Search Results (42)

Airborne viruses are a key driver of infectious disease transmission, highlighting the importance of reliable detection in public health surveillance. As atmospheric viral concentrations are very low, a sampler with a high viral collection efficiency is essential. Although multiple approaches for evaluating collection efficiency have been applied using various samplers, no standardized sampler has yet been developed. We previously developed a wet-type electrostatic precipitator (WT-ESP) and successfully collected severe acute respiratory syndrome coronavirus 2 from the public environment. However, its efficiency for quantitative collection of airborne viruses remains unclear. This study aimed to clarify the collection efficiency of the WT-ESP. We evaluated collection efficiency via two different approaches: direct spray, where virus-containing aerosols were sprayed directly into the WT-ESP inlet, and indirect spray, where aerosols were dispersed into a closed space and then collected using the sampler. The direct spray tests achieved 20.1–50.2% collection efficiency, whereas the indirect spray test achieved an efficiency <12%. These findings highlight that electrostatic precipitation has an advantage of enhancing collection efficiency compared with values reported for impingers in previous studies and provide preliminary insights into the collection efficiencies under direct and indirect spray conditions, providing foundational data that bridge the gap between both methods. Full article

The common swift is the most observed swift species in Germany. During the summer months in urban areas, juvenile swifts in need of help are frequently cared for in wild bird rescue centers. Providing adequate housing and veterinary treatment for hundreds of juvenile swifts can be very challenging for non-specialized organizations and contact with other bird species is often unavoidable. The knowledge about the transmission of infectious diseases between individuals of this bird species specialized in an airborne life and of other bird species is limited. In this presented case a wild juvenile common swift was hand-reared for about 17 days and was noticed to have increasing feather abnormalities in a wildlife rescue center with close proximity to other wild birds. At the time of the investigation, the swift was of an age of about 35 days, and in good physical condition. The affected body, wing, and tail feathers showed retentions of feather sheaths, malformation of the feather vane, and circumferential constrictions with feather loss. The virological examination of the dystrophic feathers revealed a positive result for the circovirus and a negative result for the polyoma-consensus-nested PCR. The detected sequence of the circovirus showed the highest identity in 300 base pairs of 83.11% to a Canary circovirus isolate in NCBI Blast analysis. In addition to a transmission between common swifts during the nestling phase, other wild bird species can be discussed as a possible source of the infection. Full article

Airborne and surface-residing microorganisms in indoor environments pose potential risks for infectious disease transmission. To address this issue, we developed a composite device combining a generator of vaporized free chlorine components with a fine particle removal filter. Field tests were conducted in occupied university classrooms to evaluate the device’s efficacy in reducing airborne bacterial loads. Airborne bacteria were sampled under three operational conditions [Electrolyzed (+)/Filter (+), Electrolyzed (−)/Filter (+), and Electrolyzed (−)/Filter (−)]. Significant reductions in bacterial counts were observed in the Electrolyzed (+)/Filter (+) condition, with a residual rate of 14.5% after 2.25 h (p = 0.00001). Additionally, surface contact tests demonstrated that vaporized free chlorine components, primarily consisting of hypochlorous acid (HOCl), reduced viable counts of E. coli, P. aeruginosa, and S. aureus by 59.0–99.7% even at a distance of 8.0 m. The concentrations of vaporized free chlorine components during operation remained within safe exposure limits (0–19 ppb), consistent with the effective range reported in prior literature (10–50 ppb). Computational fluid dynamics simulations confirmed the diffusion of vaporized free chlorine components throughout the room, including distant sampling points. These findings suggest the combined use of a vaporized free chlorine generator and a particulate filter effectively reduces microbial contamination in indoor environments, providing a promising approach for infection control in residential and public settings. Full article

The coronavirus (COVID-19) expanded rapidly and affected almost the whole world since December 2019. COVID-19 has an unusual ability to spread quickly through airborne viruses and substances. Taking into account the disease’s natural progression, this study considers that viral spread is unpredictable rather than deterministic. The continuous time Markov chain (CTMC) stochastic model technique has been used to anticipate upcoming states using random variables. The suggested study focuses on a model with five distinct compartments. The first class contains Lévy noise-based infection rates (termed as vulnerable people), while the second class refers to the infectious compartment having similar perturbation incidence as the others. We demonstrate the existence and uniqueness of the positive solution of the model. Subsequently, we define a stochastic threshold as a requisite condition for the extinction and durability of the disease’s mean. By assuming that the threshold value ${\mathbf{R}}_{\mathbf{0}}^{\mathbf{D}}$ is smaller than one, it is demonstrated that the solution trajectories oscillate around the disease-free state (DFS) of the corresponding deterministic model. The solution curves of the SDE model fluctuate in the neighborhood of the endemic state of the base ODE system, when ${\mathbf{R}}_{\mathbf{0}}^{\mathbf{P}}>1$ elucidates the definitive persistence theory of the suggested model. Ultimately, numerical simulations are provided to confirm our theoretical findings. Moreover, the results indicate that stochastic environmental disturbances might influence the propagation of infectious diseases. Significantly, increased noise levels could hinder the transmission of epidemics within the community. Full article

