Airborne Disease Research Articles

Waiting areas in tertiary-care hospitals in Pakistan, a major risk for airborne infections

Dear Madam, An airborne infection is any disorder transmitted through the air and caused by microorganisms including bacteria, viruses, and fungi. The most common disorders transmitted by this route include Tuberculosis, Influenza, Measles, Mumps, Coronavirus, MERS-Co V, Smallpox, Chickenpox, Aspergillosis, Blastomycosis, etc. According to the World Health Organization, “Airborne transmission of infectious agents refers to the transmission of disease caused by the dissemination of droplet nuclei that remain infectious when suspended in air over long distance and time” (1). In Pakistan, infections spread in this way also contribute to one of the major factors in the overall prevalence ratio of airborne diseases. Activities such as coughing, sneezing, and talking, which generate aerosolised particles can cause transmission. as. The possibility of spreading contagious disorders tremendously increases when susceptible individuals are placed together with index cases within confined spaces. Hospital waiting areas are among the most common confined spaces that could lead to airborne infections among individuals. (2) Personnel including patients, visitors and working staff are the most likely contributors of transmission sources in hospital boundaries. Other possible sources within the hospitals include dust or aerosols from the floor or furniture, potted plants or flowers, sinks, showers, or aspirating devices. Dust or infective aerosols from contaminated air-conditioning systems may also be a source of airborne infections (3). Airborne transmission in waiting areas of hospitals in Pakistan can be substantially reduced by taking a multi-faceted approach including environmental controls, administrative measures, usage of modern technologies, and personal protective strategies. The best way to prevent airborne infection in waiting areas is by using masks and hand sanitisers. Hand sanitisers should be placed at all the entrance and exit points of waiting areas. Improvement in the ventilatory system through natural and mechanical means plays a significant role in reducing airborne infections. Using extra doors and windows for better airflow is one of the natural ways to reduce infection. Mechanical ways to reduce airborne infection include installing high-efficiency particulate filters and air purifiers in waiting areas. The physical distance of the patients should be increased by increasing the space between seating arrangements. Separate waiting areas should be created for patients with respiratory infections and those without. Implementing screening checkpoints at the hospital entrance to separate patients with infectious diseases is also beneficial. In short, there is a need to resolve this issue for the betterment of health of patients as well as their families.

What was Killing Babies in Sundsvall? A Study of Infant Mortality Patterns Using Individual Level Cause of Death Data, 1860–1892

In this report, we analyse infant mortality in Sundsvall 1860–1892. The focus is on the pattern and development of causes of death with separate analyses of neonatal and post-neonatal mortality. Furthermore, we discuss the development of infant mortality in relation to possible determinants in the historical context in Sundsvall. The results show substantial differences between neonatal and post-neonatal mortality when it comes to causes of death as well as their seasonal pattern. For deaths in the first 28 days, a large proportion of the deaths were diagnosed as unknown disease or given vague and symptom-descriptive diagnoses. For post-neonatal mortality on the other hand, the dominant cause of death categories were water- and food-borne infections and air-borne infections. Water- and food-borne diseases had a very strong seasonal pattern with the peak in late summer — July and August. There is no indication that sanitary improvements in the 1880's led to fewer cases of diarrhoea. Mortality from air-borne diseases on the other hand was lowest during summer, instead peaking in the winter months.

Healthier Indoor Environments for Vulnerable Occupants: Analysis of Light, Air Quality, and Airborne Disease Risk

This study evaluates indoor environmental quality (IEQ) in childcare facilities, focusing on air quality and lighting—key factors affecting children’s health and development. The analysis examines a nursery in Seville, Spain, where continuous monitoring revealed challenges in maintaining suitable indoor conditions. Carbon dioxide (CO2) levels often surpassed Spanish standards (770 ppm) and stricter thresholds (550 ppm) for sensitive groups, peaking at nearly 1900 ppm. These concentrations are linked to possible cognitive impairments and increased airborne pathogen risks, with Attack Rates (ARs) exceeding 70%. Passive ventilation strategies, such as window openings, proved insufficient, emphasizing the need for Controlled Mechanical Ventilation (CMV) systems to ensure consistent air renewal while maintaining thermal comfort. Lighting assessments identified insufficient circadian stimulus during key periods. Excessive lighting during nap times disrupted rest, while morning daylight levels failed to provide adequate circadian stimulation. These findings stress the importance of integrating solar protection and dynamic daylight and electric lighting systems to align with children’s biological rhythms. This research highlights the urgent need for comprehensive IEQ strategies in childcare settings, combining advanced ventilation, hygrothermal management, and circadian-friendly lighting to create safer and healthier environments for young children.

