Search Results (59)

The influenza A virus (IAV) is a major cause of recurrent seasonal epidemics and global pandemics, posing a significant threat to public health. Although lycorine has demonstrated broad-spectrum antiviral activity, its specific mechanisms of action against IAV remain incompletely understood. In this study, we characterized the potent inhibitory effects of lycorine on seasonal and drug-resistant IAV subtypes (H1N1/H3N2) as well as the influenza B virus, showing its ability to suppress viral mRNA, viral titers, and M2 protein expression across multiple cell lines. Time-of-addition and time-course assays revealed that lycorine exerts multiphasic interference, and the critical late stage of the IAV life cycle aroused our interest to study this further. Mechanistically, we discovered that lycorine specifically interferes with the de novo synthesis of nucleoporin Nup93, thereby disrupting the nuclear export of viral nucleoprotein (NP). These findings not only establish lycorine as a promising broad-spectrum anti-influenza candidate but also provide new insights for developing host-targeted antiviral strategies. Full article

During the 2017–2018 influenza season, there was high influenza activity, with a predominance of influenza A(H1N1)pdm09 circulation in the country. The influenza circulation pattern in the area of the Yucatan Peninsula was different from that of the rest of the country. However, in the summer of 2018, there was a sudden increase in the number of identified cases. A retrospective analysis was performed using data generated by four molecular diagnostic laboratories of the Mexican Social Security Institute. Demographics, influenza positivity, seasonality and case fatality rates were recorded. We used odds ratios to compare outpatients who were confirmed by laboratory tests to be positive with those who were confirmed to be negative. The Kaplan–Meier method and Cox multivariate analysis were used to calculate cumulative risk. There were 4460 cases of ILI/SARI between Yucatan and Quintana Roo, which represented 53.1% of the total number of cases reported. Compared with that in 2009, the epidemic wave in 2018 was shorter and more expansive, with a greater number of reported cases, as well as a greater number of people who required hospitalization. The dominant pattern of A(H1N1)pdm09 influenza activity on the Yucatan Peninsula in the summer of 2018 has not been observed since the influenza pandemic of 2009. Full article

(1) Background: We aimed to analyze the epidemiological characteristics of hemorrhagic fever with renal syndrome (HFRS) in Longyou County and to provide a basis for the future response to this disease. (2) Methods: Data on hemorrhagic fever and host animals were collected from 2011 to 2023. Descriptive methods were used to analyze the epidemic. The R4.4.1 software was used to show how the host density relates to the virus levels, temperature, and rainfall and to predict the host density. (3) Results: We observed 58 cases of hemorrhagic fever, the majority of which occurred in farmers. There were two incidence peaks each year during the spring and winter seasons, accounting for 22.41% and 43.10% of the total cases, respectively. The outdoor rodent population density was significantly and positively correlated with the outdoor rodent virus prevalence (R² = 0.9411), serving as a robust predictor of the outdoor rodent virus prevalence. Additionally, the density of outdoor rodents exhibited a strong nonlinear relationship with the temperature and precipitation. (4) Conclusions: After hemorrhagic fever vaccination, rodent population density control, and rodent carrier rodent control from 1995 to 2000, the hemorrhagic fever epidemic was generally stable, and the epidemiological characteristics remained stable. In the future, we should continue to take active and effective comprehensive measures to intervene, further realize the effective control of HFRS, and prevent the recurrence of hemorrhagic fever epidemics. Full article

Background/Objectives: The impact of the coronavirus disease 2019 (COVID-19) pandemic on health was significant worldwide. The measures adopted to limit the spread of the virus had an indirect effect on the epidemiology of other infectious diseases with similar mechanisms of inter-human transmission. The present literature review analyzed the scenario of pediatric acute respiratory infections in the post-lockdown period compared to the pre-pandemic and lockdown periods. The different patterns of viruses’ outbreaks were evaluated according to the type of local COVID-19 restrictive measures and to the type of pathogen. Methods: Relevant scientific literature published between March 2020 and November 2024 was identified by means of electronic keyword searches in the PubMed, Scopus, and Cochrane Library databases. Results: Worldwide implementation of non-pharmacological public health interventions aimed at limiting the COVID-19 pandemic resulted in a measurable effect on the circulation of other common respiratory viruses, significantly affecting their usual seasonality. Most viruses significantly reduced their activity during the lockdown period but returned to or exceeded historical levels after discontinuation of preventive non-pharmacological measures. For many respiratory viruses, particularly respiratory syncytial virus, an off-season increase was reported. Conclusions: The non-pharmacological interventions, which effectively helped limit the COVID-19 pandemic, resulted in relevant epidemiologic changes in most common respiratory viruses. Given the different seasonality and clinical severity observed for some pathogens after lockdown, possible future off-season or more severe epidemics should be expected. Full article

The noise level of gravity stations is an important indicator for measuring the operating status of a station and is a prerequisite for evaluating whether the station’s observations can be used to extract weak geodynamic signals. With the continuous expansion of areas of human activity, gravity stations originally located in the wild may become increasingly closer to cities. Whether their noise levels change is an important issue that is worthy of attention. Based on power spectrum analyses and probability density function methods, the noise level of the superconducting gravimeter (SG) at Jiufeng station in Wuhan in the seismic frequency band of 0.001–0.04 Hz was calculated, and its time-varying characteristics were analyzed. The noise level of Jiufeng station did not change significantly before and after the lockdown of Wuhan due to the COVID-19 epidemic in 2020. No significant changes in the noise level were found before and after the official operation of Wuhan Metro Line 19 at the end of 2023. From October 2016 to April 2017, the noise level showed an abnormal trend of suddenly rapidly rising and then slowly declining, which was found to be caused by a tilt problem in the gravity sensor. Overall, in the seismic frequency band of 0.001–0.04 Hz, the noise level at Jiufeng station showed seasonal variation characteristics, and the noise was stronger in winter than in summer, which is consistent with the characteristics of Earth’s hum. Since January 2022, the noise level has shown an increasing trend year by year. The results of this study can provide an important reference for the operation of gravity stations and the extraction of weak geodynamic signals. Full article

Background: During seasonal influenza activity, circulation of other respiratory viruses (ORVs) may contribute to the increased disease burden that is attributed to influenza without laboratory confirmation. The objective of this study was to characterize and evaluate the magnitude of this contribution over 12 seasons of influenza using the Acute Respiratory Infection Sentinel Surveillance system in Catalonia (PIDIRAC). Methods: A retrospective descriptive study of isolations from respiratory samples obtained by the sentinel surveillance network of physicians was carried out from 2008 to 2020 in Catalonia, Spain. Information was collected on demographic variables (age, sex), influenza vaccination status, epidemic activity weeks each season, and influenza laboratory confirmation. Results: A total of 12,690 samples were collected, with 46% (5831) collected during peak influenza seasonal epidemic activity. In total, 49.6% of the sampled participants were male and 51.1% were aged <15 years. Of these, 73.7% (4298) of samples were positive for at least one respiratory virus; 79.7% (3425 samples) were positive for the influenza virus (IV), with 3067 samples positive for one IV type, 8 samples showing coinfection with two types of IV, and 350 showing coinfection of IV with more than one virus. The distribution of influenza viruses was 64.2% IVA, 35.2% IVB, and 0.1% IVC. Of the other respiratory viruses identified, there was a high proportion of human rhinovirus (32.3%), followed by human adenovirus (24.3%) and respiratory syncytial virus (18; 7%). Four percent were coinfected with two or more viruses other than influenza. The distribution of coinfections with ORVs and influenza by age groups presents a significant difference in proportions for 0–4, 5–14, 15–64 and >64 (21.5%, 10.8%, 8.2% and 7.6%: p < 0.001). A lower ORVs coinfection ratio was observed in the influenza-vaccinated population (11.9% vs. 17.4% OR: 0.64 IC 95% 0.36–1.14). Conclusions: During the weeks of seasonal influenza epidemic activity, other respiratory viruses contribute substantially, either individually or through the coinfection of two or more viruses, to the morbidity attributed to influenza viruses as influenza-like illness (ILI). The contribution of these viruses is especially significant in the pediatric and elderly population. Identifying the epidemiology of most clinically relevant respiratory viruses will aid the development of models of infection and allow for the development of targeted treatments, particularly for populations most vulnerable to respiratory viruses-induced diseases. Full article

