Biological Pathotyping of Newcastle Disease Viruses in Sudan 2008-2013.

The biological properties and pathogenicity of seven Newcastle disease virus field isolates were studied. These isolates were recovered from different outbreaks in Sudan (5 from chickens and 2 from pigeons) during 2008-2013. Based on intracerebral pathogenicity index, four NDV isolates were characterized as velogenic (their ICPI ranged 2.