Characterization of H5N2 influenza viruses from Italian poultry.
From October 1997 to January 1998, highly pathogenic H5N2 avian influenza viruses caused eight outbreaks of avian influenza in northern Italy. A nonpathogenic H5N9 influenza virus was also isolated during the outbreaks as a result of virological and epidemiological surveillance to control the spread of avian influenza to neighbouring regions. Antigenic analysis showed that the Italian H5N2 isolates were antigenically similar to, although distinguishable from, A/HK/156/97, a human influenza H5N1 virus isolated in Hong Kong in 1997. Phylogenetic analysis of the haemagglutinin (HA) genes showed that the highly pathogenic Italian viruses clustered with the Hong Kong strains, whereas the nonpathogenic H5N9 virus, despite its epidemiological association with the highly pathogenic Italian isolates, was most closely related to the highly pathogenic A/Turkey/England/91 (H5N1) strain. Like the HA phylogenetic tree, the nonstructural (NS) phylogenetic tree showed that the H5N2 Italian virus genes are clearly separate from those of the H5N9 strain. In contrast, results of the phylogenetic analysis of nucleoprotein (NP) genes indicated a closer genetic relationship between the two Italian virus groups, a finding suggesting a common progenitor. Comparison of the HA, NS and NP genes of the Italian H5 strains with those of the H5N1 viruses simultaneously circulating in Hong Kong revealed that the two groups of viruses do not share a recent common ancestor. No virological and serological evidence of bird-to-human transmission of the Italian H5N2 influenza viruses was found.
Donatelli
Isabella
I
Department of Virology1 and Department of Veterinary Medicine2, Istituto Superiore di Sanità, Rome, Italy.
Campitelli
Laura
L
Department of Virology1 and Department of Veterinary Medicine2, Istituto Superiore di Sanità, Rome, Italy.
Di Trani
Livia
L
Department of Virology1 and Department of Veterinary Medicine2, Istituto Superiore di Sanità, Rome, Italy.
Puzelli
Simona
S
Department of Virology1 and Department of Veterinary Medicine2, Istituto Superiore di Sanità, Rome, Italy.
Selli
Lucia
L
Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy3.|Department of Virology1 and Department of Veterinary Medicine2, Istituto Superiore di Sanità, Rome, Italy.
Fioretti
Alessandro
A
National Centre for Avian Influenza Viruses, Avian Pathology Section, University of Naples, Naples, Italy4.
Alexander
Dennis J
DJ
European Reference Laboratory for Avian Influenza Viruses, Central Veterinary Laboratory, New Haw, Addlestone, UK5.
Tollis
Maria
M
Department of Virology1 and Department of Veterinary Medicine2, Istituto Superiore di Sanità, Rome, Italy.
Krauss
Scott
S
Department of Virology and Molecular Biology, St Jude Children's Research Hospital, 332 N. Lauderdale, PO Box 318, Memphis, TN 38105, USA6.
Webster
Robert G
RG
Department of Virology and Molecular Biology, St Jude Children's Research Hospital, 332 N. Lauderdale, PO Box 318, Memphis, TN 38105, USA6.
D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D002645:Chickens / Q000821:virology*; D004279:DNA, Viral; D005814:Genes, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000145:classification / Q000235:genetics; D006801:Humans; D053125:Influenza A Virus, H5N2 Subtype; D009980:Influenza A virus / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D005585:Influenza in Birds / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D007558:Italy / Q000453:epidemiology; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000145:classification / Q000235:genetics; D010802:Phylogeny; D011200:Poultry; D011201:Poultry Diseases / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D016601:RNA-Binding Proteins; D017422:Sequence Analysis, DNA / Q000379:methods; D014758:Viral Core Proteins / Q000145:classification / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000145:classification / Q000235:genetics
D004279:DNA, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D016601:RNA-Binding Proteins; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins