Guijun Wang

Central nervous system (CNS) pathogenesis remains a critical but incompletely resolved aspect of flavivirus infection. Neurotropic flaviviruses usually initiate replication in peripheral tissues but can subsequently access the CNS, causing encephalitis, neurological dysfunction, or developmental abnormalities. Because these events occur along a continuum from peripheral infection to CNS injury, their temporal and mechanistic relationships are often difficult to define. In many studies, brain viral detection, blood–brain barrier (BBB) dysfunction, neuroinflammation, and neurological signs are reported together, although they represent different steps in disease progression. Studies of Japanese encephalitis virus, West Nile virus, Zika virus, dengue virus, and tick-borne encephalitis virus show that BBB dysfunction is an important component of flavivirus-associated neurological disease, but no single conserved mechanism applies across flaviviruses. Endothelial activation, cytokine and chemokine signaling, tight junction remodeling, matrix metalloproteinase activity, leukocyte trafficking, glial inflammatory amplification, and viral genetic variation can each shape barrier-related phenotypes, with distinct timing and relative importance depending on virus species and experimental context. Tembusu virus (TMUV) is an evolving avian flavivirus responsible for widespread waterfowl outbreaks, with ongoing genetic diversification and an expanding recognized host and vector range. Increasing evidence of neurological signs, brain lesions, and viral detection in neural tissues indicates that CNS-associated pathogenicity is an important feature of TMUV infection. However, the routes of TMUV CNS entry, the temporal relationship between BBB dysfunction and early brain infection, the viral genetic basis of strain-dependent neurological phenotypes, and the contribution of host inflammation to BBB injury remain unclear. Here, we review current advances in flavivirus-associated BBB dysfunction and use comparative flavivirus evidence to guide a stage-specific interpretation of TMUV neuroinvasion and neuropathogenesis. We argue that TMUV-associated neurological disease should be interpreted along a peripheral-to-CNS sequence that separates CNS access, BBB dysfunction, post-entry brain replication, neuroinflammatory amplification, and clinical disease. By linking CNS-associated phenotypes to defined disease steps, this approach may help explain the emergence of TMUV strains with enhanced neurological pathogenicity and provide a clearer basis for evaluating attenuation and vaccine safety.

Virus-like particles (VLPs) are engineered nanoplatforms that mimic viral structures, offering high immunogenicity, biocompatibility, and functional versatility for cancer immunotherapy. While widely explored in human oncology as nanovaccines and targeted delivery systems for chemo-/immuno-therapeutics and genetic payloads (e.g., mRNA, siRNA, and CRISPR/Cas systems), their potential in veterinary oncology remains underexploited. This review synthesizes recent advances in VLP design, including scaffold engineering, antigen display, cargo encapsulation, and surface functionalization, and discusses the mechanistic basis of VLP-induced antitumor immunity, encompassing dendritic cell activation, adaptive immune amplification, and tumor microenvironment remodeling. Importantly, we highlight the emerging role of companion animals with spontaneous tumors-such as lymphoma, melanoma, and mammary carcinoma-as immunocompetent translational models within the One Health framework. Comparative oncology reveals striking parallels in oncogenic pathways, immune landscapes, and therapeutic responses, supporting the use of canine and feline cancers as biologically relevant intermediates between murine studies and human clinical trials. We provide an evidence-based assessment of representative VLP platforms, evaluate their translational readiness, and examine cross-species opportunities for shared target development, biomarker discovery, and regulatory convergence, while also addressing species-specific biological and technical limitations. Finally, we propose a forward-looking roadmap that prioritizes manufacturing standardization, biomarker development, comparative validation, precision engineering, and emerging technologies such as AI-guided design and tumor-on-chip systems. Collectively, we position One Health as an operational strategy to accelerate the bidirectional translation of VLP-based immunotherapies for both human and veterinary cancer patients.