Airborne transmission has been implicated as a major route for the spread of microorganisms, causing infectious disease outbreaks worldwide. This has been emphasized by the recent COVID-19 pandemic, caused by the SARS-CoV-2 virus. There is thus an unmet need to develop technologies that arrest the spread of airborne infectious diseases by inactivating viruses in the air. In this study, the efficacy of two commercially available air ionizer systems for inactivating the bacteriophage MS2, which has been utilized as a surrogate of SARS-CoV-2 as well as a surrogate of noroviruses, was assessed. An experimental test apparatus similar to an HVAC duct system was utilized for the efficacy testing. Each of the two ionizer devices was challenged with viral aerosols of the bacteriophage MS2. The results indicate that the two ionizers were able to reduce the concentration of bacteriophage MS2 virus in the air by 82.02% and 81.72%, respectively. These results point to the efficacy of these ionizer devices in inactivating airborne microorganisms and thus making them an important tool in arresting the spread of infectious diseases. More studies are needed to assess their efficacy against other important airborne viruses such as influenza and strains of the SARS-CoV-2 virus. Full article

Recently, there has been a growing interest in understanding how respiratory particles spread within passenger cars, especially in light of ongoing challenges posed by infectious diseases. This study experimentally investigates dispersion patterns of respiratory airborne particles (<1 µm) within these confined spaces. The main objective is to introduce a manikin-based method for studying particle dispersion and assessing in-cabin air quality. To achieve this, a respiratory manikin as a particle source has been developed and tested under various use-cases, including variations in source emission (breathing vs. speaking), the HVAC ventilation mode (fresh and recirculation), and the blower level of the HVAC system (low and high). The findings reveal that for an infection source on the first row of the vehicle when cabin airflow originates from the front panel, the seat directly behind the particle source is associated with the highest particle exposure, while the seat adjacent to the source offers the lowest exposure. Among the tested configurations, the recirculation mode with an active HEPA filter and high blower level shows the lowest particle concentration at recipients’ breath levels during both breathing and speaking. These findings can be used to enhance the design of passenger cars to reduce the transmission of potentially pathogen-laden particles. Full article

(1) Background: Exposure to blood carries the risk of transmission of many infectious diseases. Healthcare workers (HCWs), including hospital-based medical students, face high and often under-reported rates of exposure to needlestick and sharps injuries. Previous studies have shown that students’ knowledge of infection control varies, highlighting the importance of pre-placement training. This study aims to assess knowledge, attitudes and practices regarding these risks in a population of medical students from Albania. (2) Methods: A validated questionnaire was administered to 134 medical students in an Italian hospital in May 2023. It assessed HBV vaccination status, adherence to infection control practices, knowledge of pathogen transmission, exposure incidents and attitudes towards infected patients. Three additional questions addressed air-borne transmission of tuberculosis and vaccination recommendations for healthcare workers. (3) Results: Most students (64%) reported being aware of occupational exposure risks. While 93% and 87%, respectively, recognised HIV and HBV as blood-borne pathogens, fewer recognised Treponema pallidum (44%). Awareness of post-exposure prophylaxis for HIV was high (85%), but although 75% reported having received training, only 45% felt it was adequate. Statistical analysis revealed an association between knowledge of infection control, awareness of pathogen transmission and understanding of the importance of vaccination. (4) Conclusions: Our study highlights gaps in medical students’ knowledge of occupational infections and highlights the need for improved pre-clerkship education. Improved education could reduce anxiety, ethical issues and misconceptions and promote safer healthcare practices. Full article

Non-human primates, due to their similarities in immune response to humans, are the preferred model for studying infectious processes and any associated cognitive impairments. Behavioral tests are indispensable for investigating pathogenesis in neuroinfections, especially those that do not manifest with noticeable clinical symptoms, as well as in the transition to a chronic form of the disease. Modeling viral infection requires specialized experimental conditions. Our work describes techniques for investigating mnemonic functions, tiredness, attentional focus, quick-wittedness, and basic behavioral responses in primates under the assumed conditions for infections with viruses that do not have an airborne route of transmission. It also outlines approaches to the training and selection of primates for virological research, as well as analyzing gender differences in learning abilities, the impact of housing conditions on the results, and the correlation between training success and behavioral test scores. These methods will allow a more detailed study of non-human primates as a model for researching cognitive and behavioral impairments under infectious and immune stress, as well as the design of less energy-intensive experiments for evaluating the efficacy and safety of therapeutic and prophylactic strategies at early stages of infection. Full article

