Transmissibility and transmission of respiratory viruses

Ultrasensitive point-of-care multiplex diagnosis for influenza virus based robust quantum dot microsphere-lateral flow immunoassay

Influenza A virus (IAV) and influenza B virus (IBV) with similar symptoms of infection caused a serious disease burden and economic losses in annual epidemic season, so it is important to quickly and accurately detect and distinguish between IAV and IBV during influenza season. Herein, the quantum dot microspheres (QDMS) were synthesized and applied to lateral flow immunoassays (LFIA), and a point-of-care (POC) biosensor that can discriminately and simultaneously diagnose IAV and IBV within 10 min was established. A double-sandwich QDMS nanotags was synthesized by immobilizing hydrophobic quantum dots (QDs) with chemical bonding method on a silica sphere template with an outer silica shell protection showed excellent stability and high fluorescence. The highly sensitive quantitative detection is achieved with the tailored hand-hold detector. The limit of detection (LOD) of the LFIA based QDMS for the simultaneous detection of IAV and IBV were 0.080 ng/mL and 0.096 ng/mL, respectively. The QDMS-LFIA system has excellent specificity and stability for quantitative detection, especially showing good accuracy for clinical samples. Furthermore, the visualization sensitivity of the low-cost biosensor was improved by nearly an order of magnitude than gold nanoparticles (AuNP)-LFIA within shorter detection time. Given the excellent performance, our proposed QDMS-LFIA biosensor can potentially be applied to the POC sensitive discriminate and simultaneous detection of IAV and IBV in epidemic season.

Infection intensity and severity of Ranavirus transmission in juvenile wood frogs

Ranaviruses are responsible for mass die offs of wood frog (Lithobates sylvaticus) tadpoles. What happens in between epidemics is less clear, but juvenile (metamorphosed) stages are hypothesized to move Ranaviruses among wetlands and introduce or reintroduce these viruses into wetlands, initiating new outbreaks. A key question is under what circumstances can juvenile L. sylvaticus infect susceptible conspecifics. We examined Ranavirus transmission between juvenile L. sylvaticus in two settings: first, we measured transmission from a Ranavirus-infected frog to a co-housed susceptible frog via cohabitation over a range of exposure periods. Second, we measured indirect transmission to susceptible frogs from a contaminated environment after a range of waiting times (i.e., from when the infected frog was removed to when the susceptible frog was exposed to the environment). We present evidence that juvenile frogs directly transmitted Ranavirus to susceptible frogs in all exposure periods (99.2% infected), with as little as 1 h of co-housing resulting in 95.8% of susceptibles infected. Indirectly, 96.8% of susceptible frogs became infected after as long as 48 h waiting times. Neither exposure period nor wait times influenced the probability of infection, because these probabilities are already high. In our linear regression models, susceptible frog viral load was significantly correlated with exposure period and cohort for the cohabitation experiment, while wait time was significantly correlated with viral load for the sequential habitation experiment. Collectively, our results suggest that Ranavirus transmission readily occurs between recently metamorphosed wood frogs and via terrestrial environmental exposure.

Optimization of An Enveloped Virus Surrogate, Bacteriophage Phi6, Recovery from Hands

Surfaces contaminated with enveloped viruses, such as severe acute respiratory syndrome coronavirus 2 and influenza virus, can potentially spread illness via hand contact. Often, the efficacy of hand hygiene interventions relies on virus recovery from hands. However, the recovery of bacteriophage phi6 (Φ6), a recommended surrogate for enveloped viruses, from the entire hands using the ASTM E2011-21 standard has not been optimized. For Φ6 recovery from the hands, three eluents [lysogeny broth (LC), tryptic soy broth (TSB), and 1.5% beef extract (BE)] and three recovery methods [glove juice method (GJM), hand rinsing, and modified dish method] were examined. The effects of inoculum application on either the palmar surface or the whole hand were compared, and virus recovery was assessed under wet and dry conditions to identify the optimal combinations for maximizing Φ6 recovery. Statistical differences among methods, inoculum application, and recovery types were identified. While no statistical difference was observed among the eluents (P = 0.281), LC demonstrated the highest Φ6 recovery efficiency, while TSB and BE had comparable recoveries. Two-way interaction effects were observed between method type vs. application type (P ≤ 0.05), method type vs. recovery type (P ≤ 0.05), and application type vs. recovery type (P ≤ 0.05), indicating these factors influencing one another. Additionally, no Φ6 recovery was obtained for the dry basis recovery type and the GJM method type. Based on the present study, to maximize Φ6 recovery from the hands during hand hygiene studies, inoculum should be applied to the palmar surface and recovered while it is still wet using LC.

Identifying the panorama of potential pandemic pathogens and their key characteristics: a systematic scoping review

The globe has recently seen several terrifying pandemics and outbreaks, underlining the ongoing danger presented by infectious microorganisms. This literature review aims to explore the wide range of infections that have the potential to lead to pandemics in the present and the future and pave the way to the conception of epidemic early warning systems. A systematic review was carried out to identify and compile data on infectious agents known to cause pandemics and those that pose future concerns. One hundred and fifteen articles were included in the review. They provided insights on 25 pathogens that could start or contribute to creating pandemic situations. Diagnostic procedures, clinical symptoms, and infection transmission routes were analyzed for each of these pathogens. Each infectious agent's potential is discussed, shedding light on the crucial aspects that render them potential threats to the future. This literature review provides insights for policymakers, healthcare professionals, and researchers in their quest to identify potential pandemic pathogens, and in their efforts to enhance pandemic preparedness through building early warning systems for continuous epidemiological monitoring.

The Microbiome and Pulmonary Immune Function

In the last decade, the lung microbiome field has matured into a promising area of translational and clinical research due to emerging evidence indicating a role for respiratory microbiota in lung immunity and pathogenesis. Here, we review recent insights pertaining to the lung microbiome's relationship with pulmonary immune function. We discuss areas of future investigation that will be essential to the development of immunomodulatory therapies targeting the respiratory microbiome.

SARS-CoV-2 infection primes cross-protective respiratory IgA in a MyD88- and MAVS-dependent manner

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is constantly evolving mutations in the Spike protein to evade humoral immunity. Respiratory tract antiviral IgA antibodies are superior to circulating IgG antibodies in preventing SARS-CoV-2 infection. However, the role of innate immune signals required for the induction of mucosal IgA against SARS-CoV-2 infection is unknown. Here we show that hamsters recovered from ancestral SARS-CoV-2 infection are cross-protected against heterologous SARS-CoV-2 alpha, gamma, delta, and omicron BA.1 variants. Intranasal vaccination with an inactivated whole virus vaccine completely protects hamsters against heterologous SARS-CoV-2 infection. In addition, we show that intranasal boost vaccination of mice recovered from SARS-CoV-2 infection with unadjuvanted Spike protein induces robust levels of respiratory anti-Spike IgA and protects the mice from a heterologous SARS-CoV-2 infection. Furthermore, our findings suggest that MyD88 and MAVS play a role in the induction of the memory IgA response following an intranasal booster with unadjuvanted Spike protein in mice recovered from the SARS-CoV-2 infection. These findings provide a useful basis for the development of cross-protective mucosal vaccines against heterologous SARS-CoV-2 infection.

Adherence to mask-wearing and its impact on the incidence and deaths of viral respiratory infectious diseases: a systematic review, meta-analysis and modelling study

BACKGROUND

This study systematically analysed global and regional adherence to mask-wearing and its impact on the incidence and deaths of viral respiratory infectious diseases (VRIDs).

METHODS

Relevant studies were sourced from PubMed, Web of Science, Embase and Scopus. We included observational studies with available raw data on mask-wearing adherence (rates of acceptability of mask-wearing, mask-wearing in public settings and correct mask-wearing) during VRID pandemics/epidemics. The COVID-19-related incidence and deaths were sourced from Global Burden of Diseases 2021. The quality of each study was assessed using the Agency for Healthcare Research and Quality Scale. Pooled rates and effects of mask-wearing were calculated using random effects models and generalised linear models.

RESULTS

We included 448 studies from 70 countries/regions. During the VRID pandemics/epidemics, global pooled rates for the acceptability of mask-wearing, mask-wearing in public settings and correct mask-wearing were 65.27% (95% CI 60.34% to 70.05%), 74.67% (95% CI 69.17% to 79.8%) and 63.63% (95% CI 59.28% to 67.87%), respectively. In individuals with chronic diseases/elderly/pregnant women, the rates of acceptability (42.54%) and correct mask-wearing (60.56%) were both low. Among the general population, the rates of mask-wearing in public settings (68.2%) and correct mask-wearing (57.45%) were the lowest. During the COVID-19 pandemic, countries with a requirement for mask-wearing exhibited a higher rate in public settings (76.10% vs 58.32%), especially in regions with more stringent containment and health measures (β=0.86, p=0.008). The mask-wearing in public settings has been found to significantly reduce the COVID-19 incidence (β=-265.26, p=0.004), COVID-19 deaths (β=-2.04, p<0.001) and other COVID-19 pandemic-related deaths (β=-0.83, p<0.001).

