الفهرس 
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Abstract
Six Newcastle disease virus (NDV) field strains (NDV-QF10,
NDV-QF13, NDV-QH10-1, NDV-QH10-2, NDV-QQ09 and NDV-QP09)
were isolated and pathotyped from samples collected in Qatar from captivated
falcons, houbara bustard, quail and pigeons, respectively, during the study
period of 2012 and 2013. Virus cultivation in specific pathogen free
embryonating chicken eggs (SPF ECE), haemagglutination (HA),
haemagglutination inhibition (HI) and mean death time (MDT) assays were
used in the investigation to reveal virus identity and pathogenicity.
Real time reverse transcriptase polymerase chain reaction (rRT-PCR) was
embloyed as a confirmatory technique and it successfully detected NDV
cDNA fragments amplified from RNA extracts of amnioallantoic fluids
(AAF) of the inoculated SPF ECE. The six NDV isolates were classified
velogenic strains.
Sequence analysis and phylogenesis of the corresponding cDNA revealed
112R-R-Q-K-R-F117 amino acid motif confirming velogenicity of three of the
six strains, and that all are belonging to NDV genotype group VII.