Proteolysis-targeting chimeras (PROTACs) are powerful tools for targeted protein degradation and are expected to contribute to a promising strategy for next-generation precision therapeutic antiviral drug development. Nanobody-based bioPROTACs can directly bind to protein and mediate target protein degradation, providing a potential antiviral strategy for RNA viruses featuring error-prone replication. Here, we aimed to establish a modular speckle-type POZ protein (SPOP)-derived bioPROTAC platform that enabled rapid antiviral drug construction through the substitution of a target protein-specific nanobody. Using porcine reproductive and respiratory syndrome virus (PRRSV) as a model pathogen, bioPROTACs molecules were successfully constructed by flexibly fusing nanobodies against PRRSV nonstructural protein 9 (Nsp9, viral RdRp) to the BTB domain of SPOP. BioPROTACs demonstrated specific degradation of target proteins in a dose-dependent manner, and a bivalent nanobody configuration enhanced the degradation efficiency to greater than 60

ABSTRACT Senecavirus A (SVA) is a causative agent of vesicular disease in pigs and has gained global attention in recent years. SVA infection leads to vesicular lesions and hoof deformities in pigs, posing a significant threat to the swine industry. The VP4 protein is a crucial component of the SVA capsid, located on the inner surface of the virus particle, and plays a key role in the viral life cycle. However, its exact function and immunological characteristics remain poorly understood. Additionally, the VP4 protein of picornaviruses is known to form antigenic epitopes during viral infection, providing potential targets for antibody development and vaccine design. Nevertheless, due to the unique location of VP4, these epitopes remain largely unexplored. In this study, a monoclonal antibody (mAb) 4E4 was successfully generated by immunizing mice with purified SVA VP4 protein. The mAb 4E4 specifically recognizes recombinant VP4 protein and the SVA‐infected cells. Further epitope mapping using truncated VP4 proteins detected with Western blotting defined a key B‐cell epitope, 7 SKDNFD 12 , which is exposed on the surface of VP4 protein and is highly conserved among different SVA strains. Additionally, mAb 4E4 showed neutralizing activity against SVA. This study provides the first identification of a conserved antigenic epitope on the SVA VP4 protein. This finding provides valuable tools for further investigation of VP4 protein function and lays the foundation for developing novel diagnostic and vaccine strategies.

Differentiating infected from vaccinated animals (DIVA) is critical for disease eradication and emerging infection surveillance. Senecavirus A (SVA), which causes vesicular disease and neonatal mortality in pigs, is clinically indistinguishable from foot-and-mouth disease virus (FMDV), posing significant economic risks to swine production. Therefore, a reliable DIVA diagnostic method is urgently needed for accurate SVA detection. In this study, we employed the IgG sero-dynamic curves to aid epitope discovery (IsDAED) approach, utilizing peptide microarrays to identify transiently produced IgG (TPI)-associated linear B-cell epitopes on SVA structural proteins. VP2-15 emerged as a dominant linear epitope shared across multiple infected samples, exhibiting a characteristic short-lived antibody response. In addition, sample-specific epitopes VP2-4, VP3-12, and VP1-24 were also identified. Vaccination trials revealed that VP2-15 has a diagnostic window between 7 and 42 days post-boost (dpb), with a DIVA window established beyond 60 dpb. Challenge experiments following inactivated vaccine immunization confirmed that VP2-15 reliably indicates new infections. Virus neutralization test (VNT) and in vitro blocking assays revealed that VP2-15 peptide could partially block the neutralization effect of neutralizing antibodies on SVA. Still, it could not induce neutralizing antibodies in pigs. A diagnostic kit based on a combination of peptide probes (VP2-15, VP2-4, VP3-12, and VP1-24) exhibited high sensitivity (97.9 %) and specificity (90.6 %) in clinical samples, with no cross-reactivity to FMDV. Collectively, the antigenic epitopes identified in this study enable DIVA via TPI detection, offering a valuable tool for SVA surveillance and advancing both control strategies and our understanding of host-virus interactions.