CONCLUSION

During the VRID pandemics/epidemics, adherence to mask-wearing was relatively low. Implementing policies requiring mask-wearing during the pandemic could enhance the mask-wearing rate, potentially leading to a significant reduction in VRID-related incidence and deaths.

TRIAL REGISTRATION NUMBER

CRD42024496464.

Quantification of droplet and contact transmission risks among elementary school students based on network analyses using video-recorded data

In elementary schools, immunologically immature students come into close contact with each other and are susceptible to the spread of infectious diseases. To analyze pathogen transmission among students, it is essential to obtain behavioral data. Questionnaires and wearable sensor devices were used for communication behavior and swab sampling was employed for contact behavior. However, these methods have been insufficient in capturing information about the processes and actions of each student that contribute to pathogen transmission. Therefore, in this study, actual behavioral data were collected using video recordings to evaluate droplet and contact transmission in elementary schools. The analysis of communication behavior revealed the diverse nature of interactions among students. By calculating the droplet transmission probabilities based on conversation duration, the risk of droplet transmission was quantified. In the contact behavior, we introduced a novel approach for constructing contact networks based on contact history. According to this method, well-known items, such as students' desks, doors, and faucets, were predicted to be potential fomite. In addition, students' shirts and shared items with high contact frequency and high centrality metrics in the network, which were not evaluated in swab sampling surveys, were identified as potential fomites. The reliability of the predictions was demonstrated through micro-simulations. The micro-simulations replicated virus transmission scenarios in which virus-carrying students were present in the actual contact history. The results showed that a significant amount of virus adhered to the items predicted to be fomites. Interestingly, the micro-simulations indicated that most viral copies were transmitted through single items. The analysis of contact history, contact networks, and micro-simulations relies on video-recorded behavioral data, highlighting the importance of this method. This study contributes significantly to the prevention of infectious diseases in elementary schools by providing evidence-based information about transmission pathways and behavior-related risks.

Virucidal activity of tiliacorinine, dioscorine, racemosol, and terrein against influenza A virus (H1N1), coronavirus 229E, SARS-CoV-2, and enterovirus 71

Emerging infectious diseases such as COVID-19 and Disease X, which was detected in the Democratic Republic of the Congo in early December 2024, underscore the importance of developing new virucidal, antiviral, and antimicrobial compounds. The virucidal activity of natural products, including tiliacorinine (1), dioscorine (2), racemosol (3), and terrein (4), against influenza A virus (H1N1), human coronavirus 229E (HCoV-229E), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and enterovirus 71 (EV71) were evaluated using the American Society for Testing and Materials E1053-20 method. Racemosol (3) from Bauhinia malabarica had the most potent virucidal activity against the H1N1, HCoV-229E, and SARS-CoV-2 viruses, followed by terrein (4), a metabolite of the fungus Aspergillus terreus. Racemosol (3) exhibited virucidal activity with a log reduction of 4 (99.99 % viral reduction) against H1N1, HCoV-229E, and SARS-CoV-2 at a concentration of 0.1250 mg/mL. The alkaloids tiliacorinine (1) from Tiliacora triandra and dioscorine (2) from Dioscorea hispida exhibited weaker virucidal activity than racemosol (3) and terrein (4). Compounds 1, 2, and 4 showed weak virucidal activity against the EV71 virus, while racemosol (3) displayed moderate activity with a log reduction of 3.813 at the concentration of 0.1250 mg/mL. This work underscores the importance of natural products as sources of virucidal agents, which may be useful for the future threats of emerging and re-emerging viral diseases.

Interpretation of indoor air surveillance for respiratory infections: a prospective longitudinal observational study in a childcare setting

BACKGROUND

Sampling the air in indoor congregate settings, where respiratory pathogens are ubiquitous, may constitute a valuable yet underutilised data source for community-wide surveillance of respiratory infections. However, there is a lack of research comparing air sampling and individual sampling of attendees. Therefore, it remains unclear how air sampling results should be interpreted for the purpose of surveillance.

METHODS

In this prospective observational study, we compared the presence and concentration of several respiratory pathogens in the air with the number of attendees with infections and the pathogen load in their nasal mucus. Weekly for 22 consecutive weeks, we sampled the air in a single childcare setting in Belgium. Concurrently, we collected the paper tissues used to wipe the noses of 23 regular attendees: children aged zero to three and childcare workers. All samples were tested for 29 respiratory pathogens using PCR.

FINDINGS

Air sampling sensitively detected most respiratory pathogens found in nasal mucus. Some pathogens (SARS-CoV-2, Pneumocystis jirovecii) were found repeatedly in the air, but rarely in nasal mucus, whilst the opposite was true for others (Human coronavirus NL63). All three pathogens with a clear outbreak pattern (Human coronavirus HKU-1, human parainfluenza virus 3 and 4) were found in the air one week before or concurrent with the first detection in paper tissue samples. The presence and concentration of pathogens in the air was best predicted by the pathogen load of the most infectious case. However, air pathogen concentrations also correlated with the number of attendees with infections. Detection and concentration in the air were associated with CO2 concentration, a marker of ventilation and occupancy.

INTERPRETATION

Our results suggest that air sampling could provide sensitive, responsive epidemiological indicators for the surveillance of respiratory pathogens. Using air CO2 concentrations to normalise such signals emerges as a promising approach.

FUNDING

KU Leuven; DURABLE project, under the EU4Health Programme of the European Commission; Thermo Fisher Scientific.

Ultra-Fast Moisture Sensor for Respiratory Cycle Monitoring and Non-Contact Sensing Applications

As human-machine interface hardware advances, better sensors are required to detect signals from different stimuli. Among numerous technologies, humidity sensors are critical for applications across different sectors, including environmental monitoring, food production, agriculture, and healthcare. Current humidity sensors rely on materials that absorb moisture, which can take some time to equilibrate with the surrounding environment, thus slowing their temporal response and limiting their applications. Here, this challenge is tackled by combining a nanogap electrode (NGE) architecture with chicked egg-derived albumen as the moisture-absorbing component. The sensors offer inexpensive manufacturing, high responsivity, ultra-fast response, and selectivity to humidity within a relative humidity range of 10-70% RH. Specifically, the egg albumen-based sensor showed negligible response to relevant interfering species and remained specific to water moisture with a room-temperature responsivity of 1.15 × 104. The nm-short interelectrode distance (circa 20 nm) of the NGE architecture enables fast temporal response, with rise/fall times of 10/28 ms, respectively, making the devices the fastest humidity sensors reported to date based on a biomaterial. By leveraging these features, non-contact moisture sensing and real-time respiratory cycle monitoring suitable for diagnosing chronic diseases such as sleep apnea, asthma, and pulmonary disease are demonstrated.

A cough simulator constructed from off-the-shelf and 3D-printed components

The development of low-cost research equipment is crucial for enhancing accessibility in scientific research, particularly in the field of respiratory disease transmission. This study presents a novel, customizable cough simulator designed for ad-hoc studies that require precise control over ejection velocity and aerosol size. Constructed from off-the-shelf parts and 3D-printed components, this programmable, piston-driven simulator offers an affordable solution for researchers. Its performance has been validated, demonstrating suitability for evaluating fluid flow and monitoring ejected particles that correspond to the velocities of mouth breathing and coughing. Potential applications for this device include assessments of aerosol ventilation, disinfection, and the efficacy of personal protective equipment, all of which contribute to advancing scientific understanding and public health outcomes.

Rapid virucidal activity of an air sanitizer against aerosolized MS2 and Phi6 phage surrogates for non-enveloped and enveloped vertebrate viruses, including SARS-CoV-2

An air sanitizer was evaluated using an aerobiology protocol, compliant with the U.S. Environmental Protection Agency's Air Sanitizer Guidelines, for virucidal activity against bacteriophages Phi6 and MS2 (used as surrogates for enveloped and non-enveloped human pathogenic viruses). The phages were suspended in a medium containing a tripartite soil load simulating body fluids and aerosolized using a six-jet Collison nebulizer in an enclosed 25 m3 aerobiology chamber at 22 ± 2°C and 50 ± 10% relative humidity. The air sanitizer was sprayed into the chamber for 30 s. Viable phages in the air were captured directly, in real time, on host bacterial lawns using a slit-to-agar sampler. Reductions in viable phage concentration ≥3.0 log10 (99.9%) were observed after a mean exposure of 3.6 min for Phi6, suggesting efficacy against enveloped viruses (e.g., SARS-CoV-2, influenza, and RSV), and ~10.6 min for MS2, suggesting virucidal efficacy for non-enveloped viruses (e.g., noroviruses and rhinoviruses). This targeted air sanitization approach represents an important non-pharmaceutical public health intervention with virucidal efficacy against airborne viral pathogens.IMPORTANCEAirborne viruses are implicated in the transmission indoors of respiratory and enteric viral infections. Air sanitizers represent a non-pharmaceutical intervention to mitigate the risk of such viral transmission. We have developed a method that is now an ASTM International standard (ASTM E3273-21) as well as a test protocol approved by the U.S. EPA to evaluate the efficacy of air sanitizing sprays for inactivating airborne MS2 and Phi6 bacteriophage (used as surrogates for non-enveloped and enveloped human pathogenic viruses, respectively). The test phages were individually suspended in a soil load and aerosolized into a room-sized aerobiology chamber maintained at ambient temperature and relative humidity. Reductions in viable phage concentration ≥3.0 log10 (99.9%) were observed after a mean exposure of 3.6 min for Phi6, suggesting efficacy against enveloped viruses (e.g., SARS-CoV-2; influenza; RSV), and ~10.6 min for MS2, suggesting virucidal efficacy for non-enveloped viruses (e.g., noroviruses and rhinoviruses). The data suggest the utility of the air sanitizer for mitigating the risk of indoor viral transmission during viral pandemics and outbreaks.

