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Swine influenza A virus subtype H1N2 in Sweden

Metreveli, Giorgi (2014). Swine influenza A virus subtype H1N2 in Sweden. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2013:93
ISBN 978-91-576-7924-6
eISBN 978-91-576-7925-3
[Doctoral thesis]

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The influenza A virus subtypes H1N1, H1N2 and H3N2 are prevalent in pig populations worldwide. All scientific data point towards swine as the key host species for new human influenza pandemics, which have been suggested to evolve in pigs from viral genes of avian, human and porcine origin. Therefore, it is of major importance to record the evolution of swine influenza viruses in pigs, and in particular monitor hallmarks of adaptation to humans. The scope of this thesis was to increase the understanding of the genetics of swine influenza virus (SIV), and to investigate the importance of different viral gene markers in association with differences in pathogenicity of two viruses of H1N2 subtype in pigs. The results from this study
demonstrate, for the first time, natural reassortment in H1N2 viruses in the pig populations of Sweden. These H1N2 viruses have an avian-like SIV H1N1 haemagglutinin (HA) and a European H3N2 SIV-like neuraminidase (NA). Nucleotide
sequence comparison revealed significant differences between the two consecutive H1N2 isolates. To be able to understand the genotypic differences observed in the
genomes of these H1N2s, and to identify the genetic markers responsible for the differences, a reverse genetic system was developed. Four recombinant SIV H1N2
viruses were constructed that displayed differences in virulence in mice, r1021 (more virulent) and r9706 (less virulent), as well as the same viruses with swapped PB1
segments. Interestingly, the current findings showed that the replacement of the PB1 segment of r9706 by that of r1021 increases the virulence of the virus that replicate
with higher titer in mice lungs, while the opposite is true when PB1 r9706 is introduced into r1021. This study demonstrates that differences in virulence of swine influenza virus subtype H1N2 are attributed at least in part to the PB1 segment. The findings presented in this thesis support the observations concerning the continuous
reassortment processes of SIVs in pigs, resulting in repeated and independent emergence of certain HA/NA combinations. This may lead to emergence of new viral
variants of severe pathogenicity of pigs. Continuous and efficient surveillance and further detailed genetic and phenotypic analysis can help to identify such novel viral
variants, having more potential to cross species barriers and to pose health risks even to humans and to other host species.

Authors/Creators:Metreveli, Giorgi
Title:Swine influenza A virus subtype H1N2 in Sweden
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :10 January 2014
Number of Pages:60
I.Bálint A, Metreveli G, Widén F, Zohari S, Berg M, Isaksson M, Renström LH, Wallgren P, Belák S, Segall T, Kiss I. (2009) The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant. Virology Journal 6:180
II.Metreveli G, Emmoth E, Zohari S, Bálint Á, Widén F, Muradrasoli S, Wallgren P, Belák S, LeBlanc N, Berg M, Kiss I. (2011) Comparison of two H1N2 swine influenza A viruses from disease outbreaks in pigs in Sweden during 2009 and 2010. Virus Genes 42, 236-244.
III.Metreveli G. et al (2013) The origin of the PB1 segment of swine influenza A virus subtype H1N2 determines viral pathogenicity in mice (submitted).
Place of Publication:Uppsala
Publisher:Dept. of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7924-6
ISBN for electronic version:978-91-576-7925-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L10 Animal genetics and breeding
L Animal production > L73 Animal diseases
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Pathobiology
Agrovoc terms:swine influenzavirus, swine, animal diseases, zoonoses, pathogenicity, genetic markers, nucleotide sequence, disease transmission, epidemiology, sweden
Keywords:Influenza A, swine influenza virus SIV, PB1 segment, reverse genetics
Permanent URL:
ID Code:10972
Department:(VH) > Dept. of Biomedical Sciences and Veterinary Public Health
Deposited By: Giorgi Metreveli
Deposited On:13 Jan 2014 09:36
Metadata Last Modified:12 Dec 2014 08:19

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