Influenza Research Articles

Influenza virus infection exacerbates gene expression related to neurocognitive dysfunction in brains of old mice

BackgroundAge > 65 years is a key risk factor for poor outcomes after human influenza infection. Specifically, in addition to respiratory disease, non-neurotropic influenza A virus (IAV) causes neuro-cognitive complications, e.g. new onset depression and increases the risk of dementia after hospitalization. This study aimed to identify potential mechanisms of these effects by determining differences between young and old mice in brain gene expression in a mouse model of non-neurotropic IAV infection.MethodsYoung (12 weeks) and old (70 weeks) C57Bl/6J mice were inoculated intranasally with 200 PFU H1N1 A/PR/34/8 (PR8) or sterile PBS (mock). Gene expression in lung and brain was measured by qRT-PCR and normalized to β-actin. Findings were confirmed using the nCounter Mouse Neuroinflammation Array (NanoString) and analyzed with nSolver 4.0 and Ingenuity Pathway Analysis (IPA, Qiagen).ResultsIAV PR8 did not invade the central nervous system. Young and old mice differed significantly in brain gene expression at baseline and during non-neurotropic IAV infection. Expression of brain Ifnl, Irf7, and Tnf mRNAs was upregulated over baseline control at 3 days post-infection (p.i.) only in young mice, but old mice expressed more Ifnl than young mice 7 days p.i. Gene arrays showed down-regulation of the Epigenetic Regulation, Insulin Signaling, and Neurons and Neurotransmission pathways in old mice 3 days p.i. while young mice demonstrated no change or induction of these pathways at the same time point. IPA revealed marked baseline differences between old and young mice. Gene expression related to Cognitive Impairment, Memory Deficits and Learning worsened in old mice relative to young mice during IAV infection. Aged mice demonstrate more severe changes in gene expression related to memory loss and cognitive dysfunction by IPA.ConclusionsThese data suggest the genes and pathways related to learning and cognitive performance that were worse at baseline in old mice were further worsened by IAV infection, similar to old patients. Early events in the brain triggered by IAV infection portend downstream neurocognitive pathology in old adults.

Sustained release system from PLGA particles co-encapsulated with inactivated influenza virus with natural killer T cell agonist α-galactosylceramide

Vaccines against influenza and many other infectious diseases require multiple boosters in addition to the primary dose to improve efficacy, but this approach is not ideal for compliance. The multiple doses could potentially be replaced by sustained or pulsatile release of antigens encapsulated in degradable microparticles (MPs). The efficacy of a vaccine is improved by adding an adjuvant, which can be co-delivered from the particles to enhance immunogenicity. Here, we developed degradable poly-lactic-co-glycolic acid (PLGA) (7–17 kDa) MPs capable of sustained release of ultraviolet killed influenza virus (A/PR/8/34) (kPR8) vaccine and the natural killer T (NKT) cell agonist alpha-galactosylceramide (α-GalCer) and tested their effectiveness at providing long-term protection against influenza virus infection in mice. Multiple formulations were developed for encapsulating the virus and adjuvant separately, and in combination. The MPs exhibited sustained release of both the virus and the adjuvant lasting more than a month. Co-encapsulation significantly increased the encapsulation efficiency (EE) of the vaccine but reduced the release duration. On the other hand, co-encapsulation led to a reduction in EE for the α-GalCer and a change in release profile to a higher initial burst followed by a linear release compared to a low initial burst and slower linear release. The α-GalCer also had considerably longer release duration compared to the vaccine. Mice injected with particle formulations co-encapsulating kPR8 and α-GalCer were protected from a lethal influenza virus infection 30 weeks after vaccination. This study demonstrates that PLGA MP based vaccines are promising for providing effective vaccination and possibly for replacing multiple doses with a single injection.

Large-Scale Serological Survey of Influenza A Virus in South Korean Wild Boar (Sus scrofa).

