scholarly journals Evolution of Novel Reassortant A/H3N2 Influenza Viruses in North American Swine and Humans, 2009–2011

2012 ◽  
Vol 86 (16) ◽  
pp. 8872-8878 ◽  
Author(s):  
Martha I. Nelson ◽  
Amy L. Vincent ◽  
Pravina Kitikoon ◽  
Edward C. Holmes ◽  
Marie R. Gramer
Keyword(s):  
North American ◽  
Matrix Protein ◽  
Age Groups ◽  
Swine Influenza ◽  
The United States ◽  
Influenza Viruses ◽  
Pandemic Threat ◽  
H3n2 Influenza ◽  
Na Sequences ◽  
M Sequences

Novel H3N2 influenza viruses (H3N2v) containing seven genome segments from swine lineage triple-reassortant H3N2 viruses and a 2009 pandemic H1N1 (H1N1pdm09) matrix protein segment (pM) were isolated from 12 humans in the United States between August and December 2011. To understand the evolution of these novel H3N2 viruses in swine and humans, we undertook a phylogenetic analysis of 674 M sequences and 388 HA and NA sequences from influenza viruses isolated from North American swine during 2009–2011, as well as HA, NA, and M sequences from eight H3N2v viruses isolated from humans. We identified 34 swine influenza viruses (termed rH3N2p) with the same combination of H3, N2, and pM segments as the H3N2v viruses isolated from humans. Notably, these rH3N2p viruses were generated in swine via reassortment events between H3N2 viruses and the pM segment approximately 4 to 10 times since 2009. The pM segment has also reassorted with multiple distinct lineages of H1 virus, especially H1δ viruses. Importantly, the N2 segment of all H3N2v viruses isolated from humans is derived from a genetically distinct N2 lineage that has circulated in swine since being acquired by reassortment with seasonal human H3N2 viruses in 2001–2002, rather than from the N2 that is associated with the 1998 H3N2 swine lineage. The identification of this N2 variant may have implications for influenza vaccine design and the potential pandemic threat of H3N2v to human age groups with differing levels of prior exposure and immunity.

scholarly journals Cluster analysis of the origins of the new influenza A(H1N1) virus

2009 ◽  
Vol 14 (21) ◽  
Author(s):  
A Solovyov ◽  
G Palacios ◽  
T Briese ◽  
W I Lipkin ◽  
R Rabadan
Keyword(s):  
Cluster Analysis ◽  
Influenza A ◽  
H1n1 Virus ◽  
Swine Influenza ◽  
The United States ◽  
Influenza Viruses ◽  
World Health ◽  
Influenza A H1n1 ◽  
The World ◽  
Health Organization

In March and April 2009, a new strain of influenza A(H1N1) virus has been isolated in Mexico and the United States. Since the initial reports more than 10,000 cases have been reported to the World Health Organization, all around the world. Several hundred isolates have already been sequenced and deposited in public databases. We have studied the genetics of the new strain and identified its closest relatives through a cluster analysis approach. We show that the new virus combines genetic information related to different swine influenza viruses. Segments PB2, PB1, PA, HA, NP and NS are related to swine H1N2 and H3N2 influenza viruses isolated in North America. Segments NA and M are related to swine influenza viruses isolated in Eurasia.

scholarly journals Genotype patterns of contemporary reassorted H3N2 virus in US swine

2013 ◽  
Vol 94 (6) ◽  
pp. 1236-1241 ◽  
Author(s):  
Pravina Kitikoon ◽  
Martha I. Nelson ◽  
Mary Lea Killian ◽  
Tavis K. Anderson ◽  
Leo Koster ◽  
...  
Keyword(s):  
North American ◽  
Swine Influenza ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
Antigenic Drift ◽  
H3n2 Virus ◽  
Specific Subset ◽  
The Usa ◽  
Genome Scale ◽  
Viral Isolates

To understand the evolution of swine-origin H3N2v influenza viruses that have infected 320 humans in the USA since August 2011, we performed a phylogenetic analysis at a whole genome scale of North American swine influenza viruses (n  =  200). All viral isolates evolved from the prototypical North American H3 cluster 4 (c4), with evidence for further diversification into subclusters. At least ten distinct reassorted H3N2/pandemic H1N1 (rH3N2p) genotypes were identified in swine. Genotype 1 (G1) was most frequently detected in swine and all human H3N2v viruses clustered within a single G1 clade. These data suggest that the genetic requirements for transmission to humans may be restricted to a specific subset of swine viruses. Mutations at putative antigenic sites as well as reduced serological cross-reactivity among the H3 subclusters suggest antigenic drift of these contemporary viruses.