Temperature-Directed Morphology Transformation Method for Precision-Engineered Polymer Nanostructures

With polymer nanoparticles now playing an influential role in biological applications, the synthesis of nanoparticles with precise control over size, shape, and chemical functionality, along with a responsive ability to environmental changes, remains a significant challenge. To address this challenge, innovative polymerization methods must be developed that can incorporate diverse functional groups and stimuli-responsive moieties into polymer nanostructures, which can then be tailored for specific biological applications. By combining the advantages of emulsion polymerization in an environmentally friendly reaction medium, high polymerization rates due to the compartmentalization effect, chemical functionality, and scalability, with the precise control over polymer chain growth achieved through reversible-deactivation radical polymerization, our group developed the temperature-directed morphology transformation (TDMT) method to produce polymer nanoparticles. This method utilized temperature or pH responsive nanoreactors for controlled particle growth and with the added advantages of controlled surface chemical functionality and the ability to produce well-defined asymmetric structures (e.g., tadpoles and kettlebells). This review summarizes the fundamental thermodynamic and kinetic principles that govern particle formation and control using the TDMT method, allowing precision-engineered polymer nanoparticles, offering a versatile and an efficient means to produce 3D nanostructures directly in water with diverse morphologies, high purity, high solids content, and controlled surface and internal functionality. With such control over the nanoparticle features, the TDMT-generated nanostructures could be designed for a wide variety of biological applications, including antiviral coatings effective against SARS-CoV-2 and other pathogens, reversible scaffolds for stem cell expansion and release, and vaccine and drug delivery systems.

Chronic CRYPTOCHROME deficiency enhances cell-intrinsic antiviral defences

The within-host environment changes over circadian time and influences the replication and severity of viruses. Genetic knockout of the circadian transcription factors CRYPTOCHROME 1 and CRYPTOCHROME 2 (CRY1-/-/CRY2-/-; CKO) leads to altered protein homeostasis and chronic activation of the integrated stress response (ISR). The adaptive ISR signalling pathways help restore cellular homeostasis by downregulating protein synthesis in response to endoplasmic reticulum overloading or viral infections. By quantitative mass spectrometry analysis, we reveal that many viral recognition proteins and type I interferon (IFN) effectors are significantly upregulated in lung fibroblast cells from CKO mice compared with wild-type (WT) mice. This basal 'antiviral state' restricts the growth of influenza A virus and is governed by the interaction between proteotoxic stress response pathways and constitutive type I IFN signalling. CKO proteome composition and type I IFN signature were partially phenocopied upon sustained depletion of CRYPTOCHROME (CRY) proteins using a small-molecule CRY degrader, with modest differential gene expression consistent with differences seen between CKO and WT cells. Our results highlight the crosstalk between circadian rhythms, cell-intrinsic antiviral defences and protein homeostasis, providing a tractable molecular model to investigate the interface of these key contributors to human health and disease.This article is part of the Theo Murphy meeting issue 'Circadian rhythms in infection and immunity'.

Development, Current Status, and Remaining Challenges for Respiratory Syncytial Virus Vaccines

Respiratory syncytial virus (RSV) causes significant morbidity and mortality, especially in young children and the elderly. RSV vaccine development puzzled vaccinologists for years. Safety concerns of initial formulations, the lack of an absolute correlate of protection, and the need for selecting appropriate virus attenuation and antigen-adjuvant combinations contributed to delayed vaccine production. The recent stabilization of the RSV-F glycoprotein in the prefusion (preF) conformation that constitutes the primary target of RSV-neutralizing antibodies was key for efficient vaccine design. Two protein subunit vaccines (GSK's Arexvy and Pfizer's Abrysvo) and one mRNA RSV vaccine (Moderna's mRESVIA) are now available. This article aims to provide a comparative overview of the safety and efficacy of novel RSV vaccines that are approved for the prevention of RSV-lower respiratory tract disease (LRTD) in adults 60 years of age and older, with updated recommendations calling for the expansion of vaccination to all adults at increased risk for severe RSV disease. Abrysvo is the only vaccine indicated for use in pregnancy to prevent RSV-LRTD in infants from birth to 6 months of age. We provide a comparative assessment of the efficacy of approved RSV vaccines over a maximum of three seasons, summarizing currently available data. We conclude that despite the decreasing vaccine efficacy over time, which should be anticipated for a virus that is characterized by short-term immunity, efficacy was clinically meaningful over placebo. The increased risk of Guillain-Barré syndrome post vaccination with Abrysvo or Arexvy, which prompted the FDA to require the inclusion of such warnings in the prescribing information of these two RSV vaccines, should be prioritized and investigated thoroughly. Furthermore, ongoing vaccine surveillance and further evaluation, particularly among immunocompromised patients, frail elderly subjects, and young infants that were under- or not represented in pivotal clinical trials, are necessary. As in the success story of combined pediatric vaccines, combination vaccines, conferring protection against several respiratory illnesses in one dose, could help improve vaccine acceptance and coverage rates in older adults.

Evaluating the effectiveness of different intervention measures for an outbreak of mycoplasma pneumoniae in hangzhou based on a dynamic model

For Mycoplasma pneumoniae (MP) infection in schools, the local Center for Disease Control and Prevention recommends nonpharmaceutical interventions, such as case isolation, school closures, suspension of group activities, reinforcement of ventilation and disinfection for influenza outbreaks. However, there is limited evidence supporting and evaluating the effectiveness of these interventions. On the basis of an outbreak of MP infection occurring in a primary school in Zhejiang Province, a susceptible-latent-overt infected-recessive infected-displaced (SEIAR) model was constructed to quantitatively evaluate the prevention and control effects by simulating the intervention measures mentioned above. With no intervention, the outbreak lasted 143 days, and the total attack rate (TAR) and total infection rate (TIR) reached 75.78% and 95.65%, respectively. The most effective single-intervention strategy was ventilation and disinfection (VD), with a TAR as low as 15.81% and a duration of outbreak (DO) of 61 days. The two- or three- combined intervention strategies, including all combinations with 90% VD, were more effective than the single-intervention strategy. In conclusion, the SEIAR model could effectively simulate the epidemic situation of MP and the intervention effect. For the outbreak of MP, the earlier comprehensive measures were taken, such as ventilation and disinfection, and case isolation, the better control effect would be.

SARS-CoV-2 surrogate bacteriophage φ6 cross-contamination between fruits and gloves, survival on discarded gloves and inactivation by photodynamic treatment

This study assessed the SARS-CoV-2 surrogate bacteriophage φ6 cross-contamination between high-density polyethylene or polyvinyl chloride gloves and fruits (tomato and cucumber) using different inoculum levels (6.0 and 4.0 log PFU/sample). Bacteriophage φ6 survival on contaminated gloves was assessed over 9 days at 25 °C. The effectiveness of photodynamic treatment using curcumin as a photosensitizer to inactivate φ6 on fruits was determined. The fruit type and the glove material influenced the φ6 transfer. Longer contact times resulted in greater φ6 transfer. The highest φ6 transfer occurred from tomato to HDPE glove (0.8% or -1.1 log % transfer) after 30 s of contact at the higher inoculum level. Bacteriophage φ6 was detected on cross-contaminated HDPE gloves for up to 6 days. Bacteriophage φ6 survived better on vinyl gloves cross-contaminated by cucumber vs. tomato (detected up to 6 vs 3 days). Photodynamic inactivation of φ6 was time-dependent and varied with the tested fruit but was not influenced by viral starting concentration. Photodynamic treatment decreased the φ6 titer by 3.0 and 2.2 log PFU/sample in tomato and cucumber, respectively. Transmission electronic microscopy showed that photodynamic treatment changed the structure of the φ6 capsid. These findings may help in the management of SARS-CoV-2 contamination risks in fruit handling. They may also help in the establishment of effective measures to manage cross-contamination risk.

