Ruiming Hu

Porcine epidemic diarrhea virus (PEDV) is a major pathogen affecting the global swine industry, causing severe diarrhea, dehydration, and high mortality in neonatal piglets. Due to the continuous emergence of viral variants, the protective efficacy of currently available vaccines remains suboptimal, highlighting the urgent need for effective antiviral agents. In this study, we investigated the anti-PEDV activity of muscone in vitro. Our results demonstrated that muscone inhibits PEDV replication in a dose-dependent manner and exerts its antiviral effect primarily during the early stages of viral infection. Further mechanistic studies revealed that muscone acts mainly by interfering with viral entry into host cells. Specifically, Western blot analysis and confocal microscopy showed that muscone treatment led to the degradation of caveolin-1, suggesting that muscone may block PEDV entry by disrupting caveolin-mediated endocytosis. Collectively, our findings provide clear evidence that muscone possesses potent anti-PEDV activity in vitro and offer mechanistic insights into its mode of action, thereby establishing muscone as a promising lead compound for the development of novel antiviral strategies against PEDV.

Duck enteritis virus (DEV), goose parvovirus (GPV), and muscovy duck parvovirus (MDPV) all have similar symptoms after infection, such as severe diarrhea, which seriously affects the healthy development of the waterfowl industry. Hence, it is important to devise a rapid and precise assay for the detection of these three viruses. In this study, a TaqMan probe-based multi-quantitative polymerase chain reaction (qPCR) assay was developed and optimized. Three specific primers and probes were designed according to the conserved regions of UL6 of DEV, REP of GPV, and VP1 of MDPV, respectively. DEV demonstrated a detection limit of 11.6 copies, GPV detected a limit of 95 copies, and MDPV showcased a detection limit of 14.8 copies. The correlation coefficient is greater than 0.99, and the amplification efficiency is 89% to 93%. These results indicate that the multiplex qPCR assay has high sensitivity, specificity, and stability. Of the 215 clinical samples used in this study, 33 tested DEV positive, 25 tested GPV positive, and 24 tested MDPV positive. Overall, the assay established in the current study presents a rapid, efficient, specific, and sensitive tool for of detecting DEV, GPV, and MDPV.

Porcine epidemic diarrhea virus (PEDV) is an enteric coronavirus that can cause acute diarrhea, vomiting, dehydration, and high mortality of newborn piglets, leading to huge economic losses to the world pig industry. Given the limited efficacy of current PEDV vaccines, there is an urgent need for the development of antiviral drugs. In this study, the antiviral effects of 17 synthesized indole alkaloid derivatives against PEDV were investigated. It was observed that indole alkaloid derivative no. 14 exhibited significant inhibition of PEDV replication in a dose-dependent manner. Furthermore, time-of-addition assays and quantitative real-time PCR (QPCR) showed that delayed administration of this compound resulted in a weaker inhibitory effect on PEDV compared to early treatment. Mechanistic analysis revealed that this compound exerts its inhibitory effects during the entry stage of the PEDV life cycle. This study demonstrates the anti-PEDV effects of indole alkaloid derivative no. 14, suggesting its potential as a candidate drug for treating PEDV infections.

Background: Porcine Teschovirus (PTV), also named Teschovirus A, is prevalent in pig populations, mainly causing neurological symptoms, diarrhea, pneumonia, and reproductive failure, however the morbidity and mortality are usually low in pig farms. Case presentation: In this study, we reported a PTV outbreak investigation in one large-scale pig farm in China with severe symptoms including diarrhea, lethargy, locomotor ataxia, nystagmus, paralysis of the hind limbs, and coma in piglets. More importantly, the mortality reached 38% in suckling pigs, which is remarkably high in PTV history. A novel PTV strain, named HeNZ1, was isolated from cerebral samples of one suckling pig and the genome sequence was obtained by NGS sequencing. Phylogenetic and evolutionary divergence analyses revealed that HeNZ1 belongs to PTV genotype 2. Surprisingly, the VP1 coding region of HeNZ1 shares the highest sequence similarity with European PTV-2 strains, instead of China domestic PTV-2 strains, implying it may not derive from China local PTV-2 strains. Multiple sequence alignment and B cell epitope prediction of PTV VP1 and VP2 protein revealed 10 B cell epitopes, 5 mutant clusters and 36 unique mutation sites, of which 19 unique mutation sites are located in B cell epitopes and exposed on the surface of VP1 or VP2, implying significant antigenic drift potential of HeNZ1. Conclusion: These results indicate that HeNZ1 is a highly virulent PTV-2 strain, which capable of causing severe neurological symptoms and high mortality in piglets. Bioinformatic analysis suggest that HeNZ1 is genetically and antigenically different from other Chinese PTV-2 strains. Overall, current case expanded our understanding of PTV-2 clinical spectrum and revealed the emergence of a highly virulent PTV-2 strain with substantial genetic diversity and antigenic drift potential in VP1 and VP2.

