Isolation and Identification of Avian Nephritis Virus from Commercial Broiler Chickens

The present study was undertaken to investigate the incidences of nephropathy encountered in young chicks of certain commercial broiler flocks in the states of Telangana, Andhra Pradesh, Tamil Nadu and Maharashtra. The mortality and growth retardation associated with the condition was a major concern, necessitating a thorough study to establish the etiology. Detailed necropsy of the dead chicks revealed marked inflammation of the kidneys along with gout. Mortality percentage recorded was up to 20%. Samples were collected from the affected flocks for isolation and identification of the causative agent. The presence of ANV RNA was detected using reverse transcriptase-polymerase chain reaction and 42 kidney samples (43.75%) were found to be ANV positive while all were IBV negative. The positive samples were successfully propagated in Specific Pathogen Free chicks and embryonated eggs as was evident from the changes observed and further confirmation using RT PCR. The nucleotide sequence of the representative ANV isolate was determined and showed high identity with ANV sequences in the NCBI database. In the constructed phlyogenetic tree, the ANV isolates were clustered together distinctly separate from the related Chicken Astro virus. This investigation confirms the involvement of ANV in cases of gout, nephritis and related mortality in commercial broiler flocks.