Commercial Strip-Inspired One-Pot CRISPR-Based Chip for Multiplexed Detection of Respiratory Viruses

The absence of sensitive, multiplexed, and point-of-care assays poses a critical obstacle in promptly responding to emerging human respiratory virus (HRV) pandemics. Herein, RECOGNIZER (re-building commercial pregnancy strips via large-size nanoflowers), an innovative one-pot CRISPR assay, is presented that employs commercially available strips to identify several types of HRVs. The superiority of the RECOGNIZER assay mainly relies on two aspects: (i) DNA nanoflowers possessing a high surface-to-volume ratio and well-defined surface allow for a considerable probe loading density and minimized non-specific interaction, achieving an impressive signal-to-noise proportion exceeding tenfold at 1 nM target. (ii) The design of the one-pot reaction, multi-channel chip, and custom-made app enables the rapid, sample-to-answer, and multiplexed analysis of four HRVs in 25 min. This assay demonstrates a sensitivity of 5.42 pM for synthetic SARS-CoV-2 RNA and 10 copies µL-1 for SARS-CoV-2 plasmids after pre-amplification. Finally, the proposed approach indicated 100% accuracy in 50 clinical swab samples, demonstrating the robust performance in distinguishing SARS-CoV-2 from other HRVs. The versatility and scalability of RECOGNIZER renders it a user-friendly platform for virus infection monitoring, offering significant potential for improving pandemic response efforts.

Burden of Acute Respiratory Infections Caused by Influenza Virus, Respiratory Syncytial Virus, and SARS-CoV-2 with Consideration of Older Adults: A Narrative Review

Influenza virus, respiratory syncytial virus (RSV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are acute respiratory infections (ARIs) that can cause substantial morbidity and mortality among at-risk individuals, including older adults. In this narrative review, we summarize themes identified in the literature regarding the epidemiology, seasonality, immunity after infection, clinical presentation, and transmission for these ARIs, along with the impact of the COVID-19 pandemic on seasonal patterns of influenza and RSV infections, with consideration of data specific to older adults when available. As the older adult population increases globally, it is of paramount importance to fully characterize the true disease burden of ARIs in order to develop appropriate mitigation strategies to minimize their impact in vulnerable populations. Challenges associated with characterizing the burden of these diseases include the shared symptomology and clinical presentation of influenza virus, RSV, and SARS-CoV-2, which complicate accurate diagnosis and highlight the need for improved testing and surveillance practices. To this end, multiple regional, national, and global virologic and disease surveillance systems have been established to provide accurate knowledge of viral epidemiology, support appropriate preparedness and response to potential outbreaks, and help inform prevention strategies to reduce disease severity and transmission. Beyond the burden of acute illness, long-term health consequences can also result from influenza virus, RSV, and SARS-CoV-2 infection. These include cardiovascular and pulmonary complications, worsening of existing chronic conditions, increased frailty, and reduced life expectancy. ARIs among older adults can also place a substantial financial burden on society and healthcare systems. Collectively, the existing data indicate that influenza virus, RSV, and SARS-CoV-2 infections in older adults present a substantial global health challenge, underscoring the need for interventions to improve health outcomes and reduce the disease burden of respiratory illnesses.Graphical abstract and video abstract available for this article.

Far-UVC (222 nm) irradiation effectively inactivates ssRNA, dsRNA, ssDNA, and dsDNA viruses as compared to germicidal UVC (254 nm)

Ultraviolet-C (UVC) irradiation is being used as an effective approach for the disinfection of pathogenic viruses present in air, surfaces, and water. Recently, far-UVC radiation (222 nm) emitted by KrCl* (krypton-chloride) excimer lamps have been recommended for disinfecting high-risk public spaces to reduce the presence and transmission of infectious viruses owing to limited human health exposure risks as compared to germicidal UVC (254 nm). In this study, the UVC inactivation performances of individual filtered KrCl* excimer lamp (222 nm) and germicidal UVC lamp (254 nm) were determined against four viruses, bacteriophages MS2, Phi6, M13, and T4, having different genome compositions (ssRNA, dsRNA, ssDNA and dsDNA, respectively) and shapes (i.e., spherical (Phi6), linear (M13), and icosahedral (MS2 and T4)). Here, the disinfection efficacies of filtered KrCl* excimer lamp (222 nm) and germicidal UVC lamp (254 nm) were evaluated for highly concentrated virus droplets that mimic the virus-laden droplets released from the infected person and deposited on surfaces as fomites. Filtered KrCl* excimer (222 nm) showed significantly better inactivation against all viruses having different genome compositions and structures compared to germicidal UVC (254 nm). The obtained sensitivity against the filtered KrCl* excimer (222 nm) was found to be in the order, T4 > M13 > Phi6 > MS2 whereas for the germicidal UVC (254 nm) it was T4 > M13 > MS2 > Phi6. These results provide a strong basis to promote the use of filtered KrCl* excimer lamps (222 nm) in disinfecting contagious viruses and to limit the associated disease spread in public places and other high-risk areas.

Viral infections in celiac disease: what should be considered for better management

Following a gluten-free diet (GFD) is known as the main effective therapy available for celiac disease (CD) patients, which in some cases is not enough to heal all patients presentations completely. Accordingly, emerging researchers have focused on finding novel therapeutic/preventive strategies for this disorder. Moreover, previous studies have shown that celiac patients, especially untreated subjects, are at increased risk of developing viral and bacterial infections, which can become a challenge for the clinician. Viruses, such as Rotavirus, Reovirus, Adenovirus, Enterovirus, Rhinovirus, Astrovirus, Hepatitis virus, COVID-19, Norovirus, and Herpesvirus, have been related to CD pathogenesis. Therefore, clinicians need to pay more attention to evaluate CD patients' viral infection history (especially nonresponders to the GFD), to look for effective preventive strategies and educate patients about important risk factors. In addition, there are still viruses whose role in CD pathogenesis has not been fully studied. In this review, current information on the association between CD and various viral infections was gathered to improve knowledge in this subject area and draw researchers'/clinicians' attention to unstudied/less studied viruses in CD pathogenesis, which might guide future prevention approaches.

Inulin biopolymer as a novel material for sustainable soil stabilization

The development of new urban areas necessitates building on increasingly scarce land, often overlaid on weak soil layers. Furthermore, climate change has exacerbated the extent of global arid lands, making it imperative to find sustainable soil stabilization and erosion mitigation methods. Thus, scientists have strived to find a plant-based biopolymer that favors several agricultural waste sources and provides high strength and durability for sustainable soil stabilization. This contribution is one of the first studies assessing the feasibility of using inulin to stabilize soil and mitigate erosion. Inulin has several agricultural waste sources, making it a sustainable alternative to traditional additives. Soil samples susceptible to wind erosion were collected from a dust-prone area in southwest Iran and treated with inulin at 0%, 0.5%, 1%, and 2% by weight. Their mechanical strength was evaluated using unconfined compressive strength tests and a penetrometer. In addition, wind tunnel tests (at 16 m/s) were performed to investigate inulin's wind erosion mitigation potential. The durability of treated samples was evaluated after ten wetting-drying cycles to assess the effect of environmental stressors. The results indicated a 40-fold increase in the unconfined compressive strength (up to 8 MPa) of the samples treated with 2% inulin and only 0.22% weight loss after ten wetting-drying cycles. SEM images revealed the formation of biopolymer-induced particle-to-particle bonds. Moreover, Raman spectroscopy indicated molecular (hydrogen) bonding of the biopolymer hydrogel-soil particles facilitated by the hydroxyl groups of inulin. The deterioration in stiffness and strength of treated samples was less noticeable after 3rd dry-wet cycle, indicating the durability of the samples. The durability of samples against wet-dry cycles was attributed to molecular bonding of soil-biopolymer hydrogel, as revealed by FTIR analysis.

Respiratory syncytial virus: A review of current basic and clinical knowledge

Background

Respiratory syncytial virus (RSV) is a highly contagious pathogen known for causing respiratory tract infections, particularly among pediatric and elderly patients. Its ability to induce outbreaks in both community and hospital settings underscores its substantial health burden. This review aims to provide a comprehensive understanding of RSV, including its biological and clinical aspects.

Methods

A comprehensive review of the literature was conducted by searching PubMed, Scopus, and Web of Science databases for relevant articles. Key topics included RSV virology, epidemiology, clinical findings, diagnostic methods, management approaches, and preventive strategies.

Results

This review encompasses the taxonomy and structure of RSV, including its genome and proteins. Various strains and their dominance patterns, alongside pathogenesis mechanisms, are explored. Diagnostic techniques such as nucleic acid amplification tests are discussed for their efficacy and accessibility. Supportive care remains the primary treatment, with antiviral therapies playing a limited role. Monoclonal antibody immunization and vaccination efforts offer promising avenues for RSV prevention. The impact of the COVID-19 pandemic on RSV epidemiology is also considered, along with the oncolytic potential of RSV in cancer treatment.

