Search Results (39)

Emerging RNA viruses such as influenza A virus (IAV), Zika virus (ZIKV), and dengue virus (DENV) continue to pose major challenges to animal and public health due to their high mutation rates, wide host ranges, and immune evasion strategies. In this study, we evaluated the in vitro antiviral activity of a marine bacterial extract derived from Parerythrobacter sp. M20A3S10 against IAV (H1N1; H3N2), influenza B virus (IBV), ZIKV, and DENV2. The extract demonstrated broad-spectrum antiviral effects with favorable selectivity indices across multiple host-derived epithelial cell lines. Notably, post-infection treatment significantly suppressed viral replication, suggesting a host-modulating or replication-inhibiting mechanism. While the extract’s active components have yet to be identified, bacteria from the Erythrobacteraceae family are known producers of bioactive metabolites with potential antiviral properties. These findings provide preliminary insight into the potential of marine-derived bacterial compounds in veterinary antiviral development and highlight the need for further characterization and in vivo validation. This work contributes to the understanding of virus–host interactions and the exploration of novel therapeutic strategies targeting the pathogenesis and immune modulation of veterinary RNA viruses. Full article

Background/Objectives: Concurrent outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A and B viruses (IAV/IBV), and respiratory syncytial virus (RSV) necessitate rapid and precise differential laboratory diagnostic methods. This study aimed to evaluate the multiplex molecular diagnostic performance of the geneLEAD VIII system (Precision System Science Co., Ltd., Matsudo, Japan), a fully automated sample-to-result precision instrument, in conjunction with the VIASURE SARS-CoV-2, Flu & RSV Real Time PCR Detection Kit (CerTest Biotec, S.L., Zaragoza, Spain). Methods: The specific detection capabilities of SARS-CoV-2, IAV/IBV, and RSV genes were evaluated using virus-spiked saliva and nasal swab samples. Using saliva samples, the viral titer detection limits of geneLEAD/VIASURE and manual referent singleplex RT-qPCR assays were compared. The performance of geneLEAD/VIASURE in analyzing single- and multiple-infection models was scrutinized. The concordance between the geneLEAD/VIASURE and the manual assays was assessed. Results: The geneLEAD/VIASURE successfully detected all the virus genes in the saliva and nasal swab samples despite some differences in the Ct values. The viral titer detection limits in the saliva samples for SARS-CoV-2, IAV, IBV, and RSV using geneLEAD/VIASURE were 10⁰, ≤10⁻², 10⁰, and 10² TCID₅₀/mL, respectively, compared to ≤10⁻¹, ≤10⁰, ≤10⁰, and ≤10⁴ TCID₅₀/mL, respectively, in the manual assays. geneLEAD/VIASURE yielded similar Ct values in the single- and multiple-infection models, with some exceptions noted in the triple-infection models when low titers of RSV were spiked with high titers of the other viruses. The concordance between geneLEAD/VIASURE and the manual assays was high, with Pearson’s R² values of 0.90, 0.85, 0.92, and 0.95 for SARS-CoV-2, IAV, IBV, and RSV, respectively. Conclusions: geneLEAD/VIASURE is a reliable diagnostic tool for detecting SARS-CoV-2, IAV/IBV, and RSV in single- and multiple-infection scenarios. Full article

Infectious bronchitis virus (IBV) and low-pathogenic avian influenza virus (LPAIV) H9N2 are commonly identified in poultry, individually or in association with other pathogens. This study monitored 183 broiler farms affected by respiratory diseases across seven regions of Morocco from January 2021 to December 2023. Among these farms, 87.98% were vaccinated against IBV, while 57.92% were against AI H9N2. Abnormally high mortality rates were observed in 44.26% of the farms, with 24.69% of cases attributed to IBV, 50.62% to LPAI H9N2, and 13.58% due to coinfection with both IBV and H9N2. RT-PCR analysis of tissue samples and cloacal and tracheal swabs collected from 183 broiler farms revealed that 33.33% were positive for IBV and 34.97% for H9N2. Coinfection by IBV and H9N2 was detected in 12.57% of cases, peaking at 17% in 2022. Co-infected flocks exhibited severe clinical signs and lesions, such as reduced food consumption, diarrhea, and renal issues. The predominant lesions were in the respiratory tract, affecting 91.26% of infected broilers. Additionally, among the 183 flocks, 50 farms that tested positive for IBV infection were randomly selected from the seven regions of Morocco for further investigation of other respiratory pathogens, including Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), and infectious laryngotracheitis (ILT), using real-time RT-PCR. Detection rates for these pathogens were 26% for MG, 30% for MS, 4% for ILTv (vaccine strain), and 18% for ILTw (wild strain). Detection rates for single, dual, triple, and quadruple infections were 34%, 42%, 18%, and 4%, respectively. The most common dual and triple coinfections were IBV + H9N2 (14%) and IBV + MG + MS (10%). Phylogenetic analysis of the S gene identified two main IBV genotypes, namely, 793B and D181, with the latter being a strain circulating for the first time in Moroccan poultry. This underscores the urgent need to establish surveillance systems to track pathogen circulation and implement strategies to control virus spread, ensuring the protection of animals and public health. Full article

Seasonal influenza epidemics caused by influenza A viruses (IAV) and influenza B viruses (IBV) pose a substantial public health burden. Despite the significant impact of IBV, its restricted host range and the absence of documented pandemics have resulted in limited research attention relative to IAV. Understanding the viral infection mechanisms of both IAV and IBV is crucial for controlling seasonal epidemics. Previously, we demonstrated that 3′-O-sulfated galactosylceramide sulfatide binds to IAV and enhances viral replication, a finding with potential therapeutic implications. However, the role sulfatide plays in other influenza virus infections, including those caused by IBV, remains unknown. Accordingly, in this paper, we investigate the function of sulfatide during IBV infection. We demonstrate that sulfatide binds to IBV hemagglutinin (HA), and that sulfatide overexpression significantly enhances IBV replication, whereas treatment with sulfatase or an anti-sulfatide antibody markedly suppressed IBV replication. Moreover, further tests involving the inhibition of sulfatide biosynthesis resulted in the suppression of viral replication with impaired nuclear export of viral ribonucleoproteins (vRNPs). These findings establish that sulfatide is a critical regulator of IBV replication, which parallels its role in IAV infection, and suggest that targeting sulfatide-virus interactions can lead to broad-spectrum therapeutic strategies against influenza virus. Full article

The Bunyavirales order includes a range of zoonotic viruses, which can cause severe disease in humans. The viral replication machinery is a logical target for the development of direct-acting antivirals. Inhibition of the cap-snatching endonuclease activity of related influenza viruses provides a proof of concept. Using the influenza B virus (IBV) RNA-dependent RNA polymerase complex as a benchmark, we conducted a comparative analysis of endonuclease activities of recombinant full-length bunyaviral L proteins using gel-based assays. The IBV complex demonstrates specific endonucleolytic cleavage and a clear preference for capped substrates. In contrast, severe fever with thrombocytopenia syndrome, Sin Nombre, and Hantaan virus L proteins readily cleave capped and uncapped RNAs to a broader spectrum of RNA fragments. Active site mutants further help to control for the potential of contaminating nucleases, exonuclease activity, and RNA hydrolysis. The influenza cap-snatching inhibitor baloxavir and derivatives have been used to validate this approach. In conclusion, the results of this study demonstrate the importance of assays with single nucleotide resolution and the use of full-length L proteins as a valuable experimental tool to identify selective endonuclease inhibitors. Full article

Despite annual vaccines, Influenza B viruses (IBVs) continue to cause severe infections and have a significant impact and burden on the healthcare system. Improving IBV vaccine effectiveness is a key focus, with various strategies under investigation. In this research, we used a computational design to select wildtype sequences for a multivalent viral-vectored vaccine (rAd-Tri-Vic) targeting the Victoria-like (Vic) hemagglutinin (HA) protein. In mouse models, the vaccine induced strong antibody and T cell responses, providing complete protection against both lineage-specific and cross-lineage (Yamagata-like) lethal challenges. The immune responses remained robust for up to six months, which demonstrated sustained protection. These results highlight the potential of HA-targeted multivalent vaccines to enhance the IBV efficacy and address protection against antigenically diverse IBV strains. Full article

Background: During the COVID-19 pandemic, we continuously monitored the epidemiology of influenza virus among pediatric patients from January 2021 to December 2023 in Hainan Island, China. Methods: In this study, we collected 54,974 nasopharyngeal swab samples for influenza A Virus (IAV) testing and 53,151 samples for influenza B Virus (IBV) testing from pediatric outpatients. Additionally, we also collected 19,687 nasopharyngeal swab samples from pediatric inpatients for IAV and IBV testing. Outpatient samples were screened for influenza viruses (IVs) infection by the colloidal gold method. Targeted Next-Generation Sequencing (tNGS) was used to detect influenza virus infections in inpatients. Influenza virus types were identified by analyzing the HA/NA partial regions. Results: The findings revealed a significant decrease in the infection rate of IBV over the specified period, while the infection rate of IAV exhibited a rising trend. Additionally, B/Victoria lineage was the dominant epidemic strain in 2021, while the epidemic strains in 2022 and 2023 underwent a dynamic transformation from A/H3N2 to A/H1N1. Phylogenetic analysis revealed close relationships among the circulating strains. Nonetheless, because the sample size is limited, additional research is required. Conclusions: Our findings suggest that the predominant types of influenza viruses in the pediatric population are undergoing dynamic changes, influenced by the implementation and relaxation of non-pharmaceutical intervention measures. These findings highlight the need for adaptive influenza vaccination and containment strategies, particularly in tropical regions like Hainan, where climate and public health policies significantly impact viral transmission patterns. The insights gained from this study could inform more effective public health strategies in similar regions to mitigate the impact of influenza outbreaks in the future. Full article

Wastewater-based surveillance (WBS) has been widely used to track SARS-CoV-2 as well as many other viruses in communities during the COVID pandemic and post-pandemic. However, it is still not clear how temperature and storage time would influence the stability of viruses in wastewater. In this study, we assessed the stability of SARS-CoV-2, pepper mild mottle virus (PMMoV), influenza viruses A (IAV) and B (IBV), respiratory syncytial virus (RSV), and enteric viruses in raw wastewater stored at room temperature, 4 °C, and −20 °C for 3 and 6 days. SARS-CoV-2, PMMoV, IAV, and enteric viruses were found to be stable up to 6 days after storing at room temperature or 4 °C. SARS-CoV-2 and RSV were more susceptible to freeze–thaw cycles compared to PMMoV and enteric viruses, which were relatively stable for up to 6 days stored at −20 °C. Low detection of IBV in wastewater made it difficult to evaluate the impact. Based on our findings, we conclude that short-term storage or transportation of wastewater samples within 6 days at ambient temperature or 4 °C is acceptable for the majority of these viruses. Freezing samples at −20 °C for even short periods is not recommended for WBS of respiratory viruses. The data obtained from this study can provide guidance for quality assurance purposes from the operational aspects of wastewater surveillance. Full article

The study highlights the significant changes in respiratory virus epidemiology following the lifting of COVID-19 restrictions. Method: In this single-centre retrospective study, the virological readouts of adenovirus (AdV), influenza virus A (IAV), influenza virus B (IBV), parainfluenza viruses (PIV) 1, 2, 3, 4, respiratory syncytial virus (RSV), and coupled enterovirus and rhinovirus (EV/RV) were extracted from the respiratory specimens of paediatric patients in Hong Kong from January 2015 to February 2024. The subjects were stratified into five age groups. Results: The study included 18,737 and 6001 respiratory specimens in the pre-COVID-19 and post-COVID-19 mask mandate period, respectively. The mean age of hospitalised patients increased from 3.49 y ± 0.03 y to 4.37 y ± 0.05 y after the COVID-19 lockdown. The rates of single-virus infection and co-infection were significantly higher in the post-COVID-19 mask mandate period. The odds ratio for AdV for all age groups (OR: 4.53, 4.03, 2.32, 2.46, 1.31) and RSV in older children from 3 years old and above (OR: 1.95, 3.38, p < 0.01) were significantly elevated after the COVID-19 outbreak. Conclusions: Our findings suggest that public health measures to contain COVID-19 may have unintended consequences on children’s natural exposure and immunity to other respiratory viruses, potentially increasing their morbidity in the post-pandemic era. Full article

