Evaluation of the protection of commercial live and inactivated NDV vaccines against Newcastle virus genotype VIId circulating in the field

The most prevalently circulating genotype of Newcastle disease (NDV)in Egypt was VII of class II NDV strains. Control of NDV by vaccinationis a common strategy in intensively raised commercial flocks andNewcastle disease vaccines have been used worldwide to protect againstclinical signs and mortalities. The aim of the present study was to evaluatethe level of protection against clinical disease and virus shedding affordedby different NDV vaccines. The strain used for challenge wasNDV/CH/EG/18/2015 (GenBank accession number- KU377781),classified as Genotype VIId with ICPI of 1.89, and MDT of 48 hrs. Broilerchickens were challenged intra-occularily at 28 days of age using 100 μl of106 EID50 per dose/bird. Results indicated that protection percent againstmortality and clinical signs was 100 % and 93.3 % for inactivated NDVvaccine and LaSota, respectively. Shedding was not prevented by anyvaccine.