenza A viruses over 50 years: Rapid, uniform rate of change in NS gene

    Science

    (1986)
  • D.R. Casimiro et al.

    Vaccine‐induced immunity in baboons by using DNA and replication‐incompetent adenovirus type 5 vectors expressing a human immunodeficiency virus type 1 gag gene

    J. Virol.

    (2003)
  • T.M. Chambers et al.

    Influenza viral infection of swine in the United States 1988–1989

    Arch. Virol.

    (1991)
  • R.W. Compans et al.

    Structure of the ribonucleoprotein of influenza virus

    J. Virol.

    (1972)
  • P.C. Crawford et al.

    Transmission of equine influenza virus to dogs

    Science

    (2005)
  • B.C. Easterday et al.

    Swine Influenza

  • M. Eloit et al.

    Construction of a defective adenovirus vector expressing the pseudorabies virus glycoprotein gp50 and its use as a live vaccine

    J. Gen. Virol.

    (1990)
  • E. Fodor et al.

    Rescue of influenza A virus from recombinant DNA

    J. Virol.

    (1999)
  • R.A. Fouchier et al.

    Characterization of a novel influenza A virus hemagglutinin subtype (H16) obtained from black‐headed gulls

    J. Virol.

    (2005)
  • A. Gamvrellis et al.

    Vaccines that facilitate antigen entry into dendritic cells

    Immunol. Cell. Biol.

    (2004)
  • A. Garcia‐Sastre

    Antiviral response in pandemic influenza viruses

    Emerg. Infect. Dis.

    (2006)
  • J.C. Gaydos et al.

    Swine influenza A at Fort Dix, New Jersey (January–February 1976). I. Case finding and clinical study of cases

    J. Infect. Dis.

    (1977)
  • M.R. Gramer
  • E. Hoffmann et al.

    A DNA transfection system for generation of influenza A virus from eight plasmids

    Proc. Natl. Acad. Sci. USA

    (2000)
  • T. Horimoto et al.

    Pandemic threat posed by avian influenza A viruses

    Clin. Microbiol. Rev.

    (2001)
  • T. Ito

    Interspecies transmission and receptor recognition of influenza A viruses

    Microbiol. Immunol.

    (2000)
  • T. Ito et al.

    Molecular basis for the generation in pigs of influenza A viruses with pandemic potential

    J. Virol.

    (1998)
  • A.I. Karasin et al.

    Isolation and characterization of H4N6 avian influenza viruses from pigs with pneumonia in Canada

    J. Virol.

    (2000)
  • A.I. Karasin et al.

    Genetic characterization of H1N2 influenza A viruses isolated from pigs throughout the United States

    J. Clin. Microbiol.

    (2002)
  • Cited by (316)

    • Avian and swine influenza viruses

      2023, Molecular Medical Microbiology, Third Edition
    View all citing articles on Scopus
    View full text