In this comprehensive large-scale study, conducted from 2015 to 2019, 7,209 wild boars across South Korea were sampled to assess their exposure to influenza A viruses (IAVs). Of these, 250 (3.5%) were found to be IAV-positive by ELISA, and 150 (2.1%) by the hemagglutination inhibition test. Detected subtypes included 23 cases of pandemic 2009 H1N1, six of human seasonal H3N2, three of classical swine H1N1, 13 of triple-reassortant swine H1N2, seven of triple-reassortant swine H3N2, and seven of swine-origin H3N2 variant. Notably, none of the serum samples tested positive for avian IAV subtypes H3N8, H5N3, H7N7, and H9N2 or canine IAV subtype H3N2. This serologic analysis confirmed the exposure of Korean wild boars to various subtypes of swine and human influenza viruses, with some serum samples cross-reacting between swine and human strains, indicating potential infections with multiple IAVs. The results highlight the potential of wild boar as a novel mixing vessel, facilitating the adaptation of IAVs and their spillover to other hosts, including humans. In light of these findings, we recommend regular and frequent surveillance of circulating influenza viruses in the wild boar population as a proactive measure to prevent potential human influenza pandemics and wild boar influenza epizootics.

Effects of Allicin on the Immune Performance and Expression of Immune-related Genes in Muchuan Black-bone Chickens

Background: In response to China’s ban on medicinal feed additives with growth-promoting functions in livestock and poultry feed, there is an urgent need in modern animal husbandry for alternatives to antibiotics to sustain livestock health and improve feed conversion efficiency. Allicin, known for its safety, efficiency, lack of drug resistance and absence of residue, regulates the intestinal flora structure; inhibits the growth of harmful bacteria; improves intestinal health, immunity and stress resistance; and improves animal production. Methods: To investigate the impact of allicin on immune performance and immune-related gene expression in Muchuan black-bone chickens, diets were supplemented with varying allicin levels (50, 100, 200 mg/kg), designated as test groups A, B and C, respectively. Initially, growth performance was assessed. Subsequently, immunoglobulins were measured via enzyme-linked immunosorbent assay (ELISA) and colorimetry; immune titers for avian influenza and Newcastle disease were evaluated using hemagglutination and hemagglutination inhibition tests and the expression of immune genes was analyzed via real-time quantitative PCR. Finally, serum biochemical indices in each group were determined. Result: Compared to the control group, allicin supplementation resulted in increased average fasting body weight in the experimental group and significantly (P less than 0.05) higher thymus and musogastric indices in groups A and C, respectively. Serum levels of immunoglobulin M in groups A and B and immunoglobulin G levels were significantly higher in all experimental groups than in controls. Antibody titers against avian influenza H5 and H7 strains were higher in all test groups, with Newcastle disease antibody titers in groups B and C significantly higher than those in controls. The mRNA expression levels of IFN-ã were lower across all experimental groups, whereas the expression levels of TLR3 in groups B and C and TLR15 in group B were higher. Serum levels of triglycerides in group A were significantly higher and blood urea nitrogen levels were significantly lower in groups B and C than in controls. These findings indicate that dietary allicin (50-200 mg/kg) significantly improves growth performance, immunity and protein and lipid metabolism in Muchuan black-bone chickens, offering valuable data for the development and use of allicin as an antibiotic alternative.

Predictors of parental acceptance to live attenuated influenza vaccine for children

ABSTRACT To determine the influencing factors of Chinese parents' intention and behavior for children to receive live attenuated influenza vaccine during the 2022–2023 influenza season. A theoretical model was developed and included seven constructs, and structural equation modeling was used to test 11 hypotheses. From October 2022 to December 2023, a survey was conducted across 38 medical institutions in four Chinese cities and their subordinate districts, counties, and rural areas. Parents who accompanied their children for vaccinations were selected through a randomization process based on their child’s medical card numbers. Measures were taken to minimize method bias, including a diverse geographical representation and random sampling. The survey resulted in the collection of 936 valid responses, exceeding the recommended sample size for structural equation model analysis and providing robust statistical inferences. During the study period, 936 respondents were included in the study. Perceived ease of use was verified to be a predictor of perceived usefulness and perceived value. Perceived usefulness was verified as a predictor of perceived value and behavioral intention. Knowledge was a significant antecedent of perceived value and risk perception of influenza disease. Risk perception of influenza disease was proved to be a significant predictor of perceived value and self-reported vaccination behavior. Perceived value significantly affected behavioral intention, and behavioral intention significantly affected self-reported vaccination behavior. Six demographic variables significantly moderate the theoretical models. The low vaccination coverage of live attenuated influenza vaccine (LAIV) among children in China suggests a need for a deeper understanding of the factors that influence vaccination rates. Particularly, effective strategies are necessary from policymakers and practitioners to elevate childhood LAIV coverage.