Conclusion

Advancements in understanding RSV virology, epidemiology, and clinical management have paved the way for improved diagnostic and preventive strategies. However, challenges remain in ensuring widespread access to diagnostics and effective treatments, particularly in resource-limited settings. Continued research and global collaboration are essential for addressing the ongoing impact of RSV and reducing its burden on public health.

Respiratory pathogen trends in queensland, australia between 2018 and 2021: A statewide cohort study before and after the initial COVID-19 outbreak

BACKGROUND

The SARS-CoV-2 pandemic and accompanying public health measures disrupted the normal transmission of respiratory viral pathogens. Less is known about the effects on bacterial pathogens.

AIMS

To assess the impact of public health restrictions on common respiratory pathogens (influenza viruses, respiratory syncytial virus (RSV) and the following bacterial pathogens: Streptococcus pneumoniae (S. pneumoniae), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus).

METHODS

This statewide cohort study used respiratory specimen result data from 237 health facilities in Queensland, Australia, collected between January 2018 and June 2021. Trends and weekly positive rates per 100 tests/cultures for weeks 11-27 (with 95% confidence intervals) were compared between pre-pandemic (2018/2019), early pandemic restrictions (2020), and easing of restrictions (2021) periods.

RESULTS

Over 260,000 viral PCRs and 180,000 cultures were analyzed. Decreases in influenza and RSV were observed in 2020 from 10.8 to 1.1 and 9.5 to 2.5 per 100 tests, respectively; S. pneumoniae decreased from 1.7 to 1.1 per 100 cultures. Influenza levels remained low until the end of the study period. There was no change in the detection of S. aureus or P. aeruginosa per 100 cultures, but cultures positive for K. pneumoniae increased from 1.2 in 2018/2019 to 1.8 in 2020 and 1.6 in 2021. After restrictions eased, RSV rates increased to levels higher than before the pandemic.

CONCLUSIONS

Transmission of droplet-spread pathogens decreased after the introduction of public health restrictions due to the COVID-19 pandemic. The increase in K. pneumoniae, often associated with nosocomial infections, warrants further investigation.

Studies on the Virucidal Effects of UV-C of 233 nm and 275 nm Wavelengths

Among the physical decontamination methods, treatment with ultraviolet (UV) radiation is a suitable means of preventing viral infections. Mercury vapor lamps (254 nm) used for room decontamination are potentially damaging to human skin (radiation) and harmful to the environment (mercury). Therefore, other UV-C wavelengths (100-280 nm) may be effective for virus inactivation on skin without damaging it, e.g., far-UV-C radiation with a wavelength of 233 nm, which is absorbed in the outer layer of the skin and thus does not reach the deeper layers of the skin. For room disinfection, 275 nm UV-C LED lamps could be a more environmentally friendly alternative, since toxic mercury is avoided. A carrier test using multiple viruses was used to determine the TCID50/mL value on stainless steel, PVC, and glass carriers. In addition to the inactivation kinetics (233 nm), the necessary UV-C dose for 4 lg inactivation (275 nm) was investigated. The impact of irradiance on the inactivation efficacy was also assessed. The inactivation of the viruses was a function of the radiation dose. UV-C-radiation at 233 nm (80 mJ/cm2) inactivated from 1.49 ± 0.08 to 4.28 ± 0.18 lg depending on the virus used. To achieve a 4 lg inactivation (275 nm) for enveloped viruses, doses of up to 70 mJ/cm2 (SuHV-1) were sufficient. For non-enveloped viruses, a maximum dose of 600 mJ/cm2 (MS2) was necessary. Enveloped viruses were inactivated with lower doses compared to non-enveloped viruses. Higher radiation doses were required for inactivation at 275 nm in comparison to 254 nm. A more environmentally friendly alternative to mercury vapor lamps is available with 275 nm LED emitters. Radiation at 233 nm could serve as an additional prophylactic or therapeutic measure for virus inactivation in direct contact with human skin.

Indoor air quality and symptoms of acute respiratory infections and gastrointestinal issues in children and employees in day-care nurseries

BACKGROUND

Children attending day-care centers (DCCs) experience more infections than those cared for at home and DCC employees have high sickness absence rates. This study aimed to investigate the association between indoor air quality and absenteeism among children and staff in DCCs.

METHODS

CO2 levels, relative humidity (RH), and temperature were continuously measured in 22 DCCs over 3 winter months. Simultaneously, absenteeism due to sickness was recorded for 721 children and 213 employees. In 11 DCCs, staff received training to improve ventilation.

RESULTS

The median CO2 concentration, RH, and temperature were 818 ppm, 38.7%, and 20.8 °C, respectively. Acute respiratory infections (ARIs) accounted for 42% of child absenteeism and 53% of staff absenteeism, while gastrointestinal symptoms (GI) were responsible for 24.7% and 27.3% of absenteeism in children and staff, respectively. No significant association was found between ARI absenteeism and CO2 concentration, RH, or temperature. However, a significant association was observed between GI and room temperature (P < .05). No significant differences in CO2 concentration or absenteeism were observed between intervention and control groups.

CONCLUSIONS

No statistical evidence was found that ARI absenteeism was associated with the measured indoor air quality parameters. GI for staff and children was significantly associated with room temperature. Absenteeism was not associated significantly with targeted interventions.

Causes of COVID-19 Outbreaks During Sports and Exercise: A Systematic Review

BACKGROUND

Physical activity is beneficial for preventing non-communicable and infectious diseases, such as pneumonia. Physical activity is also a potential protective factor for reducing coronavirus disease 2019 (COVID-19) severity. Conversely, outbreaks of respiratory viral infections are more likely to occur owing to group activities, opportunities for contact with individuals and vocalisations. Since the onset of the COVID-19 pandemic, several cases of COVID-19 outbreaks during various sports and exercise have been reported. However, the common causes underlying these outbreaks remain unclear.

OBJECTIVE

The objective of this study is to identify the causes of COVID-19 outbreaks during sports and exercise using systematic review approach.

METHODS

Our eligibility criteria were published articles reporting case investigation on COVID-19 outbreaks and the cause during sports and exercise. Studies such as reviews and observational studies without case investigations were excluded. PubMed, CINAHL, WHO COVID-19 Research Database and Ichushi Web were searched on 28 August 2023. The quality of included studies was rated using a quality criteria checklist adapted from a previous systematic review of influenza outbreaks. Vote counting of outbreak causes was performed by type of sports (team or individual).

RESULTS

Twenty-one articles reporting 22 outbreaks were identified (quality: high, 9; medium, 9; and low, 3). The outbreaks were most frequently reported in fitness classes, followed by soccer. Most studies listed multiple causes of the outbreaks. The most common suspected cause of outbreaks in individual exercise, mostly from fitness classes, was poor ventilation and not wearing masks, followed by not maintaining physical distance and participation of individuals with some symptoms. In team sports, the most common cause was interaction outside the game, such as social events.

CONCLUSIONS

This systematic review found a limited number of case investigations suggesting that COVID-19 outbreaks during sports and exercise may be associated with the inhalation of aerosols in indoor settings, interactions outside of team sports games and participation of individuals with some symptoms. Prevention strategies that focus on mitigating these issues may be effective at preventing sports and exercise-associated respiratory infectious diseases outbreaks.

PROSPERO REGISTRATION NUMBER

CRD42023443158.

Shape-dependent aerosol dynamics in indoor environments: Penetration, deposition, and dispersion

Particle shape exerts a significant influence on their dynamic behavior, and it is imperative to elucidate these effects given the potential for severe environmental toxicity associated with shaped particles. Despite extensive research on the dynamical processes of spherical particles, the behaviors of non-spherical particles have been insufficiently investigated. In this study, we have developed a suite of computation-based models that account for particle shape and have reported on the typical dynamical behaviors of non-spherical particles within indoor environments. We have explored three typical scenarios, i.e., particle penetration into indoor spaces through building cracks, indoor particle deposition, and indoor particle dispersion. The shape-induced deviations are associated with dynamical processes, showing a decrease trend among penetration, deposition, and dispersion of the non-spherical particles. The maximum discrepancy due to particle shape during the penetration process exceeds 1000 %, observed with particles of approximately 0.02 μm in diameter interacting with straight cracks 4.5 cm in length and 0.25 mm in height. Moreover, there is a discrepancy of more than 70 % in the deposition of particles with a diameter of approximately 10 μm on side walls when using side air supply ventilation. Similarly, a discrepancy of nearly 11 % is noted for particles around 0.02 μm in diameter during dispersion under displacement ventilation within indoor settings. The interaction between shape-related particle dynamics, particularly their diffusion characteristics, and the properties of the flow field leads to these shape-dependent dynamical discrepancies. These findings offer a comprehensive understanding of how the shape of particles affects their indoor dynamic behavior, thereby supporting the control of hazardous particles in indoor environments.

Implementation of facemask sampling for the detection of infectious individuals with SARS-CoV-2 in high stakes clinical examinations - a feasibility study

Introduction

SARS-CoV-2 may transmit across vaccinated cohorts during practical clinical examinations. We sought to assess the feasibility of facemask sampling (FMS) to identify individuals emitting SARS-CoV-2 during a mock PACES exam.