COVID-19 is an airborne respiratory disease that mainly affects the lungs. To date, COVID-19 has infected 580 million people with a mortality of approximately 7 million people worldwide. The emergence of COVID-19 has also affected the infectivity, diagnosis, and disease outcomes of existing diseases such as influenza, TB, and asthma in human populations. These are airborne respiratory diseases with symptoms and mode of transmission similar to those of COVID-19. It was speculated that the protracted nature of the COVID-19 pandemic coupled with vaccination could impact other respiratory diseases and mortality. In this study, we analyzed the impact of COVID-19 on flu, tuberculosis (TB), and asthma. Our analyses suggest that COVID-19 has a potential impact on the mortality of flu, TB, and asthma. These impacts vary across before the COVID-19 era, during the peak period of the pandemic, and after vaccinations/preventive measures were implemented, as well as across different regions of the world. Overall, the spread of flu generally reduced during the pandemic, resulting in a reduced expenditure on flu-related hospitalizations, although there were sporadic spikes at setting times. In contrast, TB deaths generally increased perhaps due to the disruption in access to TB services and reduction in resources. Asthma deaths, on the other hand, only marginally varied. Collectively, the emergence of COVID-19 added extra cost to the overall expenditure on some respiratory infectious diseases, while the cost for other infectious diseases was either reduced or somewhat unaffected. Full article

The airborne transmission of disease relies on the ability of microbes to survive aerosol transport and, subsequently, cause infection when interacting with a host. The length of time airborne microorganisms remain infectious in aerosol droplets is a function of numerous variables. We present measurements of mass and heat transfer from liquid aerosol droplets combined with airborne survival data for Escherichia coli MRE162, an ACDP category 1 microorganism used as a model system, under a wide range of environmental conditions, droplet compositions and microbiological conditions. In tandem, these companion measurements demonstrate the importance of understanding the complex relationship between aerosol microphysics and microbe survival. Specifically, our data consist of the correlation of a wide range of physicochemical properties (e.g., evaporation rates, equilibrium water content, droplet morphology, compositional changes in droplet solute and gas phase, etc.), with airborne viability decay to infer the impact of aerosol microphysics on airborne bacterial survival. Thus, a mechanistic approach to support prediction of the survival of microorganisms in the aerosol phase as a function of biological, microphysical, environmental, and experimental (aerosol-generation and sampling) processes is presented. Specific findings include the following: surfactants do not increase bacteria stability in aerosol, while both the bacteria growth phase and bacteria concentration may affect the rate at which bacteria decay in aerosol. Full article

During the COVID-19 pandemic, microbiological controls neglected the spread of viruses through the air. Techniques to identify this threat required additional research to enable control measures to be introduced to protect against the spread of disease through this route. Due to the very high level of risk occurring during research on the COVID-19 and SARS-CoV-2 viruses, it seems necessary to use analogous microorganisms that will allow, through an experiment, to validate or challenge a method that stops the spread of infectious microorganisms, without unnecessary risk to research staff. The presented work was carried out to assess the possibility of using airborne microorganisms that are safe for humans for this type of research. The work presents the selection process of bacteria and viruses (bacteriophages) that have the greatest potential for use in experimental studies on airborne-droplet transmission indoors, especially in hospital facilities. In the study, it was assumed that determining the survival rates of groups of organisms would allow them to be used as a proxy for studying more dangerous bacteria and viruses. Survival studies of selected microorganisms were carried out, and the paper selected microorganisms with the highest survival rate in a given environment. Full article

The measurement of carbon dioxide (CO₂) has emerged as a cost-effective and straightforward technique for indirectly managing indoor air quality, aiding in the reduction of the potentially pathogen-laden aerosol concentrations to which we are exposed. Unfortunately, inadequate practices often limit the interpretation of CO₂ levels and neglect methodologies that ensure proper air renewal. This study presents a novel methodology for measuring and controlling indoor CO₂ levels in shared spaces, comprising four stages: analysis, diagnosis, correction protocols, and monitoring/control/surveillance (MCS). This methodology underwent validation in practical settings, including a cultural center (representing spaces with uniform activities) and 40 commercial spaces (with diverse activities) in Zaragoza, Spain. The results indicate the feasibility of swiftly implementing measures to enhance shared air renewal, with the immediate opening of doors and windows being the most direct solution. The proposed methodology is practical and has the potential to mitigate the risk of the aerosol transmission of respiratory diseases. Consequently, we anticipate that this work will contribute to establishing methodological foundations for CO₂ measurement as a valuable, standardized, and reliable tool. Full article

