Virology最新文献

PEDV poses a significant threat to the sustainable development of the global swine industry, resulting in substantial economic losses. Current commercially available vaccines exhibit limited efficacy in controlling the disease. Therefore, the development of an effective vaccine for the prevention and control of PEDV is critically important. This study employed Trimer-Tag technology to express a native-like trimeric S1 subunit fusion protein using a eukaryotic expression system as a candidate vaccine, and evaluated its immunogenicity and protective efficacy in comparison with the full-length S protein. The results demonstrated that the S1-Trimer vaccine was safe, as no mortality was observed in mice and no abortions occurred in sows during the immunization period. In mouse, sow and piglet models, S1-Trimer elicits immunological responses comparable to those of the full-length S protein and induces high levels of PEDV-specific antibodies, including serum IgG, IgA, and neutralizing antibodies (Nabs). The results of the piglet challenge study demonstrated that, compared with the control group, immunization with both S1-Trimer and the full-length S protein significantly reduced diarrhea index scores, intestinal viral loads, and intestinal pathological lesions. These findings indicate that the S1-Trimer vaccine elicits strong protection against the highly pathogenic strain of PEDV, with clinical efficacy comparable to that of the full-length S protein. S1-Trimer, a promising and competitive candidate vaccine based on Trimer-Tag technology, represents a potentially significant platform for the rapid development and production of safe and effective subunit vaccines in the future.

Porcine epidemic diarrhea virus (PEDV) is a member of the family Coronaviridae and genus Alphacoronavirus in the order Nidovirales. It causes porcine epidemic diarrhea (PED) which is characterized by diarrhea, vomiting, and dehydration in swine and is fatal in neonatal piglets with a mortality rate of up to 100%. It is highly contagious, thus resulting in mass epidemics that can have a significant impact on the swine industry. The emerging strains of PEDV are majorly divided into G1b (S-INDEL), and G2b (non-S-INDEL) genogroups based on the spike S1 protein and their virulence. The current vaccines target only one genogroup. In this study, we developed a novel bivalent subunit vaccine by generating a fusion protein of the S1 proteins of both genogroups. For immunogenicity evaluation, mice were intramuscularly immunized twice with the subunit vaccine formulated with three Montanide adjuvants: IMS 1313 VGN, Gel 02 PR, or ISA 61 VG. Results showed that all adjuvanted vaccines induced robust IgG and IgA responses against S1 proteins of both genogroups. IgG1 and IgG2a quantification showed IMS 1313 VGN and ISA 61 VG formulations elicited Th2-biased immune responses, whereas Gel 02 PR adjuvanted subunit vaccine induced balanced immune responses. More importantly, the formulated vaccines elicited neutralizing antibody titers against PEDV infections of both genogroups, with the ISA 61 VG group inducing neutralizing titers greater than 1:64. These pre-clinical results demonstrate that the bivalent subunit vaccine is a promising vaccine candidate against multiple PEDV genogroups that should be further tested in pig trials.

Mosquito-borne viruses (MBVs) remain a significant public health concern in Northern Queensland, Australia, with dengue virus (DENV), Ross River virus (RRV), and Barmah Forest virus (BFV) representing the most common pathogens. Wolbachia-based biological control programs have made notable contributions to reducing dengue transmission by suppressing Aedes aegypti vector competence. Recent surveillance data indicates increased MBV activity, with national case numbers nearly doubling between 2023 and 2024 and early 2025 data suggesting sustained transmission during seasonal peak. Traditional surveillance approaches, while highly valuable for disease monitoring, have limitations in detecting novel or divergent viral strains in real time. Over the past decades, more than 919 unclassified flaviviruses have been reported nationwide, including 117 in Queensland. The advent of metagenomic and metatranscriptomic approaches now enable enhanced, field-based detection of both known and emerging arboviruses. Strengthening mosquito control programs through continued Wolbachia releases, alongside integrated genomic surveillance, predictive modelling, and community engagement will enhance early detection, guide targeted interventions, and reduce the MBV burden in Northern Queensland. This integrated framework provides a strategic pathway to sustains and expand vector control effectiveness while safeguarding public health in high-risk regions.

The ultrastructural details of SARS-CoV-2 morphogenesis and cell-to-cell spread, particularly during the later stages of infection, are still incompletely understood. In this study, we employed a multi-modal microscopy approach to characterise the late-stage infectious cell cycle of two early SARS-CoV-2 variants, A.2 and B.1.1.33, in a Vero E6 cell model. Using a combination of transmission and scanning electron microscopy, immunofluorescence, and RT-qPCR, we analysed viral-host cell interactions at key time points post-infection. Our analysis showed distinct subcellular localisations for the S and N proteins at 24 hpi, the high density of virions adhering to the host cell surface and the morphological indication that these adhered virions can directly mediate cell-cell fusion, leading to syncytium formation via a fusion-from-without (FFWO) mechanism between Vero E6 cells. Quantitative analysis of viral RNA revealed that the A.2 variant exhibited more robust replication kinetics than B.1.1.33. Furthermore, we provide direct ultrastructural indications for alternative viral propagation strategies beyond canonical exocytosis. These mechanisms, which may contribute to immune evasion, also offer new insights into viral pathogenesis relevant to the consequences of COVID-19.

Parvoviruses exhibit a broad host spectrum and possess the potential of cross-species transmission. This evolutionary adaptability raises concerns regarding the potential expansion of their host range into human populations, thus posing a significant public health threat. This review systematically summarizes the current knowledge regarding the molecular interactions between parvoviruses and host cellular components, elaborating on the entire viral life cycle-encompassing cellular entry, intracellular trafficking, nuclear transport, DNA replication, and nuclear egress. It aims to lay a foundation for advancing research on parvovirus pathogenesis and identifying novel targets for vaccine and drug development.