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Porcine sapelovirus (PSV) is a new pathogen that negatively impacts the pig industry in China. Affected pigs experience severe diarrhea and even death. Vaccination is used to control disease outbreaks, and sensitive diagnostic methods that can distinguish infected animals from vaccinated animals (DIVA) are essential for monitoring the effectiveness of disease control programs. Tests based on the detection of the nonstructural protein (NSP) 3AB are reliable indicators of viral replication in infected and vaccinated animals. In this study, the recombinant PSV 3AB protein was expressed by a prokaryotic expression system, and an indirect ELISA method was established. Serum samples from healthy animals, immunized animals, and infected animals were evaluated. The ELISA method identified 3AB with high sensitivity (99.78%) and specificity (100.0%), and no cross-reaction was observed with serum antibodies against porcine reproductive and respiratory syndrome virus (PRRSV), infection with classical swine fever virus (CSFV), pseudorabies virus (PRV), bovine viral diarrhea virus (BVDV), porcine epidemic diarrhea virus (PEDV), or foot-and-mouth disease virus (FMDV). The ELISA method described here can effectively distinguish infected and vaccinated animals and is an important inexpensive tool for monitoring serum and controlling PSV.

Background: Porcine Sapelovirus (PSV) infection has been confirmed in pigs worldwide, mostly asymptomatic, but in some cases, it can lead to significant issues in the gastrointestinal, respiratory, neurological, or reproductive systems. PSV is considered an emerging pathogen of porcine species. Recombinase polymerase amplification (RPA) is a simple and fast isothermal technique that uses three enzymes for amplification without the use of any sophisticated equipment. Methods and results: The reverse transcription recombinase polymerase amplification (RT-RPA) assay was developed and optimized for field based detection of PSV. The assay was developed by targeting 5´UTR region of PSV genome and optimized for reaction time, temperature, primer and MgOAc concentration. The analytical sensitivity and specificity of assay was determined. The assay was evaluated on 85 porcine faecal samples collected from field. In addition to conventional format, this assay was also optimized for visual dye-based detection format and lateral flow strips based detection (in combination with probe). The developed assay works at constant temperature of 35 °C for 20 min with forward primer concentration 20pm, reverse primer concentration 10pm and MgOAc concentration of 14mM. This assay is highly sensitive and detects up to 28 copies of viral nucleic acid both in the conventional as well as in fluorescent dye based detection format. Using the newly developed assay 21 samples out of 85 samples were found positive, showing positivity rate of 24.7%. The positivity rate of RT-RPA assay corroborated with the gold standard RT-PCR test. Conclusions: This study presented the development of an RT-RPA isothermal assay for rapid and accurate detection of PSV. The assay is highly sensitive, specific, works at a low and constant temperature, does not require any high-end instrument and can be a potential diagnostics tool for pen-side testing of PSV in the field conditions. The newly developed RT-RPA assay could successfully detect PSV circulating in swine population of Haryana, India. This is a first report of this kind from the region. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is a ubiquitous virus in farmed pigs that is associated with SMEDI syndrome, polioencephalomyelitis, and diarrhea. However, there are few reports on the prevalence and molecular characterization of PSV in Fujian Province, Southern China. In this study, the prevalence of PSV and a poetical combinative strain PSV2020 were characterized using real-time PCR, sequencing, and bioinformatics analysis. As a result, an overall sample prevalence of 30.8% was detected in 260 fecal samples, and a farm prevalence of 76.7% was observed in 30 Fujian pig farms, from 2020 to 2022. Noteably, a high rate of PSV was found in sucking pigs. Bioinformatics analysis showed that the full-length genome of PSV2020 was 7550 bp, and the genetic evolution of its ORF region was closest to the G1 subgroup, which was isolated from Asia and America; the similarity of nucleotides and amino acids to other PSVs was 59.5~88.7% and 51.7~97.0%, respectively. However, VP1 genetic evolution analysis showed a distinct phylogenetic topology from the ORF region; PSV2020 VP1 was closer to the DIAPD5469-10 strain isolated from Italy than strains isolated from Asia and America, which comprise the G1 subgroup based on the ORF region. Amino acid discrepancy analysis illustrated that the PSV2020 VP1 gene inserted twelve additional nucleotides, corresponding to four additional amino acids (STAE) at positions 898–902 AAs. Moreover, a potential recombination signal was observed in the 2A coding region, near the 3′ end of VP1, owing to recombination analysis. Additionally, 3D genetic evolutionary analysis showed that all reference strains demonstrated, to some degree, regional conservation. These results suggested that PSV was highly prevalent in Fujian pig farms, and PSV2020, a PSV-1 genotype strain, showed gene diversity and recombination in evolutionary progress. This study also laid a scientific foundation for the investigation of PSV epidemiology, molecular genetic characteristics, and vaccine development. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is an emerging pathogen associated with symptoms of enteritis, pneumonia, polioencephalomyelitis and reproductive disorders in swine, resulting in significant economic losses. Although PSV is reported to trigger cell apoptosis, its specific molecular mechanism is unclear. In this research, the cell apoptosis induced by PSV infection and its underlying mechanisms were investigated. The morphologic features of apoptosis include nuclear condensation and fragmentation, were observed after PSV infection. The cell apoptosis was confirmed by analyzing the apoptotic rates, caspase activation, and PARP1 cleavage. Caspase inhibitors inhibited the PSVinduced intrinsic apoptosis pathway and reduced viral replication. Among the proteins encoded by PSV, 2A is an important factor in inducing the mitochondrial apoptotic pathway. The conserved residues H48, D91, and C164 related to protease activity in PSV 2A were crucial for 2A-induced apoptosis. In conclusion, our results provide insights into how PSV induces host cell apoptosis. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is a new pathogen that negatively impacts the pig industry in China. Affected pigs experience severe diarrhea and even death. Vaccination is used to control disease outbreaks, and sensitive diagnostic methods that can distinguish infected animals from vaccinated animals (DIVA) are essential for monitoring the effectiveness of disease control programs. Tests based on the detection of the nonstructural protein (NSP) 3AB are reliable indicators of viral replication in infected and vaccinated animals. In this study, the recombinant PSV 3AB protein was expressed by a prokaryotic expression system, and an indirect ELISA method was established. Serum samples from healthy animals, immunized animals, and infected animals were evaluated. The ELISA method identified 3AB with high sensitivity (99.78%) and specificity (100.0%), and no cross-reaction was observed with serum antibodies against porcine reproductive and respiratory syndrome virus (PRRSV), infection with classical swine fever virus (CSFV), pseudorabies virus (PRV), bovine viral diarrhea virus (BVDV), porcine epidemic diarrhea virus (PEDV), or foot-and-mouth disease virus (FMDV). The ELISA method described here can effectively distinguish infected and vaccinated animals and is an important inexpensive tool for monitoring serum and controlling PSV.

