Identification of H2N3 influenza A viruses from swine in the United States.
Although viruses of each of the 16 influenza A HA subtypes are potential human pathogens, only viruses of the H1, H2, and H3 subtype are known to have been successfully established in humans. H2 influenza viruses have been absent from human circulation since 1968, and as such they pose a substantial human pandemic risk. In this report, we isolate and characterize genetically similar avian/swine virus reassortant H2N3 influenza A viruses isolated from diseased swine from two farms in the United States. These viruses contained leucine at position 226 of the H2 protein, which has been associated with increased binding affinity to the mammalian alpha2,6Gal-linked sialic acid virus receptor. Correspondingly, the H2N3 viruses were able to cause disease in experimentally infected swine and mice without prior adaptation. In addition, the swine H2N3 virus was infectious and highly transmissible in swine and ferrets. Taken together, these findings suggest that the H2N3 virus has undergone some adaptation to the mammalian host and that their spread should be very closely monitored.
Ma
Wenjun
W
Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Vincent
Amy L
AL
Gramer
Marie R
MR
Brockwell
Christy B
CB
Lager
Kelly M
KM
Janke
Bruce H
BH
Gauger
Phillip C
PC
Patnayak
Devi P
DP
Webby
Richard J
RJ
Richt
Jürgen A
JA
D000818:Animals; D005289:Ferrets; D006801:Humans; D009980:Influenza A virus / Q000737:chemistry*; D007251:Influenza, Human / Q000175:diagnosis / Q000821:virology; D007930:Leucine / Q000737:chemistry; D008168:Lung / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000175:diagnosis* / Q000821:virology*; D010802:Phylogeny; D013045:Species Specificity; D013552:Swine; D014481:United States
D007930:Leucine