Positive Selection Drives Preferred Segment Combinations during Influenza Virus Reassortment
Influenza A virus (IAV) has a segmented genome that allows for the exchange of genome segments between different strains. This reassortment accelerates evolution by breaking linkage, helping IAV cross species barriers to potentially create highly virulent strains. Challenges associated with monitoring the process of reassortment in molecular detail have limited our understanding of its evolutionary implications. We applied a novel deep sequencing approach with quantitative analysis to assess the in vitro temporal evolution of genomic reassortment in IAV. The combination of H1N1 and H3N2 strains reproducibly generated a new...
Source: Molecular Biology and Evolution - May 28, 2015 Category: Molecular Biology Authors: Zeldovich, K. B., Liu, P., Renzette, N., Foll, M., Pham, S. T., Venev, S. V., Gallagher, G. R., Bolon, D. N., Kurt-Jones, E. A., Jensen, J. D., Caffrey, D. R., Schiffer, C. A., Kowalik, T. F., Wang, J. P., Finberg, R. W. Tags: Discoveries Source Type: research
Magnitude and kinetics of multifunctional CD4 + and CD8β + T cells in pigs infected with swine influenza A virus
Abstract
Although swine are natural hosts for influenza A viruses, the porcine T-cell response to swine influenza A virus (FLUAVsw) infection has been poorly characterized so far. We have studied Ki-67 expression and FLUAVsw-specific production of IFN-γ, TNF-α and IL-2 in CD4+ and CD8β+ T cells isolated from piglets that had been intratracheally infected with a H1N2 FLUAVsw isolate. IFN-γ+TNF-α+IL-2+ multifunctional CD4+ T cells were present in the blood of all infected animals at one or two weeks after primary infection and their frequency increased in four out of six animals after homologous seco...
Source: Veterinary Research - May 14, 2015 Category: Veterinary Research Source Type: research
Control of a Reassortant Pandemic 2009 H1N1 Influenza Virus Outbreak in an Intensive Swine Breeding Farm: Effect of Vaccination and Enhanced Farm Management Practices
Conclusions
Although our study design was sub-optimal for evaluating the effectiveness of the intervention, we provided suggestive evidence that H1N1pdm-targeted vaccination in sows/gilts, enhanced biosecurity, lengthening of weaning cycles, and constrains in cross-fostering of piglets may prove useful in controlling a reassortant H1N1pdm outbreak in an intensive swine breeding farm without possibility of applying an all-in/all-out system. Maternally-derived immunity was elicited and further virus circulation in piglets dropped to undetectable levels, while keeping farm productivity at full. The present field study also su...
Source: PLOS Currents Outbreaks - April 13, 2015 Category: Epidemiology Authors: Lapo Mughini-Gras Source Type: research
Characterization of co-circulating swine influenza A viruses in North America and the identification of a novel H1 genetic clade with antigenic significance.
Abstract
Multiple genetically and antigenically distinct hemagglutinin genes of the H1 and H3 influenza A virus (IAV) subtypes co-circulate in North American swine. This diversity has evolved by repeated transmission of IAVs from humans to swine and subsequent antigenic drift in swine. To understand the evolutionary dynamics of these diverse HA lineages in North American swine, we undertook a phylogenetic analysis of 1576 H1 and 607 H3 HA gene segments, as well as 834 N1 and 1293 N2 NA gene segments, and 2126M gene segments. These data revealed yearly co-circulation of H1N1, H1N2, and H3N2 viruses, with th...
Source: Virus Research - February 18, 2015 Category: Virology Authors: Anderson TK, Campbell BA, Nelson MI, Lewis NS, Janas-Martindale A, Killian ML, Vincent AL Tags: Virus Res Source Type: research
Molecular characterization of influenza viruses collected from young children in Uberlandia, Brazil - from 2001 to 2010
Conclusions:
These results suggest that the seasonal influenza vaccine effectiveness could be reduced because of A H3N2 variants that circulated in 2001-2003 years. Thus, an early monitoring of variants circulating in the country or in a region may provide important information about the probable efficacy of the vaccine that will be administered in an influenza season. (Source: BMC Infectious Diseases)
Source: BMC Infectious Diseases - February 18, 2015 Category: Infectious Diseases Authors: Thelma de Mattos Silva OliveiraJonny YokosawaFernando MottaMarilda SiqueiraHélio da SilveiraDivina Queiróz Source Type: research
Genetic diversity of swine influenza viruses in Thai swine farms, 2011–2014
Abstract
The pig is known as a “mixing vessel” for influenza A viruses. The co-circulation of multiple influenza A subtypes in pig populations can lead to novel reassortant strains. For this study, swine influenza surveillance was conducted from September 2011 to February 2014 on 46 swine farms in Thailand. In total, 78 swine influenza viruses were isolated from 2,821 nasal swabs, and 12 were selected for characterization by whole genome sequencing. Our results showed that the co-circulation of swine influenza subtypes H1N1, H3N2, and H1N2 in Thai swine farms was observable throughout the 3 years of ...