Methods

In May 2022 we recruited participants from a mock PACES examination in Leicester, UK. Following a negative lateral flow test assay, all participants wore modified facemasks able to capture exhaled virus during the assessment (FMS). A concomitant upper respiratory tract sample (URTS) was provided prior to FMS. Exposed facemasks were processed by removal and dissolution of sampling matrices fixed within the mask and cycle thresholds values quantified by RT-qPCR. Participants were asked to grade statements regarding the comfort, effort, ethics and communication when providing FMS; laboratory technicians were asked to grade key statements surrounding suitability of samples for processing.

Results

34 participants provided concomitant URTS and FMS during the examination. One participant was positive for SARS-CoV-2, with a cycle threshold value of 22.5 on URTS, but negative (no viral RNA detected) on FMS; no transmission to others was identified from this individual. Participants responded positively to statements regarding FMS describing all four domains; however, 69% of participants felt that a positive result from FMS alone was insufficient for diagnosis and that further tests were required. All but one FMS sample was suitable for processing.

Discussion

FMS during PACES exams are acceptable among participants and samples provided are suitable for processing. Our results demonstrate feasibility of FMS within practical examination settings and support the further assessment of FMS as a scalable tool that can be compared with URTS to identify those who are infectious.

Advancing respiratory virus diagnostics: integrating the nasal IFN-I score for improved viral detection

BACKGROUND

This study aimed to demonstrate the utility of the nasal Type I interferon (IFN-I) response as a marker for respiratory viral infections (RVIs) and its potential to enhance diagnosis when combined with first-line PCR tests for Influenza A/B, RSV, and SARS-CoV-2.

METHODS

Nasopharyngeal swabs (NPS) from patients at Hospices Civils de Lyon (November 2022-April 2024) suspected of viral infections (n = 788) and from healthy controls (n = 53) were analysed. The IFN-I score was measured using the FILMARRAY® IFN-I pouch prototype, which detects four interferon-stimulated genes. The study evaluated the performance of the IFN-I score in detecting samples positive for viruses by first-line PCR and assessed its benefit in diagnosing RVIs in samples initially classified as negative by PCR.

FINDINGS

Out of 788 NPS included, 504 (64%) were positive with the first-line PCR tests, and IFN-I score was significantly higher in those samples (median [IQR]: 13.00 [2.76-45.40]) compared to ones collected from healthy controls (1.09 [0.67-1.30]; p < 0.0001), with an area under the curve (AUC; 95% CI) of 0.92 (0.90-0.92). Moreover, out of the 284 NPS negative with first-line PCR tests, suspicion of viral infection according to IFN-I score was found in 63% of cases (178/284). Second-line test (BioFire® Respiratory Panel 2.1 plus) and viral metagenomic confirmed the presence of viruses 94% of cases.

INTERPRETATION

The study highlights the potential of integrating nasal IFN-I score into clinical workflows to improve RVI diagnosis and enhance preparedness for emerging viruses.

FUNDING

Public grant overseen by the French National Research Agency (ANR21-RHUS-08/ANR-23-CHIN-0001).

Social interactions do not affect mycoplasma infection in griffon vultures

Uncovering the ways in which pathogens spread has important implications for population health and management. Pathogen transmission is influenced by various factors, including patterns of social interactions and shared use of space. We aim to understand how the social behaviour of griffon vultures (Gyps fulvus), a species of conservation interest, influences the presence or absence of mycoplasma, a group of bacteria known to cause respiratory diseases in birds. We investigated how direct and indirect social interactions of griffon vultures in the wild, in different social situations, impacted the mycoplasma infection status. We inferred interactions from high-resolution global positioning system (GPS) tracking data. Specifically, we assessed how social behaviour affects infection status when vultures share feeding and roosting locations, either at the same time (direct interactions) or subsequently, when space use is asynchronous (indirect interactions). We did not detect a significant effect of any social situation and type of interaction on infection status. However, we observed a high population prevalence of mycoplasma, suggesting that other factors might be more important than social interactions in determining the transmission of this bacteria in the Israeli vulture population. Uncovering the mechanisms that underlie infection status in wildlife is crucial for maintaining viable populations, designing containment management actions and gaining insights into the ecological mechanisms that drive infectious disease dynamics.

Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review

Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.

The pattern of childhood infections during and after the COVID-19 pandemic

The rates of most paediatric infectious diseases declined during the initial phase of the COVID-19 pandemic due to the implementation of non-pharmaceutical interventions. However, after the gradual release of these interventions, resurgences of infections occurred with notable variations in incidence, clinical manifestations, pathogen strains, and age distribution. This Review seeks to explore these changes and the rare clinical manifestations that were made evident during the resurgence of known childhood infections. The magnitude of resurgences was possibly caused by a profound population immunity debt to specific pathogens in combination with the coinciding reappearance of viral and bacterial infections, rather than novel pathogen variants, increased antimicrobial resistance, or altered childhood immune function. As the usual patterns of paediatric infectious diseases were disrupted during the COVID-19 pandemic, the consequences of a population immunity debt were unravelled, and new insights into pathogen transmissibility, disease pathogenesis, and rare clinical manifestations were revealed.

Stability of Respiratory Syncytial Virus in Nasal Aspirate From Patients Infected With RSV

BACKGROUND

Evaluation of infectious virus titer is a challenge for respiratory syncytial virus (RSV) clinical trials because of the labile nature of RSV and rapid loss of infectivity without proper specimen handling. However, there has been no rigorous investigation into RSV stability in clinical specimens.

METHODS

RSV stability was investigated by evaluating virus titers and defined as titer variation from baseline within three standard deviations of our titration assay. RSV stability in viral transport medium (VTM) at 4°C and the effect of freezing method on stability were evaluated using RSV-A2 stock. RSV stability in nasal aspirates collected in VTM at 4°C was estimated by regression analysis of virus titers measured at several time points. Stability of these specimens stored at -80°C for 10-15 months after freezing by the method, which maintained RSV-A2 stability, was also assessed.

RESULTS

Three standard deviations were calculated from our titration assay as 0.97 log10 50% tissue culture infectious dose (TCID50/mL), and RSV stability was defined as variation of virus titer from baseline within 1.0 log10TCID50/mL. RSV-A2 in VTM at 4°C was stable for at least 120 h. Freezing at -80°C negatively affected virus stability, whereas freezing in liquid nitrogen or a dry ice-ethanol bath did not. RSV in nasal aspirates was stable for 2 days at 4°C and for 10-15 months at -80°C after snap freezing.

CONCLUSIONS

RSV in nasal aspirates in VTM was estimated to be stable for 2 days at 4°C and for approximately 1 year at -80°C.

A game theoretic complex network model to estimate the epidemic threshold under individual vaccination behaviour and adaptive social connections

In today's interconnected world, the spread of information is closely linked to infectious disease dynamics. Public awareness plays a crucial role, as individual vaccination decisions significantly impact collective efforts to combat emerging health threats. This study explores disease transmission within a framework integrating social connections, information sharing, and individual vaccination decisions. We introduce a behaviour-prevalence model on an adaptive multiplex network, where the physical layer (Layer-II) captures disease transmission under vaccination. In contrast, the virtual layer (Layer-I) represents adaptive social contacts and the flow of information, shaping vaccination decisions within a socially influenced environment. We derive analytical expressions for the epidemic threshold using the microscopic Markov Chain Method (MMCM). Simulation results highlight that adaptive social contacts lead to a higher epidemic threshold than non-adaptive networks. Additionally, network characteristics, such as the power-law exponent in scale-free networks, significantly impact infection spread within populations. Our results reveal that changes in perceived infection risk and an individual's sensitivity to non-vaccinated neighbour's status strongly influence vaccine uptake across populations. These insights can guide public health officials in developing targeted vaccination programs that address the evolving dynamics of social connections, information dissemination, and vaccination choice in the digital era.

One-Step Multiplex RT-PCR Method for Detection of Melon Viruses

This study presents a one-step multiplex reverse transcription polymerase chain reaction (RT-PCR) method for the simultaneous detection of multiple viruses affecting melon crops. Viruses such as Watermelon mosaic virus (WMV), Cucumber mosaic virus (CMV), Zucchini yellow mosaic virus (ZYMV), Squash mosaic virus (SqMV), Tobacco mosaic virus (TMV), Papaya ring spot virus (PRSV), and Melon yellow spot virus (MYSV) pose a great threat to melons. The mixed infection of these viruses is the most common observation in the melon-growing fields. In this study, we surveyed northern Xingjiang (Altay, Changji, Wujiaqu, Urumqi, Turpan, and Hami) and southern Xingjiang (Aksu, Bayingolin, Kashgar, and Hotan) locations in Xinjiang province and developed a one-step multiplex RT-PCR to detect these melon viruses. The detection limits of this multiplex PCR were 103 copies/μL for ZYMV and MYSV and 102 copies/μL for WMV, SqMV, PRSV, CMV, and TMV. The detection results in the field showed 242 samples were infected by one or more viruses. The multiplex RT-PCR protocol demonstrated rapid, simultaneous, and relatively effective detection of viruses such as WMV, CMV, ZYMV, SqMV, TMV, PRSV, and MYSV. The technique is designed to identify these melon viruses in a single reaction, enhancing diagnostic efficiency and reducing costs, thus serving as a reference for muskmelon anti-virus breeding in Xinjiang.