Porcine sapelovirus (PSV) is a ubiquitous virus in farmed pigs that is associated with SMEDI syndrome, polioencephalomyelitis, and diarrhea. However, there are few reports on the prevalence and molecular characterization of PSV in Fujian Province, Southern China. In this study, the prevalence of PSV and a poetical combinative strain PSV2020 were characterized using real-time PCR, sequencing, and bioinformatics analysis. As a result, an overall sample prevalence of 30.8% was detected in 260 fecal samples, and a farm prevalence of 76.7% was observed in 30 Fujian pig farms, from 2020 to 2022. Noteably, a high rate of PSV was found in sucking pigs. Bioinformatics analysis showed that the full-length genome of PSV2020 was 7550 bp, and the genetic evolution of its ORF region was closest to the G1 subgroup, which was isolated from Asia and America; the similarity of nucleotides and amino acids to other PSVs was 59.5~88.7% and 51.7~97.0%, respectively. However, VP1 genetic evolution analysis showed a distinct phylogenetic topology from the ORF region; PSV2020 VP1 was closer to the DIAPD5469-10 strain isolated from Italy than strains isolated from Asia and America, which comprise the G1 subgroup based on the ORF region. Amino acid discrepancy analysis illustrated that the PSV2020 VP1 gene inserted twelve additional nucleotides, corresponding to four additional amino acids (STAE) at positions 898–902 AAs. Moreover, a potential recombination signal was observed in the 2A coding region, near the 3′ end of VP1, owing to recombination analysis. Additionally, 3D genetic evolutionary analysis showed that all reference strains demonstrated, to some degree, regional conservation. These results suggested that PSV was highly prevalent in Fujian pig farms, and PSV2020, a PSV-1 genotype strain, showed gene diversity and recombination in evolutionary progress. This study also laid a scientific foundation for the investigation of PSV epidemiology, molecular genetic characteristics, and vaccine development.

