Smart microfluidics: Synergy of machine learning and microfluidics in the development of medical diagnostics for chronic and emerging infectious diseases

The COVID-19 pandemic, emerging/re-emerging infections as well as other non-communicable chronic diseases, highlight the necessity of smart microfluidic point-of-care diagnostic (POC) devices and systems in developing nations as risk factors for infections, severe disease manifestations and poor clinical outcomes are highly represented in these countries. These POC devices are also becoming vital as analytical procedures executable outside of conventional laboratory settings are seen as the future of healthcare delivery. Microfluidics have grown into a revolutionary system to miniaturize chemical and biological experimentation, including disease detection and diagnosis utilizing muPads/paper-based microfluidic devices, polymer-based microfluidic devices and 3-dimensional printed microfluidic devices. Through the development of droplet digital PCR, single-cell RNA sequencing, and next-generation sequencing, microfluidics in their analogous forms have been the leading contributor to the technical advancements in medicine. Microfluidics and machine-learning-based algorithms complement each other with the possibility of scientific exploration, induced by the framework's robustness, as preliminary studies have documented significant achievements in biomedicine, such as sorting, microencapsulation, and automated detection. Despite these milestones and potential applications, the complexity of microfluidic system design, fabrication, and operation has prevented widespread adoption. As previous studies focused on microfluidic devices that can handle molecular diagnostic procedures, researchers must integrate these components with other microsystem processes like data acquisition, data processing, power supply, fluid control, and sample pretreatment to overcome the barriers to smart microfluidic commercialization.Copyright © 2023 by Begell House, Inc.

Electrostatic Precipitator Design Optimization for the Removal of Aerosol and Airborne Viruses

In the midst of the COVID-19 pandemic, new requirements for clean air supply are introduced for heating, ventilation, and air conditioning (HVAC) systems. One way for HVAC systems to efficiently remove airborne viruses is by filtering them. Unlike disposable filters that require repeated purchases of consumables, the electrostatic precipitator (ESP) is an alternative option without the drawback of reduced dust collection efficiency in high-efficiency particulate air (HEPA) filters due to dust buildup. The majority of viruses have a diameter ranging from 0.1 μm to 5 μm. This study proposed a two-stage ESP, which charged airborne viruses and particles via positive electrode ionization wire and collected them on a collecting plate with high voltage. Numerical simulations were conducted and revealed a continuous decrease in collection efficiencies between 0.1 μm and 0.5 μm, followed by a consistent increase from 0.5 μm to 1 μm. For particles larger than 1 μm, collection efficiencies exceeding 90% were easily achieved with the equipment used in this study. Previous studies have demonstrated that the collection efficiency of suspended particles is influenced by both the ESP voltage and turbulent flow at this stage. To improve the collection efficiency of aerosols ranging from 0.1 μm to 1 μm, this study used a multi-objective genetic algorithm (MOGA) in combination with numerical simulations to obtain the optimal parameter combination of ionization voltage and flow speed. The particle collection performance of the ESP was examined under the Japan Electrical Manufacturers' Association (JEMA) standards and showed consistent collection performance throughout the experiment. Moreover, after its design was optimized, the precipitator collected aerosols ranging from 0.1 μm to 3 μm, demonstrating an efficiency of over 95%. With such high collection efficiency, the proposed ESP can effectively filter airborne particles as efficiently as an N95 respirator, eliminating the need to wear a mask in a building and preventing the spread of droplet infectious diseases such as COVID-19 (0.08 μm–0.16 μm). © 2023 by the authors.

Effect of Elevator Design on the Risk Associated with COVID Transmission – A Comparative Study between a Sliding Door and a Collapsible Gate Elevator

The ominous spread of the COVID-19 pandemic is attributed to the droplets respired during coughing, sneezing or speaking. These droplets undergo evaporation to become aerosols, which, along with the larger droplets, are believed to ultimately spread the virus. In this current work, a small, enclosed region like an elevator (containing a COVID infected passenger) is considered where the risk of infection is high as the commonly practiced norm of social distancing is not possible. Numerical simulations are performed using OpenFOAM. Two different types of elevators – one equipped with a sliding door and the other with a collapsible gate, are considered and the change in droplet behavior is examined. Certain parameters pertaining to the risk of virus transmission have been quantified and assessed thoroughly, such as the percentage of droplets floating in the height range from a person's waist height to his mouth height, the radial span of the floating droplets from the infected passenger's mouth. From these parameters, the safety measures to be adopted by other copassengers can be determined. After an extensive study, it has been found that the collapsible gate elevator is safer than the sliding door elevator along with added advantages in the context of disease transmission. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Microscopic Droplet Size Analysis (MDSA) of "Five Thieves' Oil" (Olejek Pieciu Zlodziei) Essential Oil after the Nebulization Process.