Influenza A virus (IAV) is known for causing seasonal epidemics ranging from flu to more severe outcomes like pneumonia, cytokine storms, and acute respiratory distress syndrome. The innate immune response and inflammasome activation play pivotal roles in sensing, preventing, and clearing the infection, as well as in the potential exacerbation of disease progression. This study examines the complex relationships between donor-specific characteristics and cytokine responses during H3N2 IAV infection using an ex vivo model. At 24 h post infection in 31 human lung explant tissue samples, key cytokines such as interleukin (IL)-6, IL-10, tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ) were upregulated. Interestingly, a history of lung cancer did not impact the acute immune response. However, cigarette smoking and programmed death-ligand 1 (PD-L1) expression on macrophages significantly increased IL-2 levels. Conversely, age inversely affected IL-4 levels, and diabetes mellitus negatively influenced IL-6 levels. Additionally, both diabetes mellitus and programmed cell death protein 1 (PD-1) expression on CD3⁺/CD4⁺ T cells negatively impacted TNF-α levels, while body mass index was inversely associated with IFN-γ production. Toll-like receptor 2 (TLR2) expression emerged as crucial in mediating acute innate and adaptive immune responses. These findings highlight the intricate interplay between individual physiological traits and immune responses during influenza infection, underscoring the importance of tailored and personalized approaches in IAV treatment and prevention. Full article

Background: During the 2022–2023 influenza season, the influenza activities in most regions of China were postponed, including Beijing. The unusually delayed influenza epidemic posed a challenge to the effectiveness of the influenza vaccine. Methods: Using the test-negative design, we evaluated influenza vaccine effectiveness (VE) during the 2022–2023 influenza season against influenza A-associated outpatient and emergency-department-attended influenza-like illness (ILI) in Beijing, China, from 9 January to 30 April 2023. Results: The analysis included 8301 medically attended ILI patients, of which 1342 (46.2%) had influenza A(H1N1)pdm09, 1554 (53.4%) had influenza A(H3N2), and 11 (0.4%) had co-infection of the two viruses. VE against influenza A-associated ILI patients was 23.2% (95% CI: −6.5% to 44.6%) overall, and 23.1%, 9.9%, and 33.8% among children aged 6 months to 17 years, adults aged 18–59 years, and adults aged ≥60 years, respectively. VE against influenza A(H1N1)pdm09 and against influenza A(H3N2) were 36.2% (95% CI: −1.9% to 60.1%) and 9.5% (95% CI: −34.1% to 39.0%), respectively. VE of the group with vaccination intervals of 14–90 days (70.1%, 95% CI: −145.4 to 96.4) was higher than that of the groups with a vaccination interval of 90–149 days (18.7%, 95% CI: −42.4% to 53.6%) and ≥150 days (21.2%, 95% CI: −18.8% to 47.7%). Conclusions: A moderate VE against influenza A(H1N1)pdm09 and a low VE against influenza A(H3N2) were observed in Beijing during the 2022–2023 influenza season, a season characterized with a delayed and high-intensity influenza epidemic. VE appears to be better within three months after vaccination. Our findings indicate a potential need for the optimization of vaccination policies and underscore the importance of continuous monitoring of influenza to enhance vaccines and optimizing vaccination timing. Full article

Influenza A virus (IAV) poses a global threat worldwide causing pandemics, epidemics, and seasonal outbreaks. Annual modification of vaccines is costly due to continual shifts in circulating genotypes, leading to inadequate coverage in low- and middle-income countries like India. Additionally, IAVs are evolving resistance to approved antivirals, necessitating a search for alternative treatments. In this study, the antiviral role of the FDA-approved antibiotic minocycline against IAV strains was evaluated in vitro and in vivo by quantifying viral gene expression by qRT-PCR, viral protein levels by Western blotting, and viral titers. Our findings demonstrate that minocycline at a non-toxic dose effectively inhibits IAV replication, regardless of viral strain or cell line. Its antiviral mechanism operates independently of interferon signaling by targeting the MEK/ERK signaling pathway, which is crucial for the export of viral ribonucleoproteins (vRNPs). Minocycline prevents the assembly and release of infectious viral particles by causing the accumulation of vRNPs within the nucleus. Moreover, minocycline also inhibits IAV-induced late-stage apoptosis, further suppressing viral propagation. The antiviral activity of minocycline against IAVs could offer a promising solution amidst the challenges posed by influenza and the limitations of current treatments. Full article

Influenza virus possesses an RNA genome of single-stranded, negative-sensed, and segmented configuration. Influenza virus causes an acute respiratory disease, commonly known as the “flu” in humans. In some individuals, flu can lead to pneumonia and acute respiratory distress syndrome. Influenza A virus (IAV) is the most significant because it causes recurring seasonal epidemics, occasional pandemics, and zoonotic outbreaks in human populations, globally. The host innate immune response to IAV infection plays a critical role in sensing, preventing, and clearing the infection as well as in flu disease pathology. Host cells sense IAV infection through multiple receptors and mechanisms, which culminate in the induction of a concerted innate antiviral response and the creation of an antiviral state, which inhibits and clears the infection from host cells. However, IAV antagonizes and escapes many steps of the innate antiviral response by different mechanisms. Herein, we review those host and viral mechanisms. This review covers most aspects of the host innate immune response, i.e., (1) the sensing of incoming virus particles, (2) the activation of downstream innate antiviral signaling pathways, (3) the expression of interferon-stimulated genes, (4) and viral antagonism and escape. Full article

