Occurrence and spread of influenza A(H1N1)pdm09 virus infection in Norwegian pig herds based on active serosurveillance from 2010 to 2014

Er, Chiek; Skjerve, Eystein; Brun, Edgar; Framstad, Tore; Lium, Bjørn

doi:10.1017/s0950268816001424

Cited by 14 publications

(19 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results suggested that gene segments from the A(H1N1)pdm09 lineage are widely distributed among SIVs circulating in Japan. Our results are consistent with previous studies demonstrating that the internal genes of the viruses belonging to the A(H1N1)pdm09 lineage have been replacing the classical enzootic SIV genes in pig populations globally (Er, Skjerve, Brun, Framstad, & Lium, ; Howden et al., ). These reports, as well as our results, suggest that the internal gene segments of the A(H1N1)pdm09 lineage may confer more efficient replication and/or transmission in pig populations than classical enzootic SIV internal genes.…”

Section: Discussionsupporting

confidence: 93%

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Okuya

Matsuu

Kawabata

et al. 2018

Transbound Emerg Dis

View full text Add to dashboard Cite

Swine influenza viruses (SIVs) are important not only for pig farming, but also for public health. In fact, pandemic A(H1N1) 2009 viruses [A(H1N1)pdm09] were derived from SIVs. Therefore, timely characterization of locally circulating SIVs is necessary for understanding the global status of SIVs. To genetically characterize SIVs circulating in Japanese pig populations, we isolated 24 SIVs of three subtypes (17 H1N1, four H1N2 and three H3N2 strains) from 14 pig farms in Japan from 2013 to 2016. Genetic analyses revealed that the haemagglutinin (HA) and neuraminidase (NA) genes of the 17 H1N1 and the HA gene of one H1N2, A/swine/Aichi/02/2016 (H1N2), SIVs belonged to the A(H1N1)pdm09 lineage. More importantly, all of the remaining six gene segments (i.e., PB1, PB1, PA, NP, M and NS) of the 24 SIVs, regardless of the HA and NA subtype, were also classified as belonging to the A(H1N1)pdm09 lineage. These results indicate that gene segments of A(H1N1)pdm09 lineage are widely distributed in SIVs circulating in Japanese pig populations In addition, the NA gene of A/swine/Aichi/02/2016 (H1N2) shared less than 88.5% nucleotide identity with that of the closest relative A/swine/Miyagi/5/2003 (H1N2), which was isolated in Japan in 2003. These results indicate the sustained circulation of classical H1N2-derived SIVs with remarkable diversity in the NA genes in Japanese pig populations. These findings highlight the necessity of both intensive biosecurity systems and active SIV surveillance in pig populations worldwide for both animal and public health.

show abstract

Section: Discussionsupporting

confidence: 93%

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Okuya

Matsuu

Kawabata

et al. 2018

Transbound Emerg Dis

View full text Add to dashboard Cite

show abstract

“…However, a seroprevalence of 9.6% was the lowest, compared to other subtypes. A comparable seroprevalence rate of 13.9% was observed in Greek pigs ( 8 ) whereas in Norway, approximately 25% of sampled pigs had antibodies against H1N1pdm09 ( 5 ). One reason for the observed differences between H1N1pdm09 seroprevalence rates might be associated with a lack of cross-protection against viruses of the same HA and/or NA subtypes, since the Norwegian pig population was free from all SIV subtypes, prior to the emergence of H1N1pdm09 in October 2009 ( 5 ).…”

Section: Discussionmentioning

confidence: 73%

“…A comparable seroprevalence rate of 13.9% was observed in Greek pigs ( 8 ) whereas in Norway, approximately 25% of sampled pigs had antibodies against H1N1pdm09 ( 5 ). One reason for the observed differences between H1N1pdm09 seroprevalence rates might be associated with a lack of cross-protection against viruses of the same HA and/or NA subtypes, since the Norwegian pig population was free from all SIV subtypes, prior to the emergence of H1N1pdm09 in October 2009 ( 5 ). According to previous studies, immunity promoted by the avian-like swine H1N1 infection could protect pigs against the H1N1pdm09 infection ( 1 , 4 , 19 ).…”

Section: Discussionmentioning

confidence: 73%

Serological survey of the influenza A virus in Polish farrow-to-finish pig herds in 2011–2015

Czyżewska‐Dors

Dors

Kwit

et al. 2017

Journal of Veterinary Research

View full text Add to dashboard Cite

IntroductionThe aim of this study was to assess the seroprevalence of swine influenza A virus (SIV) in Polish farrow-to-finish pig herds.Material and MethodsSerum samples collected from 5,952 pigs, from 145 farrow-to-finish herds were tested for the presence of antibodies against H1N1, H1N1pdm09, H1N2, and H3N2 SIV subtypes using haemagglutination inhibition (HI) test. Samples with HI titres equal or higher than 20 were considered positive.ResultsHI antibodies to at least one of the analysed SIV subtypes were detected in 129 (89%) herds and in 2,263 (38%) serum samples. Antibodies to multiple SIV subtypes were detected in 104 (71.7%) herds and in 996 (16.7%) serum samples. Concerning the seroprevalence rate, according to age category, the highest prevalence of the antibodies was detected in weaners, with regard to the H1N1, H1N2, and H3N2, and in sows, with regard to the H1N1pdm09. The lowest seroprevalence for all evaluated SIV subtypes was detected in finishers.ConclusionThe study indicates that antibodies against single and multiple SIV subtypes are circulating in Polish farrow-to-finish herds and highlights the importance of conducting a molecular surveillance programme in future studies.