scholarly journals Unseasonal Transmission of H3N2 Influenza A Virus During the Swine-Origin H1N1 Pandemic

2010 ◽  
Vol 84 (11) ◽  
pp. 5715-5718 ◽  
Author(s):  
Elodie Ghedin ◽  
David E. Wentworth ◽  
Rebecca A. Halpin ◽  
Xudong Lin ◽  
Jayati Bera ◽  
...  
Keyword(s):  
New York ◽  
Influenza A Virus ◽  
Influenza A ◽  
New York State ◽  
The United States ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
York State ◽  
Low Incidence ◽  
H3n2 Influenza

ABSTRACT The initial wave of swine-origin influenza A virus (pandemic H1N1/09) in the United States during the spring and summer of 2009 also resulted in an increased vigilance and sampling of seasonal influenza viruses (H1N1 and H3N2), even though they are normally characterized by very low incidence outside of the winter months. To explore the nature of virus evolution during this influenza “off-season,” we conducted a phylogenetic analysis of H1N1 and H3N2 sequences sampled during April to June 2009 in New York State. Our analysis revealed that multiple lineages of both viruses were introduced and cocirculated during this time, as is typical of influenza virus during the winter. Strikingly, however, we also found strong evidence for the presence of a large transmission chain of H3N2 viruses centered on the south-east of New York State and which continued until at least 1 June 2009. These results suggest that the unseasonal transmission of influenza A viruses may be more widespread than is usually supposed.

scholarly journals The enigma of the apparent disappearance of Eurasian highly pathogenic H5 clade 2.3.4.4 influenza A viruses in North American waterfowl

2016 ◽  
Vol 113 (32) ◽  
pp. 9033-9038 ◽  
Author(s):  
Scott Krauss ◽  
David E. Stallknecht ◽  
Richard D. Slemons ◽  
Andrew S. Bowman ◽  
Rebecca L. Poulson ◽  
...  
Keyword(s):  
United States ◽  
North America ◽  
North American ◽  
Influenza A ◽  
Wild Bird ◽  
Animal Health ◽  
The United States ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Highly Pathogenic

One of the major unresolved questions in influenza A virus (IAV) ecology is exemplified by the apparent disappearance of highly pathogenic (HP) H5N1, H5N2, and H5N8 (H5Nx) viruses containing the Eurasian hemagglutinin 2.3.4.4 clade from wild bird populations in North America. The introduction of Eurasian lineage HP H5 clade 2.3.4.4 H5N8 IAV and subsequent reassortment with low-pathogenic H?N2 and H?N1 North American wild bird-origin IAVs in late 2014 resulted in widespread HP H5Nx IAV infections and outbreaks in poultry and wild birds across two-thirds of North America starting in November 2014 and continuing through June 2015. Although the stamping out strategies adopted by the poultry industry and animal health authorities in Canada and the United States—which included culling, quarantining, increased biosecurity, and abstention from vaccine use—were successful in eradicating the HP H5Nx viruses from poultry, these activities do not explain the apparent disappearance of these viruses from migratory waterfowl. Here we examine current and historical aquatic bird IAV surveillance and outbreaks of HP H5Nx in poultry in the United States and Canada, providing additional evidence of unresolved mechanisms that restrict the emergence and perpetuation of HP avian influenza viruses in these natural reservoirs.

scholarly journals North American Triple Reassortant and Eurasian H1N1 Swine Influenza Viruses Do Not Readily Reassort to Generate a 2009 Pandemic H1N1-Like Virus

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Wenjun Ma ◽  
Qinfang Liu ◽  
Chuanling Qiao ◽  
Gustavo del Real ◽  
Adolfo García-Sastre ◽  
...  
Keyword(s):  
Cell Cultures ◽  
North American ◽  
Influenza A ◽  
H1n1 Virus ◽  
Rare Event ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Pandemic H1n1 ◽  
Continuous Cell Lines ◽  
Reassortant Viruses