Porcine sapelovirus (PSV) is the causative pathogen of reproductive obstacles, acute diarrhea, respiratory distress, or severe polioencephalomyelitis in swine. Nevertheless, the pathogenicity and pathogenic mechanism of PSV infection are not fully understood, which hinders disease prevention and control. In this study, we found that PSV was sensitive to type I interferon (IFN-β). However, PSV could not activate the IFN-β promoter and induce IFN-β mRNA expression, indicating that PSV has evolved an effective mechanism to block IFN-β production. Further study showed that PSV inhibited the production of IFN-β by cleaving mitochondrial antiviral signaling (MAVS) and degrading melanoma differentiation-associated gene 5 (MDA5) and TANK-binding kinase 1 (TBK1) through viral 3Cpro. In addition, our study demonstrated that PSV 3Cpro degrades MDA5 and TBK1 through its protease activity and cleaves MAVS through the caspase pathway. Collectively, our results revealed that PSV inhibits the production of type I interferon to escape host antiviral immunity through cleaving and degrading the adaptor molecules. [ABSTRACT FROM AUTHOR]

Abstract Background Porcine sapelovirus (PSV) infection can lead severe polioencephalomyelitis with high morbidity and mortality, which result in significant economic losses. Infection with the PSV is believed to be common yet limited information is available on the prevalence and molecular characterization of PSV in China. Therefore, the objective of this study was to characterize the prevalence and genome of PSV strains identified in the western Jiangxi province of China. Results A high specificity and sensitivity SYBR Green I-based RT-PCR method for PSV detection was developed. Two hundred and ninety four fecal samples were collected from December 2018 to March 2019 in 4 farms. An overall PSV-positivity rate of 11.22% (33/294) was detected with the real-time RT-PCR method, and a high infection rate and viral load of PSV were found in nursery pigs. In total, complete VP1 gene sequences of 11 PSV strains (PSV-YCs) were obtained. Homology comparisons of the VP1 gene of the 11 PSV-YCs with previously reported PSVs revealed nucleotide sequence identities ranging from 63% to 96.8%, and deduced amino acid sequence identities from 61.4% to 99.7%. Phylogenetic analyses based on the VP1 gene exhibited 2 main clades corresponding to PSV-1 and PSV-2, and all PSV-YCs prevalent in western Jiangxi belonged to the traditional genotype (PSV-1). In addition, the pairwise distances of VP1 gene sequences between PSV-YCs ranged from 0.009 to 0.198, which indicating that substantial genetic diversity among the PSVs in western Jiangxi. Conclusions To the authors’ knowledge, this is the first description of PSV in the Jiangxi province pig herds in China, and it is crucial to understand the epidemiology of the viruses in China. The results also provide an important theoretical foundation for diagnosis and early warning of epidemic diseases caused by PSVs prevailing in this region.

ABSTRACT Diarrhea is one of the most important problems associated with the production of piglets, which have a wide range of possible pathogens. This study identified a strain of porcine sapelovirus (PSV) by using next-generation sequencing (NGS) technologies as the pathogen among fecal samples in a pig herd. Phylogenetic analysis showed that the PSV isolates shared a unique polyprotein and clustered with Chinese isolates identified before 2013. The PSV strain was then isolated and named GS01. The in vitro and in vivo biological characteristics of this virus were then described. Our pathogenicity investigation showed that GS01 could cause an inflammatory reaction and induce serious diarrhea in neonatal piglets. To our knowledge, this is the first isolation and characterization of PSV in western China. Our results demonstrate that the PSV GS01 strain is destructive to neonatal piglets and might show an expanded role for sapeloviruses. IMPORTANCE Porcine sapelovirus (PSV) infection leads to severe polioencephalomyelitis with high morbidity and mortality, resulting in significant economic losses. In previous studies, PSV infections were always subclinical or only involved a series of mild symptoms, including spinal cord damage, inappetence, diarrhea, and breathless. However, in our study, we isolated a novel PSV by virome analysis. We also determined the biological characteristics of this virus in vitro and in vivo. Our study showed that this novel PSV could cause an inflammatory response and induce serious diarrhea in neonatal piglets. To our knowledge, this is the first isolation and characterization of PSV in western China. These findings highlight the importance of prevention for the potential threats of PSV.

