Genetic reassortment between avian and human influenza A viruses in Italian pigs.
Pandemic strains of influenza A virus arise by genetic reassortment between avian and human viruses. To examine the possibility that pigs serve as "mixing vessels" for such reassortment events (Scholtissek et al., Virology 147, 287-294, 1985), we phylogenetically analyzed the internal protein genes of classic H1N1, avian-like H1N1, and human-like H3N2 viruses circulating among Italian pigs. The results show that human-like H3N2 strains isolated from 1985 to 1989 contained the internal protein genes of avian-like H1N1 viruses, whereas those isolated in 1977 and 1983 did not. Thus, at some time between 1983 and 1985, genetic reassortment took place between avian- and human-like viruses in Italian pigs. This study provides the first evidence supporting genetic reassortment between human and avian viruses in a natural swine environment.
Castrucci
M R
MR
Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38101.
Donatelli
I
I
Sidoli
L
L
Barigazzi
G
G
Kawaoka
Y
Y
Webster
R G
RG
D000818:Animals; D001717:Birds; D005814:Genes, Viral / Q000235:genetics*; D006801:Humans; D009980:Influenza A virus / Q000235:genetics*; D007558:Italy; D010802:Phylogeny; D016865:Reassortant Viruses / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics*; D013552:Swine / Q000382:microbiology*