Clinicopathological characterization of Chicken origin velogenic Avian AvulaVirus-1 isolated from backyard poultry

The present study details characterization of velogenic Avian Avula virus-1 (AAvV-1) (VPP-5) isolated from a naturally infected unvaccinated Aseel flock. Isolation of AAvV-1 was attempted using embryonated chicken eggs and the isolates were confirmed by HI using hyperimmune serum raised against LaSota and RT-PCR targeting partial fusion gene. The virus had an ICPI and MDT of 2.0 and 44 h, respectively. Fusion protein cleavage site motif was found to have multiple basic amino acids (¹¹²RRRKRF¹¹⁷) with phenylalanine at 117 position. Phylogenetic classification based on full- length fusion gene grouped the isolate under genotype XIII sub- genotype 2.2. Experimental inoculation of VPP-5 in three- week old chicks resulted in virulent ND with 100% mortality in the infected as well as in- contact birds. This study highlights the significance of regular vaccinations to curtail the economic losses to the poultry entrepreneurs.