Porcine sapelovirus (PSV) is the causative pathogen of reproductive obstacles, acute diarrhea, respiratory distress, or severe polioencephalomyelitis in swine. Nevertheless, the pathogenicity and pathogenic mechanism of PSV infection are not fully understood, which hinders disease prevention and control. In this study, we found that PSV was sensitive to type I interferon (IFN-β). However, PSV could not activate the IFN-β promoter and induce IFN-β mRNA expression, indicating that PSV has evolved an effective mechanism to block IFN-β production. Further study showed that PSV inhibited the production of IFN-β by cleaving mitochondrial antiviral signaling (MAVS) and degrading melanoma differentiation-associated gene 5 (MDA5) and TANK-binding kinase 1 (TBK1) through viral 3Cpro. In addition, our study demonstrated that PSV 3Cpro degrades MDA5 and TBK1 through its protease activity and cleaves MAVS through the caspase pathway. Collectively, our results revealed that PSV inhibits the production of type I interferon to escape host antiviral immunity through cleaving and degrading the adaptor molecules.

Background: Porcine sapelovirus (PSV) infection can lead severe polioencephalomyelitis with high morbidity and mortality, which result in significant economic losses. Infection with the PSV is believed to be common yet limited information is available on the prevalence and molecular characterization of PSV in China. Therefore, the objective of this study was to characterize the prevalence and genome of PSV strains identified in the western Jiangxi province of China. Results: A high specificity and sensitivity SYBR Green I-based RT-PCR method for PSV detection was developed. Two hundred and ninety four fecal samples were collected from December 2018 to March 2019 in 4 farms. An overall PSV-positivity rate of 11.22% (33/294) was detected with the real-time RT-PCR method, and a high infection rate and viral load of PSV were found in nursery pigs. In total, complete VP1 gene sequences of 11 PSV strains (PSV-YCs) were obtained. Homology comparisons of the VP1 gene of the 11 PSV-YCs with previously reported PSVs revealed nucleotide sequence identities ranging from 63% to 96.8%, and deduced amino acid sequence identities from 61.4% to 99.7%. Phylogenetic analyses based on the VP1 gene exhibited 2 main clades corresponding to PSV-1 and PSV-2, and all PSV-YCs prevalent in western Jiangxi belonged to the traditional genotype (PSV-1). In addition, the pairwise distances of VP1 gene sequences between PSV-YCs ranged from 0.009 to 0.198, which indicating that substantial genetic diversity among the PSVs in western Jiangxi. Conclusions: To the authors' knowledge, this is the first description of PSV in the Jiangxi province pig herds in China, and it is crucial to understand the epidemiology of the viruses in China. The results also provide an important theoretical foundation for diagnosis and early warning of epidemic diseases caused by PSVs prevailing in this region. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is an important emerging pathogen associated with a wide variety of diseases in swine, including acute diarrhoea, respiratory distress, skin lesions, severe neurological disorders, and reproductive failure. Although PSV is widespread, serological assays for field-based epidemiological studies are not yet available. Here, four PSV strains were recovered from diarrheic piglets, and electron microscopy revealed virus particles with a diameter of ~32 nm. Analysis of the entire genome sequence revealed that the genomes of PSV isolates ranged 7569–7572 nucleotides in length. Phylogenetic analysis showed that the isolated viruses were classified together with strains from China. Additionally, monoclonal antibodies for the recombinant PSV-VP1 protein were developed to specifically detect PSV infection in cells, and we demonstrated that isolated PSVs could only replicate in cells of porcine origin. Using recombinant PSV-VP1 protein as the coating antigen, we developed an indirect ELISA for the first time for the detection of PSV antibodies in serum. A total of 516 swine serum samples were tested, and PSV positive rate was 79.3%. The virus isolates, monoclonal antibodies and indirect ELISA developed would be useful for further understanding the pathophysiology of PSV, developing new diagnostic assays, and investigating the epidemiology of the PSV.