Nowadays, due to a higher resistance to drugs, antibiotics, and antiviral medicaments, new ways of fighting pathogens are intensively studied. The alternatives for synthesized compositions are natural products, most of which have been known in natural medicine for a long time. One of the best-known and intensively investigated groups are essential oils (EOs) and their compositions. However, it is worth noting that the method of application can play a second crucial part in the effectiveness of the antimicrobial activity. EOs possess various natural compounds which exhibit antimicrobial activity. One of the compositions which is based on the five main ingredients of eucalyptus, cinnamon, clove, rosemary, and lemon is named "five thieves' oil" (Polish name: olejek pieciu zlodziei) (5TO) and is used in natural medicine. In this study, we focused on the droplet size distribution of 5TO during the nebulization process, evaluated by the microscopic droplet size analysis (MDSA) method. Furthermore, viscosity studies, as well as UV-Vis of the 5TO suspensions in medical solvents such as physiological salt and hyaluronic acid, were presented, along with measurements of refractive index, turbidity, pH, contact angle, and surface tension. Additional studies on the biological activity of 5TO solutions were made on the P. aeruginosa strain NFT3. This study opens a way for the possible use of 5TO solutions or emulsion systems for active antimicrobial applications, i.e., for surface spraying.

A Negative-Pressure Face-Mounted System Reduces Aerosol Spread during Endonasal Endoscopic Surgery.

Purpose Due to the potential risk of COVID-19 transmission during endonasal surgery, we studied methods to reduce droplet and aerosol generation during these procedures. Methods Droplet spread was assessed using ultraviolet light and a camera that detected fluorescence in the operative field and surgeon's personal protective equipment. Density of aerosols sized <10 µm was measured using a photometric particle counter. We designed a face-mounted negative-pressure mask placed on the patients' face during endoscopic endonasal surgery. Sixteen patients were recruited between October 2020 and March 2021 and randomly assigned to the mask and no-mask groups. We compared droplet spread and aerosols generated in both groups, with copious irrigation and continuous suction during drilling forming the mainstay of surgical technique in all cases. Results Droplet contamination due to direct spillage of fluorescein from the syringe was noted in two patients. Aerosol density rose during sphenoid drilling in both groups, with no significant difference when continuous suction and irrigation were employed (1.27 times vs. 1.07 times the baseline, p = 0 .248 ). Aerosol density rose significantly when suction and irrigation were interrupted in the no-mask group (44.9 times vs. 1.2 times, p = 0 .028) , which was not seen when the mask was used. Conclusion Aerosol generation increases during drilling in endonasal procedures and is a concern during this pandemic. The use of a rigid suction close to the drill along with copious irrigation is effective in reducing aerosol spread. The use of a negative pressure mask provides additional safety when inadvertent blockage of suction and inadequate irrigation occur.

On-Chip Nucleic Acid Purification Followed by ddPCR for SARS-CoV-2 Detection.

We developed a microfluidic chip integrated with nucleic acid purification and droplet-based digital polymerase chain reaction (ddPCR) modules to realize a 'sample-in, result-out' infectious virus diagnosis. The whole process involved pulling magnetic beads through drops in an oil-enclosed environment. The purified nucleic acids were dispensed into microdroplets by a concentric-ring, oil-water-mixing, flow-focusing droplets generator driven under negative pressure conditions. Microdroplets were generated with good uniformity (CV = 5.8%), adjustable diameters (50-200 µm), and controllable flow rates (0-0.3 µL/s). Further verification was provided by quantitative detection of plasmids. We observed a linear correlation of R2 = 0.9998 in the concentration range from 10 to 105 copies/µL. Finally, this chip was applied to quantify the nucleic acid concentrations of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The measured nucleic acid recovery rate of 75 ± 8.8% and detection limit of 10 copies/µL proved its on-chip purification and accurate detection abilities. This chip can potentially be a valuable tool in point-of-care testing.