Review of Application YOLOv8 in Medical Imaging

Deep learning has revolutionized medical imaging analysis, with YOLOv8 emerging as a promising tool forvarious tasks like lesion detection, organ segmentation and disease classification. This review investigates YOLOv8’sapplications across diverse medical imaging modalities (X-Ray, CT-Scan and MRI). We conducted a systematic literaturesearch across databases like Pubmed, ScienceDirect and IEEE to identify relevant studies evaluating YOLOv8’sperformance in medical imaging analysis. YOLOv8 achieved high performance for meningioma and pituitary tumorswith and without data augmentation (precision >0.92, recall >0.90, mAP >0.93). Glioma detection showed lowerperformance but still promising results (precision >0.86, recall >0.81, mAP >0.86). Breast cancer detection with SGDoptimizer yielded best performance with an average mAP of 0.87 for mass detection. The model achieved high accuracyin detecting normal (mAP 0.939) and malignant lesions (mAP 0.911). YOLO v8 on Dental radiograph successfullydetected cavities, impacted teeth, fillings and implants (precision of >0.82, recall of >0.78 and F1-Score of >0.80). Lastly,for lung disease classification, YOLOv8 achieved high accuracy (99.8% training and 90% validation) in classifyingnormal, COVID-19, influenza and lung cancer disease. With the importance to improve clinical decision-making andpatient outcomes in healthcare, the YOLOv8 algorthm underscores the importance of pre-processing, augmentation andoptimization of key hyperparameters.

IBM Pemberdayaan Masyarakat dalam Penanganan Demam pada Anak dengan Water Tepid Sponge

Children under 5 years of age have an immune system that is still developing, not perfect and not yet strong. This is what causes children to be susceptible to disease. The diseases most frequently experienced by toddlers in Indonesia are flu, diarrhea, rotavirus, allergies, asthma, hand, foot and mouth disease and Fever. Fever is condition when the body temperature rises or is above normal. Efforts to treat fever by providing pharmacological and non-pharmacological therapy. Pharmacological therapy can be carried out by administering antipyretics, while non-pharmacological therapy includes Water Tepid Sponge. Increase knowledge is urgently needed to strengthen awareness in increasing knowledge and behavior in handling fever. One of the efforts made is health education activities about treating fever with Water Tepid Sponge. The result of this community service activity is that there is an increase in knowledge and skills regarding treating fever with Water Tepid Sponge before and after providing Health Education.

Isolation of human antibodies against influenza B neuraminidase and mechanisms of protection at the airway interface

Influenza B viruses (IBVs) comprise a substantial portion of the circulating seasonal human influenza viruses. Here, we describe the isolation of human monoclonal antibodies (mAbs) that recognized the IBV neuraminidase (NA) glycoprotein from an individual following seasonal vaccination. Competition-binding experiments suggested the antibodies recognized two major antigenic sites. One group, which included mAb FluB-393, broadly inhibited IBV NA sialidase activity, protected prophylactically invivo, and bound to the lateral corner of NA. The second group contained an active site mAb, FluB-400, that broadly inhibited IBV NA sialidase activity and virus replication invitro in primary human respiratory epithelial cell cultures and protected against IBV invivo when administered systemically or intranasally. Overall, the findings described here shape our mechanistic understanding of the human immune response to the IBV NA glycoprotein through the demonstration of two mAb delivery routes for protection against IBV and the identification of potential IBV therapeutic candidates.

EPIDEMIOLOGICAL ANALYSIS OF MORTALITY FROM INFLUENZA IN THE REPUBLIC OF CROATIA

Introduction: Influenza is an acute infectious disease of the respiratory system caused by one of the influenza viruses A, B or C, which inevitably appears every year in the form of larger or smaller epidemics, with a pronounced rapid spread within the population. A higher number of deaths occurs in the months when the epidemic lasts and is associated with an increased number of pneumonia, especially in older people.Objective: Analyze the mortality from influenza inthe Republic of Croatia and consider the connection of mortality with vaccination status.Subjects and methods: A retrospective cross -sectional epidemiological study was conducted between January and April 2024. Data on deaths from influenza between January 2014 and December 2023 were analyzedin the Republic of Croatia collected at the Service for Epidemiology of Infectious Diseases of the Croatian Institute of Public Health.Results: In the observed period in the Republic of Croatia, 65321 people fell ill with the flu, of which 227 reports had a fatal outcome caused by the flu infection. Among the deceased, 70 % are people aged 65 and older, and 20 % are people aged 30 to 65. On average, more male persons died, and 63 % of respondents were not vaccinated, 32 % of respondents did not know their vaccination status, and 5 % of them were vaccinated against influenza. Conclusion: In all flu seasons, we record the highest number of deaths in people aged 65 and older. Most of the deceased persons were not vaccinated against influenza.Keywords: Human Influenza, Mortality Rate, Epidemiology, Vaccination, Croatia, Prevention

MUC5AC: A potential biomarker of severity in pediatric patients infected with influenza.

