Isolation and detection of avian nephritis virus by RT-PCR from commercial broiler flocks affected with visceral gout in India

Abstract

The present study reports pathomorphology, isolation and detection of Avian Nephritis Virus (ANV) by RT-PCR from a field outbreak in commercial broiler in Raipur, Chhattisgarh. Clinical signs and age wise mortality were recorded and detailed post mortem examination were performed in died chicks. The kidney tissues were collected for histopathology and isolation of virus. Clarified suspensions (10% w/v) of homogenate were prepared and inoculated into allantoic cavity of 11 day old embryonated SPF eggs. After three passages the embryos were examined for any lesions and the collected tissue samples were used for RNA extraction. The mortality was ranged from 3 to 8% in different affected flocks with 6% average mortality. During post mortem examination, the major gross lesions were renal damage and visceral uricosis. The kidneys were pale and enlarged with dilated ureters indicated acute tubular nephrosis. Microscopically moderate, multifocal, peri glomerular and interstitial mononuclear cells infiltration were the most prominent lesions. Cytoplasmic eosinophilic inclusion bodies were found in necrotized epithelial cells and desquamated tubular epithelial cells. After three passages, three embryos revealed pale swollen kidneys with full of chalky deposits and dilatation of ureters. For RT-PCR, RNA extract from pooled kidney samples of five embryos were processed. The visualization by agarose gel electrophoresis showed a product of expected size of 325 bp Avian Nephritis Virus (ANV) specific product. The RT-PCR used in the present study can be a potential tool for routine diagnosis of samples submitted from cases of gout and nephropathy in chickens.