Identification and characterization of a novel avian nephritis virus variant in chickens with enteritis in Hunan province, China.

Avian nephritis virus (ANV) infection is associated with diarrhea, uricosis, stunting, tubulonephrosis, interstitial nephritis, and mortality of chicken flocks, leading to economic losses in the poultry industry. In this study, an ANV strain designated as HNU-ANV-ML-2020 was identified in tissue samples collected from chickens with severe enteritis on a poultry farm in Hunan province, China, and analyzed. The genome of HNU-ANV-ML-2020 is 6943 nucleotides in length. It showed the highest sequence identity (88.1%) to ANV strain CHN/GXJL815/2017 (MN732559) from Guangxi province, China, while it showed less than 86% identity to other astrovirus (AstV) genome sequences available in the GenBank database. The capsid protein of this virus showed the highest sequence identity to ANV strains HQ330482 and HQ330498 from the UK (81.2% and 81.06%, respectively), while it showed only 73.9% identity to MN732559 and less than 80% identity to the capsid proteins of other AstVs available in GenBank. Further phylogenetic analysis demonstrated that HNU-ANV-ML-2020 belongs to group 4, together with ANV strains identified in Australia, Brazil, the UK, and the Netherlands. Furthermore, ANV strains identified in chickens in China were found to be separated into four distinct groups/genotypes, indicating substantial genetic divergence and a complex circulation pattern in China. The virus characterized in the present study is a novel ANV variant identified for the first time in Hunan province, China.

Identification and genomic characterization of a novel porcine CRESS DNA virus from a pig suffering from diarrhea in China.

The circular replication-associated protein (Rep)-encoding ssDNA (CRESS-DNA) viruses show high diversity and have a very wide range of hosts, including all three domains of cellular life. In the present study, a novel CRESS DNA virus, provisionally named "kirkovirus HNU-XX-2020" was discovered in a growing pig with watery diarrhea. The virus has a circular genome of 2961 nucleotides (nt) and three major putative open reading frames (ORFs), encoding a Rep protein (327 amino acids), a capsid protein (175 amino acids), and one protein (209 amino acids) of unknown function. The genome showed the highest sequence similarity (68.6% identity) to the genome of porcine circo-like virus 51 (JF713719), which was identified in pig faeces, and it showed very limited sequence similarity (less than 40% identity) to other virus genomes. Further phylogenetic analysis suggested that it could be a novel member in the proposed family "Kirkoviridae".