Source: Virus Genes - December 11, 2014 Category: Genetics & Stem Cells Source Type: research
Two different genotypes of H1N2 swine influenza virus isolated in northern China and their pathogenicity in animals
Publication date: Available online 9 December 2014 Source:Veterinary Microbiology Author(s): Huanliang Yang , Yan Chen , Chuanling Qiao , Chuantian Xu , Minghua Yan , Xiaoguang Xin , Zhigao Bu , Hualan Chen During 2006 and 2007, two swine-origin triple-reassortant influenza A (H1N2) viruses were isolated from pigs in northern China, and the antigenic characteristics of the hemagglutinin protein of the viruses were examined. Genotyping and phylogenetic analyses demonstrated different emergence patterns for the two H1N2 viruses, Sw/Hebei/10/06 and Sw/Tianjin/1/07. Sequences for the other genes encoding the intern...
Source: Veterinary Microbiology - December 11, 2014 Category: Veterinary Research Source Type: research
Temporal insight into the natural generation of a new reassortant porcine influenza virus in a swine holding
Publication date: 7 November 2014 Source:Veterinary Microbiology, Volume 174, Issues 1–2 Author(s): Chiara Chiapponi , Laura Baioni , Andrea Luppi , Ana Moreno , Alberto Castellan , Emanuela Foni The influenza A virus (IAV) subtypes H1N1, H3N2 and H1N2 are the most prevalent subtypes in swine in Italy. Reassortant influenza A viruses subtypes in swine appeared in European pig population. In particular reassortant viruses carrying genome segment from the pandemic H1N1 (H1N1pdm) are reported in many European countries, including Italy. In a 1000 sows farrow-to feeder farm, in Northern Italy, we isolated 10 IAVs f...
Source: Veterinary Microbiology - November 8, 2014 Category: Veterinary Research Source Type: research
Novel triple reassortant H1N2 influenza viruses bearing six internal genes of the pandemic 2009/H1N1 influenza virus were detected in pigs in China
At present, three predominant influenza virus subtypes, H1N1, H1N2, and H3N2, circulate among pigs worldwide. The wholly avian-like H1N1 virus, known as Eurasian avian-like H1N1, was first isolated from pigs in Italy in 1979, and appeared in China in the 1990s [1]. H1N2 viruses, first reported in Japan in 1978, which contained a variety of gene combinations or reassortment patterns between the H1N1 and H3N2 influenza viruses also concurrently circulate among swine herds in various counties [2]. In 1999, North American triple-reassortant H1N2 viruses, which resulted from human-, swine-, and avian-origin genes of influenza v...
Source: Journal of Clinical Virology - October 28, 2014 Category: Virology Authors: Chuanling Qiao, Liping Liu, Huanliang Yang, Yan Chen, Huiyang Xu, Hualan Chen Source Type: research
Live attenuated influenza A virus vaccine protects against A(H1N1)pdm09 heterologous challenge without vaccine associated enhanced respiratory disease.
Abstract
Live-attenuated influenza virus (LAIV) vaccines may provide cross-protection against contemporary influenza A virus (IAV) in swine. Conversely, whole inactivated virus (WIV) vaccines have the potential risk of vaccine-associated enhanced respiratory disease (VAERD) when challenged with IAV of substantial antigenic drift. A temperature sensitive, intranasal H1N2 LAIV was compared to wild type exposure (WT) and an intramuscular WIV vaccine in a model shown to induce VAERD. WIV vaccinated swine challenged with pandemic A/H1N1 (H1N1pdm09) were not protected from infection and demonstrated severe respi...
