Background Porcine epidemic diarrhea virus (PEDV) is an α-coronavirus that causes highly contagious intestinal infectious disease, involving clinically characterized by diarrhea, dehydration, vomiting, and high mortality to suckling piglets. As a strategy for antiviral therapy, artificial microRNA (amiRNA) mediated suppression of viral replication has recently become increasingly important. In this study, we evaluated the advantages of using an amiRNA vector against PEDV. Methods In this study, we evaluated the advantages of using an amiRNA vector against PEDV. We designed two single amiRNA sequences for different conserved sequences of the PEDV S and N genes, and tested their inhibitory effects on PEDV in Vero cells. Results It was obvious from the CCK-8 results that the transient transfection of amiRNA was non-toxic to the cells. In addition, our results showed that the transient expression of two amiRNAs (amiRNA-349 and amiRNA-1447) significantly reduced the expression of viral RNA and protein in the cells. The TCID50 results showed that the release of virus particles into the culture supernatant was significantly reduced, with an effect as high as 90%. To avoid virus mutation escape, the above two single amiRNA sequences were tandem in this study (amiRNA-349 + 1447), enabling a single microRNA to be expressed simultaneously. The real-time PCR and Western blot results showed that the inhibitory effect was significantly enhanced in each of the different time periods. The TCID50 results showed that the release of virus particles in the culture supernatant was significantly reduced at the different time periods. Conclusions In summary, these results suggest that an RNAi based on amiRNA targeting the conserved region of the virus is an effective method to improve PEDV nucleic acid inhibitors and provide a novel treatment strategy for PEDV infection.

Background: Porcine epidemic diarrhea (PED) is an acute and highly contagious infectious disease caused by the porcine epidemic diarrhea virus (PEDV) that occurs most frequently from winter to spring. It is associated with high morbidity and mortality rates, especially among piglets, and causes huge losses in the pig industry. The aim of this molecular epidemiological study was to identify the current strains of PEDV that are prevalent in Jiangsu Province, China.Methods: From winter 2020 to spring 2021, 793 small intestine tissue, fecal, and anal swab samples were collected from 72 pig farms in 11 counties in the jurisdiction of 5 regions of Jiangsu Province (Yancheng, Suqian, Changzhou, Xuzhou, and Yangzhou). A highly variable region of the S gene was amplified and sequenced, and phylogenetic analysis was conducted to compare this sequence with corresponding sequences from reference strains deposited in GenBank. Results: A total of 457 samples from 57 pig farms were positive for PEDV: this implies a positivity rate of 79% (57/72) for pig farms and a sample positivity rate of 57.6% (457/793). The positivity rates were 78% (107/137) in Yancheng, 53% (218/409) in Suqian, 48% (94/195) in Changzhou, 80% (16/20) in Xuzhou, and 88% (14/16) in Yangzhou. Seven representative samples were selected for sequencing, and phylogenetic analysis showed that the seven isolated strains exhibited 88.0%–100% nucleotide identity and 87.3%–99% amino acid identity. Additionally, our isolates exhibited 88.3%–99.7% nucleotide identity and 88%–98.5% amino acid identity with the reference PEDV strains. Phylogenetic tree analysis indicated that there were considerable difference in the sources of the variants.Conclusions: PEDV had a high infection rate among pigs and is possibly the main pathogenic agent of pig diarrhea in Jiangsu province. Importantly, vaccines must be screened for their efficacy against the newly identified variants.

Background: Porcine epidemic diarrhea (PED) is an acute and highly contagious infectious disease caused by the porcine epidemic diarrhea virus (PEDV) that occurs most frequently from winter to spring. It is associated with high morbidity and mortality rates, especially among piglets, and causes huge losses in the pig industry. The aim of this molecular epidemiological study was to identify the current strains of PEDV that are prevalent in Jiangsu Province, China.Methods: From winter 2020 to spring 2021, 793 small intestine tissue, fecal, and anal swab samples were collected from 72 pig farms in 11 counties in the jurisdiction of 5 regions of Jiangsu Province (Yancheng, Suqian, Changzhou, Xuzhou, and Yangzhou). A highly variable region of the S gene was amplified and sequenced, and phylogenetic analysis was conducted to compare this sequence with corresponding sequences from reference strains deposited in GenBank. Results: A total of 457 samples from 57 pig farms were positive for PEDV: this implies a positivity rate of 79% (57/72) for pig farms and a sample positivity rate of 57.6% (457/793). The positivity rates were 78% (107/137) in Yancheng, 53% (218/409) in Suqian, 48% (94/195) in Changzhou, 80% (16/20) in Xuzhou, and 88% (14/16) in Yangzhou. Seven representative samples were selected for sequencing, and phylogenetic analysis showed that the seven isolated strains exhibited 88.0%–100% nucleotide identity and 87.3%–99% amino acid identity. Additionally, our isolates exhibited 88.3%–99.7% nucleotide identity and 88%–98.5% amino acid identity with the reference PEDV strains. Phylogenetic tree analysis indicated that there were considerable difference in the sources of the variants.Conclusions: PEDV had a high infection rate among pigs and is possibly the main pathogenic agent of pig diarrhea in Jiangsu province. Importantly, vaccines must be screened for their efficacy against the newly identified variants.