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 from captivated falcons, houbara bustard, quail and pigeon, respectively, during the study period of 2012 and 2013 in Qatar. Virus cultivation in specific pathogen free embryonating chicken eggs (SPF ECE), haemagglutination (HA), haemagglutination inhibition (HI) and mean death time (MDT) assays used in the investigation

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... virus identity and pathogenicity. The six NDV isolates were classified velogenic strains. Sequence analysis of 150bp of the amplified 216bp nucleotides of the functional region of the F-gene encoding the F2-F1 cleavage site, and phylogenies of three of the six strains revealed 112 R-R-Q-K-R-F 117 amino acid motif confirming velogenicity, and that, the three strains clustered under NDV genotype VII either subgroup d or f.