Exploring the effects of ventilation and air-conditioned environments, on droplet and airborne transmission of SARS-COV-2

To assess the implications of air conditioning and ventilation on droplet and airborne transmission of SARS-COV-2, several scientific research databases were searched and cross-referenced. Then, an analysis was conducted on the findings pertinent to interaction between several environmental variables affected by HVAC systems and their effect on Virus transmission. The results suggest that airflow velocity may interfere with the trajectories of large respiratory droplets and aerosols. Lower relative humidity provided suitable conditions for virus survival whereas higher temperatures increased aerosol formation, but were detrimental to virus survival. Suboptimal temperatures and humidity can compromise pathogen filtration functions in the nose, while proper use of HVAC functions can help preserve them. Transmission of SARS-COV-2 is not affected solely by the virus's internal properties. Ambient conditions, whether natural or modified by HVAC systems can have a significant effect on the transmissibility and virulence of both the virus and virus-related sickness. The current infection prevention measures, such as social distancing, need to be revised in certain scenarios where natural ventilation or HVAC systems are involved. This will offer, hopefully, higher protection from infections with SARS-COV-2 and similar pathogens. © 2023 by the authors.

Aerosol-Generating Medical Procedures: Controversies in Definition, Risks, and Mitigation Strategies

An aerosol-generating medical procedure (AGMP) is any procedure performed on a patient that can induce the production of aerosols of various sizes, including droplet nuclei. AGMPs have become a subject of increasing interest during the COVID-19 pandemic for two critical reasons. First, AGMP likely increases the risk of transmission from patients infected with respiratory infections to healthcare personnel and other patients in their environment. Second, special risk mitigation strategies, including selection of specific types of personal protective equipment and environmental controls, are necessary to protect staff during the performance of AGMPs. Heightened awareness for AGMPs began during the 2003 severe acute respiratory syndrome (SARS) pandemic, where it was noted that, in outbreaks, many frontline HCWs had increased risk of contracting the virus related to certain procedures performed on the respiratory tract (Tran et al. PLoS One 7:e35797, 2012). Numerous clinical guidelines were published attempting to categorize and classify the risk associated with various AGMP. However, while numerous procedures have been identified as "aerosol generating, " the scientific evidence for the creation of aerosols associated with these procedures, the burden of potential viable microbes within the created aerosols, and the mechanism of transmission to the host have not been well studied (Davies et al. J Infect Prev 10:122-6, 2009). Almost 20 years later, there are still large gaps in knowledge around AGMPs - what defines them, what is the added risk associated with them, and which strategies are most effective at mitigating the risks associated with them. Here, we summarize the current knowledge around AGMPs including the types, risk, and mitigation strategies. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Estimation of infection fields and pathways for SARS-CoV-2 and its variant based on the relationship among dose-response function parameter, quantum emission rate, and basic reproductive number

The theoretical model of the relationship among dose-response function parameters, quantum emission rate, and basic reproductive number for SARS-CoV-2 was constructed. Then, using this model, infection fields and pathways for SARS-CoV-2 and its variant were estimated. The parameters of the time activity, the number of contacts by the microenvironments and groups, and the COVID-19 risk from multiple pathways in near and far fields were used. Consequently, in lower transmissibility, droplet spray transmission in the near field was dominant, whereas in higher transmissibility, transmission from inhalation of smaller aerosols in the far field was dominant. Moreover, it was suggested that transmission from droplet spray, indirect contacts, and inhalation of smaller aerosols in the near field and inhalation of smaller aerosols in the far field was dominant for the wild-type strain, while transmission from inhalation of smaller aerosols in the far field were dominant for the Delta variant. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

Detection of SARS-CoV-2 RNA in stool and urine specimens of COVID-19 positive patients by Droplet Digital RT-PCR (dd RT- PCR)