Swine diarrhea can be caused by multiple agents, including porcine epidemic diarrhea virus (PEDV), porcine sapelovirus (PSV), and porcine sapovirus (SaV). We designed a one-step triplex reverse-transcription PCR (RT-PCR) detection method including 3 pairs of primers that focused on the S1 gene of PEDV, a conserved gene of PSV, and the VP1 gene of SaV. The optimal concentrations of upstream and downstream primers in the triplex RT-PCR were 0.24 μM for PEDV, 0.15 μM for PSV, and 0.2 μM for SaV, and the optimal annealing temperature was 55.5°C. Triplex RT-PCR assessment of 402 piglet diarrhea samples was compared with conventional individual RT-PCR. Concordance rates in both tests for individual viruses were 100%, 97.6%, and 94.4% for PEDV, PSV, and SaV, respectively. PEDV, PSV, and SaV were detected in 57.2%, 10.4%, and 9.0% of the samples, respectively. The high sensitivity and specificity of this triplex RT-PCR–based detection method for PEDV, PSV, and SaV could allow rapid detection and analysis of mixed infections by these 3 viruses. [ABSTRACT FROM AUTHOR]

The present study describes an immunocytochemistry (ICC) assay with self-raised hyperimmune sera and a Baby Hamster Kidney-21 (BHK-21) cell line infected with Porcine Sapelovirus (PSV). Sapelovivus/IVRI/SPF-c-6/2015 strain Indian PSV was isolated from the porcine IBRS-2 cell line and investigated for growth on non-porcine cell lines. After two passages, PSV was successfully grown in BHK-21 and produced the same cytopathic effects as in IBRS-2 such as shrinking of cytoplasm, rounding of cells and detachment of cells from the surface of flask within 24 h. For raising of hyperimmune sera, PSV was grown in IBRS-2 cell line up to the required volume and purified by ultracentrifugation. With self-raised hyperimmune sera in laboratory rats, ICC was performed in BHK-21 cells infected with PSV. Positive signals consisted of large granular aggregates of virus in the cytoplasm near the nucleus, suggesting that PSV can infect cell lines other than those of porcine origin. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present study was to pathological and molecular investigation of porcine sapelovirus (PSV) in naturally infected Indian pigs of various age groups. Eight samples (16%) out of 49 necropsied animals were positive for PSV on the basis of pathological and molecular investigation. Major lesions of PSV positive cases were thickening and clouding of meninges, congestion in brain, severe to moderate congestion in lungs along with froathy exudates in trachea, thickening of intestinal mucosa, especially mucosal folds of ileum. Microscopic lesions of PSV positive cases in CNS were perivascular cuffing, neuronophagia and focal gliosis. In lungs, interstitial pneumonia was noticed in all cases, and intestinal lesions comprised of sloughing of villi epithelium, moderate to severe congestion of blood vessels and infiltration of mononuclear cells mainly plasma cells in both large and small intestine. RT-PCR results of total cases examined for PSV were targeted for PSV 3D Polymerase, 5′UTR region and VP1 gene respectively. Genetic characterization was done on the basis of viral capsid protein 1 (VP1) gene of PSV. The sequencing and phylogenetic analysis of amplified VP1 gene product showed maximum identity 85–90% with South Korean, KJ821021.1 and Indian, KY053835.1 strain of PSV. Further explorative surveillance and epidemiological studies are suggested to find out the real impact of this economically important disease affecting pigs population of India. Highlights • The present study was to pathological and molecular investigation of porcine sapelovirus (PSV) in Indian pigs of various age groups. • Eight samples (16%) out of 49 necropsied animals were positive for PSV. • The sequencing and phylogenetic analysis of amplified VP1 gene product showed maximum identity 85-90% with South Korean and Indian strain of PSV. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) belongs to the genus Sapelovirus of the family Picornaviridae. PSV infects pigs asymptomatically, but it can also cause severe neurologic, enteric, and respiratory symptoms or reproductive failure. Sapelovirus infections have been reported worldwide in pigs. The objective of this study was to investigate the presence and the prevalence of PSV in Italian swine farms in animals of different ages to clarify the occurrence of the infection and the genetic characteristics of circulating strains. In the present study, 92 pools of fecal samples, collected from pigs across three farms, were analyzed by Reverse Transcriptase-polymerase Chain Reaction-PCR (RT-PCR). Fecal pools from young growers (63/64) were found positive for Sapelovirus in all farms while detection in sows (4/28) was observed in only one farm. Phylogenetic analyses of the 19 partial capsid protein nucleotide sequences (VP1) (6–7 each farm) enable the classification of the virus sequences into three distinct clades and highlighted the high heterogeneity within one farm. The whole genome sequence obtained from one strain showed the highest correlation with the Italian strain detected in 2015. The study adds novel information about the circulation and heterogeneity of PSV strains in Italy and considering the movement of pigs across Europe would also be informative for other countries.