Senecavirus A (SVA), an emerging pathogen causing vesicular disease in pigs, poses a significant threat to the swine industry. The nonstructural protein 3A of SVA plays an essential role in the viral replication cycle. In this study, we immunized mice with the prepared SVA 3A protein and produced two monoclonal antibodies (mAbs), AG4 and 2F3. MAb AG4 showed specific reactivity to the linear and conformational 3A protein, whereas mAb 2F3 did not recognize linear epitope of 3A protein. Through truncated 3A protein expression and alanine mutation analysis, we identified 1SPNEND6 as the minimal motif recognized by mAb AG4, with Asn3 being the critical residue. Additionally, we demonstrated that mAb 2F3 failed to recognize the SVA mutant with the 75QEETEG80 deletion in 3A protein, indicating that 75QEETEG80 constitutes an essential epitope for mAb 2F3. Further deletion analysis confirmed that 75QE76 is the crucial motif for mAb 2F3 recognition. Moreover, we found that 1SPNEND6 and 75QEETEG80 are highly conserved among different SVA strains and are exposed on the surface of the 3A protein. This study contributes to further explore the function of SVA 3A protein and develop diagnostic tools for SVA detection.

Pseudorabies virus (PRV), a major swine pathogen, causes severe neurological, respiratory, and reproductive disorders, resulting in substantial economic losses to the global swine industry. Previous studies have shown that the gD glycoprotein of PRV has an effective protective effect. In this study, we constructed a plasmid DNA vaccine (pVAX1-GD-Fc) encoding a gD protein fused with pig IgG Fc and evaluated the adjuvant effects of porcine cGAS, the universal STING complex mimic (UniSTING), or IFN-α in mice. The mice were immunized three times (days 0, 14, and 21) with pVAX1-GD-Fc in the presence or absence of an adjuvant, followed by lethal challenge with PRV-HLJ8 3 days after the final immunization. The results revealed that the pVAX1-GD-Fc group exhibited 20% mortality (1/5 mice) on day 7 postchallenge, and all adjuvanted groups achieved 100% survival during the 14-day observation period. Flow cytometric analysis of splenocytes one week after the second immunization revealed significantly greater CD8+ T cell proportions in the adjuvant groups than in both the mock and pVAX1-GD-Fc-only control groups (p < 0.01). Furthermore, T cell proliferation assays demonstrated a significantly increased stimulation index in the adjuvant-treated mice, confirming enhanced cellular immunity. These findings demonstrate that cGAS, UniSTING, and IFN-α can serve as effective vaccine adjuvants to rapidly enhance cellular immune responses to PRV, highlighting their potential application in veterinary vaccines.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a significant infectious disease impacting the global swine industry. Due to high frequency of viral mutation and recombination, PRRSV exhibits complex genetic diversity; however, its lineage classification, restriction fragment length polymorphism (RFLP) patterns, and spatiotemporal distribution have not been systematically analyzed in China. In this study, we sequenced PRRSV‐2 open reading frame (ORF)5 sequences from clinical samples ( n = 364) and retrieved all the available PRRSV‐2 ORF5 sequences in China in 1991–2023 from GenBank ( n = 5773). Systematically analysis revealed that PRRSV‐2 strains in China were classified into five lineages (L1, L3, L5, L8, and L9) and eight sublineages (L1A‐L1C, L5A, L5B, L8C, L8E, and L9B), the L8E and L1C PRRSV‐2 were widely distributed across almost all provinces in China, the L1C and L1A strains were increasing and gradually replacing L8 as dominant epidemic strains, and L1B PRRSV‐2 in China was analyzed for the first time. The L3 PRRSV‐2 has a trend of spreading gradually from the southern to the northern provinces, which needs to be paid attention to the monitoring and prevention of PRRSV‐2. Meanwhile, PRRSV‐2 strains in China were classified into 112 different RFLP patterns. RFLP 1‐4‐4 PRRSVs were detectable in China, which accounted for 12.71% of all Chinese PRRSV‐2 strains. Although they are different from the RFLP 1‐4‐4 L1C variant in the United States, it is necessary to enhance surveillance of the RFLP 1‐4‐4 L1C PRRSVs. These results contributed the understanding of genetic diversity and spatiotemporal distribution of PRRSV‐2 in China and provide important references for future PRRSV‐2 monitoring and control in China.

