Higher #virulence of #swine #H1N2 #influenza viruses containing #avian-origin #HA and 2009 #pandemic PA and NP in #pigs and mice (Arch Virol., abstract)

[Source: Archives of Virology, full page: (LINK). Abstract, edited.]

Higher virulence of swine H1N2 influenza viruses containing avian-origin HA and 2009 pandemic PA and NP in pigs and mice

Yunyueng Jang, Taehyun Seo & Sang Heui Seo

Archives of Virology (2020)



Pigs are capable of harbouring influenza A viruses of human and avian origin in their respiratory tracts and thus act as an important intermediary host to generate novel influenza viruses with pandemic potential by genetic reassortment between the two viruses. Here, we show that two distinct H1N2 swine influenza viruses contain avian-like or classical swine-like hemagglutinins with polymerase acidic (PA) and nucleoprotein (NP) genes from 2009 pandemic H1N1 influenza viruses that were found to be circulating in Korean pigs in 2018. Swine H1N2 influenza virus containing an avian-like hemagglutinin gene had enhanced pathogenicity, causing severe interstitial pneumonia in infected pigs and mice. The mortality rate of mice infected with swine H1N2 influenza virus containing an avian-like hemagglutinin gene was higher by 100% when compared to that of mice infected with swine H1N2 influenza virus harbouring classical swine-like hemagglutinin. Further, chemokines attracting inflammatory cells were strongly induced in lung tissues of pigs and mice infected by swine H1N2 influenza virus containing an avian-like hemagglutinin gene. In conclusion, it is necessary for the well-being of humans and pigs to closely monitor swine influenza viruses containing avian-like hemagglutinin with PA and NP genes from 2009 pandemic H1N1 influenza viruses.

Keywords: Influenza A; Avian Influenza; Swine Influenza; H1N1pdm09; H1N2; Reassortant strain; Pigs; Animal models.


#Human #infection with a novel #reassortant #Eurasian-avian lineage #swine #H1N1 virus in northern #China (Emerg Microbes Infect., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Emerg Microbes Infect. 2019;8(1):1535-1545. doi: 10.1080/22221751.2019.1679611.

Human infection with a novel reassortant Eurasian-avian lineage swine H1N1 virus in northern China.

Li X1, Guo L1, Liu C2, Cheng Y3, Kong M1, Yang L3, Zhuang Z1, Liu J3, Zou M1, Dong X1, Su X1, Gu Q1.

Author information: 1 Tianjin Centers for Disease Control and Prevention, Tianjin, People’s Republic of China. 2 Jizhou District Center for Disease Control and Prevention, Tianjin, People’s Republic of China. 3 Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China.



Influenza A virus infections occur in different species, causing mild to severe respiratory symptoms that lead to a heavy disease burden. Eurasian avian-like swine influenza A(H1N1) viruses (EAS-H1N1) are predominant in pigs and occasionally infect humans. An influenza A(H1N1) virus was isolated from a boy who was suffering from fever and headache and designated as A/Tianjin-baodi/1606/2018(H1N1). Full-genome sequencing and phylogenetic analysis revealed that A/Tianjin-baodi/1606/2018(H1N1) is a novel reassortant EAS-H1N1 containing gene segments from EAS-H1N1 (HA and NA), classical swine H1N1(NS) and A(H1N1)pdm09(PB2, PB2, PA, NP and M) viruses. The isolation and analysis of A/Tianjin-baodi/1606/2018(H1) provide further evidence that EAS-H1N1 poses a threat to human health and greater attention should be paid to surveillance of influenza virus infection in pigs and humans.

KEYWORDS: EAS-H1N1; Influenza A virus; Phylogenetic analysis; molecular characteristics; triple-reassortant

PMID: 31661383 PMCID: PMC6830285 DOI: 10.1080/22221751.2019.1679611 [Indexed for MEDLINE] Free PMC Article

Keywords: Influenza A; Swine Influenza; H1N1; H1N1pdm09; Reassortant strain; Human; China.


#Interspecies #Transmission of #Reassortant #Swine #Influenza A Virus Containing #Genes from Swine Influenza A #H1N1pdm09 and A(#H1N2) Viruses (Emerg Infect Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Volume 26, Number 2—February 2020 / Research

Interspecies Transmission of Reassortant Swine Influenza A Virus Containing Genes from Swine Influenza A(H1N1)pdm09 and A(H1N2) Viruses

Helen E. Everett  , Bethany Nash, Brandon Z. Londt1, Michael D. Kelly, Vivien Coward, Alejandro Nunez, Pauline M. van Diemen, Ian H. Brown, and Sharon M. Brookes

