Scientific
understanding the epidemiology of NDV outbreaks as demon-
strated in the recent (1998-2000) NSW disease episode.9
Molecular characterisation of 87 Victorian NDV isolates
revealed the presence of four distinct deduced amino acid
profiles for the F0 protein cleavage site. Examination of the
DNA sequence from each isolate highlighted the presence of
single nucleotide differences at the first and second codon posi-
tion of the F1 polypeptide that has led to these distinct F0
cleavage signal profiles. Sequence analysis further classified each
F protein profile as being ‘avirulent’ due to the absence of two
virulent sequence features; a ‘dibasic’ amino acid pair within the
penta-amino acid sequence motif of the F0 cleavage site and a
phenylalanine residue at amino acid position 117 of the F2
polypeptide N-terminus.
analysis revealed the presence of genetic diversity within these
profiles as indicated by the varied C-terminus extension lengths.
The ‘P4’ isolate with a deduced HN C-terminus extension
length of 45 aa was identical to that of V4. However, the HN
nucleotide and amino acid sequence of this isolate revealed
numerous differences, suggesting that it is ‘V4 like’.
Results from this study contribute to the existing database of
Victorian NDV F0 cleavage signal sequences. In the event of an
NDV outbreak in Victoria, having reference to such genetic
information of past and present NDV F0 cleavage signal
sequences and HN C-terminus amino acid extension lengths,
will assist in understanding the likely origin of the infecting
strain and the epidemiology of the disease.
Most characterised avian NDV isolates were obtained from
poultry (67%) and ostrich (16%) samples. A significant propor-
tion of isolates possessed a ‘P2’ (67%) F0 protein cleavage site
amino acid profile. The remainder contained a ‘P1’ (29%)
profile and only 2% of isolates possessed either a ‘P3 or P4’
profile. However, access to a greater number of NDV isolates
will assist in supporting these findings.
Acknowledgments
We would like to thank Dr David Boyle and Mr Ian
Pritchard from the Australian Animal Health Laboratory for
their assistance in technology transfer.
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Isolates with P2 and P4 profiles have F0 cleavage signal
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(Accepted for publication 6 March 2002)
Predictors of outcome after dorsal decompressive laminectomy for degenerative lumbosacral stenosis in dogs: 69
cases (1987-1997)
ecompressive laminectomy was succesful for the treatment of degenerative lumbosacral stenosis in 54 of 69(78%) dogs over follow-up
D
periods of 16 to 50 months (mean 38 months). Preoperative signs persisted in the remaining 15 (22%) dogs, six of which had been incon-
tinent for a median of 8 weeks before surgery. Five of those with a successful outcome had been incontinent for a median of 2 weeks before
surgery. Whereas urinary or faecal incontinence was the only clinical sign significantly associated with the outcome, the pre-operative dura-
tion of urinary incontinence was the sole temporal variable significantly associated with that outcome. The authors conclude that prognosis is
guarded in those cases where incontinence, particularly urinary incontinence, exceeds 1 month.
De Risio L et al. J Am Vet Med Assoc 2001;219:624-628.
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