Filtration efficiency of medical and community face masks against particles carrying SARS-CoV-2

Introduction: Airborne bioaerosols like SARS-CoV-2 can pose a significant threat to the respiratory system of humans. Airborne bioaerosols, such as SARS-CoV-2, pose significant respiratory risks. Wearing respiratory masks is a preventive measure to reduce exposure and control the transmission of airborne diseases. Hence, this study aims to assess the effectiveness of the masks in filtering airborne particulates, specifically those that carry SARS- CoV-2. Materials and methods: The filtration efficiency of three types of face masks was investigated for particulate matters in a laboratory setup using a custom-designed system, including a human head mannequin and controlled aerosol injection. Air samples were also collected from the breathing zone of COVID-19 patients in hospital settings, both with and without masks. Data analysis used Python tools, including Seaborn and Matplotlib, to generate visual insights. Results: The study findings revealed variations in particle penetration and filtration efficiency of the tested masks for particles and SARS-CoV-2 based on mask types. The particles smaller than 700 nm penetrated N95 masks by 4.61%, with efficiency reaching 99.2% as particle size increased. Particle filtration efficiency for other masks, including surgical masks, ranged from 31%-68%, and for cloth masks, it was between 28%-86%. Conclusion: The effectiveness of respiratory masks in preventing the transmission of airborne particles and viruses, like SARS-CoV-2, into the human respiratory system and regular use of suitable respiratory masks can help control disease transmission, especially in high-risk environments such as hospitals. In summary, using respiratory masks is essential in reducing the spread of airborne viruses and improving public health.

Volatile organic compounds of hoary stock are responsible for suppressing downy mildew of grape in an intercropping system

Grape downy mildew (Plasmopara viticola) is an air-borne disease and difficult to control. It has been observed that intercropping grapevines (Vitis vinifera) with aromatic plants can effectively suppress the airborne disease and volatile organic compounds (VOCs) from the aromatic plants are believed to have antimicrobial activities. In this study, a two-year field trial was established by intercropping grapevine and hoary stock (Matthiola incana) to evaluate the control of grape downy mildew. The field results showed that intercropping effectively suppressed grape downy mildew, particularly during the blooming stage of hoary stock. VOCs from hoary stock plants exhibited a dosage-dependent antimicrobial activity against grape downy mildew. To examine the role of VOCs, hoary stock plants were grown in an enclosed chamber, and VOCs were collected at the time points before and post blooming. The collected VOCs were subjected to gas chromatography-mass spectrometry (GC–MS) analysis and in vitro bioassays. Twenty-four VOCs found from pre-blooming and 36 VOCs from post-blooming hoary stock plants were identified. Seventeen VOCs demonstrated consistent inhibitory activities against P. viticola, including seven terpenoids, five benzenoids, and five aliphatics. Among the 17 VOCs, five were unique to post-blooming hoary stock, while 12 were common to both pre- and post-blooming hoary stock. The antimicrobial VOCs offers a potential eco-friendly alternative to managing downy mildew.

Open-set deep learning-enabled single-cell Raman spectroscopy for rapid identification of airborne pathogens in real-world environments.

Pathogenic bioaerosols are critical for outbreaks of airborne disease; however, rapidly and accurately identifying pathogens directly from complex air environments remains highly challenging. We present an advanced method that combines open-set deep learning (OSDL) with single-cell Raman spectroscopy to identify pathogens in real-world air containing diverse unknown indigenous bacteria that cannot be fully included in training sets. To test and further enhance identification, we constructed the Raman datasets of aerosolized bacteria. Through optimizing OSDL algorithms and training strategies, Raman-OSDL achieves 93% accuracy for five target airborne pathogens, 84% accuracy for untrained air bacteria, and 36% reduction in false positive rates compared to conventional close-set algorithms. It offers a high detection sensitivity down to 1:1000. When applied to real air containing >4600 bacterial species, our method accurately identifies single or multiple pathogens simultaneously within an hour. This single-cell tool advances rapidly surveilling pathogens in complex environments to prevent infection transmission.