The development of an effective and broadly protective influenza vaccine against circulating and emerging strains remains elusive. In this study, we evaluated a potentially universal influenza vaccine based on single-component self-assembling protein nanoparticles (1c-SApNPs) presenting the conserved matrix protein 2 ectodomain (M2e) from influenza A and B viruses (IAV and IBV, respectively). We previously designed a tandem antigen comprising three IAV M2e domains of human, avian/swine, and human/swine origins (termed M2ex3). The M2ex3-presenting 1c-SApNPs conferred complete protection in mice against sequential lethal challenges with H1N1 and H3N2. To broaden this protection to cover IBVs, we designed a series of antigens incorporating different arrangements of three IAV M2e domains and three copies of IBV M2e. Tandem repeats of IAV and IBV (termed influenza A-B) M2e arrayed on the I3-01v9a 60-mer 1c-SApNP, when formulated with an oil-in-water emulsion adjuvant, generated greater M2e-specific immunogenicity and protective efficacy than the soluble influenza A-B M2e trimer, indicated by higher survival rates and reduced weight loss post-challenge. Importantly, one of the influenza A-B M2e SApNP constructs elicited 100% protection against a lethal influenza A/Puerto Rico/8/1934 (H1N1) challenge in mice and 70% protection against a lethal influenza B/Florida/4/2006 (Yamagata lineage) challenge, the latter of which has not been reported in the literature to date. Our study thus provides a promising M2e-based single-component universal vaccine candidate against the two major types of influenza virus circulating in humans. Full article

Lateral flow immunoassay (LFIA) technology serves a significant role as a simple and rapid biosensor in the detection of influenza viruses. The focus of this study is the development of a rapid and convenient screening method for influenza B virus (IBV) proteins using a fluorescence lateral flow biosensor based on Ag-doped ZnIn₂S₄ quantum dots (Ag: ZIS QDs) as signal reporters. These Ag: ZIS QDs-emitting orange fluorescence are loaded onto dendritic mesoporous silica nanoparticles (DMSNs) and are further coated with a layer of silica shell to form a core–shell structured composite nanomaterial (SiO₂ @ Ag: ZIS QDs @ DMSNs). The orange fluorescence effectively eliminates the interference of blue background fluorescence, significantly enhancing the detection sensitivity. This technology demonstrates outstanding performance in the immediate detection of IBV, with a minimum detection limit of 1 ng/mL, compared to the traditional colloidal gold strip with a detection limit of 6 ng/mL. Furthermore, both intra-assay and inter-assay coefficients of variation (CV) are less than 9%. This method holds promise for wide application in early diagnosis, epidemiological investigation, and epidemic surveillance of IBV. Full article

Background: Influenza viruses continue to cause a significant social and economic burden globally. Vaccination is recognized as the most effective measure to control influenza. Live attenuated influenza vaccines (LAIVs) are an effective means of preventing influenza, especially among children. A reverse genetics (RG) system is required to rapidly update the antigenic composition of vaccines, as well as to design LAIVs with a broader spectrum of protection. Such a system has been developed for the Russian LAIVs only for type A strains, but not for influenza B viruses (IBV). Methods: All genes of the B/USSR/60/69 master donor virus (B60) were cloned into RG plasmids, and the engineered B60, as well as a panel of IBV LAIV reassortants were rescued from plasmid DNAs encoding all viral genes. The engineered viruses were evaluated in vitro and in a mouse model. Results: The B60 RG system was successfully developed, which made it possible to rescue LAIV reassortants with the desired antigenic composition, including hybrid strains with hemagglutinin and neuraminidase genes belonging to the viruses from different IBV lineages. The LAIV candidate carrying the HA of the B/Victoria-lineage virus and NA from the B/Yamagata-lineage virus demonstrated optimal characteristics in terms of safety, immunogenicity and cross-protection, prompting its further assessment as a broadly protective component of trivalent LAIV. Conclusions: The new RG system for B60 MDV allowed the rapid generation of type B LAIV reassortants with desired genome compositions. The generation of hybrid LAIV reassortants with HA and NA genes belonging to the opposite IBV lineages is a promising approach for the development of IBV vaccines with broad cross-protection. Full article

