PMID- 17494593
OWN - NLM
STAT- MEDLINE
DCOM- 20070613
LR  - 20080507
IS  - 0005-2086 (Print)
IS  - 0005-2086 (Linking)
VI  - 51
IP  - 1 Suppl
DP  - 2007 Mar
TI  - Induced increase in virulence of low virulence highly [corrected] pathogenic 
      avian influenza by serial intracerebral passage in chickens.
PG  - 396-400
AB  - Two highly pathogenic avian influenza (HPAI) virus clones that met the criteria 
      for high-pathogenicity avian influenza viruses, by possessing a multibasic 
      hemagglutinin (HA) cleavage site, were isolated from an H5N1 outbreak in Norfolk, 
      England, in 1991-92. These two isolates, A/turkey/England/50-92/91 (50-92) and 
      A/turkey/England/87-92/91 (87-92), displayed differences in virulence as 
      determined by intravenous pathogenicity index-3 and -0, respectively. DNA 
      sequencing of these two isolates identified 10 amino acid differences throughout 
      the genome: three in HA and polymerase B2 (PB2) and two in polymerase B1 (PB1) 
      and single mutations in nucleoprotein (NP) and polymerase A (PA). Serial 
      intracerebral passages were performed in 1- or 2-day-old specific pathogen free 
      (SPF) chicks with 87-92. Viruses reisolated from each bird passage displayed 
      increases in intracerebral pathogenicity index values (from 0 to 1.9) and 
      therefore virulence. Reverse transcriptase polymerase chain reaction and DNA 
      sequencing on viruses isolated at each passage displayed nine out of the 10 
      mutations associated with the higher pathogenic genotype of 50-92, except for the 
      mutation found in NP, which retained the amino acid residue associated with 
      87-92. Serial passage through 9-day-old SPF embryonated chicken eggs and serial 
      intravenous passage in 6-wk-old birds could not reproduce these results. These 
      results further highlight that nucleotide changes in the genome other than at the 
      HA cleavage site can attenuate the virulence of HPAI viruses.
FAU - Londt, B Z
AU  - Londt BZ
AD  - Veterinary Laboratory Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, 
      United Kingdom.
FAU - Banks, J
AU  - Banks J
FAU - Gardner, R
AU  - Gardner R
FAU - Cox, W J
AU  - Cox WJ
FAU - Brown, I H
AU  - Brown IH
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Avian Dis
JT  - Avian diseases
JID - 0370617
RN  - 0 (Hemagglutinin Glycoproteins, Influenza Virus)
RN  - 0 (hemagglutinin, avian influenza A virus)
SB  - IM
EIN - Avian Dis. 2008 Mar;52(1):195
MH  - Amino Acid Sequence
MH  - Animals
MH  - Chickens/*virology
MH  - Gene Expression Regulation, Viral
MH  - Hemagglutinin Glycoproteins, Influenza Virus/chemistry/genetics/metabolism
MH  - Influenza A virus/*pathogenicity
MH  - Influenza in Birds/*virology
MH  - Molecular Sequence Data
MH  - Telencephalon/*virology
MH  - Virulence
EDAT- 2007/05/15 09:00
MHDA- 2007/06/15 09:00
CRDT- 2007/05/15 09:00
PHST- 2007/05/15 09:00 [pubmed]
PHST- 2007/06/15 09:00 [medline]
PHST- 2007/05/15 09:00 [entrez]
AID - 10.1637/7665-061206R.1 [doi]
PST - ppublish
SO  - Avian Dis. 2007 Mar;51(1 Suppl):396-400. doi: 10.1637/7665-061206R.1.