Subunit vaccines are promising for disease prevention because of their safety and cost-effectiveness. However, their efficacy is limited by low immunogenicity and gastrointestinal degradation after oral administration. To address this issue, low-endotoxin Salmonella choleraesuis strain SC-L3 was engineered via lipid A modification to generate bacterial biomimetic vesicles (BBVs) with reduced endotoxin activity. BBVs were functionalized using ClyA-embedded SpyCatcher and Streptococcus protein G for dual antigen coupling, and further coated with chitosan oligosaccharides (COS) to enhance mucosal penetration and gastrointestinal stability. Using mCherry as a model antigen, we obtained optimized mCherry-CSS-BBV@COS that showed high antigen protection rates (83% and 63% in simulated gastric and intestinal fluids, respectively), capacity for lysosomal escape and effective stimulation of M1 macrophage polarization in vitro. Oral administration of mCherry-CSS-BBV@COS elicited robust systemic IgG and mucosal sIgA responses in mice. Furthermore, dual-antigen BBV conjugates (GDH-gD-Fc-CSS-BBV@COS) co-delivering Streptococcus suis glutamate dehydrogenase and pseudorabies virus gD-Fc induced antigen-specific humoral, mucosal and cellular immunity, conferring complete protection against lethal challenges with the respective pathogens. In summary, we generated a versatile, low-endotoxin BBV platform for oral combination subunit vaccines, offering a novel strategy for protection against viral and bacterial infections.

The membrane-associated RING-CH (MARCH) family of proteins are members of the E3 ubiquitin ligase family and are essential for a variety of biological functions. Currently, MARCH proteins are discovered to execute antiviral functions by directly triggering viral protein degradation or blocking the furin cleavage of viral class I fusion proteins. Here, we report a novel antiviral mechanism of MARCH1 and MARCH2 (MARCH1/2) in the replication of Pseudorabies virus (PRV), a member of the Herpesviridae family. We discovered MARCH1/2 restrict PRV replication at the cell-to-cell fusion step. Furthermore, MARCH1/2 block gB cleavage, and this is dependent on their E3 ligase activity. Interestingly, the blocking of gB cleavage by MARCH1/2 does not contribute to their antiviral activity in vitro. We discovered that MARCH1/2 are associated with the cell-to-cell fusion complex of gB, gD, gH, and gL and trap these viral proteins in the trans-Golgi network (TGN) rather than degrading them. Overall, we conclude that MARCH1/2 inhibit PRV by trapping the viral cell-to-cell fusion complex in TGN.

A cost-effective Escherichia coli expression system has gained popularity for producing virus-like particle (VLP) vaccines. However, the challenge lies in balancing the endotoxin residue and removal costs, as residual endotoxins can cause inflammatory reactions in the body. In this study, porcine parvovirus virus-like particles (PPV-VLPs) were successfully assembled from Decreased Endotoxic BL21 (BL21-DeE), and the effect of structural changes in the lipid A of BL21 on endotoxin activity, immunogenicity, and safety was investigated. The lipopolysaccharide purified from BL21-DeE produced lower IL-6 and TNF-α than that from wild-type BL21 (BL21-W) in both RAW264.7 cells and BALB/c mice. Additionally, mice immunized with PPV-VLP derived form BL21-DeE (BL21-DeE-VLP) showed significantly lower production of inflammatory factors and a smaller increase in body temperature within 3 h than those immunized with VLP from BL21-W (BL21-W-VLP) and endotoxin-removed VLP (ReE-VLP). Moreover, mice in the BL21-DeE-VLP immunized group had similar levels of serum antibodies as those in the BL21-W-VLP group but significantly higher levels than those in the ReE-VLP group. Furthermore, the liver, lungs, and kidneys showed no pathological damage compared with the BL21-W-VLP group. Overall, this study proposes a method for producing VLP with high immunogenicity and minimal endotoxin activity without chemical or physical endotoxin removal methods. This method could address the issue of endotoxin residues in the VLP and provide production benefits.

The membrane-associated RING-CH 8 protein (MARCH8), a member of the E3 ubiquitin ligase family, has broad-spectrum antiviral activity. However, some viruses hijack MARCH8 to promote virus replication, highlighting its dual role in the viral lifecycle. Most studies on MARCH8 have focused on RNA viruses, leaving its role in DNA viruses largely unexplored. Pseudorabies virus (PRV) is a large DNA virus that poses a potential threat to humans. In this study, we found that MARCH8 inhibited PRV replication at the cell-to-cell fusion stage. Interestingly, our findings proved that MARCH8 blocks gB cleavage by recruiting furin but this activity does not inhibit viral infection in vitro. Furthermore, we confirmed that MARCH8 inhibits cell-to-cell fusion independent of its E3 ubiquitin ligase activity but dependent on the interaction with the cell-to-cell fusion complex (gB, gD, gH, and gL). Finally, we discovered that the distribution of the cell-to-cell fusion complex is significantly altered and trapped within the trans-Golgi network. Overall, our results indicate that human MARCH8 acts as a potent antiviral host factor against PRV via trapping the cell-to-cell fusion complex in the trans-Golgi network.