SARS-CoV-2 infected cases diagnosis is based on the count of realtime reverse transcription-polymerase chain reaction (RT-PCR). The widely used reverse transcription-polymerase chain reaction (RTPCR) method has some limitations for clinical diagnosis and treatment. However, there are only few reports on the detection of the viral load in the stool and urine samples. While information about other modes of transmission is relatively less, some published literature supporting the possibility of a faecal-oral mode of transmission has been accumulating. Objective(s): The current study's objective was to assess the performance of real-time RT-qPCR assay and a droplet digital RT-PCR (dd RT-PCR) for detecting SARS-CoV-2 in stool and urine specimens. Methodology: One hundred and seven paired samples from 107 COVID-19-confirmed patients were analysed by dd RT-PCR and RTPCR based target gene (N1 and N2). Stool and urine were collected from COVID Care Centers of Pune Region. RNA was isolated using MagMax magnetic beads base procedure for further analysis. Real Time RT-PCR and DD PCR was performed from all the patients. Result(s): In 107 patients, all the stool samples showed 100% positive concordance by both methods, the average of 28.88 cycle threshold (Ct) of RT-PCR was highly correlated with the average copy number of 327.10 copies/mul analyzed in ddPCR. Whereas 27.1% urine samples were tested positive in ddPCR & 1.86% were positive with the average of 36.41 cycle threshold (Ct) in RT-PCR. Using Pangolin COVID-19 Lineage Assigner variants were analyzed and found to be delta prevalent. Conclusion(s): In the context of the COVID-19 pandemic, environmental surveillance for the detection of SARS-CoV-2 has become increasingly important. The findings of this study not only show that SARS-CoV-2 is present in urine and faeces, but they also raise the possibility that low concentrations of the viral target may make it easier to identify positive samples and help resolve situations of inconclusive diagnosis.

IMPACT OF SARS-CoV-2-MEDIATED CD4 T CELL ACTIVATION AND HIV DNA PERSISTANCE IN VIVO

Background: Antigen-driven CD4+ T cell proliferation is a proposed mechanism of HIV-1 reservoir persistence. We previously reported that SARSCoV- 2 infection leads to increased detectable low-level HIV-1 plasm RNA blips months after COVID-19, but the impact of SARS-CoV-2-mediated T cell activation on expansion of HIV-1 reservoirs is not known. We sought to identify if SARSCoV- 2 infection leads to expansion of preferentially HIV-infected CD4+ T cells in people with HIV (PWH) on ART. Method(s): Five PWH with samples collected prior to and approximately two months after SARS-CoV-2 infection were identified. We performed a surface activation induced marker (AIM) assay using a CD4-optimized overlapping SARS-CoV-2 peptide pool to measure OX40/CD137 expression following peptide stimulation and sorted CD4+ T cells based on surface marker expression. ddPCR quantification of genomic HIV-1 DNA was performed on sorted subsets. Result(s): We observed an increase in the frequency of SARS-CoV-2 AIM+ non-naive CD4+ T cells following COVID-19 in samples from 4 of 5 participants (mean AIM+ % 0.13 pre- vs 0.31 post). A large percentage of non-naive AIM+ CD4+ T cells expressed PD1 compared with total non-naive cells before (76% vs 36%) and after (65% vs 19%) COVID-19;PD1 expression was lower following SARS-CoV-2 in both AIM+ and AIM- CD4+ T cell subsets (although very few cells were AIM+ prior to COVID-19). HIV-1 DNA levels in non-naive AIM- CD4+ T cells prior to COVID-19 unexpectedly decreased following infection (mean 3,522 to 766 copies/106 cells). The numbers of AIM+ cells obtained by cell sorting were overall low ( 3,863 mean) and only one participant had detectable DNA in post-COVID AIM+ CD4+ T cells. However, a large majority of this participant's post-COVID AIM+ cells harbored HIV-1 DNA (0.89 copies per cell) whereas HIV DNA in their AIM- cells decreased from 8,387 to not detected following SARSCoV- 2 infection. No HIV-1 DNA was detected in the small number of AIM+ cells obtained prior to COVID-19 in this participant. Conclusion(s): COVID-19 in PWH led to a modest SARS-CoV-2-specific CD4+ cell response approximately two months following acute presentation. One participant may have preferentially expanded HIV-1-infected, SARS-CoV-2- specific CD4+ T cells following COVID-19 but studies involving larger numbers of participants and larger numbers of cells will be needed to fully understand the impact of SARS-CoV-2 on clonal expansion and HIV persistence.

