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Circulation of multiple genotypes of H1N2 viruses in a swine farm in Italy over a two-month period

Author:
Beato, Maria Serena, Tassoni, Luca, Milani, Adelaide, Salviato, Annalisa, Di Martino, Guido, Mion, Monica, Bonfanti, Lebana, Monne, Isabella, Watson, Simon James, Fusaro, Alice
Source:
Veterinary microbiology 2016 v.195 pp. 25-29
ISSN:
0378-1135
Subject:
Influenza A virus, breeding, disease control, finishing, genetic variation, genome, genotype, hemagglutinins, livestock and meat industry, monitoring, nose, pandemic, piglets, sequence analysis, sows, vaccination, vaccines, viruses, Italy
Abstract:
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 H1N1 (A(H1N1)pdm09) lineage. To control infection, a vaccination program using vaccines against the A(H1N1)pdm09, human-like H1N2 (H1huN2), human-like H3N2 (H3N2), and H1avN1 viruses was implemented in sows in November 2013. Vaccine efficacy was assessed by sampling nasal swabs for two months in 35–75 day-old piglets born from vaccinated sows. Complete genome sequencing of eight swIAV-positive nasal swabs collected longitudinally from piglets after the implementation of the vaccination program was conducted to investigate the virus characteristics.Over the two-month period, two different genotypes involving multiple reassortment events were detected. The unexpected circulation of multiple reassortant genotypes in such a short time highlights the complexity of the genetic diversity of swIAV and the need for a better surveillance plan, based on the combination of clinical signs, epidemiological data and whole genome characterization.
Agid:
5508517