Author affiliations: Animal and Plant Health Agency, Weybridge, UK



Influenza A(H1N1)pdm09 (pH1N1) virus has become established in swine in the United Kingdom and currently co-circulates with previously enzootic swine influenza A virus (IAV) strains, including avian-like H1N1 and human-like H1N2 viruses. During 2010, a swine influenza A reassortant virus, H1N2r, which caused mild clinical disease in pigs in the United Kingdom, was isolated. This reassortant virus has a novel gene constellation, incorporating the internal gene cassette of pH1N1-origin viruses and hemagglutinin and neuraminidase genes of swine IAV H1N2 origin. We investigated the pathogenesis and infection dynamics of the H1N2r isolate in pigs (the natural host) and in ferrets, which represent a human model of infection. Clinical and virologic parameters were mild in both species and both intraspecies and interspecies transmission was observed when initiated from either infected pigs or infected ferrets. This novel reassortant virus has zoonotic and reverse zoonotic potential, but no apparent increased virulence or transmissibility, in comparison to pH1N1.

Keywords: Swine Influenza; Influenza A; Reassortant strain; H1N1pdm09; H1N2; Pigs; UK.


Emergence of an #Eurasian #avian-like #swine #influenza A (#H1N1) virus from #mink in #China (Vet Microbiol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Vet Microbiol. 2020 Jan;240:108509. doi: 10.1016/j.vetmic.2019.108509. Epub 2019 Nov 22.

Emergence of an Eurasian avian-like swine influenza A (H1N1) virus from mink in China.

Liu J1, Li Z1, Cui Y1, Yang H1, Shan H1, Zhang C2.

Author information: 1 College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China. 2 College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China. Electronic address: zhangchuanmei100@163.com.



We evaluated the phenotype and genotype of a fatal influenza/canine distemper virus coinfection found in farmed mink in China. We identified a novel subtype H1N1 influenza virus strain from the lungs of infected mink designated A/Mink/Shandong/1121/2017 (H1N1). The results of phylogenetic analysis of 8 gene fragments of the H1N1 strain showed the virus was a swine origin triple-reassortant H1N1 influenza virus: with the 2009 pandemic H1N1 segments (PB2, PB1, PA, NP and M), Eurasian avian-like H1N1 swine segments (HA and NA) and classical swine (NS) lineages. The EID50/0.2 mL of this strain was 10-6.2 and pathogenicity tests were 100 % lethal in a mouse model of infection. We found that while not lethal and lacking any overt signs of infection in mink, the virus could proliferate in the upper respiratory tracts and the animals were converted to seropositive for the HA protein.

Copyright © 2019 Elsevier B.V. All rights reserved.

KEYWORDS: Eurasian avian-like swine influenza virus; H1N1; Mink influenza virus; Phylogenetic analysis; Reassortment

PMID: 31902506 DOI: 10.1016/j.vetmic.2019.108509

Keywords: Avian Influenza; Swine Influenza; H1N1pdm09; H1N1; Reassortant strain; Wildlife; China.


Heterologous #Antibody Responses Conferred by A #H3N2v and Seasonal #Influenza #Vaccination against Newly Emerged 2016-2018 A H3N2v Viruses in Healthy Persons (Clin Infect Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Clin Infect Dis. 2019 Dec 20. pii: ciz1203. doi: 10.1093/cid/ciz1203. [Epub ahead of print]

Heterologous Antibody Responses Conferred by A(H3N2) Variant and Seasonal Influenza Vaccination against Newly Emerged 2016-2018 A(H3N2) Variant Viruses in Healthy Persons.

Liu F1, Levine MZ1.

Author information: 1 Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.




Swine origin A(H3N2) variant (A(H3N2)v) viruses continue to evolve and remain a public health threat. Recent outbreaks in humans in 2016-2018 were caused by a newly emerged A(H3N2)v cluster 2010.1 which are genetically and antigenically distinct from the previously predominant cluster IV. To address the public health risk, we evaluated the levels of heterologous cross-reactive antibodies to A(H3N2)v cluster 2010.1 viruses induced from an existing cluster IV A(H3N2)v vaccine and several seasonal inactivated influenza vaccines (IIVs) in adults, elderly and children.


Human vaccine sera and ferret antisera were analyzed by hemagglutination inhibition (HI) and neutralization assays against representative A(H3N2)v viruses from clusters IV and 2010.1, and seasonal A(H3N2) viruses.


Ferret antisera detected no or little cross-reactivity between the two A(H3N2)v clusters, or between A(H3N2)v and seasonal A(H3N2) viruses. In humans, cluster IV A(H3N2)v vaccine induced antibodies cross-reactive to cluster 2010.1 viruses in about 1/3 of the 89 adult and elderly vaccinees. Seasonal IIVs did not induce seroprotective antibodies (≥ 40) to A(H3N2)v viruses in young children, but induced higher antibodies to A(H3N2)v viruses in cluster 2010.1 than those in cluster IV in adults.