Source: Virology - October 28, 2014 Category: Virology Authors: Gauger PC, Loving CL, Khurana S, Lorusso A, Perez DR, Kehrli ME, Roth JA, Golding H, Vincent AL Tags: Virology Source Type: research
Comparative pathology of pigs infected with Korean H1N1, H1N2, or H3N2 swine influenza A viruses
Conclusions:
We demonstrated that Korean SIV subtypes had different pulmonary pathologic patterns. The Korean H3N2 rapidly induced acute lung lesions such as broncho-interstitial pneumonia, while the Korean H1N1 showed longer course of infection as compared to other strains. (Source: Virology Journal)
Source: Virology Journal - September 24, 2014 Category: Virology Authors: Kwang-Soo LyooJeong-Ki KimKwonil JungBo-Kyu KangDaesub Song Source Type: research
Influenza A virus hemagglutinin protein subunit vaccine elicits vaccine-associated enhanced respiratory disease in pigs.
Abstract
Vaccine-associated enhanced respiratory disease (VAERD) can occur when pigs are challenged with heterologous virus in the presence of non-neutralizing but cross-reactive antibodies elicited by whole inactivated virus (WIV) vaccine. The aim of this study was to compare the effects of heterologous δ1-H1N2 influenza A virus (IAV) challenge of pigs after vaccination with 2009 pandemic H1N1 virus (H1N1pdm09) recombinant hemagglutinin (HA) subunit vaccine (HA-SV) or temperature-sensitive live attenuated influenza virus (LAIV) vaccine, and to assess the role of immunity to HA in the development of VAERD...
Source: Vaccine - July 28, 2014 Category: Allergy & Immunology Authors: Rajão DS, Loving CL, Gauger PC, Kitikoon P, Vincent AL Tags: Vaccine Source Type: research
Reassortant swine influenza viruses isolated in Japan contain genes from pandemic A(H1N1) 2009
ABSTRACT
In 2013, three reassortant swine influenza viruses (SIVs)—two H1N2 and one H3N2—were isolated from symptomatic pigs in Japan; each contained genes from the pandemic A(H1N1) 2009 virus and endemic SIVs. Phylogenetic analysis revealed that the two H1N2 viruses, A/swine/Gunma/1/2013 and A/swine/Ibaraki/1/2013, were reassortants that contain genes from the following three distinct lineages: (i) H1 and nucleoprotein (NP) genes derived from a classical swine H1 HA lineage uniquely circulating among Japanese SIVs; (ii) neuraminidase (NA) genes from human‐like H1N2 swine viruses; and (iii) other genes from pandemic ...
Source: Microbiology and Immunology - June 9, 2014 Category: Microbiology Authors: Katsushi Kanehira, Nobuhiro Takemae, Yuko Uchida, Hirokazu Hikono, Takehiko Saito Tags: Original Article Source Type: research
The influence of experimental infection of gilts with swine H1N2 influenza A virus during the second month of gestation on the course of pregnancy, reproduction parameters and clinical status
Conclusions:
The results of the study indicate that infection of pregnant gilts with swine H1N2 IAV in the second month of pregnancy does not cause abortion and other reproduction disorders. No evidence for transplacental transmission of swine H1N2 IAV was found. However, due to subclinical course of influenza in the present experiment caution should be taken in extrapolating these results to the cases of acute influenza. The other limitation is IAV diversity. It cannot be excluded that other subtypes of IAV could be associated to reproduction failure in pigs. (Source: BioMed Central)
Source: BioMed Central - June 4, 2014 Category: Journals (General) Authors: Krzysztof KwitMa¿gorzata Pomorska-MólIwona Markowska-Daniel Source Type: research
Reassortant swine influenza viruses isolated in Japan contain genes from pandemic A(H1N1)2009
Abstract
In 2013, three ressortant swine influenza viruses (SIVs)—two H1N2 and one H3N2—were isolated from symptomatic pigs in Japan; each contained genes from the pandemic A(H1N1)2009 virus and endemic SIVs. Phylogenetic analysis revealed that the two H1N2 viruses, A/swine/Gunma/1/2013 and A/swine/Ibaraki/1/2013, were reassortants that contain genes from three distinct lineages: 1) H1 and NP genes derived from a classical swine H1 HA lineage uniquely circulating among Japanese SIVs; 2) NA genes from human‐like H1N2 swine viruses; and 3) other genes from pandemic A(H1N1)2009 viruses. The H3N2 virus, A/swine/Miyazaki/...
Source: Microbiology and Immunology - April 17, 2014 Category: Microbiology Authors: Katsushi Kanehira, Nobuhiro Takemae, Yuko Uchida, Hirokazu Hikono, Takehiko Saito Tags: Original Article Source Type: research
