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Porcine deltacoronavirus (PDCoV) is a newly identified virus that causes watery diarrhea in newborn piglets and results in significant economic losses to the pig industry. Since first reported in Hong Kong in 2012, PDCoV has been subsequently detected in USA, South Korea, Thailand, and mainland China. Here we isolated a strain of PDCoV, named CHN-GD-2016, from the intestinal content of a diseased newborn piglet with severe diarrhea in a pig farm in Guangdong, China. PDCoV CHN-GD-2016 could be identified by immunofluorescence with PDCoV specific rabbit antisera, and typical crown-shaped particles with spiky surface projections of this PDCoV were observed with electron microscopy. Genomic analysis showed that the PDCoV CHN-GD-2016 was closely related to other Chinese PDCoV strains, with the highest sequence similarity with the strain CHN/Tianjin/2016. Importantly, inoculation of newborn piglets with 1 × 10 5 TCID 50 of CHN-GD-2016 by oral feeding successfully reproduced clear clinical symptoms, including vomiting, dehydration, and severe diarrhea in piglets. In addition, the virus RNA in rectal swabs from 1 to 7 days post inoculation was detected, macroscopic and microscopic lesions in small intestine were observed, and viral antigen was also detected in the small intestines with immunohistochemical staining. Collectively, the data show in this study confirms that PDCoV is present in Guangdong, China and is highly pathogenic in newborn piglets.

QY2010 is a highly pathogenic North American-type porcine reproductive and respiratory syndrome virus (PRRSV). The complete genome sequence shows that QY2010 shares low sequence identity (60 to 88.7%) to all known PRRSV isolates. Phylogenetic analyses further reveal that QY2010 constitutes a novel subgroup within the North American genotype of PRRSV.

Swine acute diarrhoea syndrome coronavirus (SADS‐CoV) is a newly identified swine enteropathogenic coronavirus that causes watery diarrhoea in neonatal piglets, leading to significant economic losses to the swine industry. Currently, there are no suitable serological methods to assess the infection of SADS‐CoV and effectiveness of vaccines, making an urgent need to exploit effective enzyme‐linked immunosorbent assay (ELISA) to compensate for this deficiency. Here, a recombinant plasmid that expresses the spike (S) protein of SADS‐CoV fused to the Fc domain of human IgG was constructed to generate recombinant baculovirus and expressed in HEK 293F cells. The S‐Fc protein was purified with protein G Resin, which retained reactivity with anti‐human Fc and anti‐SADS‐CoV antibodies. The S‐Fc protein was then used to develop an indirect ELISA (S‐iELISA) and the reaction conditions of S‐iELISA were optimized. As a result, the cut‐off value was determined as 0.3711 by analyzing OD450nm values of 40 SADS‐CoV‐negative sera confirmed by immunofluorescence assay (IFA) and western blot. The coefficient of variation (CV) of 6 SADS‐CoV‐positive sera within and between runs of S‐iELISA were both less than 10%. The cross‐reactivity assays demonstrated that S‐iELISA was non‐cross‐reactive with other swine viruses' sera. Furthermore, the overall coincidence rate between IFA and S‐iELISA was 97.3% based on testing 111 clinical serum samples. Virus neutralization test with seven different OD450nm values of the sera showed that the OD450nm values tested by S‐iELISA are positively correlated with the virus neutralization assay. Finally, a total of 300 pig field serum samples were tested by S‐iELISA and commercial kits of other swine enteroviruses showed that the IgG‐positive for SADS‐CoV, TGEV, PDCoV and PEDV was 81.7, 54, 65.3 and 6%, respectively. The results suggest that this S‐iELISA is specific, sensitive, repeatable and can be applied for the detection of the SADS‐CoV infection in the swine industry. [ABSTRACT FROM AUTHOR]

Porcine enteric alphacoronavirus (PEAV) was first discovered in China in February 2017, and the origin and virulence of this novel porcine coronavirus were not fully characterized. Here, we isolated a strain of PEAV, named GDS04 that is identified by immunofluorescence and typical crown‐shaped particles observed with electron microscopy. Genomic analysis reveals that PEAV GDS04 shares a close relationship with SADS‐CoV and SeACoV. Furthermore, newborn piglets orally challenged with PEAV GDS04 developed typical clinical symptoms as watery diarrhoea in neonatal piglets. Viral RNA was detected in faeces and various tissues of the infected piglets. Moreover, macroscopic and microscopic lesions in whole intestinal tract were observed, and viral antigen could be detected in the small intestines by immunohistochemical staining and electron microscopy. Importantly, the mortality rate of inoculated‐newborn piglets was 100% and half of the cohabiting piglets died. Collectively, we demonstrate that PEAV is highly pathogenic in newborn piglets. [ABSTRACT FROM AUTHOR]

We identified from suckling piglets with diarrhea in China a new bat-HKU2-like porcine coronavirus (porcine enteric alphacoronavirus). The GDS04 strain of this coronavirus shares high aa identities (>90%) with the reported bat-HKU2 strains in Coronaviridae-wide conserved domains, suggesting that the GDS04 strain belongs to the same species as HKU2. [ABSTRACT FROM AUTHOR]

Since October 2010, an outbreak of porcine epidemic diarrhea (PED) has been observed in some provinces of China. Here we report the complete genome sequence of porcine epidemic diarrhea virus (PEDV) strain LC, which was recently isolated from sucking piglets that suffered from severe watery diarrhea in Guangdong. It will help in understanding the epidemiological and molecular characteristics of PEDV in China. [ABSTRACT FROM AUTHOR]