Incipient and subclinical tuberculosis: a narrative review.

Mycobacterium tuberculosis has been known to infect humans for eons. It is an airborne infectious disease transmitted through droplet nuclei of 1 to 5 µm in diameter. Historically, tuberculosis (TB) was considered a distinct condition characterized by TB infection and active TB disease. However, recently, the concept of a dynamic spectrum of infection has emerged, wherein the pathogen is initially eradicated by the innate or adaptive immune system, either in conjunction with or independently of T cell priming. Other categories within this spectrum include TB infection, incipient TB, subclinical TB, and active TB disease. Various host- and pathogen-related factors influence these categories. Furthermore, subclinical TB can facilitate the spread of infection within the community. Due to its asymptomatic nature, there is a risk of delayed diagnosis, and some patients may remain undiagnosed. Individuals with subclinical TB may stay in this stage for an indeterminate period without progressing to active TB disease, and some may even experience regression. Early diagnosis and treatment of TB are essential to meet the 2035 targets outlined in the end-TB strategy. This strategy should also include incipient and subclinical TB. This review will focus on the definition, natural history, burden, trajectory, transmissibility, detection, and management of early-stage TB.

Molecular genotyping revealed the gene flow of Puccinia striiformis f. sp. tritici clonal lineage from Uzbekistan of Central Asia to Xinjiang of China

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an air-borne fungal disease, and its spores can be spread far away from its origin to colonize in new territory, causing inter-regional epidemics. Xinjiang not only is an important and independent epidemic region from other stripe rust epidemiological regions in China but also has distinguished Pst genetic structure and spatial features. However, the inoculum source of the rust in Xinjiang has remained unknown. It is not clear whether inocula in Central Asian countries migrate to Xinjiang and whether mutual gene flows possibly occur between both regions. We conducted a comparative population study of Pst populations in Xinjiang and Uzbekistan to better understand the Pst migration pattern and inoculum source of the rust in Xinjiang. Our results revealed high genetic diversity in Xinjiang (0.86, 63 MLGs out of 207 samples), compared with the Uzbekistan population (0.76, 47 MLGs out of 255 samples). Our analyses uncovered the clear migration of Uzbekistan Pst populations to Northwest Xinjiang, which is in proximity to Central Asia. The migration of clonal lineage could cause genetic drift and potential threat changing the genetic structure and virulence pattern of Pst in China. Further studies need to be conducted in the Xinjiang region to understand and evaluate the behavior of foreign genotypes in the local environment and their overall impact on local wheat crops.

Optimizing School Classroom Facades to Control Airborne Diseases Transmission through Human Centric-CFD Framework

Optimizing School Classroom Facades to Control Airborne Diseases Transmission through Human Centric-CFD Framework

Aerosol dynamics in dental clinics: Effects of ventilation mode on the mitigation of airborne diseases transmission.

Dental operations inherently involve a high risk of airborne cross-infection among medical staff and patients due to the exposure of respiratory secretions, which contain pathogenic microorganisms and typically spread in the form of aerosols. In order to contribute to the understanding of aerosol dynamics during dental operation and efficiently mitigate their dispersion and deposition through appropriate ventilation, 3D numerical simulations and full-scale experimental measurements were performed in this study. The indoor airflow distribution and dynamic aerosol behaviors observed under three optimized ventilation schemes (Scenario I-III) were compared with those observed under the current ventilation system. Qualitative analysis was performed together with quantitative examination using the air age, air change efficiency, contaminant removal effectiveness, and deposition ratio. It is demonstrated that the ventilation currently in use is unable to effectively discharge aerosols, resulting in most of them depositing on surfaces routinely accessed by dental workers. The pronounced air mixing effect induced by the design of Scenario I facilitates the rapid dispersion of aerosols throughout the clinic, impeding the efficient removal via the outlet. Moreover, the effective elimination of indoor aerosols is only attainable by implementing high ventilation rates in Scenario II. The Scenario III exhibits better overall performance, as evidenced by the successful discharge of approximately 69.8% of injected aerosols with limited deposition on indoor surfaces under ACH=6h-1, and further enhanced performance is observed at higher ACHs for contaminant removal. The prevailing ventilation design in dental clinics, which primarily focuses on maintaining a desirable temperature and relative humidity, often overlooks the necessity of proper ventilation for reducing the exposure risk of occupants. This study provides solid evidence for the upgrading or reconstruction of ventilation systems in dental clinics, aiming to promote a safe and healthy treatment environment.