Influenza viruses can cause highly infectious respiratory diseases, posing noteworthy epidemic and pandemic threats. Vaccination is the most cost-effective intervention to prevent influenza and its complications. However, reliance on embryonic chicken eggs for commercial influenza vaccine production presents potential risks, including reductions in efficacy due to HA gene mutations and supply delays due to scalability challenges. Thus, alternative platforms are needed urgently to replace egg-based methods and efficiently meet the increasing demand for vaccines. In this study, we employed a baculovirus expression vector system to engineer HA, NA, and M1 genes from seasonal influenza strains A/H1N1, A/H3N2, B/Yamagata, and B/Victoria, generating virus-like particle (VLP) vaccine antigens, H1N1-VLP, H3N2-VLP, Yamagata-VLP, and Victoria-VLP. We then assessed their functional and antigenic characteristics, including hemagglutination assay, protein composition, morphology, stability, and immunogenicity. We found that recombinant VLPs displayed functional activity, resembling influenza virions in morphology and size while maintaining structural integrity. Comparative immunogenicity assessments in mice showed that our quadrivalent VLPs were consistent in inducing hemagglutination inhibition and neutralizing antibody titers against homologous viruses compared to both commercial recombinant HA and egg-based vaccines (Vaxigrip). The findings highlight insect cell-based VLP vaccines as promising candidates for quadrivalent seasonal influenza vaccines. Further studies are worth conducting. Full article

Respiratory tract infections (RTIs) can lead to both recurrent seasonal epidemic outbreaks and devastating pandemics. The aim of this study was to evaluate the epidemiologic characteristics and pathogen spectrum of RTIs using a multiplex RT-PCR panel. A total of 9354 cases with suspected RTIs between February 2021 and July 2023 were included in this study. A total of 11,048 nasopharyngeal and oropharyngeal samples from these patients were analyzed for 23 respiratory tract pathogens using multiplex RT-PCR. H. influenzae and S. pneumoniae were considered as colonizing bacteria. At least one pathogen was detected in 70.66% of the samples; viral pathogens were detected in 48.41% of the samples, bacterial pathogens were detected in 16.06% of the samples, and viral + bacterial pathogens were detected in 35.53% of the samples. The most frequently detected viral pathogen was rhinovirus/enterovirus (RV/EV) (19.99%). Interestingly, in 2021, respiratory syncytial virus A/B showed atypical activity and replaced RV/EV as the most prevalent pathogen. Human bocavirus, H. influenzae, and S. pneumoniae were detected at higher rates in males (p: 0.038, p: 0.042, and p: 0.035, respectively), while SARS-CoV-2 and B. pertussis were detected at higher rates in females (p < 0.001 and p: 0.033). RTIs were found at higher rates in children (p < 0.001). SARS-CoV-2 and human coronaviruses 229E were detected at higher rates in adults (p < 0.001 and p: 0.001). This comprehensive study with a large sample size investigating RTI pathogens was the first in Türkiye. Understanding the current viral circulation using multiplex RT-PCR panels enables clinicians to predict the most likely pathogens affecting patients and contributes to patient management, in addition to anticipating potential threats. Full article

Influenza is a potentially fatal acute respiratory viral disease caused by the influenza virus. Influenza viruses vary in antigenicity and spread rapidly, resulting in seasonal epidemics. Vaccination is the most effective strategy for lowering the incidence and fatality rates of influenza-related disorders, and it is also an important method for reducing seasonal influenza infections. Mammalian Madin–Darby canine kidney (MDCK) cell lines are recommended for influenza virus growth, and such cell lines have been utilized in several commercial influenza vaccine productions. The limit dilution approach was used to screen ATCC-MDCK cell line subcellular strains that are especially sensitive to H1N1, H3N2, BV, and BY influenza viruses to increase virus production, and research on influenza virus culture media was performed to support influenza virus vaccine development. We also used RNA sequencing to identify differentially expressed genes and a GSEA analysis to determine the biological mechanisms underlying the various levels of susceptibility of cells to influenza viruses. MDCK cell subline 2B6 can be cultured to increase titer and the production of the H1N1, H3N2, BV, and BY influenza viruses. MDCK-2B6 has a significantly enriched and activated in ECM receptor interaction, JAK-STAT signaling, and cytokine receptor interaction signaling pathways, which may result in increased cellular susceptibility and cell proliferation activity to influenza viruses, promote viral adsorption and replication, and elevate viral production, ultimately. The study revealed that MDCK-2B6 can increase the influenza virus titer and yield in vaccine production by increasing cell sensitivity and enhancing proliferative activity. Full article

