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Pseudorabies virus (PRV) can establish lifelong latent infection in peripheral nervous ganglion, and persistent infections in peripheral blood lymphocytes. Establishing an infection in the lymphocytes does not only enable the PRV to escape host immune surveillance but pass through the placental barrier, leading to fetal death and abortion. Due to the pathogenicity of the PRV, it poses a huge challenge in its prevention and control. The PRV escapes host immunity through downregulation of swine leukocyte antigen class I (SLA I) molecules on infected cells. However, data on the molecular mechanisms of the SLA I suppression remains scant. Here, in order to verify the effect of candidate proteins PRV pUL44 and pUS6 on PRV immune escape related molecules SLA I and peptide loading complex (PLC), we detected the expression of SLA I and PLC components after expressing PRV pUL44 and pUS6. The effects of pUS6 and pUL44 on SLA I and PLC were analyzed by qRT-PCR and Western blot at mRNA and protein level, respectively. Cells expressing pUS6 or pUL44 genes showed a significantly suppressed expression of surface and total SLA I molecules. In addition, unlike UL44, the US6 gene was shown to downregulate the transporter associated with antigen processing 1 (TAP1), TAP2 and Tapasin molecules. The results show that PRV pUS6 may participate in virus immune escape by directly regulating the SLA I, TAP dimer and Tapasin molecules, thus blocking the transportation of TAP-bound peptides to the ER to bind SLA I molecules. We provide a theoretical basis on the mechanism of TAP mediated immune escape by the PRV.

In May 2025, a female giraffe in poor body condition died unexpectedly at a zoo in Henan Province, China. A bacterial strain, designated HN-1, was isolated from the heart, liver, spleen, lungs, and kidneys of the deceased animal. After 24 h of incubation at 37 °C on Luria–Bertani (LB) agar, the colonies appeared round, smooth, pale yellow, translucent, and raised. Gram staining revealed that the isolate was a Gram-positive, rod-shaped, and non-spore-forming bacterium. Based on 16S rRNA gene sequencing, the strain showed more than 99.7% homology with reference sequences of E. mexicanum from various sources in GenBank. The results of the susceptibility test showed that E. mexicanum was susceptible to levofloxacin, clindamycin, chloramphenicol, trimethoprim, rifampicin, tetracycline, minocycline, gentamicin, erythromycin, and doxycycline, but resistant to oxacillin, penicillin, ciprofloxacin, and linezolid. These findings provide valuable insights for the diagnosis and treatment of infections caused by E. mexicanum in giraffes.

Porcine circovirus type 3 (PCV3) has been widely detected throughout the world since it was first discovered on pig farms in 2015. PCV3 is closely associated with cardiac and multisystem inflammation, respiratory disease, congenital tremors, myocarditis, diarrhea, encephalitis and neurologic disease, and periarteritis. However, there have been few reports on the relationship between PCV3 and inflammatory pathways. The NF-κB signaling pathway plays an important role in the defense against viral infection. Here, we demonstrate that the capsid protein (Cap) of PCV3 plays a key role in the activation of NF-κB signaling in HEK-293T cells. Furthermore, PCV3 Cap promotes the mRNA expression of the pro-inflammatory cytokines IL6 and TNFα. In addition, PCV3 Cap promotes RIG-I and MDA5 mRNA expression in RIG-like receptor (RLR) signaling and MyD88 mRNA expression in Toll-like receptor (TLR) signaling but does not influence TRIF mRNA expression in TLR signaling. These results show that PCV3 Cap activates NF-κB signaling, possibly through the RLR and the TLR signaling pathways. This work illustrates that PCV3 Cap activates NF-κB signaling and thus may provide a basis for the pathogenesis of PCV3 and the innate immunity of the host.