Duration of transients in outbreaks: when can infectiousness be estimated?

We investigate sub-leading orders of the classic SEIR-model using contact matrices from modeling of the Omicron and Delta variants of COVID-19 in Denmark. The goal of this is to illustrate when the growth rate, and by extension the infection transmission potential (basic or initial reproduction number), can be estimated in a new outbreak, e.g. after introduction of a new variant of a virus. In particular, we look at the time scale on which this happens in a realistic outbreak to guide future data collection. We find that as long as susceptible depletion is a minor effect, the transients are gone within around 3 weeks corresponding to about 4-5 times the incubation time. We also argue that this result generalizes to other airborne diseases in a fully mixed population.

Pressure Difference Measuring System for Clean Rooms

This article presents the development and implementation of a pressure difference measuring system tailored for clean rooms, essential in medical facilities to control airflow and reduce nosocomial infections. The study evaluates various pressure sensors, leading to the selection of intelligent sensors that meet specific performance criteria. Key features and operating principles of the system are outlined, including sensor types, measurement techniques, and system architecture. A detailed comparison of sensors such as BMP180 and BMP280 highlights their suitability based on parameters like resolution, power consumption, and communication interfaces. The system’s structure includes dual pressure sensor units connected to a main control unit, enabling real- time pressure monitoring across different room zones. The sensors, equipped with a microcontroller for initial data processing, relay information to the control unit for further analysis and display. Designed with a calibration feature, the system ensures measurement accuracy by allowing recalibration under identical atmospheric conditions. Operating on low voltage, the system provides safe and reliable performance with applications extending to isolation rooms and environments requiring precise pressure regulation. Integrating the measuring system with ventilation systems significantly mitigates the risk of airborne disease transmission, contributing to the maintenance of sterile environments. The article concludes that this cost-effective, intelligent pressure monitoring solution not only enhances safety in healthcare settings but also supports regulatory compliance and improves overall infection control measures in high-risk areas.

Wavelength-Dependent DNA Damage Induced by Single Wavelengths of UVC Light (215 to 255 nm) in a Human Cornea Model.

Scientific bodies overseeing UV radiation protection recommend safety limits for exposure to ultraviolet light in the workplace based on published peer-reviewed data. To support this goal, a 3D model of the human cornea was used to assess the wavelength dependence of corneal damage induced by UVC light. In the first set of experiments the models were exposed with or without simulated tears; at each wavelength (215-255 nm) cells with DNA dimers and their distribution within the epithelium were measured. Simulated tears reduced the fraction of damaged cells to an extent dependent on the wavelength and tissue layer. Another set of models were exposed without tears; yields of DNA-damaged cells and their distribution within the corneal epithelium were evaluated at each wavelength, together with other markers of cell and tissue integrity. Unlike relatively longer wavelengths, the range commonly referred to as far-UVC (215-235 nm) only induced dimers in the uppermost layers of the epithelium and did not result in lasting damage or halt proliferation of the germinative cells. These results provide evidence for the recommended exposure limits for far-UVC wavelengths, which have been proposed as a practical technology to reduce the risk of transmission of airborne diseases in occupied locations.

