Avian nephritis virus (ANV) infects poultry flocks worldwide, but no confirmed cases have been reported from India so far. In the current study, disease investigation was carried out in 21 broiler flocks at different parts of India with clinical signs of nephritis, uneven and stunted growth, diarrhoea, reduced body weight, and mortality up to 9.72%. Out of the 21 flocks screened, two were found positive for ANV in RT-PCR assay. BLAST analysis revealed that the ANV of Indian origin was closely related to ANV-1 strains reported from Japan, Hungary and China. However, comparison of a small portion (~12% of nucleotides, i.e. ~60 nts, common site for ANV-1 and ANV-3, position 2200-2260 of ORF 1a gene) of the Indian ANV sequence with ANV-3 sequences revealed 89-93% identities with different ANV-3 isolates. Phylogenetically, ANV-1 forms three clades, and the Indian ANV clustered under clade II. This study confirms the existence of ANV in Indian poultry flocks and is the first report on the molecular detection and genetic characterisation of ANV from India.
Keywords: Avian nephritis virus; ORF 1a gene; RT-PCR; astrovirus; clade II; phylogenetic analysis.