Real Time PCR Detection, Sequencing, and Phylogenetic Tree Analysis of Newcastle Diseases Virus Isolated from an Outbreak in Layer Flocks in Baghdad Capital, Iraq

The definition of the Newcastle disease (ND) under the World Organization for Animal Health strategy is that chicken which infected with ND virulent (NDV) strains of avian paramyxovirus (APM). The current work included the identification of pathogenic properties (PPs) of serotype 1 belongs to AP that was detected in samples collected from severe-ND-affected chickens. The detection was performed measuring heamaglutination inhibition (HI), intracerebral pathogenicity index (ICPI), and mean death time (MDT) for in vivo exploration and real time-quantitative polymerase chain reaction (RT-qPCR), restriction enzyme analysis (REA), and DNA sequencing of the F2/F1 cleavage site for the in vitro investigation. This study is the first genetic-based analysis of the ND virus in Iraq. Complete correlation between the in vivo and in vitro results was recognized. The findings of the in vivo investigation showed that the strain was pathogenic and at the same time the structural patterns of the restriction plus the sequence of the amino acids were typical for virulent strain which resemble with 99% Iranian strain.

This study adds new information about the pathology and antigen distribution of this novel virus in Iraq and additional work is needed to get a complete data base of viral diversity and procedure for vaccinating and eliminating from this disease in our country.