Human exhalation characterization: Techniques and implications for airborne disease transmission

Human exhalation characterization: Techniques and implications for airborne disease transmission

Impact of room heat load on ventilation effectiveness and probability of transmission of airborne diseases on the example of chosen scenarios

Impact of room heat load on ventilation effectiveness and probability of transmission of airborne diseases on the example of chosen scenarios

In-vehicle air quality in public buses during real-world trips in Kathmandu Valley, Nepal

Urban air quality shows notable variability across various microenvironments. Transport-related microenvironments often have one of the highest air pollution levels, where commuters have significant exposure to air pollutants. In Kathmandu Valley (KV), Nepal, passengers’ exposure to air pollutants in such microenvironments remain a poorly understood issue. In this study, we analyzed cabin air quality and ventilation rates in public buses operated in KV. In-cabin and in-route ambient air pollution levels were monitored during real-world bus operations in 32 trips on a test route selected in the core city area. A CO2 mass balance model was applied to estimate cabin ventilation rates. The mean in-cabin and outdoor PM2.5 concentrations were 95.9 ± 40.4 (mean ± standard deviation) and 94.7 ± 32.4 μg/m3, respectively. Likewise, mean in-cabin and outdoor PM1 concentrations were 72.5 ± 31.3 and 69.7 ± 25.3 μg/m3, respectively, with mean PM1 to PM2.5 ratio >0.75, indicating that a majority of particle mass was in the sub-micron size range, which is often more health-hazardous. We estimated passengers’ inhalation dose for PM2.5 and PM1 as 5.65 ± 2.32 and 4.27 ± 1.79 μg/km, respectively. Among various factors considered, traffic hour significantly affected both in-cabin and ambient particulate matter concentrations. The trip-average in-cabin CO2 concentration ranged from 513 to 1230 ppm, whereas cabin ventilation rates ranged from 8.0 to 72.4 L/s/person. Ventilation levels in a majority of bus trips were inadequate, especially considering the recommended thresholds to reduce the transmission risk of airborne diseases. Setting standards for ventilation and air conditioning systems in public buses is crucial to ensure thermal comfort, protect bus commuters from the harmful impacts of air pollution, and to improve public transport services in KV.

Breathing time: a longue-durée multidisciplinary study of respiratory illnesses and airborne diseases in Switzerland (16th-21st century CE).

This research is the first of its kind to assess of the impact of respiratory illnesses and airborne diseases (acronymized as "RIAD" hereafter) on Swiss mortality in the long run, between the 16th and the 21st century CE. It reviews historical, demographical, statistical, medical, and bioarchaeological, primary and secondary data originating from archive material or previously published specific analyses into the topic (n = 55). An innovative intersectional and multidisciplinary approach was developed in order to apprehend, collect, organize, and analyze data stemming from several different disciplinary fields. Through this approach, this research endeavors to answer the following questions: 1) what are the social and environmental factors guiding the risk or not of suffering from RIAD, 2) do these factors appear to be constant on a territorial scale and through time, 3) can the evolution of RIAD occurrences be correlated to the local history of a particular region? And 4) does a better understanding of RIAD dynamics in the past allow us to draw any useful lessons for their future sustainable management? Accordingly, collected raw data were converted and normalized into crude mortality, natality, and RIAD mortality rates per thousand individuals and subsequently set within the demographic and epidemiological transition model. This model serves as a relevant reading grid for the understanding of the pathological and demographic evolutions that this study highlights. Indeed, this data compilation effort enabled to reconstruct crude birth and death rates for Switzerland from 1580 CE to the present day and to present the latter in graphical form. This graphical presentation is a breakthrough in the field of RIAD research in Switzerland and further enabled to assess internal data coherence and trend evolutions by means of joinpoint regression analysis. Main results include the confirmation of the considerable impact of industrialization on the respiratory health of peri-alpine populations. They also underline the selective and versatile nature of the pressure exerted by respiratory diseases on specific socio-economic and demographic classes, whose composition has varied through time. This research was impeded by the uneven quality of the available sources. Nonetheless, it still provides a robust outlook on the longue-durée evolution of respiratory health. The obtained results might thus be of interest to a wide array of scholars active in the study of respiratory diseases through time, but also clinicians and health policy makers, as this study highlights particular aspect of the current health situation, and the future worldwide challenges posed notably by global urbanization, with regard to respiratory health issues. Future research could develop similar approaches in neighboring regions, or focus on specific types of RIAD, in order to contrast other local pathological signatures with the one presented in this manuscript.