The year 2020 will likely be remembered as the year dominated by COVID-19, or coronavirus disease. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for this pandemic, can be traced back to late 2019 in China. The COVID-19 pandemic has significantly impacted the tuberculosis (TB) care system, reducing TB testing and reporting. This can be attributed to the disruption of TB services and restrictions on patient movement, consequently increasing TB-related deaths. This perspective review aims to highlight the intersection between COVID-19 and TB, highlighting their dual threat and identifying shared solutions to address these two infectious diseases effectively. There are several shared commonalities between COVID-19 and tuberculosis, particularly the transmission of their causative agents, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Mycobacterium tuberculosis. Both pathogens are transmitted via respiratory tract secretions. TB and COVID-19 are diseases that can be transmitted through droplets and airborne particles, and their primary target is typically the lungs. Regarding COVID-19 diagnostics, several methods are available for rapid and accurate detection. These include RT-PCR, which can provide results within two hours, and rapid antigen test kits that offer results in just a few minutes. The availability of point-of-care self-testing further enhances convenience. On the other hand, various approaches are employed for TB diagnostics to swiftly identify active TB. These include sputum microscopy, sputum for reverse transcription polymerase chain reaction (RT-PCR), and chest X-rays. These methods enable the rapid detection of active TB on the same day, while culture-based testing may take significantly longer, ranging from 2 to 8 weeks. The utilization of diverse diagnostic tools helps ensure the timely identification and management of COVID-19 and TB cases. The quality of life of patients affected by COVID-19 and tuberculosis (TB) can be significantly impacted due to the nature of these diseases and their associated challenges. In conclusion, it is crucial to emphasize the urgent need to address the dual threat of COVID-19 and TB. Both diseases have devastated global health, and their convergence poses an even greater challenge. Collaborative efforts, research investments, and policy reforms are essential to tackle this dual threat effectively. Full article

Many respiratory viruses, including influenza and SARS-CoV-2, are transmitted via the emission and inhalation of infectious respiratory aerosols in indoor environments. Resuspended particles from indoor surfaces and clothing can be a major source of airborne microbiological contaminants in indoor environments; however, it is unknown whether resuspended viruses contribute substantially to disease transmission. In this study, we investigated the resuspension via human walking activity of influenza A virus H3N2 laboratory strain, which was generated through a nebulizer into a sealed, unventilated biosafety level 2 (BSL-2) laboratory. The mean airborne viral concentrations following the resuspension events ($3.7\times {10}^3$ viral RNA copies ${\mathrm{m}}^{-3}$) were two orders of magnitude lower than those following direct emission via the nebulizer ($1.1\times {10}^5$ viral RNA copies ${\mathrm{m}}^{-3}$). The calculated resuspension emission factor (normalized ratio of the airborne mass to mass available for resuspension on the surface) of ${10}^{-3}$ was similar to reported values for 1–2 $\mathsf{\mu }$m particles. Thus, depending on the infectious dose and viability of the virus, resuspension of settled respiratory viruses could lead to transmission, but the risk appears to be much lower than for direct respiratory emissions. To our knowledge, this is the first full-scale experimental study designed to quantify virus resuspension. Full article

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly contagious and continues to spread worldwide. To avoid the spread of infection, it is important to control its transmission routes. However, as methods to prevent airborne infections are lacking, people are forced to take measures such as keeping distance from others or wearing masks. Here, we evaluate the antiviral activity of propylene glycol (PG), which is safe, odorless, and volatile. PG showed pronounced antiviral activity against the influenza virus (IAV) at concentrations above 55% in the liquid phase. Given its IAV inactivation mechanism, which involves increasing the fluidity of the viral membrane, PG is expected to have a broad effect on enveloped viruses. PG showed antiviral activity against SARS-CoV-2. We also developed a system to evaluate the antiviral effect of PG in spray and volatilized forms. PG was found to be effective against aerosol IAV in both forms; the effective PG concentration against IAV in the vapor phase was 87 ppmv (0.27 mg/L). These results demonstrate that PG is an effective means for viral inactivation in various situations for infection control. This technology is expected to control the spread of current and future infectious diseases capable of causing outbreaks and pandemics. Full article