ABSTRACTThe 2009 pandemic H1N1 virus (pH1N1) was derived through reassortment of North American triple reassortant and Eurasian avian-like swine influenza viruses (SIVs). To date, when, how and where the pH1N1 arose is not understood. To investigate viral reassortment, we coinfected cell cultures and a group of pigs with or without preexisting immunity with a Eurasian H1N1 virus, A/Swine/Spain/53207/2004 (SP04), and a North American triple reassortant H1N1 virus, A/Swine/Kansas/77778/2007 (KS07). The infected pigs were cohoused with one or two groups of contact animals to investigate viral transmission. In coinfected MDCK or PK15 continuous cell lines with KS07 and SP04 viruses, more than 20 different reassortant viruses were found. In pigs without or with preexisting immunity (immunized with commercial inactivated swine influenza vaccines) and coinfected with both viruses, six or seven reassortant viruses, as well as the parental viruses, were identified in bronchoalveolar lavage fluid samples from the lungs. Interestingly, only one or two viruses transmitted to and were detected in contact animals. No reassortant containing a gene constellation similar to that of pH1N1 virus was found in either coinfected cells or pigs, indicating that the reassortment event that resulted in the generation of this virus is a rare event that likely involved specific viral strains and/or a favorable, not-yet-understood environment.IMPORTANCEThe 2009 pandemic-like H1N1 virus could not be reproduced either in cell cultures or in pigs coinfected with North American triple reassortant H1N1 and Eurasian H1N1 swine influenza viruses. This finding suggests that the generation of the 2009 pandemic H1N1 virus by reassortment was a rare event that likely involved specific viral strains and unknown factors. Different reassortant viruses were detected in coinfected pigs with and without preexisting immunity, indicating that host immunity plays a relevant role in driving viral reassortment of influenza A virus.

scholarly journals Efficacy of Heterologous Prime-Boost Vaccination with H3N2 Influenza Viruses in Pre-Immune Individuals: Studies in the Pig Model

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 968
Author(s):  
Sharon Chepkwony ◽  
Anna Parys ◽  
Elien Vandoorn ◽  
Koen Chiers ◽  
Kristien Van Reeth
Keyword(s):  
Lymph Nodes ◽  
Influenza A ◽  
Serum Antibody ◽  
Swine Influenza ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
Antibody Responses ◽  
Pig Model ◽  
Boost Vaccination ◽  
H3n2 Influenza

In a previous study in influenza-naïve pigs, heterologous prime-boost vaccination with monovalent, adjuvanted whole inactivated vaccines (WIV) based on the European swine influenza A virus (SwIAV) strain, A/swine/Gent/172/2008 (G08), followed by the US SwIAV strain, A/swine/Pennsylvania/A01076777/2010 (PA10), was shown to induce broadly cross-reactive hemagglutination inhibition (HI) antibodies against 12 out of 15 antigenically distinct H3N2 influenza strains. Here, we used the pig model to examine the efficacy of that particular heterologous prime-boost vaccination regimen, in individuals with pre-existing infection-immunity. Pigs were first inoculated intranasally with the human H3N2 strain, A/Nanchang/933/1995. Seven weeks later, they were vaccinated intramuscularly with G08 followed by PA10 or vice versa. We examined serum antibody responses against the hemagglutinin and neuraminidase, and antibody-secreting cell (ASC) responses in peripheral blood, draining lymph nodes, and nasal mucosa (NMC), in ELISPOT assays. Vaccination induced up to 10-fold higher HI antibody titers than in naïve pigs, with broader cross-reactivity, and protection against challenge with an antigenically distant H3N2 strain. It also boosted ASC responses in lymph nodes and NMC. Our results show that intramuscular administration of WIV can lead to enhanced antibody responses and cross-reactivity in pre-immune subjects, and recall of ASC responses in lymph nodes and NMC.

scholarly journals The global antigenic diversity of swine influenza A viruses

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Nicola S Lewis ◽  
Colin A Russell ◽  
Pinky Langat ◽  
Tavis K Anderson ◽  
Kathryn Berger ◽  
...  
Keyword(s):  
Influenza A ◽  
Disease Burden ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Antigenic Diversity ◽  
Continental Scale ◽  
Pandemic Threat ◽  
Different Parts

Swine influenza presents a substantial disease burden for pig populations worldwide and poses a potential pandemic threat to humans. There is considerable diversity in both H1 and H3 influenza viruses circulating in swine due to the frequent introductions of viruses from humans and birds coupled with geographic segregation of global swine populations. Much of this diversity is characterized genetically but the antigenic diversity of these viruses is poorly understood. Critically, the antigenic diversity shapes the risk profile of swine influenza viruses in terms of their epizootic and pandemic potential. Here, using the most comprehensive set of swine influenza virus antigenic data compiled to date, we quantify the antigenic diversity of swine influenza viruses on a multi-continental scale. The substantial antigenic diversity of recently circulating viruses in different parts of the world adds complexity to the risk profiles for the movement of swine and the potential for swine-derived infections in humans.

