BACKGROUND: Since the influenza A(H1N1)pdm09 virus was first introduced to the Norwegian pig population in September 2009, it has repeatedly been detected in pigs in Norway. No other subtypes of influenza virus are circulating in Norwegian pigs. OBJECTIVE: To follow the diversity of A(H1N1)pdm09 viruses circulating in pigs in Norway and to investigate the relationship between viruses circulating in Norwegian pigs and in humans. METHODS: Between January 2011 and January 2013, nasal swabs from 507 pigs were tested for A(H1N1)pdm09 virus by real-time RT-PCR. The hemagglutinin (HA) gene of virus-positive samples was sequenced and compared with publically available sequences from viruses circulating in humans at the time. RESULTS: Sequencing and phylogenetic analysis of the HA gene showed that the A(H1N1)pdm09 virus circulating in Norwegian pigs early in 2011 resembled the A(H1N1)pdm09 virus circulating in humans during this time. Viruses detected in pigs by the end of 2011 had acquired four characteristic amino acid substitutions (N31D, S84I S164F, and N473D) and formed a distinct phylogenetic group. CONCLUSIONS: A(H1N1)pdm09 virus detected in Norwegian pigs by the end of 2011 formed a distinct genetic lineage. Also, our findings indicate that reverse-zoonotic transmission from humans to pigs of the A(H1N1)pdm09 virus is still important.
BACKGROUND: Since the influenza A(H1N1)pdm09 virus was first introduced to the Norwegian pig population in September 2009, it has repeatedly been detected in pigs in Norway. No other subtypes of influenza virus are circulating in Norwegian pigs. OBJECTIVE: To follow the diversity of A(H1N1)pdm09 viruses circulating in pigs in Norway and to investigate the relationship between viruses circulating in Norwegian pigs and in humans. METHODS: Between January 2011 and January 2013, nasal swabs from 507 pigs were tested for A(H1N1)pdm09 virus by real-time RT-PCR. The hemagglutinin (HA) gene of virus-positive samples was sequenced and compared with publically available sequences from viruses circulating in humans at the time. RESULTS: Sequencing and phylogenetic analysis of the HA gene showed that the A(H1N1)pdm09 virus circulating in Norwegian pigs early in 2011 resembled the A(H1N1)pdm09 virus circulating in humans during this time. Viruses detected in pigs by the end of 2011 had acquired four characteristic amino acid substitutions (N31D, S84I S164F, and N473D) and formed a distinct phylogenetic group. CONCLUSIONS: A(H1N1)pdm09 virus detected in Norwegian pigs by the end of 2011 formed a distinct genetic lineage. Also, our findings indicate that reverse-zoonotic transmission from humans to pigs of the A(H1N1)pdm09 virus is still important.
Authors: M D Welsh; P M Baird; M P Guelbenzu-Gonzalo; A Hanna; S M Reid; S Essen; C Russell; S Thomas; L Barrass; F McNeilly; J McKillen; D Todd; V Harkin; S McDowell; B Choudhury; R M Irvine; J Borobia; J Grant; I H Brown Journal: Vet Rec Date: 2010-05-22 Impact factor: 2.695
Authors: Elke Lange; Donata Kalthoff; Ulrike Blohm; Jens P Teifke; Angele Breithaupt; Christina Maresch; Elke Starick; Sasan Fereidouni; Bernd Hoffmann; Thomas C Mettenleiter; Martin Beer; Thomas W Vahlenkamp Journal: J Gen Virol Date: 2009-07-10 Impact factor: 3.891
Authors: Sharon M Brookes; Alejandro Núñez; Bhudipa Choudhury; Mikhail Matrosovich; Stephen C Essen; Derek Clifford; Marek J Slomka; Gaëlle Kuntz-Simon; Fanny Garcon; Bethany Nash; Amanda Hanna; Peter M H Heegaard; Stéphane Quéguiner; Chiara Chiapponi; Michel Bublot; Jaime Maldonado Garcia; Rebecca Gardner; Emanuela Foni; Willie Loeffen; Lars Larsen; Kristien Van Reeth; Jill Banks; Richard M Irvine; Ian H Brown Journal: PLoS One Date: 2010-02-05 Impact factor: 3.240
Authors: Yi-Mo Deng; Pina Iannello; Ina Smith; James Watson; Ian G Barr; Peter Daniels; Naomi Komadina; Bruce Harrower; Frank Y K Wong Journal: Influenza Other Respir Viruses Date: 2012-02-15 Impact factor: 4.380
Authors: Siri Kulberg Sjurseth; Britt Gjerset; Karoline Bragstad; Olav Hungnes; Helene Wisløff; Chiek Er; Mette Valheim; Siri M Løtvedt; Bruce David; Skjalg A Hanssen; Siri H Hauge; Merete Hofshagen Journal: Infect Ecol Epidemiol Date: 2017-12-19