Molecular epidemiology of swine influenza A viruses in the Southeastern United States, highlights regional differences in circulating strains

This study investigated the prevalence of IAV in commercial swine herds. A total of 1,878 oral fluid samples were collected from pigs of all ages from 201 commercial farms located in North Carolina and South Carolina. Sixty-eight oral fluid samples from 35 farms were positive by MP gene PCR with an overall IAV-positivity of 3.6%. On the herd level, the percentage of IAV positivity was 17.4%. Fifty-six viruses were subtyped, while 12 were partly subtyped or not subtyped at all. Using de novo assembly, complete sequences were obtained for 59 HA genes. The majority of IAVs subtyped had an H1 HA demonstrating a considerable prevalence over H3 viruses. Furthermore, only six out of eleven HA types were detected which has implications for the selection of vaccines used by swine producers in the region.
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research

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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
AbstractPurpose of ReviewZoonotic influenza viruses are those that cross the animal-human barrier and can cause disease in humans, manifesting from minor respiratory illnesses to multiorgan dysfunction. They have also been implicated in the causation of deadly pandemics in recent history. The increasing incidence of infections caused by these viruses worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. In this first part of a two-part review, we describe the structure of zoonotic influenza viruses, the relationship between mutation and pandemic capacity, pathogenesis of i...
Source: Current Infectious Disease Reports - Category: Infectious Diseases Source Type: research
Publication date: 1 September 2018Source: Preventive Veterinary Medicine, Volume 157Author(s): Sébastien Grech-Angelini, Séverine Hervé, Nicolas Rose, Nicolas Barbier, François Casabianca, Oscar Maestrini, Alessandra Falchi, Gaëlle SimonAbstractCorsica is a mountainous French island in the north-western Mediterranean Sea. It is a rural area, where pig farming is a major economic activity. Although no acute respiratory outbreaks due to swine influenza A viruses (swIAVs) have ever been reported in this free-ranging pig breeding system, influenza A viruses (IAVs) could be circulating within th...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research
Publication date: Available online 7 September 2016 Source:Veterinary Microbiology Author(s): Maria Serena Beato, Luca Tassoni, Adelaide Milani, Annalisa Salviato, Guido Di Martino, Monica Mion, Lebana Bonfanti, Isabella Monne, Simon James Watson, Alice Fusaro In August 2012 repeated respiratory outbreaks caused by swine influenza A virus (swIAV) were registered for a whole year in a breeding farm in northeast Italy that supplied piglets for fattening. The virus, initially characterized in the farm, was a reassortant Eurasian avian-like H1N1 (H1avN1) genotype, containing a haemagglutinin segment derived from the pandemic ...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research
In this study, we examined and compared haemagglutination inhibition (HI) antibody titres against previously established IAVs and pH1N1 in 908 swine sera from 88 herds, collected before and after the 2009 pandemic. While we confirmed the historic presence of the three IAVs established in European swine, we also found that 4% of the pig sera examined after 2009 had HI antibodies only against the pH1N1 virus. Our results indicate that pH1N1 is circulating in Greek pigs and stress out the importance of a vigorous virological surveillance programme.
Source: Zoonoses and Public Health - Category: Infectious Diseases Authors: Tags: Original Article Source Type: research
Discussion Through new surveillance efforts and phylogenetic analysis of IAV-S in Mexico and Chile, we have expanded our understanding of the extensive IAV-S diversity that circulates in swine in Latin America. Most notably, we have identified multiple novel clades of H3N2 and H1N1 viruses of human origin in Mexico and Chile that have not been identified in swine previously, highlighting the importance of the human-swine interface in the evolution of IAV-S diversity in Latin America. The presence of two different IAV-S lineages in Mexico that are related to North American IAV-S (classical H1N1 and H3-cluster IV) also demon...
Source: PLOS Currents Outbreaks - Category: Epidemiology Authors: Source Type: research
Abstract In 2011-2012, contemporary North American-like H3N2 swine influenza viruses (SIVs) possessing the 2009 pandemic H1N1 matrix gene (H3N2pM-like virus) were detected in domestic pigs of South Korea where H1N2 SIV strains are endemic. More recently, we isolated novel reassortant H1N2 SIVs bearing the Eurasian avian-like swine H1-like hemagglutinin and Korean swine H1N2-like neuraminidase in the internal gene backbone of the H3N2pM-like virus. In the present study, we clearly provide evidence on the genetic origins of the novel H1N2 SIVs virus through genetic and phylogenetic analyses. In vitro studies demonst...
Source: Infection, Genetics and Evolution - Category: Genetics & Stem Cells Authors: Tags: Infect Genet Evol Source Type: research
The objectives of this study were to describe the control measures implemented since October 2013 in response to this outbreak and to compare virus occurrence in piglets ‒ the subpopulation likely responsible for viral maintenance within the herd5,6 ‒ using a pre-post intervention study design. Additionally, the pattern of maternally-derived immunity in piglets sourced from the affected herd was assessed. Methods Study farm The study farm consisted of an intensive, closed-cycle swine breeding farm housing approximately 1,100 sows/gilts and 23,000 piglets located in North-East Italy. This farm supplies ~90 day-old pi...
Source: PLOS Currents Outbreaks - Category: Epidemiology Authors: Source Type: research
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