Numerous factors can increase the risk of severe influenza; however, a majority of severe cases occur in previously healthy children. Identification of high-risk children is important for targeted preventive interventions and prompt treatment. The aim of this study was to evaluate MUC5AC as a biomarker for influenza disease severity in children. For this, aprospective cohort study was conducted in 2019. Children hospitalized with acute respiratory infection (ARI) with confirmed positive influenza infection were enrolled. Influenza cases were identified by reverse transcriptase-polymerase chain reaction. Life-threatening disease (LTD) was defined by the need for intensive care and ventilatory support. MUC5AC, epidemiologic, and clinical risk factors were assessed. Three hundred and forty-two patients were hospitalized with ARI, of which 49 (14%) had confirmed influenza infection and 6 (12%) of them developed LTD. MUC5AC levels were higher in those patients with mild diseasecompared to cases with poorer outcomes. Our results show that the severity of influenza infection in children is significantly associated with low levels of MUC5AC. These findings suggest its potential as a suitable biomarker for predicting disease severity.

The antigenic landscape of human influenza N2 neuraminidases from 2009 until 2017.

Human H3N2 influenza viruses are subject to rapid antigenic evolution which translates into frequent updates of the composition of seasonal influenza vaccines. Despite these updates, the effectiveness of influenza vaccines against H3N2-associated disease is suboptimal. Seasonal influenza vaccines primarily induce hemagglutinin-specific antibody responses. However, antibodies directed against influenza neuraminidase (NA) also contribute to protection. Here, we analysed the antigenic diversity of a panel of N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017. The antigenic breadth of these NAs was determined based on the NA inhibition (NAI) of a broad panel of ferret and mouse immune sera that were raised by infection and recombinant N2 NA immunisation. This assessment allowed us to distinguish at least four antigenic groups in the N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017. Computational analysis further revealed that the amino acid residues in N2 NA that have a major impact on susceptibility to NAI by immune sera are in proximity of the catalytic site. Finally, a machine learning method was developed that allowed to accurately predict the impact of mutations that are present in our N2 NA panel on NAI. These findings have important implications for the renewed interest to develop improved influenza vaccines based on the inclusion of a protective NA antigen formulation.

The antigenic landscape of human influenza N2 neuraminidases from 2009 until 2017

Human H3N2 influenza viruses are subject to rapid antigenic evolution which translates into frequent updates of the composition of seasonal influenza vaccines. Despite these updates, the effectiveness of influenza vaccines against H3N2-associated disease is suboptimal. Seasonal influenza vaccines primarily induce hemagglutinin-specific antibody responses. However, antibodies directed against influenza neuraminidase (NA) also contribute to protection. Here, we analysed the antigenic diversity of a panel of N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017. The antigenic breadth of these NAs was determined based on the NA inhibition (NAI) of a broad panel of ferret and mouse immune sera that were raised by infection and recombinant N2 NA immunisation. This assessment allowed us to distinguish at least four antigenic groups in the N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017. Computational analysis further revealed that the amino acid residues in N2 NA that have a major impact on susceptibility to NAI by immune sera are in proximity of the catalytic site. Finally, a machine learning method was developed that allowed to accurately predict the impact of mutations that are present in our N2 NA panel on NAI. These findings have important implications for the renewed interest to develop improved influenza vaccines based on the inclusion of a protective NA antigen formulation.