scholarly journals Genetic composition of contemporary swine influenza viruses in the West Central region of the United States of America

2011 ◽  
Vol 5 (3) ◽  
pp. 188-197 ◽  
Author(s):  
Vasiliy A. Evseenko ◽  
Adrianus C. M. Boon ◽  
Christy Brockwell-Staats ◽  
John Franks ◽  
Adam Rubrum ◽  
...  
Keyword(s):  
United States ◽  
Central Region ◽  
United States Of America ◽  
Swine Influenza ◽  
The United States ◽  
Influenza Viruses ◽  
Genetic Composition ◽  
The West ◽  
West Central

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

2006 ◽  
Vol 118 (3-4) ◽  
pp. 212-222 ◽  
Author(s):  
Amy L. Vincent ◽  
Kelly M. Lager ◽  
Wenjun Ma ◽  
Porntippa Lekcharoensuk ◽  
Marie R. Gramer ◽  
...  
Keyword(s):  
United States ◽  
Swine Influenza ◽  
The United States ◽  
Influenza Viruses

scholarly journals Pathogenicity and Transmissibility of Novel Reassortant H3N2 Influenza Viruses with 2009 Pandemic H1N1 Genes in Pigs

2014 ◽  
Vol 89 (5) ◽  
pp. 2831-2841 ◽  
Author(s):  
Jingjiao Ma ◽  
Huigang Shen ◽  
Qinfang Liu ◽  
Bhupinder Bawa ◽  
Wenbao Qi ◽  
...  
Keyword(s):  
Binding Site ◽  
Receptor Binding ◽  
The United States ◽  
Influenza Viruses ◽  
H3n2 Virus ◽  
Pandemic H1n1 ◽  
M Gene ◽  
Receptor Binding Site ◽  
H3n2 Influenza ◽  
Swine Herds

ABSTRACTAt least 10 different genotypes of novel reassortant H3N2 influenza viruses with 2009 pandemic H1N1 [A(H1N1)pdm09] gene(s) have been identified in U.S. pigs, including the H3N2 variant with a single A(H1N1)pdm09 M gene, which has infected more than 300 people. To date, only three genotypes of these viruses have been evaluated in animal models, and the pathogenicity and transmissibility of the other seven genotype viruses remain unknown. Here, we show that three H3N2 reassortant viruses that contain 3 (NP, M, and NS) or 5 (PA, PB2, NP, M, and NS) genes from A(H1N1)pdm09 were pathogenic in pigs, similar to the endemic H3N2 swine virus. However, the reassortant H3N2 virus with 3 A(H1N1)pdm09 genes and a recent human influenza virus N2 gene was transmitted most efficiently among pigs, whereas the reassortant H3N2 virus with 5 A(H1N1)pdm09 genes was transmitted less efficiently than the endemic H3N2 virus. Interestingly, the polymerase complex of reassortant H3N2 virus with 5 A(H1N1)pdm09 genes showed significantly higher polymerase activity than those of endemic and reassortant H3N2 viruses with 3 A(H1N1)pdm09 genes. Further studies showed that an avian-like glycine at position 228 at the hemagglutinin (HA) receptor binding site is responsible for inefficient transmission of the reassortant H3N2 virus with 5 A(H1N1)pdm09 genes. Taken together, our results provide insights into the pathogenicity and transmissibility of novel reassortant H3N2 viruses in pigs and suggest that a mammalian-like serine at position 228 in the HA is critical for the transmissibility of these reassortant H3N2 viruses.IMPORTANCESwine influenza is a highly contagious zoonotic disease that threatens animal and public health. Introduction of 2009 pandemic H1N1 virus [A(H1N1)pdm09] into swine herds has resulted in novel reassortant influenza viruses in swine, including H3N2 and H1N2 variants that have caused human infections in the United States. We showed that reassortant H3N2 influenza viruses with 3 or 5 genes from A(H1N1)pdm09 isolated from diseased pigs are pathogenic and transmissible in pigs, but the reassortant H3N2 virus with 5 A(H1N1)pdm09 genes displayed less efficient transmissibility than the endemic and reassortant H3N2 viruses with 3 A(H1N1)pdm09 genes. Further studies revealed that an avian-like glycine at the HA 228 receptor binding site of the reassortant H3N2 virus with 5 A(H1N1)pdm09 genes is responsible for less efficient transmissibility in pigs. Our results provide insights into viral pathogenesis and the transmission of novel reassortant H3N2 viruses that are circulating in U.S. swine herds and warrant future surveillance.

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