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In November 2018, an outbreak of respiratory disease occurred in foals at an equestrian club in Changji, northern Xinjiang, China. We applied viral metagenomics to investigate this outbreak and identify potential pathogens involved in this equine respiratory syndrome. The metagenomics data revealed the presence of sequences matching those of equid herpesvirus (EHV) 2, 4, and 5. PCR with specific primers targeting ORF33 of EHV-4 and ORF8 of EHV-2 and EHV-5 revealed coinfection with these viruses in this respiratory syndrome. To investigate the prevalence of these viruses in China, 453 nasal swabs from clinically healthy thoroughbred foals (36/453, 7.9%) and horses (417/453, 92.1%) were collected from several equestrian clubs. Forty-five (9.9%) of the samples tested positive for EHV-5 DNA, and seven (1.5%) tested positive for EHV-2, but all were negative for EHV-4 DNA. Forty-nine (10.8%) samples tested positive for both EHV-5 and EHV-2 DNA. Using these samples, one complete EHV-4 ORF33, 10 partial EHV-2 ORF8, and 50 partial EHV-5 ORF8 sequences from the 10 diseased foals and 50 thoroughbred horses were then determined. Sequence analysis indicated that EHV-4 ORF33 and EHV-5 ORF8, in contrast to EHV-2 ORF8, had high sequence similarity to those of published sequences. Our data provide the first evidence that EHV-2, -4, and -5 co-circulate in China and that EHV-4 is potentially involved in this respiratory disease in foals. [ABSTRACT FROM AUTHOR]

Background: In May 2018, a 8 year old thoroughbred mare died at an equestrian club in Changji, Xinjiang, China. The horse had been imported from the United States in 2013. She became pregnant in December 2016 but, after foaling, gradually lost weight and died in May 2018. This study aim to identify the pathogen, who cause of horse death, using virome. Results: We have identified an Equ1-like virus from the fecal virome of a dead thoroughbred mare in China. Full genomic sequencing and phylogenetic analysis of the virus, tentatively named "kirkovirus Cj-7-7", showed that it was closely related to kirkovirus Equ1 and clustered together with po-circo-like viruses 21, 22, 41, and 51, suggesting that it should be assigned to the proposed family "Kirkoviridae". An epidemiological investigation showed that kirkovirus Cj-7-7 circulates in horses of northern Xinjiang and may specifically infect intestinal cells. Conclusions: Our findings demonstrate the genetic diversity and geographic distribution of Kirkoviruses, and the prevalence of Kirkovirus Cj-7-7 in Xinjiang, China. [ABSTRACT FROM AUTHOR]

NS5A is a multifunctional non-structural protein of classical swine fever virus (CSFV) that plays an important role in viral replication, but how it exerts its functions is unknown. Here, we report the cleavage of NS5A of the vaccine C-strain, resulting in two truncated forms (b and c). Further experiments using calpain- and caspase-family-specific inhibitors, followed by a caspase-6-specific shRNAs and inhibitor, showed that the cleavage of C-strain NS5A to produce truncated form c is mediated by caspase-6, mapping to DTTD, while the cleavage producing truncated form b is probably mediated by another unknown protease. shRNA-mediated downregulation of caspase-6 and blocking of enzyme activity in ST cells significantly impaired genome replication and virus production, indicating that NS5A cleavage is required for CSFV replication. [ABSTRACT FROM AUTHOR]