Senecavirus A (SVA) is an important emerging swine pathogen that causes vesicular lesions in swine and acute death in newborn piglets. VP2 plays a significant role in the production of antibodies, which can be used in development of diagnostic tools and vaccines. Herein, the aim of the current study was to identify B-cell epitopes (BCEs) of SVA for generation of epitope-based SVA marker vaccine. Three monoclonal antibodies (mAbs), named 2E4, 1B8, and 2C7, against the SVA VP2 protein were obtained, and two novel linear BCEs, 177SLGTYYR183 and 266SPYFNGL272, were identified by peptide scanning. The epitope 177SLGTYYR183 was recognized by the mAb 1B8 and was fully exposed on the VP2 surface, and alanine scanning analysis revealed that it contained a high continuity of key amino acids. Importantly, we confirmed that 177SLGTYYR183 locates on “the puff” region within the VP2 EF loop, and contains three key amino acid residues involved in receptor binding. Moreover, a single mutation, Y182A, blocked the interaction of the mutant virus with the mAb 1B8, indicating that this mutation is the pivotal point for antibody recognition. In summary, the BCEs that identified in this study could be used to develop diagnostic tools and an epitope-based SVA marker vaccine.

Thermo-hydro-mechanical (THM) treatment is an effective way to improve the performance of bamboo. However, to date, research on the impact of moisture content (MC) on THM treatment has been relatively little. This study examined the microstructure and physical and chemical properties of bamboo treated with THM under different initial moisture content conditions. The interaction and influencing relationships among the three were explored to provide a reference for THM in the bamboo industry. According to the results of the Three-point Bending test and Nanoindentation test, it is indicated that humidity has a relatively minor impact on the mechanical performance and micro-mechanical properties of compressed samples. However, Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP) tests have shown that an increase in moisture content effectively improves the uneven deformation of bamboo cell walls during compression, thereby reducing their porosity. However, appropriate moisture content in the experiment affected the softening effect of bamboo and caused slight cracking of the fiber tube during compression. With respect to Fourier Transform Infrared Spectrometer (FTIR) spectroscopy, differences in the initial moisture content can also affect the chemical composition. The X-ray diffraction (XRD) analysis has also shown that the crystallinity of the treated samples was higher than that of the untreated samples. Moisture content has a significant impact on the hygroscopicity and dimensional stability of compressed samples by influencing changes in the chemical composition, microstructure, and crystallinity during thermo-hydro-mechanical treatments. In this experiment, bamboo with a moisture content of 12% had a pronounced softening effect during the hot-pressing process while exhibiting the dimensional stability and low moisture absorption required.

Virus-like particles (VLPs) are used as nanocontainers for targeted drug, protein, and vaccine delivery. The phage P22 VLP is an ideal macromolecule delivery vehicle, as it has a large exterior surface area, which facilitates multivalent genetic and chemical modifications for cell recognition and penetration. Arginine-rich cell-penetrating peptides (CPPs) can increase cargo transport efficiency in vivo. However, studies on the tissue distribution and retention of P22 VLPs mediated by TAT and 8R are lacking. This study aimed to analyze the TAT and 8R effects on the P22 VLPs transport efficiency and tissue distribution both in vitro and in vivo. We used a prokaryotic system to prepare P22 VLP self-assembled particles and expressed TAT-or 8R-conjugated mCherry on the VLP capsid protein as model cargoes and revealed that the level of P22 VLP-mCherry penetrating the cell membrane was low. However, both TAT and 8R significantly promoted the cellular uptake efficiency of P22 VLPs in vitro, as well as enhanced the tissue accumulation and retention of P22 VLPs in vivo. At 24 h postinjection, TAT enhanced the tissue distribution and retention in the lung, whereas 8R could be better accumulation in brain. Thus, TAT was superior in terms of cellular uptake and tissue accumulation in the P22 VLPs delivery system. Understanding CPP biocompatibility and tissue retention will expand their potential applications in macromolecular cargo delivery.