Although the COVID-19 pandemic appears to be diminishing, the emergence of SARS-CoV-2 variants represents a threat to humans due to their inherent transmissibility, immunological evasion, virulence, and invulnerability to existing therapies. The COVID-19 pandemic affected more than 500 million people and caused over 6 million deaths. Vaccines are essential, but in circumstances in which vaccination is not accessible or in individuals with compromised immune systems, drugs can provide additional protection. Targeting host signaling pathways is recommended due to their genomic stability and resistance barriers. Moreover, targeting host factors allows us to develop compounds that are effective against different viral variants as well as against newly emerging virus strains. In recent years, the globe has experienced climate change, which may contribute to the emergence and spread of infectious diseases through a variety of factors. Warmer temperatures and changing precipitation patterns can increase the geographic range of disease-carrying vectors, increasing the risk of diseases spreading to new areas. Climate change may also affect vector behavior, leading to a longer breeding season and more breeding sites for disease vectors. Climate change may also disrupt ecosystems, bringing humans closer to wildlife that transmits zoonotic diseases. All the above factors may accelerate the emergence of new viral epidemics. Plant-derived products, which have been used in traditional medicine for treating pathological conditions, offer structurally novel therapeutic compounds, including those with anti-viral activity. In addition, plant-derived bioactive substances might serve as the ideal basis for developing sustainable/efficient/cost-effective anti-viral alternatives. Interest in herbal antiviral products has increased. More than 50% of approved drugs originate from herbal sources. Plant-derived compounds offer diverse structures and bioactive molecules that are candidates for new drug development. Combining these therapies with conventional drugs could improve patient outcomes. Epigenetics modifications in the genome can affect gene expression without altering DNA sequences. Host cells can use epigenetic gene regulation as a mechanism to silence incoming viral DNA molecules, while viruses recruit cellular epitranscriptomic (covalent modifications of RNAs) modifiers to increase the translational efficiency and transcript stability of viral transcripts to enhance viral gene expression and replication. Moreover, viruses manipulate host cells’ epigenetic machinery to ensure productive viral infections. Environmental factors, such as natural products, may influence epigenetic modifications. In this review, we explore the potential of plant-derived substances as epigenetic modifiers for broad-spectrum anti-viral activity, reviewing their modulation processes and anti-viral effects on DNA and RNA viruses, as well as addressing future research objectives in this rapidly emerging field. Full article

Following the detection of the quarantine bacterium Xylella fastidiosa (Wells et al.) in the Apulia region (southern Italy) and the identification of spittlebugs as the main vector species that contributes to its epidemic spread, monitoring activities have been intensified in an attempt to implement vector control strategies. To date, sweep nets have been the most widely used sampling method to monitor adult spittlebug populations. Field experiments were carried out, during 2018 and 2019, to evaluate the effectiveness of sticky traps in capturing spittlebugs in different woody crops. The attractiveness of different traps was compared: four colored sticky traps (white, red, blue, and yellow), with the yellow sticky traps having three different background patterns (plain yellow, yellow with a black circle pattern, and yellow with a black line pattern). In addition, the efficiency of the yellow sticky traps was evaluated by placing the traps on the ground or hanging them from the canopies in orchards with different spittlebug population densities. Trap catches of Philaenus spumarius (Linnaeus) and Neophilaenus campestris (Fallén) (Hemiptera: Aphrophoridae) were compared with those collected using sweep nets. The two spittlebug species showed a similar response to the colored traps and were mainly attracted to the yellow sticky traps. Captures throughout the adult season indicated that an accurate estimation of the presence and abundance of spittlebugs can be obtained by integrating the two sampling methods. Moreover, sweep nets appeared to be more efficient in collecting adults soon after their emergence, while the use of sticky traps was more efficient in the rest of the adult season when the use of traps can significantly expedite vector monitoring programs. Full article