Porcine sapelovirus (PSV) has been detected worldwide in pig populations. Although PSV causes various symptoms such as encephalomyelitis, diarrhea, and pneumonia in pigs, the economic impact of PSV infection remains to be determined. However, information on the distribution and genetic diversity of PSV is quite limited, particularly in Africa. In this study, we investigated the prevalence of PSV infection in Zambia and characterized the isolated PSVs genetically and biologically. We screened 147 fecal samples collected in 2018 and found that the prevalences of PSV infection in suckling pigs and fattening pigs were high (36.2% and 94.0%, respectively). Phylogenetic analyses revealed that the Zambian PSVs were divided into three different lineages (Lineages 1−3) in the clade consisting of Chinese strains. The Zambian PSVs belonging to Lineages 2 and 3 replicated more efficiently than those belonging to Lineage 1 in Vero E6 and BHK cells. Bioinformatic analyses revealed that genetic recombination events had occurred and the recombination breakpoints were located in the L and 2A genes. Our results indicated that at least two biologically distinct PSVs could be circulating in the Zambian pig population and that genetic recombination played a role in the evolution of PSVs.

Porcine sapelovirus (PSV) is an important emerging swine pathogen that causes diarrhoea, respiratory distress, severe reproductive system and neurological disorders in pigs, posing huge threat to swine industry. However, there are no effective serological diagnostic products and the epitope characterization of PSV VP1 protein is still largely unknown. In current study, we successfully expressed recombinant His-VP1 protein by prokaryotic expression system and the recombinant VP1 protein had good immunogenicity. BALB/C mice were then selected and immunized with purified recombinant VP1 protein, and two monoclonal antibodies (Mabs) 9F10 and 15E4 against VP1 were successfully prepared by hybrioma technology. The isotype of these two Mabs were identified and showed that Mab 9F10 with the heavy chain subtype was IgG1 and the light chain subtype was kappa. Mab 15E4 was identified as IgG2 for the heavy chain subtype and Kappa for the light chain subtype. The antigen epitopes of prepared two VP1 Mabs were clearly identified. The minimal unit of B cell specific epitope recognized by Mab 15E4 was 203YDGDG207 and conserved in different strain genotypes of PSV, indicating this epitope may be a good target for serological detection of PSV. However, the epitope recognized by Mab 9F10 was 8QAIVNRT14 and varied greatly among different PSV strains. Structural modeling analysis showed that the identified two novel B cell epitopes were located on the surface of VP1. Our study provides useful tool for the establishment the serological detection methods of PSV and may support the study of VP1 protein function. • Two Mabs 9F10 and 15E4 against VP1 were successfully prepared by hybrioma technology. • The core epitope of Mab 15E4 was 203YDGDG207 and conserved in different strains of PSV. • The Mab 9F10 epitope was 8QAIVNRT14 and varied among different PSV strains. • The two novel B cell epitopes were located on the surface of VP1. [ABSTRACT FROM AUTHOR]

Summary: Porcine sapelovirus (PSV) A belongs to the genus Sapelovirus, family Picornaviridae. PSV infections in pigs have been reported from European countries, United States, Japan, China, Korea and Brazil. The virus has been isolated/detected from faeces of healthy pigs as well as those affected with diarrhoea, respiratory signs, encephalitis, skin lesions and fertility disorders. This study was planned to investigate whether PSV is prevalent among pigs in India and to characterize PSV encountered in the study population. The study revealed that five of 70 (7.14%) faecal samples were found positive for PSV using RT‐PCR. Three viruses were successfully isolated from faecal samples using IB‐RS‐2 cell line. Complete genome sequencing and analysis of one Indian PSV isolate revealed highest homology (88%) with V13 strain from England. Phylogenetic analysis of the complete polyprotein nucleotide sequences of 14 strains of PSV classified the viruses into four distinct clades. This first report from India adds to our knowledge on genetic diversity of PSV detected so far among pigs in different countries. A large‐scale surveillance of the virus is required to understand its genomic diversity and economic impact. [ABSTRACT FROM AUTHOR]