A qualitative assessment of influenza vaccine uptake among children in Kenya

BackgroundInfluenza is a significant contributor to acute respiratory infections (ARI), and children < 5 years are at increased risk of severe influenza disease. In Kenya the influenza vaccine is not included in the Kenya Expanded Programme on Immunization (KEPI). To inform roll-out of a national influenza vaccination program, we implemented an influenza vaccine demonstration project in Nakuru and Mombasa counties in Kenya from 2019 to 2021 and set out to establish factors driving influenza vaccine acceptance and hesitancy among caregivers of children aged 6–23 months. MethodsUsing semi-structured questionnaires, we conducted eight focus group discussions among community members and twelve key informant interviews among healthcare workers to elicit both lay and expert opinions. Thematic analysis of the interviews was conducted using the World Health Organization’s “3 Cs” model of vaccine hesitancy to determine reasons for acceptance or hesitancy of the influenza vaccine. ResultsThe influenza vaccine was well received among community members and healthcare workers though concerns were raised. Vaccine hesitancy was fuelled by misconceptions about reasons for introducing the vaccine (confidence), perceptions that influenza was not a serious disease (complacency) and administrative fees required at some facilities (convenience). Despite the use of various advocacy, communication and social mobilisation strategies targeted at educating the community on the influenza disease and importance of vaccination, there remained a perception of inadequate reach of the sensitization among some community members. Contextual factors such as the COVID-19 pandemic affected uptake, and parents expressed concern over the growing number of vaccines recommended for children. ConclusionDespite lingering concerns, caregivers had their children vaccinated indicating that vaccine hesitancy exists, even among those who accepted the vaccine for their children. Efforts targeted at increasing confidence in and reducing misconceptions towards vaccines through effective communication strategies, are likely to lead to increased vaccine uptake.

Mathematical Modeling Suggests That Monocyte Activity May Drive Sex Disparities during Influenza Infection.

In humans, females of reproductive age often experience a more severe disease during influenza A virus infection, which may be due to differences in their innate immune response. Sex-specific outcomes to influenza infection have been recapitulated in mice, enabling researchers to study viral and immune dynamics in vivo in order to identify immune mechanisms that are differently regulated between the sexes. This study is based on the hypothesis that sex-specific outcomes emerge due to differences in the rates/speeds that select immune components respond. Using publicly available sex-specific murine data, we utilized dynamic mathematical models of the innate immune response to identify candidate mechanisms that may lead to increased disease severity in female mice. We implemented a large computational screen using the Bayesian information criterion (BIC), wherein the goodness of fit of the competing model scenarios is balanced against complexity (i.e., the number of parameters). Our results suggest that having sex-specific rates for proinflammatory monocyte induction by interferon and monocyte inhibition of virus replication provides the simplest (lowest BIC) explanation for the difference observed in the male and female immune responses. Markov-chain Monte Carlo (MCMC) analysis and global sensitivity analysis of the top performing scenario were performed to provide rigorous estimates of the sex-specific parameter distributions and to provide insight into which parameters most affect innate immune responses. Simulations using the top-performing model suggest that monocyte activity could be a key target to reduce influenza disease severity in females. Overall, our Bayesian statistical and dynamic modeling approach suggests that monocyte activity and induction parameters are sex-specific and may explain sex-differences in influenza disease immune dynamics.

UV-Inactivated rVSV-M2e-Based Influenza Vaccine Protected against the H1N1 Influenza Challenge.

To investigate the immune responses and protection ability of ultraviolet light (UV)-inactivated recombinant vesicular stomatitis (rVSV)-based vectors that expressed a fusion protein consisting of four copies of the influenza matrix 2 protein ectodomain (tM2e) and the Dendritic Cell (DC)-targeting domain of the Ebola Glycoprotein (EΔM), (rVSV-EΔM-tM2e). In our previous study, we demonstrated the effectiveness of rVSV-EΔM-tM2e to induce robust immune responses against influenza M2e and protect against lethal challenges from H1N1 and H3N2 strains. Here, we used UV to inactivate rVSV-EΔM-tM2e and tested its immunogenicity and protection in BALB/c mice from a mouse-adapted H1N1 influenza challenge. Using Enzyme-Linked Immunosorbent Assay (ELISA) and Antibody-Dependent Cellular Cytotoxicity (ADCC), the influenza anti-M2e immune responses specific to human, avian and swine influenza strains induced were characterized. Likewise, the specificity of the anti-M2e immune responses induced in recognizing M2e antigen on the surface of the cell was investigated using Fluorescence-Activated Cell Sorting (FACS) analysis. Like the live attenuated rVSV-EΔM-tM2e, the UV-inactivated rVSV-EΔM-tM2e was highly immunogenic against different influenza M2e from strains of different hosts, including human, swine, and avian, and protected against influenza H1N1 challenge in mice. The FACS analysis demonstrated that the induced immune responses can recognize influenza M2 antigens from human, swine and avian influenza strains. Moreover, the rVSV-EΔM-tM2e also induced ADCC activity against influenza M2e from different host strains. These findings suggest that UV-inactivated rVSV-EΔM-tM2e could be used as an inactivated vaccine against influenza viruses.

