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Online Journal of Veterinary Research©
(Including Medical and Laboratory Research)
Volume 26 (4): 196-201, 2022.
Virulent and non-virulent Newcastle disease viruses in broilers isolated by RT-PCR.
PD Fazel MSc1, MJ Mehrabanpour Phd2*, A Rahimian PhD2, S Khoobyar MSc1
1Islamic Azad University Jahrom Branch, 2Department of virology, Razi Vaccine and Serum Research Institute, Shiraz, Iran.
Fazel PD, Mehrabanpour MJ, Rahimian A, Khoobyar S., Virulent and non-virulent Newcastle disease viruses in broilers isolated by RT-PCR, 26 (4): 196-201, 2022. Newcastle disease (ND) a highly contagious infection of poultry induces nervous signs and high mortality in poultry. We identified Newcastle disease virus and time of death to differentiate virulent from non-virulent viruses during severe outbreaks, Newcastle disease virus (NDV) was isolated from tracheal and cloacal swabs samples. Pathogenicity was determined by mean death time MDT in embryonated eggs. We used RT-PCR and MDT to determine virulent strains of NDV in broilers. From 30 broiler flocks with high mortality, 6 had signs of Newcastle disease. Two oligonucleotide primers, representing the sequence at the cleavage site of the F protein of both virulent and non-virulent NDV strains, respectively, were used to differentiate NDV. RT-PCR was able to differentiate 6 NDV reference strains 6 of which were virulent. MDT ranged 46.2 to 60h with primer pair A+B confirming NDV in allantoic fluid whereas primer pair A+C revealed virulent strain. Our results suggest that primer pair A+B was specific for all NDV, and A+C for virulent strains, detected and differentiated virulent from non-virulent NDV.
Keywords: Newcastle disease; RT-PCR; MDT; virulent strain; broiler flocks; Iran.