Porcine epidemic diarrhea virus (PEDV), an enteric coronavirus, causes neonatal pig acute gastrointestinal infection with a characterization of severe diarrhea, vomiting, high morbidity, and high mortality, resulting in tremendous damages to the swine industry. Neither specific antiviral drugs nor effective vaccines are available, posing a high priority to screen antiviral drugs. The aim of this study is to investigate anti-PEDV effects of carbazole alkaloid derivatives. Eighteen carbazole derivatives (No.1 to No.18) were synthesized, and No.5, No.7, and No.18 were identified to markedly reduce the replication of enhanced green fluorescent protein (EGFP) inserted-PEDV, and the mRNA level of PEDV N. Flow cytometry assay, coupled with CCK8 assay, confirmed No.7 and No.18 carbazole derivatives displayed high inhibition effects with low cell toxicity. Furthermore, time course analysis indicated No.7 and No.18 carbazole derivatives exerted inhibition at the early stage of the viral life cycle. Collectively, the analysis underlines the benefit of carbazole derivatives as potential inhibitors of PEDV, and provides candidates for the development of novel therapeutic agents.

Pseudorabies virus (PRV) is an economically significant swine infectious agent. A PRV outbreak took place in China in 2011 with novel virulent variants. Although the association of viral genomic variability with pathogenicity is not fully confirmed, the knowledge concerning PRV genomic diversity and evolution is still limited. Here, we sequenced 54 genomes of novel PRV variants isolated in China from 2012 to 2017. Phylogenetic analysis revealed that China strains and US/Europe strains were classified into two separate genotypes. PRV strains isolated from 2012 to 2017 in China are highly related to each other and genetically close to classic China strains such as Ea, Fa, and SC. RDP analysis revealed 23 recombination events within novel PRV variants, indicating that recombination contributes significantly to the viral evolution. The selection pressure analysis indicated that most ORFs were under evolutionary constraint, and 19 amino acid residue sites in 15 ORFs were identified under positive selection. Additionally, 37 unique mutations were identified in 19 ORFs, which distinguish the novel variants from classic strains. Overall, our study suggested that novel PRV variants might evolve from classical PRV strains through point mutation and recombination mechanisms.

This study aims to evaluate the anti–heat stress effect of Chinese herbal medicine (CHM) prescription, rumen‐protected γ‐aminobutyric acid (RP‐GABA), and CHM plus RP‐GABA co‐medication on growth performance, apparent digestibility, and serum parameters in heat‐stressed beef cattle. Forty beef cattle were randomly divided into four groups. Control group was supplied with basal diet, while CHM, γ‐aminobutyric acid (GABA), and CHM + GABA groups were, respectively, supplied with CHM, RP‐GABA, and CHM plus RP‐GABA in basal diet. Our result indicated that CHM + GABA elevated apparent digestibility including crude protein, Ca, P, crude fat (CF) (p < .01), and neutral detergent fiber (NDF) (p < .05), but no difference was found with CF and NDF digestibility both in CHM and GABA group (p > .05). More importantly, average daily gain (ADG) was improved in CHM, GABA, and CHM + GABA groups, while average daily feed intake (ADFI) significantly increased only in CHM + GABA groups (p < .05). Meanwhile, CHM + GABA displayed notably more positive effect in serum hormones, immune globulin, ions contents, and blood inflammatory cytokines than other treatment groups and control group. These results demonstrated that both CHM and GABA are effective in alleviating heat stress response and the co‐medication has a synergistic effect on anti–heat stress.