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Highlights: [•] We developed a fast and accurate RT-LAMP detection method for Porcine Sapelovirus. [•] The amplification can be carried out at consistent 63°C in a water bath. [•] The sensitivity of this method was 10 copies/μL. [•] The primers were specific to Porcine Sapelovirus with no cross-reaction with other related viruses. [•] The RT-LAMP for detection of Porcine Sapelovirus was better than SYBR RT-PCR and/or conventional RT-PCR. [ABSTRACT FROM AUTHOR]

Highlights: [•] A 5′ conjugated minor groove binder (MGB) probe real-time PCR assay was developed in this study for porcine sapelovirus (PSV) detection and quantitation. [•] The developed assay was capable of detecting about 103 copies/μl of standard template per reaction. [•] The coefficients of variation of intra- and inter-assay reproducibility were both lower than 2%. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is an emerging pathogen associated with symptoms of enteritis, pneumonia, polioencephalomyelitis and reproductive disorders in swine, resulting in significant economic losses. Although PSV is reported to trigger cell apoptosis, its specific molecular mechanism is unclear. In this research, the cell apoptosis induced by PSV infection and its underlying mechanisms were investigated. The morphologic features of apoptosis include nuclear condensation and fragmentation, were observed after PSV infection. The cell apoptosis was confirmed by analyzing the apoptotic rates, caspase activation, and PARP1 cleavage. Caspase inhibitors inhibited the PSV-induced intrinsic apoptosis pathway and reduced viral replication. Among the proteins encoded by PSV, 2A is an important factor in inducing the mitochondrial apoptotic pathway. The conserved residues H48, D91, and C164 related to protease activity in PSV 2A were crucial for 2A-induced apoptosis. In conclusion, our results provide insights into how PSV induces host cell apoptosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mou, Wang, Pan, Shi and Chen.)

Diarrhea is one of the most important problems associated with the production of piglets, which have a wide range of possible pathogens. This study identified a strain of porcine sapelovirus (PSV) by using next-generation sequencing (NGS) technologies as the pathogen among fecal samples in a pig herd. Phylogenetic analysis showed that the PSV isolates shared a unique polyprotein and clustered with Chinese isolates identified before 2013. The PSV strain was then isolated and named GS01. The in vitro and in vivo biological characteristics of this virus were then described. Our pathogenicity investigation showed that GS01 could cause an inflammatory reaction and induce serious diarrhea in neonatal piglets. To our knowledge, this is the first isolation and characterization of PSV in western China. Our results demonstrate that the PSV GS01 strain is destructive to neonatal piglets and might show an expanded role for sapeloviruses. IMPORTANCE Porcine sapelovirus (PSV) infection leads to severe polioencephalomyelitis with high morbidity and mortality, resulting in significant economic losses. In previous studies, PSV infections were always subclinical or only involved a series of mild symptoms, including spinal cord damage, inappetence, diarrhea, and breathless. However, in our study, we isolated a novel PSV by virome analysis. We also determined the biological characteristics of this virus in vitro and in vivo . Our study showed that this novel PSV could cause an inflammatory response and induce serious diarrhea in neonatal piglets. To our knowledge, this is the first isolation and characterization of PSV in western China. These findings highlight the importance of prevention for the potential threats of PSV.

Porcine sapelovirus (PSV) is the causative pathogen of reproductive obstacles, acute diarrhea, respiratory distress, or severe polioencephalomyelitis in swine. Nevertheless, the pathogenicity and pathogenic mechanism of PSV infection are not fully understood, which hinders disease prevention and control. In this study, we found that PSV was sensitive to type I interferon (IFN-β). However, PSV could not activate the IFN-β promoter and induce IFN-β mRNA expression, indicating that PSV has evolved an effective mechanism to block IFN-β production. Further study showed that PSV inhibited the production of IFN-β by cleaving mitochondrial antiviral signaling (MAVS) and degrading melanoma differentiation-associated gene 5 (MDA5) and TANK-binding kinase 1 (TBK1) through viral 3C pro . In addition, our study demonstrated that PSV 3C pro degrades MDA5 and TBK1 through its protease activity and cleaves MAVS through the caspase pathway. Collectively, our results revealed that PSV inhibits the production of type I interferon to escape host antiviral immunity through cleaving and degrading the adaptor molecules., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yin, Wen, Wang, Zhao, Zhu, Chen, Li and Qian.)