Many picornaviruses require the myristoylation of capsid proteins for viral replication. Myristoylation is a site-specific lipidation to the N-terminal G residue of viral proteins, which is catalyzed by the ubiquitous eukaryotic enzyme N-myristoyltransferase (NMT) by allocating the myristoyl group to the N-terminal G residue. IMP-1088 and DDD85646 are two inhibitors that can deprive NMT biological functions. Whether Senecavirus A (SVA) uses NMT to modify VP0 and regulate viral replication remains unclear. Here, we found that NMT inhibitors could inhibit SVA replication. NMT1 knock-out in BHK-21 cells significantly suppressed viral replication. In contrast, the overexpression of NMT1 in BHK-21 cells benefited viral replication. These results indicated that VP0 is a potential NMT1 substrate. Moreover, we found that the myristoylation of SVA VP0 was correlated to the subcellular distribution of this protein in the cytoplasm. Further, we evaluated which residues at the N-terminus of VP0 are essential for viral replication. The substitution of N-terminal G residue, the myristoylation site of VP0, produced a nonviable virus. The T residue at the fifth position of the substrates facilitates the binding of the substrates to NMT. And our results showed that the T residue at the fifth position of VP0 played a positive role in SVA replication. Taken together, we demonstrated that SVA VP0 myristoylation plays an essential role in SVA replication.

Infection with the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) results in a chronic and occasionally severe illness that affects pregnant sows and is characterized by respiratory issues, weight loss, poor growth performance, and reproductive failure. The emerged messenger RNA (mRNA) is a promising approach to preventing various diseases due to its favorable safety profile, ease of design, and scalable production. In this study, we developed a messenger RNA (mRNA) vaccine against a highly pathogenic PRRSV strain HuN4. Recombined multiple antigenic proteins, including GP5-M, GP3-NSP9, and GP2-GP4, were designed and codon-optimized. Indirect immunofluorescence assay (IFA) and Western blot detected the expression levels of different mRNA-LNPs. The outcomes of IFA demonstrated that GP3-NSP9 and GP2-GP4 had stronger fluorescence in their mRNA-LNP expressions, GP3-NSP9 expressing themselves better than GP2-GP4. Conversely, GP5-M exhibited hardly little fluorescence. The GP2-GP4 and GP3-NSP9 fusion proteins were expressed in the cells, according to the Western blot data. However, GP5-M was not. The GP3-NSP9 and GP2-GP4 were used to immunize pigs alone or in combination. The challenge of PRRSV HuN4 after immunization revealed that N protein antibody titers and viral load in the blood and lungs were much lower than those of mock-challenged pigs. All piglets were euthanized, and their lungs were examined macroscopically and histopathologically. In addition, the GP2-GP4 and GP3-NSP9 combined mRNA immunization showed effective and protective immune response than GP3-NSP9 mRNA individual immunization.

A survey of China flooring industry was conducted in 2022.Based on the data from 293 surveyed sample enterprises,this paper analyzed the situation of these enterprises,including factory distribution,enterprise scale,production capacity,production,sales,etc,in order to reflect the development of the national flooring industry to a certain extent and provide data reference for the production and operation of flooring enterprises.

In recent years, an increasing number of emerging and remerging virus outbreaks have occurred and the rapid development of vaccines against these viruses has been crucial. Controlling the replication of premature termination codon (PTC)-containing viruses is a promising approach to generate live but replication-defective viruses that can be used for potent vaccines. Here, we used anticodon-engineered transfer RNAs (ACE-tRNAs) as powerful precision switches to control the replication of PTC-containing viruses. We showed that ACE-tRNAs display higher potency of reading through PTCs than genetic code expansion (GCE) technology. Interestingly, ACE-tRNA has a site preference that may influence its read-through efficacy. We further attempted to use ACE-tRNAs as a novel viral vaccine platform. Using a human immunodeficiency virus type 1 (HIV-1) pseudotyped virus as an RNA virus model, we found that ACE-tRNAs display high potency for read-through viral PTCs and precisely control their production. Pseudorabies virus (PRV), a herpesvirus, was used as a DNA virus model. We found that ACE-tRNAs display high potency for reading through viral PTCs and precisely controlling PTC-containing virus replication. In addition, PTC-engineered PRV completely attenuated and lost virulence in mice in vivo, and immunization with PRV containing a PTC elicited a robust immune response and provided complete protection against wild-type PRV challenge. Overall, replication-controllable PTC-containing viruses based on ACE-tRNAs provide a new strategy to rapidly attenuate virus infection and prime robust immune responses. This technology can be used as a platform for rapidly developing viral vaccines in the future.