Background Pseudorabies (PR) caused by the re-emerging of pseudorabies virus (PRV) variant has outbroken among PRV vaccine immunized swine in many pig farms, which has caused serious social and economic consequences since the end of 2011. The PRV UL49.5 protein can inactivate the transporter associated with antigen processing (TAP), thereby downregulating the cell surface expression of swine leukocyte antigen class I (SLA-I) to evade host immune surveillance. Methods In this study, based on the PRV ΔgE/TK strain, PRV ΔgE/TK/UL49.5 triple gene deletion strain was constructed through homologous recombination and deletion of the PRV UL49.5 gene by the Cre-LoxP system. Its growth curve and effect on SLA-I transcription level were determined. Preliminary studies were carried out on serum neutralizing antibody levels, IFN-γ and IL-4 cytokines levels in mice immunized with PRV ΔgE/TK/UL49.5, and the viral load and challenge protection in mice tissues after challenge. Results The growth characteristics of PRV ΔgE/TK/UL49.5 strain were similar to those of PRV ΔgE/TK strain. The level of SLA-I was returned to normal after the deletion of PRV UL49.5 gene. The immunization of PRV ΔgE/TK/UL49.5 did not affect the weight gain of mice. Immunized mice could induce high levels of serum neutralization antibodies and immune cytokines, including IFN-γ and IL-4, which could provide complete protection against virulent PRV challenge. No obvious pathological damage was observed in lung, brain and trigeminal ganglion of mice immunized with PRV ΔgE/TK/UL49.5, and the tissue viral load was the lowest. Conclusions PRV ΔgE/TK/UL49.5 strain can induce enhanced immunogenicity and had the potential to be used as a candidate strain.

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious infectious disease caused by porcine reproductive and respiratory syndrome virus (PRRSV), which inflicts major economic losses on the global pig farming industry. Based on its similarity to highly pathogenic strains, the GDzj strain isolated in this study was predicted to be highly pathogenic. We therefore analyzed the pathogenicity of this strain experimentally in piglets. All piglets challenged with this virus experienced fever or high fever, loss of appetite, decreased food intake, daily weight loss, shortness of breath, and listlessness, and the necropsy results showed that they had experienced severe interstitial pneumonia. We then used the BAC system to construct a full-length cDNA infectious clone of GDzj, and the rescued virus displayed in vitro proliferation characteristics similar to those of the parental PRRSV strain. In summary, we successfully isolated a highly pathogenic PRRSV strain and constructed a full-length infectious cDNA clone from it, thereby providing an effective reverse genetics platform for further study of viral pathogenesis.

Porcine epidemic diarrhea (PED) is an acute enteric disease caused by porcine epidemic diarrhea virus (PEDV). In China, variant PEDV causes severe watery diarrhea, vomiting, and dehydration in piglets, leading to very high morbidity and mortality. However, the pathogenesis of PEDV is still not fully understood. In our study, we analyzed the long noncoding RNA (lncRNA) and mRNA expression profiles of PEDV GDgh16 in infected Vero cells at 60 h postinfection. A total of 61,790 annotated mRNAs, 14,247 annotated lncRNAs and 1290 novel lncRNAs were identified. A total of 227 annotated lncRNAs and 13 novel lncRNAs were significantly and differentially expressed after viral infection. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases were used to identify genes adjacent to the lncRNAs, and it was found that these lncRNAs were enriched in pathways related to immune and antiviral responses. Next, we selected candidate lncRNAs and their predicted target genes for study. RT-qPCR demonstrated that these lncRNAs and genes were differentially expressed after PEDV infection. Our study investigated the function of lncRNAs involved in PEDV infection, providing new insight into the pathogenic mechanisms of PEDV.

Background Porcine reproductive and respiratory syndrome (PRRS) has leaded to an enormous loss per year to the swine industry, its etiology porcine reproductive and respiratory syndrome virus (PRRSV) is a highly mutated virus in pigs. To fully understand the genetic characteristics of PRRSV genome in South China, this study collected the lung samples infected with PRRSV in Guangdong and Hainan province from 2014 to 2015 and tried to isolate the PRRSV. Finally, the complete genomes of isolated strains were sequenced and analyzed. Methods Virus isolation was performed in MARC-145 cells. The 13 fragments of PRRSV genome were amplified by RT-PCR and the complete PRRSV genome sequence was obtained by SeqMan program of DNASTAR7.0 software. Nucleotide and deduced amino acid (AA) sequences of NSP2 and ORF5 were aligned using the MegAlign program of DNASTAR7.0 software to determine sequence homology. A phylogenetic tree was constructed using MEGA5.2 software with the neighbor-joining method to analyze the evolutionary relationship. Results 11 PRRSV strains were isolated in South China from 2014 to 2015. All the isolated strains clustered into subgenotype V along with the HP-PRRSV representative strains JXA1, HuN4 and JXwn06. The subgenotype V was furtherly divided into two groups. AA sequence alignment analysis indicated that all the isolated strains had 1 AA deletion and 29 AA continuous deletion at position 481 and 533-561. Notably, GDHY strain had another 120 AA continuous deletion at position 629-748. All the isolated strains had an A137S mutation in the residue A137 of GP5 which was considered to differentiate vaccine strains. All the isolated strains had a L39I mutation in the primary neutralizing epitope (PNE) of GP5. Except GDHZ had a N34T mutation, all the other isolated strains had conserved N30, N44 and N51 glycosylation sites in the four potential N-glycosylation sites (N30, N34, N44 and N51) of GP5. Conclusions Our study showed that the prevalent strains in this region were highly pathogenic PRRS virus-like. Moreover, one new strain having another 120 amino acids continuous deletion except the discontinuous 30 (29+1) amino acids deletion in NSP2 region had emerged. Besides, the isolated strains had extensive amino acids substitutions in the putative signal, extravirion and intravirion regions of GP5. These results showed that PRRSV has undergone extensive variation in South China, providing some theoretical basis for researching effective vaccince to better controling the PRRSV in this area.