A novel sapelovirus-like virus was isolated from a wild boar ( Sus scrofa). In this study, partial viral genomic nucleotide sequences were determined using the rapid determination system of viral nucleic acid sequences (RDV) ver. 3.1, which we recently developed for discovering novel viruses. Phylogenetic analysis of VP1 and 3A proteins and their encoding nucleotide sequences of enteroviruses and sapeloviruses indicated that the isolated virus was closely related to porcine sapelovirus. RT-PCR detected viral sequences in six of 48 wild boar fecal samples. [ABSTRACT FROM AUTHOR]

Porcine sapelovirus (PSV) is an important emerging pathogen associated with a wide variety of diseases in swine, including acute diarrhoea, respiratory distress, skin lesions, severe neurological disorders, and reproductive failure. Although PSV is widespread, serological assays for field-based epidemiological studies are not yet available. Here, four PSV strains were recovered from diarrheic piglets, and electron microscopy revealed virus particles with a diameter of ~32 nm. Analysis of the entire genome sequence revealed that the genomes of PSV isolates ranged 7569–7572 nucleotides in length. Phylogenetic analysis showed that the isolated viruses were classified together with strains from China. Additionally, monoclonal antibodies for the recombinant PSV-VP1 protein were developed to specifically detect PSV infection in cells, and we demonstrated that isolated PSVs could only replicate in cells of porcine origin. Using recombinant PSV-VP1 protein as the coating antigen, we developed an indirect ELISA for the first time for the detection of PSV antibodies in serum. A total of 516 swine serum samples were tested, and PSV positive rate was 79.3%. The virus isolates, monoclonal antibodies and indirect ELISA developed would be useful for further understanding the pathophysiology of PSV, developing new diagnostic assays, and investigating the epidemiology of the PSV. [ABSTRACT FROM AUTHOR]

Conventionally, Porcine sapelovirus (PSV) has been considered to comprise a single geno- type, PSV-1; however, a potentially novel member of PSV was recently discovered. In the present study, we propose a genotype definition of PSV based on phylogenetic and genetic analyses of the polyprotein, P1, and VP1 genes of available PSV sequences. Two genotypes, with proposed names PSV-1 and PSV-2, were identified. Moreover, the cut-off values (number of differences per site between amino acid sequences) for the definition of genotypes were established to be 0.1115 (polyprotein), 0.176 (P1), and 0.272 (VP1). The findings of this study are expected to enrich knowledge of PSV classification., (Copyright© by the Polish Academy of Sciences.)

Simple Summary: Sapelovirus (PSV) is known to infect pigs asymptomatically but, sporadically, can cause reproductive failure and severe neurologic, enteric, or respiratory signs. Sapelovirus infections have been reported worldwide in pigs. However, information about PSV circulation in Italy is unavailable and rarely investigated across Europe. In this study, we reported the circulation of PSV in three Italian pig farms and added novel information about evolutionary heterogeneity of PSV strains showing a low genetic correlation with the other strains detected worldwide. The present study gives information about PSV circulation in intensive pig farms and highlights the need for further investigation. Porcine sapelovirus (PSV) belongs to the genus Sapelovirus of the family Picornaviridae. PSV infects pigs asymptomatically, but it can also cause severe neurologic, enteric, and respiratory symptoms or reproductive failure. Sapelovirus infections have been reported worldwide in pigs. The objective of this study was to investigate the presence and the prevalence of PSV in Italian swine farms in animals of different ages to clarify the occurrence of the infection and the genetic characteristics of circulating strains. In the present study, 92 pools of fecal samples, collected from pigs across three farms, were analyzed by Reverse Transcriptase-polymerase Chain Reaction-PCR (RT-PCR). Fecal pools from young growers (63/64) were found positive for Sapelovirus in all farms while detection in sows (4/28) was observed in only one farm. Phylogenetic analyses of the 19 partial capsid protein nucleotide sequences (VP1) (6–7 each farm) enable the classification of the virus sequences into three distinct clades and highlighted the high heterogeneity within one farm. The whole genome sequence obtained from one strain showed the highest correlation with the Italian strain detected in 2015. The study adds novel information about the circulation and heterogeneity of PSV strains in Italy and considering the movement of pigs across Europe would also be informative for other countries. [ABSTRACT FROM AUTHOR]