Critically ill patients will benefit from single isolated laminar-air-flow wards by improving the environmental microbial composition

BACKGROUND

Hospital-associated infection (HAI) is an important issue in intensive care units (ICUs). We still lack direct evidence on whether the ICU patients and/or the medical system can benefit from single isolated laminar-air-flow (LAF) wards.

METHODS

High-touched-surface (HTS) swabs from 5 sites in two kinds of wards with different ventilation systems were longitudinally collected for 16 S rRNA sequencing and Type IIB restriction site-associated DNA sequencing for Microbiome (2bRAD-M). Samples were collected for 3 months. The clinical data of patients admitted to different wards during the sampling time and the whole year were collected and compared.

RESULTS

The α-diversity of single wards with isolated LAF was significantly higher than open regions without LAF (p<0.01). β-diversity analysis showed differences between different wards and similarities among the same region. We also identified 3 genera attributed to the most difference between the two kinds of wards. 2bRAD-M analysis further revealed community divergence among different HTS sites. There was an overlap between HTS microbiome profiling and the clinically cultivated pathogens of patients with HAI. People in single wards had a better outcome than those in open regions (p<0.05), indicating that single wards had a protective effect for critically ill patients.

CONCLUSION

Overall, there was a prominent difference in the microbiome community between single wards and open regions. Single wards had more balanced communities which may lead to better outcomes for patients. For critically ill patients, single ward is recommended when arranging and constructing.

Factors associated with outcome in a national cohort of rhinovirus hospitalized patients in Brazil in 2022

The common cold is the primary cause of illness in the community, with over 200 viral strains identified, and rhinovirus infections being the most prevalent. Coronavirus Disease 19 (COVID-19) is also a significant cause of severe illness. The burden of acute respiratory infections has a significant impact on the economy, resulting in absenteeism from work and school. Rhinovirus infections can exacerbate asthma and other chronic diseases, leading to hospitalization. The objective of this study is to investigate the factors associated with death and survival in patients hospitalized for rhinovirus in Brazil in 2022. This is a retrospective cohort study using data from the national surveillance of Severe Acute Respiratory Syndrome (SARS) in 2022 in Brazil, with all the norrifications. We analysed and compared clinical and epidemiological factors and outcomes between survivors and deaths in patients hospitalised for rhinovirus. The absolute and relative frequencies were calculated according to the states. Bivariate analysis was performed using chi-squared test and Fisher's exact test, while multivariate analysis was performed using COX regression. Out of 8,130 cases of SARS caused by rhinovirus, 291 (3.58%) resulted in death while 7839 (96.47%) patients survived. The factors associated with death were invasive ventilation (p- < 0.001 HR 4.888 CI 95% 3.816-6.262), bocavirus (p- < 0.001 HR 4.204 CI 95% 2.595-6.812), immunodepression/Immunosuppression (p- < 0.001 HR 2.417 CI 95% 1. 544-3, 786), COVID-19 (p- < 0.001 HR 2.167 CI 95% 1.495-3.142), chronic neurological diseases (p-0.007 HR 1.610 CI 95% 1.137-2.280), abdominal pain (p-0.005 HR 1.734 CI 95% 1.186-2.537), age (p- < 0.001 HR 1.038 CI 95% 1.034-1.042). The survival factors identified in this study were dyspnea (p = 0.005; HR 0.683; CI 95% 0.524-0.889), cough (p < 0.001; HR 0.603; CI 95% 0.472-0.769), and asthma (p = 0.052; HR 0.583; CI 95% 0.339-1.004). Additionally, the study found that receiving a COVID-19 booster dose was also a significant survival factor (p = 0.001; HR 0.570; CI 95% 0.415-0.784). The factors associated with death were similar to those in the literature, and the factors associated with survival were also similar, except for the booster dose of the COVID-19 vaccine, which we didn't find in any studies. Our study is the first to associate the full course of the COVID-19 vaccine with survival in those hospitalized for rhinovirus, regardless of COVID-19 and rhinovirus co-detection.

Comparing strategies for the mitigation of SARS-CoV-2 airborne infection risk in tiered auditorium venues

The COVID-19 pandemic demonstrated that reliable risk assessment of venues is still challenging and resulted in the indiscriminate closure of many venues worldwide. Therefore, this study used an experimental, numerical and analytical approach to investigate the airborne transmission risk potential of differently ventilated, sized and shaped venues. The data were used to assess the magnitude of effect of various mitigation measures and to develop recommendations. Here we show that, in general, positions in the near field of an emission source were at high risk, while the risk of infection from positions in the far field varied depending on the ventilation strategy. Occupancy, airflow rate, residence time, virus variants, activity level and face masks affected the individual and global infection risk in all venues. The global infection risk was lowest for the displacement ventilation case, making it the most effective ventilation strategy for keeping airborne transmission and the number of secondary cases low, compared to mixing or natural ventilation.

Seasonality of common respiratory viruses: Analysis of nationwide time-series data

BACKGROUND AND OBJECTIVE

Understanding the seasonal behaviours of respiratory viruses is crucial for preventing infections. We evaluated the seasonality of respiratory viruses using time-series analyses.

METHODS

This study analysed prospectively collected nationwide surveillance data on eight respiratory viruses, gathered from the Korean Influenza and Respiratory Surveillance System. The data were collected on a weekly basis by 52 nationwide primary healthcare institutions between 2015 and 2019. We performed Spearman correlation analyses, similarity analyses via dynamic time warping (DTW) and seasonality analyses using seasonal autoregressive integrated moving average (SARIMA).

RESULTS

The prevalence of rhinovirus (RV, 23.6%-31.4%), adenovirus (AdV, 9.2%-16.6%), human coronavirus (HCoV, 3.0%-6.6%), respiratory syncytial virus (RSV, 11.7%-20.1%), influenza virus (IFV, 11.7%-21.5%), parainfluenza virus (PIV, 9.2%-12.6%), human metapneumovirus (HMPV, 5.6%-6.9%) and human bocavirus (HBoV, 5.0%-6.4%) were derived. Most of them exhibited a high positive correlation in Spearman analyses. In DTW analyses, all virus data from 2015 to 2019, except AdV, exhibited good alignments. In SARIMA, AdV and RV did not show seasonality. Other viruses showed 12-month seasonality. We describe the viruses as winter viruses (HCoV, RSV and IFV), spring/summer viruses (PIV, HBoV), a spring virus (HMPV) and all-year viruses with peak incidences during school periods (RV and AdV).

CONCLUSION

This is the first study to comprehensively analyse the seasonal behaviours of the eight most common respiratory viruses using nationwide, prospectively collected, sentinel surveillance data.

Respiratory Disease Surveillance in the Middle East and Latin America during the COVID-19 Pandemic, 2020-2022

Characterizing the epidemiology of circulating respiratory pathogens during the COVID-19 pandemic could clarify the burden of acute respiratory infections and monitor outbreaks of public health and military relevance. The US Department of Defense supported 2 regions for influenza-like illness and severe acute respiratory infections surveillance, one in the Middle East through US Naval Medical Research Unit EURAFCENT, and another in Latin America through US Naval Medical Research Unit SOUTH. During 2020‒2022, coinciding with the COVID-19 pandemic, we collected a total of 16,146 nasopharyngeal and oropharyngeal swab samples from sentinel sites in Jordan (n = 11,305) and Latin America (n = 4,841). Samples were tested for SARS-CoV-2, influenza, and other respiratory pathogens. SARS-CoV-2 was the most frequently detected pathogen during 2020; other respiratory pathogens had distinct temporal and frequency distributions according to geographic location. Our findings support the need for continued sentinel surveillance as a vital tool for assessing the burden of respiratory diseases globally.

The Effect of Online Teaching on Vocal Health Among Saudi Teachers During COVID-19 Pandemic

PURPOSE

The goal of this study is to determine how online education affects the vocal health of schoolteachers in Saudi Arabia's Eastern Province. Teachers' phono trauma is well-known as a serious occupational hazard, and online education was the primary mode of delivering instruction to students during COVID-19.

METHODS

This is a descriptive cross-sectional study conducted among teachers in the Eastern Province area of Saudi Arabia. Teachers completed a self-administered questionnaire via an online platform, which included socio-demographic data, academic status, and the Voice Handicap Index-10 questionnaire, which assessed their vocal difficulties.