ABSTRACT Trueperella pyogenes can cause severe pulmonary disease in swine, but the mechanism of pathogenesis is not well defined. T. pyogenes- induced damage to porcine bronchial epithelial cells (PBECs), porcine precision-cut lung slices (PCLS), and respiratory epithelium of mice remains unknown. In this study, we used T. pyogenes 20121 to infect PBECs in air-liquid interface conditions and porcine PCLS. T. pyogenes could adhere to, colonize, and induce cytotoxic effect on PBECs and the luminal surface of bronchi in PCLS, which damaged the bronchiolar epithelium. Moreover, bronchiolar epithelial cells showed extensive degeneration in the lungs of infected mice. Furthermore, western blot showed that the NOD-like receptor (NLR)/C-terminal caspase recruitment domain (ASC)/caspase-1 axis and nuclear factor-kappa B pathway were involved in inflammation in PCLS and lungs of mice, which also confirms that porcine PCLS provide a platform to analyze the pulmonary immune response. Meanwhile, the levels of p-c-Jun N-terminal kinase, p-extracellular signal-regulated kinase, and p-protein kinase B (AKT) were increased significantly, which indicated the mitogen-activated protein kinase and Akt pathways were also involved in inflammation in T. pyogenes- infected mice. In addition, we used T. pyogenes 20121 to infect tumor necrosis factor-alpha (tnf-α -/- ) mice, and the results indicated that apoptosis and injury in respiratory epithelium of infected tnf-α -/- mice were alleviated. Thus, the pro-inflammatory cytokine TNF-α played a role in apoptosis and the respiratory epithelium injury in mouse lungs. Collectively, our study provides insight into the inflammatory injury induced by T. pyogenes and suggests that blocking NLR may be a potential therapeutic strategy against T. pyogenes infection.

为了研究非洲猪瘟(ASF)暴发后我国猪繁殖与呼吸综合征病毒(PRRSV)的流行变化,本研究经PCR检测了 2017年1月～2020年12月全国18个省、市和自治区1 374份疑似PRRSV感染的病料样品,并对其中阳性病料样品的ORF5、nsp2基因测序并统计阳性样品的检出率,分析不同地区在ASF暴发前后PRRSV阳性检出率的变化趋势;分别利用GraphPad Prism 8.0及ORF5基因的进化树分析ASF暴发前后我国各亚型PPRSV及各地区PPRSV的流行变化趋势;根据nsp2基因推导氨基酸序列分析其缺失特征.ORF5基因和nsp2基因测序及统计分析结果显示,共检出PRRSV阳性病料样品779份(779/1374),其中ASF暴发前397份,ASF暴发后382份.ASF暴发后(2019年～2020年)我国各地PRRSV阳性检出率均有上升,华北地区PRRSV阳性检出率由60.47％上升至66.33％;东北地区由52.76％上升至53.27％;华东地区由60.93％上升至62.59％;中南地区由53.43％上升至57.50％.ASF暴发前后我国各亚型及各地区PPRSV流行变化趋势统计分析结果显示,ASF暴发后,NADC30-like PRRSV作为主要流行株,其检出率显著增长,从47.36％上升至65.97％;NADC34-like PRRSV的检出率也明显增长,从1.76％上升至 5.50％;但 HP-PRRSV、VR2332-like PRRSV 和 QYYZ-like PRRSV 的检出率明显降低,分别从 34.01％降至20.68％、6.80％降至3.40％、7.30％降至0.52％.可见ASF暴发后,我国大部分地区(华北、东北、华东、中南)NADC30-like PRRSV的流行趋势有所上升,但HP-PRRSV的流行趋势明显下降,并且随着ASF的流行,除中南地区外,我国各地NADC34-like PRRSV检出率明显上升.ORF5基因的遗传演化分析结果显示,ASF暴发前(2017年～2018 年)检测到 6 种基因亚型的 PRRSV(NADC30-like PRRSV、HP-PRRSV、NADC34-like PRRSV、VR2332-like PRRSV、QYYZ-like PRRSV、Type Ⅰ PRRSV),而 ASF暴发后还检测到 CH-1a like PRRSV.Nsp2氨基酸缺失特征分析结果显示,ASF暴发前后我国各亚型PRRSV Nsp2氨基酸序列特征均未发生变化.以上结果表明,ASF疫情的暴发对我国PRRSV的流行造成了较大影响,国内大部分地区PRRSV的流行加重,病毒亚型也变得更加多元化,NADC30-like PRRSV作为主要流行株在国内大部分地区的流行趋势不断升高,HP-PRRSV检出率虽有降低但仍在流行,NADC34-like PRRSV作为潜在流行株,其检出率不断上升.本研究聚焦在ASF暴发前后国内PRRSV的流行变化,对了解我国PRRSV流行现状及对PRRS的防控具有重要的指导意义.