Egg adaptive mutation patterns of H3N2 human influenza A viruses

A recent study in this journal reported the cross-species transmission of a novel swine H3N2 influenza A virus (IAV) to humans and suggested a heavy threat from the H3N2 IAVs (1). Vaccination remains the primary option for the control of influenza, but the protective efficiency of seasonal vaccines against H3N2 IAVs are suboptimal. Recent human H3N2 IAVs have shown poor growth in MDCK cells and eggs due to their low receptor binding affinities. A high yield strain is required for the vaccine manufacture, however, mutations of vaccine seeds during egg adaptation has reported to reduce the vaccine effectiveness (2).
Source: Journal of Infection - Category: Infectious Diseases Authors: Source Type: research

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Influenza A virus infection is a global health threat to livestock and humans, causing substantial mortality and morbidity. As both pigs and humans are readily infected with influenza viruses of similar subtype, the pig is a robust and appropriate model for investigating swine and human disease. We evaluated the efficacy of the human cold-adapted 2017–2018 quadrivalent seasonal LAIV in pigs against H1N1pdm09 challenge. LAIV immunized animals showed significantly reduced viral load in nasal swabs. There was limited replication of the H1N1 component of the vaccine in the nose, a limited response to H1N1 in the lung lym...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
This study reports virological and epidemiological data accumulated through passive surveillance conducted during 1,825 herd visits from 2011 to 2018. Among them, 887 (48.6%) tested swIAV-positive. The proportion of positive cases remained stable year-on-year and year-round. The European avian-like swine H1N1 (H1avN1) virus was the most frequently identified (69.6%), and was widespread across the country. The European human-like reassortant swine H1N2 (H1huN2) virus accounted for 22.1% and was only identified in the north-western quarter and recently in the far north. The 2009 pandemic H1N1 (H1N1pdm) virus (3.6%) was detec...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research
Publication date: Available online 12 October 2019Source: Veterinary MicrobiologyAuthor(s): Haiyan Sun, Jung-Hyang Sur, Sarah Sillman, David Steffen, Hiep L.X. VuAbstractThe substantial genetic diversity exhibited by influenza A viruses of swine (IAV-S) represents the main challenge for the development of a broadly protective vaccine against this important pathogen. The consensus vaccine immunogen has proven an effective vaccinology approach to overcome the extraordinary genetic diversity of RNA viruses. In this project, we sought to determine if a consensus IAV-S hemagglutinin (HA) immunogen would elicit broad protective ...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research
Mark K. Slifka1* and Ian J. Amanna2 1Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &Science University, Beaverton, OR, United States2Najít Technologies, Inc., Beaverton, OR, United States Vaccines play a vital role in protecting our communities against infectious disease. Unfortunately, some vaccines provide only partial protection or in some cases vaccine-mediated immunity may wane rapidly, resulting in either increased susceptibility to that disease or a requirement for more booster vaccinations in order to maintain immunity above a protective level. The durability of a...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
In conclusion, the reported results highlight the importance of AIV attachment to trachea in many avian species. Finally, the importance of chickens and mallards in AIVs dynamics was illustrated by the abundant AIV attachment observed. Introduction Influenza A viruses (IAVs) are pathogens of global concern in both human and veterinary medicine (Webster et al., 1992; Stöhr, 2002; Olsen et al., 2006; Wiethoelter et al., 2015). Wild birds are well-described hosts of avian influenza viruses (AIVs) and longitudinal surveillance studies have demonstrated a plethora of low pathogenic AIVs (LPAIVs) circulating in wild...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
In this study, we used a swine pH1N1 challenge virus to investigate the efficacy of whole inactivated virus vaccines homologous or heterologous to the challenge virus as well as a commercial vaccine. We found that vaccine-mediated protection was most effective when vaccine antigen and challenge virus were homologous and correlated with the specific production of neutralising antibodies and a cellular response to the challenge virus. We conclude that a conventional whole inactivated SwIV vaccine must be antigenically matched to the challenge strain to be an effective control measure. PMID: 30914224 [PubMed - as supplied by publisher]
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
Publication date: Available online 12 March 2019Source: Veterinary MicrobiologyAuthor(s): Svenja Mamerow, Robert Scheffter, Susanne Röhrs, Olga Stech, Ulrike Blohm, Theresa Schwaiger, Charlotte Schröder, Reiner Ulrich, Jan Schinköthe, Martin Beer, Thomas C. Mettenleiter, Jürgen StechAbstractInfluenza A viruses (IAV) have caused seasonal epidemics and severe pandemics in humans. Novel pandemic strains as in 2009 may emerge from pigs, serving as perpetual virus reservoir. However, reliably effective vaccination has remained a key issue for humans and swine. Here, we generated a novel double-attenuated inf...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research
We describe here that pre-exposure with a live virus generated via a A/WSN/1933(H1N1) reverse genetics system resulted in a significant reduction of viral shedding from pigs exposed to either a swine H1N1 virus or a swine H3N2 virus. At 3-day post challenge (DPC), approximately 1 log and 1.5 logs reductions of viral shedding were observed in the swine H1N1- and H3N2-challenged vaccinated pigs when compared to unvaccinated animals. A further decline in viral load was observed at 5 DPC where viral shedding was decreased by greater than 3 logs in vaccinated pigs receiving either the H1N1 or H3N2 virus challenge. Although the ...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research
W, Taylor C, Wentworth DE, Xu X, Zanders N, Katz J, Jernigan D Abstract During May 20-October 13, 2018,* low levels of influenza activity were reported in the United States, with a mix of influenza A and B viruses circulating. Seasonal influenza activity in the Southern Hemisphere was low overall, with influenza A(H1N1)pdm09 predominating in many regions. Antigenic testing of available influenza A and B viruses indicated that no significant antigenic drift in circulating viruses had emerged. In late September, the components for the 2019 Southern Hemisphere influenza vaccine were selected and included an incremen...
Source: MMWR Morb Mortal Wkl... - Category: Epidemiology Authors: Tags: MMWR Morb Mortal Wkly Rep Source Type: research
This study is carried out to unravel the key features of the genes encoding the matrix proteins that manoeuvre the codon usage profile in the H3N2 strains. The findings reveal differential codon choice for both matrix protein 1 and matrix protein 2. The overall codon usage bias is less pronounced in both the datasets which is evident from higher value of effective number of codons (>55). Comparison of the codon usage for both the genes under study with that of humans revealed that the viral codon usage is not fully optimized for the human host conditions. Both the genes enrolled in the study showed variation which was r...
Source: Infection, Genetics and Evolution - Category: Genetics & Stem Cells Authors: Tags: Infect Genet Evol Source Type: research
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