Quantifying viruses in wastewater via RT-qPCR provides total genomic data but does not indicate the virus capsid integrity or the potential risk for human infection. Assessing virus capsid integrity in sewage is important for wastewater-based surveillance, since discharged effluent may pose a public health hazard. While integrity assays using cell cultures can provide this information, they require specialised laboratories and expertise. One solution to overcome this limitation is the use of photo-reactive monoazide dyes (e.g., propidium monoazide [PMAxx]) in a capsid integrity-RT-qPCR assay (ci-RT-qPCR). In this study, we tested the efficiency of PMAxx dye at 50 μM and 100 μM concentrations on live and heat-inactivated model viruses commonly detected in wastewater, including adenovirus (AdV), hepatitis A (HAV), influenza A virus (IAV), and norovirus GI (NoV GI). The 100 μM PMAxx dye concentration effectively differentiated live from heat-inactivated viruses for all targets in buffer solution. This method was then applied to wastewater samples (n = 19) for the detection of encapsulated AdV, enterovirus (EV), HAV, IAV, influenza B virus (IBV), NoV GI, NoV GII, and SARS-CoV-2. Samples were negative for AdV, HAV, IAV, and IBV but positive for EV, NoV GI, NoV GII, and SARS-CoV-2. In the PMAxx-treated samples, EV, NoV GI, and NoV GII showed −0.52–1.15, 0.9–1.51, and 0.31–1.69 log reductions in capsid integrity, indicating a high degree of potentially infectious virus in wastewater. In contrast, SARS-CoV-2 was only detected using RT-qPCR but not after PMAxx treatment, indicating the absence of encapsulated and potentially infectious virus. In conclusion, this study demonstrates the utility of PMAxx dyes to evaluate capsid integrity across a diverse range of viruses commonly monitored in wastewater. Full article

Influenza B virus (IBV) significantly impacts the health and the economy of the global population. WHO global health estimates project 1 billion flu cases annually, with 3 to 5 million resulting in severe disease and 0.3 to 0.5 million influenza-related deaths worldwide. Influenza B virus epidemics result in significant economic losses due to healthcare expenses, reduced workforce productivity, and strain on healthcare systems. Influenza B virus epidemics, such as the 1987–1988 Yamagata lineage outbreak and the 2001–2002 Victoria lineage outbreak, had a significant global impact. IBV’s fast mutation and replication rates facilitate rapid adaptation to the environment, enabling the evasion of existing immunity and the development of resistance to virus-targeting treatments. This leads to annual outbreaks and necessitates the development of new vaccination formulations. This review aims to elucidate IBV’s evolutionary genomic organization and life cycle and provide an overview of anti-IBV drugs, resistance, treatment options, and prospects for IBV biology, emphasizing challenges in preventing and treating IBV infection. Full article

SARS-CoV-2, influenza A/B virus (IAV/IBV), and respiratory syncytial virus (RSV) are among the common viruses causing acute respiratory infections. Clinical diagnosis to differentiate these viruses is challenging due to similar clinical presentations; thus, laboratory-based real-time RT PCR is the gold standard for diagnosis. This retrospective study aimed to evaluate the diagnostic performance of STANDARD M10 Flu/RSV/SARS-CoV-2 (SD Biosensor Inc., Seoul, Korea) using archived positive and negative respiratory samples for SARS-CoV-2, IAV, IBV, and RSV. A total of 322 respiratory samples were tested, comprising 215 positive samples (49 SARS-CoV-2, 48 IAV, 53 IBV, 65 RSV) and 107 negative samples. All samples were tested with both STANDARD M10 and compared to either Xpert Xpress SARS-CoV-2 or Xpert Xpress Flu/RSV (Cepheid, Sunnyvale, CA, USA). The sensitivity, specificity, positive predictive value, and negative predictive value rates of STANDARD M10 were very similar to Xpert Xpress SARS-CoV-2 or Xpert Xpress Flu/RSV ranges for each virus (98–100%). The duration of testing and workflows were similar. The overall agreement was 99.4%, including 99.1% agreement for positive samples and 100% agreement for negative samples. In conclusion, the STANDARD M10 point-of-care test is suitable for rapid simultaneous detection of SARS-CoV-2, IAV, IBV, and RSV. Full article