Quantum Congestion Game for Overcrowding Prevention Within Airport Common Areas

Quantum game theory merges principles from quantum mechanics with game theory, exploring how quantum phenomena such as superposition and entanglement can influence strategic decision making. It offers a novel approach to analyzing and optimizing complex systems where traditional game theory may fall short. Congestion of passengers, if considered as a network, may fall into the categories of optimization cases of quantum games. This paper explores the application of quantum potential games to minimize congestion in common areas at airports. The players/passengers of the airport have identical interests and they share the same utility function. A metric is introduced that considers a passenger’s visit to a common area by setting their preferences, in order to avoid congestion. Passengers can decide whether to visit a specific common area or choose an alternative. This study demonstrates that the proposed game is a quantum potential game for tackling congestion, with identical interests, ensuring the existence of a Nash equilibrium. We consider passengers to be players that want to ensure their interests. Quantum entanglement is utilized to validate the concept, and the results highlight the effectiveness of this approach. The objective is to ensure that not all passengers select the same common place of the airport to reduce getting crowded; hence, the airborne disease infection probability increases due to overcrowding. Our findings provide a promising framework for optimizing passenger flow and reducing congestion in airport common areas through quantum game theory. We showed that the proposed system is stable by encapsulating the Lyapunov stability. We compared it to a simulated annealing approach to show the efficacy of the quantum game approach. We acknowledge that this framework can be utilized in other disciplines as well. For our future work, we will research different strategies than binary ones to investigate the efficacy of the approach.

Modelling indoor airborne transmission combining architectural design and people movement using the VIRIS simulator and web app

A Viral Infection Risk Indoor Simulator (VIRIS) has been developed to quickly assess and compare mitigations for airborne disease spread. This agent-based simulator combines people movement in an indoor space, viral transmission modelling and detailed architectural design, and it is powered by topologicpy, an open-source Python library. VIRIS generates very fast predictions of the viral concentration and the spatiotemporal infection risk for individuals as they move through a given space. The simulator is validated with data from a courtroom superspreader event. A sensitivity study for unknown parameter values is also performed. We compare several non-pharmaceutical interventions (NPIs) issued in UK government guidance, for two indoor settings: a care home and a supermarket. Additionally, we have developed the user-friendly VIRIS web app that allows quick exploration of diverse scenarios of interest and visualisation, allowing policymakers, architects and space managers to easily design or assess infection risk in an indoor space.

A subunit vaccine based on P97R1, P46, P42, and P65 from Mycoplasma hyopneumoniae can induce significant immune response in piglets.

Mycoplasma pneumonia (MPS), caused by Mycoplasma hyopneumoniae (Mhp), is a chronic, airborne respiratory disease that poses a significant threat to the global swine industry. The P97 and P46 proteins are major antigens of Mhp, with the R1 region of P97 possessing full adhesive capability. Studies have shown that the main antigenic regions of Mhp P42 and P65 proteins exhibit strong immunogenicity. In this study, we first linked the genes encoding P97R1 and P46 proteins to form the P97R1P65 gene and subsequently constructed three shuttle plasmids: pFBD-P97R1P46, pFBD-P97R1P46-p65, and pFBD-P65-P42. These proteins were expressed using the Bac to Bac system and formulated into subunit vaccines for mouse immunization. Mouse experiments indicated that the P97R1P46 + P65-P42 protein combination elicited higher levels of specific antibodies, IL-2, IL-4, and CD8+ T cells compared to other subunit vaccine groups, a finding further validated in subsequent mouse challenge protection experiments. Therefore, we utilized the MultiBac expression system to co-express P97R1P46, P65, and P42 proteins in the pFastMultibacDual vector for immunization experiments in piglets. The piglet immunization experiments demonstrated that the Mhp subunit vaccine prepared in this study could induce specific antibodies against Mhp, with the combination of P97R1P46, P65, and P42 proteins inducing the highest level of humoral immunity. This study provides valuable insights for the development of Mhp subunit vaccines.