Trends in serotype distribution and antimicrobial susceptibility pattern of invasive Haemophilus influenzae isolates from Brazil, 2009-2021.

Invasive Haemophilus influenzae (Hi) disease poses a significant global health challenge. With the relaxation of COVID-19 pandemic measures and declining H. influenzae serotype b (Hib) vaccination coverage, there is concern about a potential increase in Hi cases worldwide. This study analyzed 1437 invasive Hi isolates in Brazil over 13years, determining capsular serotypes, antimicrobial susceptibility, and genetic relatedness through multilocus sequence typing. The primary source of isolation for these invasive H. influenzae isolates was blood (54.4%), followed by cerebrospinal fluid (37.1%) and lung specimens (8.5%), respectively. Consequently, bacteremia (47%) was the most common clinical presentation, followed by meningitis (39.6%) and pneumonia (13.4%). Non-encapsulated Hi (NTHi) predominated among the isolates (51.4%), along with serotype a (22%) and serotype b (21.5%) among the encapsulated isolates. The majority of the encapsulated isolates were isolated from children under 14years of age (76.7%), while NTHi isolates were identified in patients older than 15years, particularly those ≥ 60years old (40%). Ampicillin resistance was observed in 17.1% of cases, displaying β-lactamase production as the principal resistance mechanism. MLST revealed a diverse NTHi population, whereas the encapsulated isolates presented a clonal structure. This study describes the prevalence of NTHi isolates circulating in Brazil after two decades of the Hib vaccine immunization program. Continuous universal surveillance is crucial for implementing prompt public health measures to prevent and control invasive Hi disease and monitor changes in antibiotic resistance profiles.

The A2ml1-Knockout mouse as an animal model for non-syndromic otitis media

BackgroundInflammation and infection of the middle ear, known as otitis media (OM), is a leading cause of hearing loss and the most frequently diagnosed disease in children worldwide. Traditionally, mouse models for OM rely on inducing acute infection through inoculation of the middle ear, e.g. with the human otopathogen non-typeable Haemophilus influenzae (NTHi), and with very few genetic models with spontaneous or chronic OM. A2ML1 variants, including loss-of-function variants, were associated with susceptibility to OM in humans, but no animal model has been reported for A2ml1-related OM. Here, we report our middle ear findings in a mouse line with a CRISPR-induced knockout (KO) of A2ml1. MethodsMice were X-rayed prior to harvest to determine if there are craniofacial or skeletal abnormalities. Tissue from mouse middle ears, as well as other upper respiratory mucosal tissues, were harvested. The harvested middle ear bullae were examined under microscope and submitted for histologic preparation to study phenotypic indications of OM. RNA samples isolated from middle ear tissue were assayed for expression of genes correlated with A2ML1 expression in humans. ResultsData from a total of 119 mice (35 wildtype, 40 heterozygous, 44 homozygous) are presented here, with each analyses being performed on subsets of these mice. There were no significant craniofacial differences by genotype (n = 22). Findings in mice with the A2ml1-KO indicated an increased incidence of OM (n=29; odds ratio = 11; CI: 1.1, 573.6; Fisher exact two-sided p = 0.02) with tympanic membrane perforations or thickening, as well as cases of middle ear effusion, inflammatory cells, or fluid from histologic sections. Dsp was upregulated in the middle ear tissues of homozygous mice (Wilcoxon test p = 0.001). ConclusionThus far, our results in this A2ml1-KO mouse line indicate spontaneous occurrence of OM and dysregulation of Dsp in the middle ear as a potential disease mechanism for A2ml1-related OM.

Diet-induced obesity affects influenza disease severity and transmission dynamics in ferrets.