Since 2010, Porcine epidemic diarrhea virus (PEDV) has caused severe diarrhea disease in piglets in China, resulting in large economic losses. To understand the genetic characteristics of the PEDV strains that circulated in some provinces of China between 2015 and 2018, 375 samples of feces and small intestine were collected from pigs and tested. One hundred seventy-seven samples tested positive and the PEDV-positive rate was 47.20%. A phylogenetic tree analysis based on the entire S gene showed that these strains clustered into four subgroups, GI-a, GI-b, GII-a, and GII-b, and that the GII-b strains have become dominant in recent years. Compared with previous strains, these strains have multiple variations in the SP and S1-NTD domains and in the neutralizing epitopes of the S protein. We also successfully isolated and identified a new virulent GII-b strain, GDgh16, which is well-adapted to Vero cells and caused a high mortality rate in piglets in challenge experiments. Our study clarifies the genetic characteristics of the prevalent PEDV strains in parts of China, and suggests that the development of effective novel vaccines is both necessary and urgent.

Porcine epidemic diarrhea virus (PEDV) causes severe economic loss in the pig industry each year. To better understand the relationship between cytokines and PEDV replication, in this study, pro-inflammatory cytokine and chemokine expression profiles in Vero cells infected with PEDV were analyzed. Real-time quantitative PCR assay indicated that IL-1α, IL-1β, TNF-α, CCL2, CCL5 and CXCL8 expression levels were significantly upregulated. Moreover, overexpression and siRNA silencing assays showed that overexpression of IL-1α, IL-1β, TNF-α, CCL2, CCL5 and CXCL8 could significantly inhibit PEDV replication, while silencing of IL-1α, IL-1β, TNF-α, CCL2, CCL5 and CXCL8 could significantly promote PEDV replication. Finally, a dual-luciferase reporter assay showed that nsp4 contributed to the expression of IL-1α, IL-1β, TNF-α, CCL2, CCL5 and CXCL8 via the NF-κB pathway. Together, these data determined that PEDV nsp4 could upregulate pro-inflammatory cytokine and chemokine expression, inhibiting viral replication in vitro. These results provided novel insights for understanding the roles of cytokines in PEDV replication.

The spread of Getah virus (GETV) in China has become increasingly severe due to long‐term neglect and the lack of vaccines, posing a threat to animal safety and public health. In this study, we isolated and identified a novel GETV strain, designated GETV‐CX7. Phylogenetic analysis of the E2 gene and the complete genome showed that GETV‐CX7 belongs to Group III. Notably, sequence analysis revealed a novel 14‐nucleotide deletion near the 5 ’ end of the 3 ’ untranslated region (UTR) of GETV‐CX7. RNA Secondary Structure Package (RNAfold) predictions further revealed that this deletion changes the RNA secondary structure of the 3 ’ UTR in GETV‐CX7. Additionally, pathogenicity experiments demonstrated 100% mortality in mice infected with GETV‐CX7 via subcutaneous or intracerebral routes. GETV‐CX7‐infected mice exhibited tissue lesions, including hemorrhaging in the brain, lungs, and kidneys, as well as intestinal wall thinning. GETV‐CX7 exhibits broad tissue tropism, particularly in the brain, with a viral load of up to 6.2 log 10 PFU/g by 3 days postchallenge (dpc). In summary, we isolated a novel GETV Group III strain, GETV‐CX7, characterized by a 14‐nt deletion in the 3 ’ UTR, which exhibited high pathogenicity in 5‐day‐old mice.