METFORMIN REDUCED SARS-CoV-2 VIRAL LOAD IN A PHASE 3 RANDOMIZED CLINICAL TRIAL

Background: Metformin has in vitro activity against SARS-CoV-2. In a published phase 3, quadruple-blinded, placebo-controlled randomized trial of outpatient COVID-19 therapy, metformin resulted in a 42% reduction in ER visits/hospitalizations/deaths by day 14, 58% reduction in hospitalizations/ death by day 28, and 42% reduction in Long Covid through 10 months. This analysis presents the results of viral load sampling performed during that clinical trial. Method(s): Covid-Out trial (NCT04510194) enrolled adults aged 30 to 85 within 3 days of a documented SARS-CoV-2 infection and < 7 days after symptom onset. The trial randomized 1323 participants to metformin (1000mg/day days 2-5;1500mg/day days 6 to 14), ivermectin, fluvoxamine, and/or exact-matching placebo in a 2x3 factorial trial design. Nasal swabs for viral load were an optional component, self-collected from the anterior nares on day 1, 5, and 10. Viral loads were measured via RT-qPCR using N1 and N2 targets in the SARSCoV- 2 nucleocapsid protein, with relative Ct values converted to absolute copy number via calibration to droplet digital PCR. A linear Tobit regression model was used to assess change over time while accounting for left censoring due to the viral load limit of detection. Results were adjusted for other treatment allocations within the factorial design, vaccination status, and baseline viral load. Repeated measures were accounted for using clustered standard errors within participants. Result(s): Samples were available from n = 945, 871, and 775 participants on days 1, 5, and 10, respectively. The mean change from baseline to followup was -0.64 log10 copies/mL (95%CI, -1.16 to -0.13) for metformin versus placebo, which equates to a 4.4-fold greater decrease. The mean change in SARS-CoV-2 from baseline to day 5 was -0.48 log10 copies/mL, and was -0.81 log10 copies/mL from baseline to day 10. The anti-viral effect increased with increased metformin dosing days 6-14. The antiviral effect was larger in those unvaccinated (mean -0.95 log copies/mL) than vaccinated (mean -0.39 log copies/mL). There was no change in viral load vs. placebo for ivermectin or fluvoxamine. Conclusion(s): Metformin lowered SARS-CoV-2 viral load in this quadrupleblinded, randomized clinical trial. The temporal relationship to dose titration suggests a dose-dependent effect. The magnitude of antiviral effect was similar to nirmatrelvir at day 5, greater than nirmatrelvir at day 10. Metformin is safe, widely available, and has few contraindications.

Nanomaterials and Biosensing Technology for the SARS-CoV-2 Detection

The outbreak of corona virus disease 2019 (COVID-19) has aroused great attention around the world. SARS-CoV-2 possesses characteristics of faster transmission, immune escape, and occult transmission by many mutation, which caused still grim situation of prevention and control. Early detection and isolation of patients are still the most effective measures at present. So, there is an urgent need for new rapid and highly sensitive testing tools to quickly identify infected patients as soon as possible. This review briefly introduces general characteristics of SARS-CoV-2, and provides recentl overview and analysis based on different detection methods for nucleic acids, antibodies, antigens as detection target. Novel nano-biosensors for SARS-CoV-2 detection are analyzed based on optics, electricity, magnetism, and visualization. In view of the advantages of nanotechnology in improving detection sensitivity, specificity and accuracy, the research progress of new nano-biosensors is introduced in detail, including SERS-based biosensors, electrochemical biosensors, magnetic nano-biosensors and colorimetric biosensors. Functions and challenges of nano-materials in construction of new nano-biosensors are discussed, which provides ideas for the development of various coronavirus biosensing technologies for nanomaterial researchers.

Virus-laden droplet nuclei in vortical structures associated with recirculation zones in indoor environments: A possible airborne transmission of SARS-CoV-2.