Obesity, and the associated metabolic syndrome, is a risk factor for increased disease severity with a variety of infectious agents, including influenza virus. Yet, the mechanisms are only partially understood. As the number of people, particularly children, living with obesity continues to rise, it is critical to understand the role of host status on disease pathogenesis. In these studies, we use a diet-induced obese ferret model and tools to demonstrate that, like humans, obesity resulted in notable changes to the lung microenvironment, leading to increased clinical disease and viral spread to the lower respiratory tract. The decreased antiviral responses also resulted in obese animals shedding higher infectious virus for a longer period, making them more likely to transmit to contacts. These data suggest that the obese ferret model may be crucial to understanding obesity's impact on influenza disease severity and community transmission and a key tool for therapeutic and intervention development for this high-risk population.

Effect of human H3N2 influenza virus reassortment on influenza incidence and severity during the 2017–18 influenza season in the USA: a retrospective observational genomic analysis

During the 2017-18 influenza season in the USA, there was a high incidence of influenza illness and mortality. However, no apparent antigenic change was identified in the dominant H3N2 viruses, and the severity of the season could not be solely attributed to a vaccine mismatch. We aimed to investigate whether the altered virus properties resulting from gene reassortment were underlying causes of the increased case number and disease severity associated with the 2017-18 influenza season. Samples included were collected from patients with influenza who were prospectively recruited during the 2016-17 and 2017-18 influenza seasons at the Johns Hopkins Hospital Emergency Departments in Baltimore, MD, USA, as well as from archived samples from Johns Hopkins Health System sites. Among 647 recruited patients with influenza A virus infection, 411 patients with whole-genome sequences were available in the Johns Hopkins Center of Excellence for Influenza Research and Surveillance network during the 2016-17 and 2017-18 seasons. Phylogenetic trees were constructed based on viral whole-genome sequences. Representative viral isolates of the two seasons were characterised in immortalised cell lines and human nasal epithelial cell cultures, and patients' demographic data and clinical outcomes were analysed. Unique H3N2 reassortment events were observed, resulting in two predominant strains in the 2017-18 season: HA clade 3C.2a2 and clade 3C.3a, which had novel gene segment constellations containing gene segments from HA clade 3C.2a1 viruses. The reassortant re3C.2a2 viruses replicated with faster kinetics and to a higher peak titre compared with the parental 3C.2a2 and 3C.2a1 viruses (48 h vs 72 h). Furthermore, patients infected with reassortant 3C.2a2 viruses had higher Influenza Severity Scores than patients infected with the parental 3C.2a2 viruses (median 3·00 [IQR 1·00-4·00] vs 1·50 [1·00-2·00]; p=0·018). Our findings suggest that the increased severity of the 2017-18 influenza season was due in part to twointrasubtypes, cocirculating H3N2 reassortant viruses with fitness advantages over the parental viruses. This information could help inform future vaccine development and public health policies. The Center of Excellence for Influenza Research and Response in the US, National Science and Technology Council, and Chang Gung Memorial Hospital in Taiwan.

Viral respiratory infections and air pollution: A review focused on research in Poland

The COVID-19 pandemic has reinforced an interest in the relationship between air pollution and respiratory viral infections, indicating that their burden can be increased under poor air quality. This paper reviews the pathways through which air pollutants can enhance susceptibility to such infections and aggravate their clinical course and outcome. It also summarizes the research exploring the links between various viral infections and exposure to solid and gaseous pollution in Poland, a region characterized by poor air quality, especially during a heating season. The majority of studies focused on concentrations of particulate matter (PM; 86.7%); the other pollutants, i.e., BaP, benzene, CO, NOx, O3, and SO2, were studied less often and sometimes only in the context of a particular infection type. Most research concerned COVID-19, showing that elevated levels of PM and NO2 correlated with higher morbidity and mortality, while increased PM2.5 and benzo[a]pyrene levels were related to worse clinical course and outcome in hospitalized, regardless of age and dominant SARS-CoV-2 variant. PM10 and PM2.5 levels were also associated with the incidence of influenza-like illness and, along with NO2 concentrations, with a higher rate of children's hospitalizations due to lower respiratory tract RSV infections. Higher levels of air pollutants also increased hospitalization due to bronchitis (PM, NOx, and O3) and emergency department admission due to viral croup (PM10, PM2.5, NOx, CO, and benzene). Although the conducted studies imply only correlations and have other limitations, as discussed in the present paper, it appears that improving air quality through reducing combustion processes in energy production in Poland should be perceived as a part of multilayered protection measures against respiratory viral infections, decreasing the healthcare costs of COVID-19, lower tract RSV infections, influenza, and other respiratory viral diseases prevalent between autumn and early spring, in addition to other health and climate benefits.