Duck Tembusu virus (DTMUV), a mosquito‐borne flavivirus, has caused widespread outbreaks in poultry and has exhibited an expanding host range among avian species, accompanied by ongoing genetic variation and adaptation. As many mosquito‐borne flaviviruses can infect mammals and cross species barriers, it remains unclear whether recently emerged DTMUV variants have acquired similar potential. To address this, we assessed whether the circulating variant AQ‐19 can establish infection in mammals via peripheral routes. Despite its enhanced virulence in avian species, this variant failed to establish infection in mice following peripheral inoculation, indicating that a substantial barrier still restricts cross‐species transmission to mammals. We next investigated whether additional adaptive changes are required for DTMUV to overcome this barrier. Through serial intracranial passage in Institute of Cancer Research (ICR) mice, we generated a mouse‐adapted strain (F13) that exhibited markedly enhanced virulence and, notably, acquired the ability to invade the central nervous system (CNS) via intranasal (i.n.) inoculation, resulting in lethal infection. This neuroinvasive phenotype was strictly route‐dependent, as infection remained ineffective via intraperitoneal (i.p.) and subcutaneous (s.c.) routes. We found that the adapted virus invades the CNS via the olfactory route and disseminates broadly, exhibiting strong neurotropism and inducing severe neural damage. Functional disruption of the olfactory epithelium using ZnSO ₄ significantly delayed disease onset and reduced viral burden in the brain, supporting its role as a major route for nasal‐to‐brain transmission. Importantly, genomic analysis identified only four nonsynonymous amino acid substitutions in the adapted strain, suggesting that a limited number of mutations may be sufficient to confer enhanced neurovirulence and enable neuroinvasion in a mammalian host. Collectively, these findings demonstrate that the emerging DTMUV variant AQ‐19 remains restricted in mammals, whereas limited adaptive changes acquired during experimental mouse adaptation are associated with the acquisition of neuroinvasive capacity, providing new insights into the evolutionary potential of DTMUV for mammalian adaptation.

Canine distemper, a fatal and highly transmissible disease caused by the canine distemper virus (CDV), poses a major threat to the companion animal industry. An urgent need exists for a rapid, specific, and simple method for the detection of this disease in order to improve its prevention and control. In this research, two monoclonal antibodies (mAbs), 1D3E9 and 1H9B7, were prepared, both of which specifically recognize the nucleoprotein (N protein) of CDV, and an immunochromatographic assay for CDV detection was subsequently developed using these mAbs. The results showed that both mAbs belong to the IgG1 subclass with kappa light chains. 1D3E9 was found to recognize the linear epitope ⁴¹⁰AGPKQSQITFLH⁴²¹, while 1H9B7 targeted the epitope ⁴⁵⁰HFNDERFPGH⁴⁵⁹. The test strips exhibited high specificity and good stability for up to two months when stored at 4, 25, and 37 °C. The assay exhibited a sensitivity of 10^2.39 TCID₅₀/0.1 mL. When compared with RT-PCR for detecting CDV in clinical samples, the concordance rate was 91.67%. Thus, this method shows great potential for facilitating rapid on-site detection of CDV and could be highly beneficial from the viewpoint of disease surveillance and control.

A novel goose astrovirus (GAstV) has broken out across China in recent years, causing widespread damage to the poultry industry. In goslings infected with GAstV, the leading cause of death is visceral gout. However, our understanding of the mechanism of gout formation in GAstV infection is largely inadequate. The aim of this study was to examine the pathogenicity of a GAstV strain and explore the molecular mechanisms of visceral gout caused by viral infection in goslings. The virulent GAstV strain HR2105/1 was effectively isolated from the visceral tissue of goslings in gout-affected areas. The whole genome of the HR2105/1 strain was sequenced and analyzed. Subsequently, we established a gosling gout models with experimental GAstV infection. Finally, we conducted a study on the mechanism of GAstV induced acute kidney injury. Phylogenetic analysis of the complete genome sequence showed that it was closely related to the strain circulating in China since 2016, and it was grouped within the GAstV-1 cluster. The clinical signs were reproduced by experimental infection of healthy goslings with the isolated strain and were found to be similar to those reported in clinical cases. Moreover, the virus exhibits strong renal tropism. Infection with the GAstV strain HR2105/1 was found to cause acute kidney injury, as evidenced by increased levels of uric acid and creatinine as well as severe pathological damage. Mechanistic experiments with Masson and Picrosirius Red staining revealed fibrosis in renal tissues after GAstV infection. Furthermore, TUNEL staining revealed that GAstV infection triggered renal cell apoptosis. Additionally, RT-qPCR revealed that GAstV infection caused an excessive inflammatory response by upregulating the expression of IL-1β, IL-6, IL-10, TGF-β, and iNOS in renal tissues. Overall, our findings demonstrate that GAstV infection causes renal damage by inducing renal cell apoptosis, fibrosis, and excessive inflammatory response, which subsequently leads to hyperuricemia and lethal visceral gout formation. This is the first systematic study on the etiology of lethal gout in goslings caused by GAstV infection, and we believe that the findings can guide vaccine development and therapeutic targets for GAstV-associated renal diseases.