RESULTS

A total of 335 teachers responded to the survey (78.2% females vs. 21.8% males). Nearly half (48.7%) were primary school teachers. 45.7% were currently teaching distance learning. Earphones and microphones (49.3%) were the most commonly used distance learning accessories. Noise in the classroom was a very much disturbing factor in teaching implied by 44.8% of the teachers. During the COVID-19 pandemic, the vocal handicap index-10 was significantly higher among females (P = 0.007), primary school teachers (P < 0.001), moreover those currently teaching distance learning (P = 0.001) and those who perceived that there is more work in distance teaching (P < 0.001).

CONCLUSION

Compared to in-person teaching, online teaching may have a positive impact on vocal health among Saudi teachers. Of all the teachers, phono trauma tends to be more among females who were primary school teachers, currently teaching distance learning, and those who perceived distance learning to be laborious.

Identification of JC polyomavirus in upper respiratory samples from Portuguese children

Background

JC polyomavirus (JCPyV) is ubiquitous in the human population and the causative agent of a rare, fatal and demyelinating disease of the central nervous system named Progressive Multifocal Leukoencephalopathy (PML). The route of JCPyV transmission remains unclear, but high values of seroprevalence suggest an easy and frequent mode, such as respiratory route.

Objectives

The present study aims to investigate the presence of JCPyV in upper respiratory samples and contribute to the elucidation of the JCPyV transmission pathway.

Study design

Nasopharyngeal swabs from 587 Portuguese individuals, including 380 children (≤18 years) and 207 adults (>18 years), collected for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis between September and November 2021 were evaluated for the presence of JCPyV DNA.

Results

JCPyV DNA was detected in 3.1 % of the nasopharyngeal swabs analysed, with higher frequency of detection in samples from children (4.5 %) than from adults (0.5 %) (p = 0.005). Infection with SARS-CoV-2 does not potentiate the presence of JCPyV in upper respiratory tract, once only one adult of 28 years with confirmed SARS-CoV-2 infection showed detectable JCPyV DNA. JCPyV DNA was more frequently detected in respiratory samples from children without SARS-CoV-2 infection (6.4 %). As for this group, children under six years of age presents the highest frequency of detection (10.3 %).

Conclusions

The present study demonstrates that upper respiratory secretions of children, particularly under the age of six, may be implicated in JCPyV transmission, regardless of SARS-CoV-2 infection.

The circulating characteristics of common respiratory pathogens in Ningbo, China, both before and following the cessation of COVID-19 containment measures

To assess the circulating characteristics of common respiratory pathogens following the complete relaxation of non-pharmaceutical interventions (NPIs) and the cessation of the dynamic zero-COVID policy. The retrospective analysis was conducted from 14,412 patients with acute respiratory infections (ARIs) from January 24, 2020, to December 31, 2023, including Influenza A virus (IFV-A), Influenza B virus (IFV-B), Respiratory Syncytial Virus (RSV), Human Rhinovirus (HRV), Human Parainfluenza Virus (HPIV), Human Metapneumovirus (HMPV), Human Coronavirus (HCoV), Human Bocavirus (HBoV), Human Adenovirus (HAdV), and Mycoplasma pneumoniae (MP). Compared with 2020-2022, Joinpoint analysis indicated a monthly increase in overall pathogen activity in 2023, rising from an average of 43.05% to an average of 68.46%. The positive rates of IFV-A, IFV-B, HMPV, HPIV, HCoV, and MP increased, while those of HRV and RSV decreased, and no differences in HAdV and HBoV. The outbreak of IFV-A and MP was observed, the positive rate of MP has surpassed pre-COVID-19 pandemic levels and the spread of RSV was interrupted by IFV-A. Infants and toddlers were primarily infected by HRV and RSV, Children and adolescents exhibited a higher prevalence of infections with MP, IFV-A, and HRV, whereas Adults and the elderly were primarily infected by IFV-A. The incidence of co-infections rose from 4.25 to 13.73%. Restricted cubic spline models showed that the susceptible age ranges for multiple pathogens expanded. These changes serve as a reminder to stay alert in the future and offer clinicians a useful guide for diagnosing and treating.

Combating Emerging Respiratory Viruses: Lessons and Future Antiviral Strategies

Emerging viral diseases, including seasonal illnesses and pandemics, pose significant global public health risks. Respiratory viruses, particularly coronaviruses and influenza viruses, are associated with high morbidity and mortality, imposing substantial socioeconomic burdens. This review focuses on the current landscape of respiratory viruses, particularly influenza and SARS-CoV-2, and their antiviral treatments. It also discusses the potential for pandemics and the development of new antiviral vaccines and therapies, drawing lessons from past outbreaks to inform future strategies for managing viral threats.

Features that matter: Evolutionary signatures can predict viral transmission routes

Routes of virus transmission between hosts are key to understanding viral epidemiology. Different routes have large effects on viral ecology, and likelihood and rate of transmission; for example, respiratory and vector-borne viruses together encompass the majority of rapid outbreaks and high-consequence animal and plant epidemics. However, determining the specific transmission route(s) can take months to years, delaying mitigation efforts. Here, we identify the viral features and evolutionary signatures which are predictive of viral transmission routes and use them to predict potential routes for fully-sequenced viruses in silico and rapidly, for both viruses with no observed routes, as well as viruses with missing routes. This was achieved by compiling a dataset of 24,953 virus-host associations with 81 defined transmission routes, constructing a hierarchy of virus transmission encompassing those routes and 42 higher-order modes, and engineering 446 predictive features from three complementary perspectives. We integrated those data and features to train 98 independent ensembles of LightGBM classifiers. We found that all features contributed to the prediction for at least one of the routes and/or modes of transmission, demonstrating the utility of our broad multi-perspective approach. Our framework achieved ROC-AUC = 0.991, and F1-score = 0.855 across all included transmission routes and modes, and was able to achieve high levels of predictive performance for high-consequence respiratory (ROC-AUC = 0.990, and F1-score = 0.864) and vector-borne transmission (ROC-AUC = 0.997, and F1-score = 0.921). Our framework ranks the viral features in order of their contribution to prediction, per transmission route, and hence identifies the genomic evolutionary signatures associated with each route. Together with the more matured field of viral host-range prediction, our predictive framework could: provide early insights into the potential for, and pattern of viral spread; facilitate rapid response with appropriate measures; and significantly triage the time-consuming investigations to confirm the likely routes of transmission.

Artificial intelligence-based prediction of pathogen emergence and evolution in the world of synthetic biology

The emergence of new techniques in both microbial biotechnology and artificial intelligence (AI) is opening up a completely new field for monitoring and sometimes even controlling the evolution of pathogens. However, the now famous generative AI extracts and reorganizes prior knowledge from large datasets, making it poorly suited to making predictions in an unreliable future. In contrast, an unfamiliar perspective can help us identify key issues related to the emergence of new technologies, such as those arising from synthetic biology, whilst revisiting old views of AI or including generative AI as a generator of abduction as a resource. This could enable us to identify dangerous situations that are bound to emerge in the not-too-distant future, and prepare ourselves to anticipate when and where they will occur. Here, we emphasize the fact that amongst the many causes of pathogen outbreaks, often driven by the explosion of the human population, laboratory accidents are a major cause of epidemics. This review, limited to animal pathogens, concludes with a discussion of potential epidemic origins based on unusual organisms or associations of organisms that have rarely been highlighted or studied.

Air quality in a small city: criteria pollutants, volatile organic compounds, metals, and microbes

This work presents a year-long integral study of air quality parameters in Ciudad Real, a small city in the center of Spain, and its influence on the nearby national park, Las Tablas de Daimiel. The study covers meteorological parameters and criteria pollutants such as O3, NO, NO2, SO2, and PM10. Additionally, for each month, a 1-week campaign was performed sampling air in sorbent tubes with 8-h time resolution to analyze anthropogenic volatile organic compounds and the effects of seasons, daytime, and working-weekend days. During these campaigns, 24-h PM2.5 samples were also collected to measure the load of bacteria and fungi, as well as the trace concentrations of elements.The city and the national park NOx profiles showed that emissions from the town had a non-perceivable effect on the protected area. PM10 levels in Ciudad Real were influenced by Saharan intrusions, as was the national park; however, Ciudad Real had a higher contribution from anthropogenic sources. Ozone levels were lower in the city during the cold season due to the higher concentration of NOx and have not changed significantly in the last decade.The VOCs with higher average concentrations were toluene, m,p-xylene, benzene, methylene chloride, and o-xylene, with traffic being the main source of these pollutants in the city. For benzene and carbon tetrachloride levels, weak carcinogenic risks were estimated. In PM2.5, the most abundant metals were Na, Zn, Mg, Ca, Al, Fe, and K. The carcinogenic and non-carcinogenic risks estimated from the levels of the studied metals were negligible. Bacterial and fungal counts positively correlated with the concentration of PM2.5. Microbial community composition showed seasonal variability, with the dominance of human pathogenic bacteria which correlated with certain pollutants such as SO2. Bacillus and Cutibacterium were the most abundant genera.