show abstract

“…The absence of statistically significant fluctuations in the HAIT titre level or GMT longitudinally from 2009 to 2017 reflected that the Norwegian pig herds have been endemic with the sole IAVs, H1N1pdm09, since 2009 [28]. Furthermore there has been no variation in the sampling strategy (composition of pig production type in the sampling frame) from year to year (90% sow herds and 10% fattening herds) or selection pressure from intervention measures or incursion of new IAVs that could cause fluctuations to the HAIT titre longitudinally [29]. Sows had higher HAIT titre than fattening pigs because of the age effect.…”

Section: Regression Models With Only Data On Immunogen H1n1pdm09mentioning

confidence: 99%

Antibodies of influenza A(H1N1)pdm09 virus in pigs’ sera cross-react with other influenza A virus subtypes. A retrospective epidemiological interpretation of Norway's serosurveillance data from 2009–2017

Lium

Framstad

2020

Epidemiol. Infect.

View full text Add to dashboard Cite

Since the incursion of influenza A(H1N1)pdm09 virus in 2009, serosurveillance every year of the Norwegian pig population revealed the herd prevalence for influenza A(H1N1)pdm09 (HIN1pdm09) has stabilised between 40% and 50%. Between 30 September 2009 and 14 September 2017, the Norwegian Veterinary Institute and Norwegian Food Safety Authority screened 35,551 pigs for antibodies to influenza A viruses (IAVs) from 8,636 herds and found 26% or 8,819 pigs' sera ELISA positive (titre ≥40). Subtyping these IAV antibodies from 8,214 pigs in 3,629 herds, by a routine haemagglutination inhibition test (HAIT) against four standard antigens produced 13,771 positive results (HAIT titre ≥40) of binding antibodies. The four antigen subtypes eliciting positive HAIT titre in descending frequencies were immunogen H1N1pdm09 (n = 8,200 or 99.8%), swine influenza A virus (SIVs) subtypes swH1N1 (n = 5,164 or 62%), swH1N2 (n = 395 or 5%) and swH3N2 (n = 12 or 0.1%). Of these 8,214 pig pigs sera, 3,039 produced homologous HAIT subtyping, almost exclusively immunogen H1N1pdm09 (n = 3,026 or 99.6%). Using HAIT titre of pig and herd geometric mean titre (GMT) as two continuous outcome variables, and with the data already structured hierarchically, we used mixed effects linear regression analysis to investigate the impact of predictors of interests had on the outcomes. For the full data, the predictors in the regression model include categorical predictors antigen subtype (H1N1pdm09, swH1N1, swH1N2 & swH3N2), and production type (sow herd or fattening herd), ordinal predictors year (longitudinally from 2009 to 2017) and number of antigens in heterologous reactions (1, 2, 3, 4) in the same pig serum. The last predictor, the proportion of HAIT positive (antigen specific) in tested pigs within the herd, was a continuous predictor, which served as a proxy for days post-infection (dpi) or humoral response time in the pig or herd. Regression analysis on individual pig HAIT titres showed that antigen as a predictor, the coefficient for immunogen H1N1pdm09 was at least fourfold higher (P < 0.001) than the three SIVs antigen subtypes, whose much lower coefficients were statistically no different between the three SIVs antigen subtypes. Correspondingly, for herd GMT, immunogen H1N1pdm09 was 28–40-fold higher than the three SIVs antigen subtypes. Excluding the HAIT data of the three SIVs antigen subtypes, regression analysis focusing only on immunogen H1N1pdm09 increased greatly the coefficients of the predictors in the models. Homologous reactions (99.6% H1N1pdm09) have lower HAIT titres while the likelihood of the number of antigens involved in HAIT heterologous reactions in a single pig serum increased with higher HAIT titres of immunogen H1N1pdm09. For predictor ‘production’, sows and sow herds had higher HAIT titres and GMT compared to fattening pigs and fattening herds respectively. Herds with ‘higher proportion of pigs tested positive’ also had higher HAIT titre in the pig and herd GMT.

show abstract

Occurrence and spread of influenza A(H1N1)pdm09 virus infection in Norwegian pig herds based on active serosurveillance from 2010 to 2014

Cited by 14 publications

References 37 publications

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Serological survey of the influenza A virus in Polish farrow-to-finish pig herds in 2011–2015

Antibodies of influenza A(H1N1)pdm09 virus in pigs’ sera cross-react with other influenza A virus subtypes. A retrospective epidemiological interpretation of Norway's serosurveillance data from 2009–2017

Contact Info

Product

Resources

About