Cluster IV A(H3N2)v vaccine did not provide sufficient heterologous antibody responses against the new 2010.1 cluster A(H3N2)v viruses. Seasonal IIV could not induce seroprotective antibodies to 2010.1 cluster A(H3N2)v viruses in young children, suggesting that young children are still at high risk to the newly emerged A(H3N2)v viruses. Continued surveillance on A(H3N2)v viruses is critical for risk assessment and pandemic preparedness.

Published by Oxford University Press for the Infectious Diseases Society of America 2019. This work is written by (a) US Government employee(s) and is in the public domain in the US.

KEYWORDS: A(H3N2) variant viruses (A(H3N2)v); HI and MN antibody responses; antigenic analysis; heterologous responses; influenza vaccine; seasonal Influenza A(H3N2) viruses

PMID: 31858129 DOI: 10.1093/cid/ciz1203

Keywords: Seasonal Influenza; Swine Influenza; H3N2v; Human; Vaccines.


#Surveillance of #swine #influenza viruses in sentinel #familial #farms in Hung Yen province in Northern #Vietnam in 2013-2014 (Zoonoses Public Health, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Zoonoses Public Health. 2019 Dec 19. doi: 10.1111/zph.12671. [Epub ahead of print]

Surveillance of swine influenza viruses in sentinel familial farms in Hung Yen province in Northern Vietnam in 2013-2014.

Baudon E1,2, Peyre M2, Tung DD3, Thi Nga P3, Khong NV3, Cowling BJ1, Peiris M1.

Author information: 1 The University of Hong Kong, Hong Kong, China. 2 French Agricultural Research Center for International Development (CIRAD), Montpellier, France. 3 National Institute of Veterinary Research, Hanoi, Vietnam.



From May 2013 to April 2014, 15 swine family-run farms (17 pig litters) in two districts in Hung Yen province, near Hanoi, were virologically and epizootiologically monitored for swine influenza viruses (SIV) monthly. No SIV was isolated from nasal swabs. Maternal antibodies were detected in 10 litters, and seroconversion against SIV was detected in six litters. There was a marked difference in patterns of SIV transmission in the two districts. Van Lam district which has low density of swine with mainly smallholder farms had low intensity of SIV, with much of the infection caused by H1N1 2009 pandemic-like viruses A(H1N1)pdm09, likely originated from humans. In contrast, Van Giang district, which has high swine density and larger farms, had high levels of typical SIV (triple reassortants H3N2 and H3N2 Binh Duong lineage viruses) circulating within swine. With one exception, the SIV lineages detected were those we concurrently isolated from studies in a large central abattoir in Hanoi. Influenza-like illness symptoms reported by farmers were poorly correlated with serological evidence of SIV infection.

© 2019 Blackwell Verlag GmbH.

KEYWORDS: Vietnam; familial farm; maternal antibody; surveillance; swine influenza; value chain

PMID: 31855326 DOI: 10.1111/zph.12671

Keyword: Swine Influenza; Influenza A; H1N1pdm09; H3N2; Serology; Pigs; Vietnam.


Re-evaluation of the #evolution of #influenza #H1 viruses using direct PCA (Sci Rep., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Sci Rep. 2019 Dec 17;9(1):19287. doi: 10.1038/s41598-019-55254-z.

Re-evaluation of the evolution of influenza H1 viruses using direct PCA.

Konishi T1.

Author information: 1 Graduate School of Bioresource Sciences, Akita Prefectural University, Akita, Japan. konishi@akita-pu.ac.jp.



The history of influenza H1 virus was re-evaluated by applying a new methodology to sequencing data; this objective method enables comparisons among viral types. The approach led to the segregation of all segments of swine and human viruses into three distinct groups: two of them included the pandemic 1977 and 2009 human viruses, and the remaining group may be new in humans. These three groups might have originated from avian viruses and drifted out independently. Genome shifts occurred occasionally among swine viruses; however, distances between avian and swine/human viruses negated the existence of direct shifts from avian viruses. In humans, only one or two viruses appeared each year, which suggests the presence of competition among viruses that migrated freely. All segments drifted continuously under certain rules and constant velocity. Viruses that had caused an outbreak did not appear again over subsequent decades, which may mean populations had become immune to such viruses. In contrast, the viruses in livestock were rather conserved and maintained unique strains in small, separate areas. Such collections of swine strains included human segments, which could become an epidemic in the future.

PMID: 31848356 DOI: 10.1038/s41598-019-55254-z

Keywords: Influenza; H1N1; Seasonal Influenza; Swine Influenza; Pigs.