Since 2010, the Tembusu virus (TMUV) has been highly prevalent in China, causing significant economic losses to the poultry industry. In 2022, a suspected outbreak of TMUV occurred at a goose farm located in Anhui Province. A strain of TMUV, TMUV HQ-22, was isolated from the infected geese. Phylogenetic analysis using the E gene of the HQ-22 strain demonstrated its affiliation with cluster 3, a less commonly reported cluster in comparison to the main circulating cluster, cluster 2. Through a comparison of the envelope (E) protein of HQ-22 with other typical TMUV strains, a mutation at the 157th amino acid position was identified, wherein valine (V) in cluster 3 changed to alanine (A), a characteristic that is unique to cluster 2. These findings highlight the diversity and complexity of the TMUV strains circulating in China. In our experimental analysis, an injection of TMUV HQ-22 into the muscles of 3-day-old goslings resulted in severe neurological symptoms and a mortality rate of 60%. Similarly, the intracranial or intranasal infection of 3-week-old ICR mice with TMUV HQ-22 led to severe neurological symptoms and respective mortality rates of 100% or 10%. In summary, our study isolated a TMUV strain, TMUV HQ-22, from geese that belongs to cluster 3 and exhibits significant pathogenicity in both goslings and ICR mice. These results emphasize the genetic diversity of the TMUV circulating in China and expand the host range beyond mosquitoes to include ducks, chickens, geese, and even mice. It is crucial to not underestimate the risk of TMUV infection in mammals, warranting our utmost attention.

Duck Tembusu virus (DTMUV) is a neurotropic virus in the genus Flavivirus that causes massive economic losses to the poultry industry in China and neighbouring countries. Autophagy is pivotal in cellular responses to pathogens and in viral pathogenesis. However, little is known about the roles of autophagy in DTMUV replication and viral pathogenesis, especially in neuropathogenesis. In this study, mouse neuroblastoma cells (Neuro-2a) were used to establish a cell model of DTMUV infection. Our experiments indicated that DTMUV infection induced incomplete autophagy in Neuro-2a cells. Then, we used different autophagy regulators to alter the autophagy induced by DTMUV and found that incomplete autophagy promoted DTMUV replication. Furthermore, we showed that DTMUV infection activated the ERK and AMPK pathways, resulting in decreased phosphorylation of the autophagy repressor mTOR, subsequently leading to autophagic induction. In addition, we utilized ICR mice in an animal model of DTMUV infection to evaluate the autophagic responses in brain tissues and investigate the effects of autophagy on viral replication and tissue lesions. Our results confirmed that DTMUV induced incomplete autophagy in mouse brain tissues and that autophagy inducer treatment promoted DTMUV replication and aggravated DTMUV-induced lesions, whereas autophagy inhibitor treatment had the opposite effects. In summary, DTMUV infection induced incomplete autophagy through the ERK/mTOR and AMPK/mTOR signalling pathways to promote viral replication in mouse neuronal cells, and DTMUV-induced incomplete autophagy contributed to the neuropathogenesis of DTMUV.

Duck Tembusu virus (DTMUV) is a neurotropic virus belonging to the genus Flavivirus, and causes massive economic losses to the poultry industry in China and neighbouring countries. Autophagy plays a pivotal role in cellular responses to pathogens and viral pathogenesis. However, little is known about the roles of autophagy in DTMUV replication and virus pathogenesis, especially in neuropathogenesis. In this study, mouse neuroblastoma cells (Neuro-2a) were used to establish a DTMUV infection cell model. Our experiments indicated that DTMUV infection induced incomplete autophagy in Neuro-2a cells. Then, autophagy induced by DTMUV was altered with different autophagy regulators, and we found that incomplete autophagy promoted DTMUV replication. Furthermore, we showed that DTMUV infection activated both the ERK and AMPK pathways, resulting in decreased phosphorylation levels of the autophagy repressor mTOR, subsequently leading to autophagic induction. In addition, we utilized ICR mice as the DTMUV-infected animal model to evaluate the autophagic responses in brain tissues and investigate the effects of autophagy on viral replication and tissue lesions. As a result, we confirmed that DTMUV induced incomplete autophagy in mouse brain tissues and that autophagy inducer treatment promoted DTMUV replication and aggravated DTMUV-induced lesions, whereas autophagy inhibitor treatment led to the opposite effects. Collectively, DTMUV infection induced incomplete autophagy through the ERK/mTOR and AMPK/mTOR signalling pathways to promote viral replication in mouse neuronal cells, and DTMUV-induced incomplete autophagy contributed to the neuropathogenesis of DTMUV.