First detection of Tetraparvovirus ungulate 1 in diseased cattle (Chinese Simmental) from Hunan province, China.

Tetraparvovirus is an emerging parvovirus infecting a variety of mammals and humans, and associated with human diseases including severe acute respiratory infection and acute encephalitis syndrome. In the present study, a Tetraparvovirus ungulate 1 (formerly known as bovine hokovirus) strain HNU-CBY-2023 was identified and characterized from diseased Chinese Simmental from Hunan province, China. The nearly complete genome of HNU-CBY-2023 is 5346 nt in size and showed genomic identities of 85-95.5% to the known Tetraparvovirus ungulate 1 strains from GenBank, indicating a rather genetic variation. Phylogenetic and genetic divergence analyses indicated that Tetraparvovirus ungulate 1 could be divided into two genotypes (I and II), and HNU-CBY-2023 was clustered into genotype II. This study, for the first time, identified Tetraparvovirus ungulate 1 from domestic cattle from mainland China, which will be helpful to understand the prevalence and genetic diversity of Tetraparvovirus ungulate 1.

Isolation and characterization of a novel goose ovaritis-associated cluster 3 Tembusu virus.

Tembusu virus (TMUV) is a member of the genus Flavivirus in the family Flaviviridae. Currently, TMUV was classified into 4 distinct clusters, with cluster 2 strains widely distributed in duck and goose populations in Asia, causing significant economic losses to the producing industries. In this study, a novel TMUV strain TMUV/goose/CHN/2019/HNU-NX2 (HNU-NX2-2019) was isolated and characterized from geese with ovaritis from Hunan province, China. Phylogenetic analyses of genome and the E gene indicated the present TMUV could be grouped into the newly defined TMUV cluster 3. The genome of HNU-NX2-2019 showed the highest identities of 98.1% to 98.2% to the cluster 3 TMUVs newly identified in 2020 and 2021 from chickens with a severe egg-drop syndrome from Guangdong, Guangxi and Shandong provinces of China, which were all showing a close relation to a mosquito-origin TMUV (KT607936) identified in 2012. Further experiments confirmed HNU-NX2-2019 could grow well in chicken fibroblast cell line DF-1 and in SPF chicken embryos, with titers varied from 107.3 to 108.8 viral genomic copies per mL in the culture solutions. A pilot virus challenge study in 3-day-old chicks demonstrated that this virus could efficiently infect chicks with virus distributed in the brains, small intestines and other visceral organs, with titers varied from 105.4 to 106.7viral genomic copies per gram of the tissues. Furthermore, HNU-NX2-2019 can induce specific antibody in ducklings but with no obvious disease and virus shedding, and on necropsy no TMUV was detected in the tissues in the present study. This is the first report to identify a novel cluster 3 TUMV from goose, and further demonstrated this goose TMUV strain could infect chicken efficiently but not in ducklings under the present experimental conditions, which highlighted intensive attentions may be paid to this novel mosquito-origin cluster 3 TMUV.

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 characterization of a novel circovirus species in domestic laying ducks designated as duck circovirus 3 (DuCV3) from Hunan province, China.

Duck circovirus (DuCV) is an immunosuppressive virus and can induce immunosuppression increasing rates of infection caused by other pathogens, which has resulted in gross economic losses in poultry industries. The genome sizes of DuCVs varied from 1987 to 1996 nucleotides (nt). Up to date two DuCV genotypes/lineages, DuCV1 and DuCV2, have been defined, with genome identities of around 83% between each other. In this study, a novel duck circovirus having a genome size of 1755 nt was identified from laying ducks with a disease of egg production declining or abrogation from Hunan province, China. Two major open reading frames (ORFs) were identified, with ORF1 (882 nt) and ORF2 (738 nt) encoding replicase (Rep) and capsid protein (Cap), respectively. Its genome showed the highest identities of 62.3-63.7% and 66.3%- 67.8% to the known genomes of DuCVs and goose circoviruses (GoCVs) available in GenBank, respectively, while it showed less than 50% identities to the genomes of other circoviruses. The amino acid sequence of capsid of this virus showed the highest identities of 45.4%- 47.3% and 42.9%- 44.5% to capsids of the known DuCVs and GoCVs, respectively, while it showed less than 27% identity to the capsid proteins of other circoviruses available in GenBank. Further phylogenetic analyses based on genomes, amino acid sequences of Rep and Cap proteins demonstrated that the present duck circovirus was clustered in a separate clade, distinct from other DuCVs and GoCVs, corroborating it is a distinct novel circovirus species in ducks, tentatively designated as duck cirovirus 3 (DuCV3). The clinical significance and pathogenesis of this virus needs further investigation.

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".