Droplet nuclei dispersion patterns in indoor environments are reviewed from a physics view to explore the possibility of airborne transmission of SARS-CoV-2. This review analyzes works on particle dispersion patterns and their concentration in vortical structures in different indoor environments. Numerical simulations and experiments reveal the formation of the buildings' recirculation zones and vortex flow regions by flow separation, airflow interaction around objects, internal dispersion of airflow, or thermal plume. These vortical structures showed high particle concentration because particles are trapped for long periods. Then a hypothesis is proposed to explain why some medical studies detect the presence of SARS-CoV-2 and others do not detect the virus. The hypothesis proposes that airborne transmission is possible if virus-laden droplet nuclei are trapped in vortical structures associated with recirculation zones. This hypothesis is reinforced by a numerical study in a restaurant that presented possible evidence of airborne transmission by a large recirculating air zone. Furthermore, a medical study in a hospital is discussed from a physical view for identifying the formation of recirculation zones and their relation with positive tests for viruses. The observations show air sampling site located in this vortical structure is positive for the SARS-CoV-2 RNA. Therefore, the formation of vortical structures associated with recirculation zones should be avoided to minimize the possibility of airborne transmission. This work tries to understand the complex phenomenon of airborne transmission as a way in the prevention of transmission of infectious diseases.

Influence of natural ventilation design on the dispersion of pathogen-laden droplets in a coach bus.

Natural ventilation is an energy-efficient design approach to reduce infection risk (IR), but its optimized design in a coach bus environment is less studied. Based on a COVID-19 outbreak in a bus in Hunan, China, the indoor-outdoor coupled CFD modeling approach is adopted to comprehensively explore how optimized bus natural ventilation (e.g., opening/closing status of front/middle/rear windows (FW/MW/RW)) and ceiling wind catcher (WCH) affect the dispersion of pathogen-laden droplets (tracer gas, 5 µm, 50 µm) and IR. Other key influential factors including bus speed, infector's location, and ambient temperature (Tref) are also considered. Buses have unique natural ventilation airflow patterns: from bus rear to front, and air change rate per hour (ACH) increases linearly with bus speed. When driving at 60 km/h, ACH is only 6.14 h-1 and intake fractions of tracer gas (IFg) and 5 µm droplets (IFd) are up to 3372 ppm and 1394 ppm with ventilation through leakages on skylights and no windows open. When FW and RW are both open, ACH increases by 43.5 times to 267.50 h-1, and IFg and IFd drop rapidly by 1-2 orders of magnitude compared to when no windows are open. Utilizing a wind catcher and opening front windows significantly increases ACH (up to 8.8 times) and reduces IF (5-30 times) compared to only opening front windows. When the infector locates at the bus front with FW open, IFg and IFd of all passengers are <10 ppm. More droplets suspend and further spread in a higher Tref environment. It is recommended to open two pairs of windows or open front windows and utilize the wind catcher to reduce IR in coach buses.

Study of Air Recirculation Zones in Shared Spaces

The Air borne transmission is a very big concern for highly infectious diseases like Covid-19 and other airborne diseases. A micro droplet and aerosol can be carried out in the air and can remain flowing in air over a distance in a confined space, leading to affecting high number of people getting prone to infection and it is very dangerous in enclosed spaces or shared spaces. Public places, shared facilities are the areas, where infectious aerosol can be present in the air for a long duration. Ventilation of closed spaces, shared spaces is the need of hour to have analysed and deep study in context of infectious airborne diseases. Introduction of fresh air into the enclosed environment at regular interval of times may lead to fast dilution of air present in the enclosed space. The prominent building codes and HVAC guidelines allows as to calculate ACPH (Air changes per hour) in an enclosed space as per the occupancy and flow rate. The age of air is the criteria to define the amount of air residing in the enclosed space when it enters the space till its exhaust from that space. The more the age of air in the particular area the more can be the infection probability among the occupants. It is predominant to study the airflow pattern caused due to ventilation which can be collaborated with age of air to know about the infection probability. Typically, a classroom geometry is assumed with inlet outlet boundary conditions where exhaust fan is playing a major role of displacement ventilation. Study of air recirculation zones and dead zones is the point of interest of this study. Computational fluid dynamics is the most powerful tool in the present era to study the air flow pattern in enclosed and shared spaces.Copyright © 2022, Anka Publishers. All rights reserved.

Medically important airborne viruses

Airborne viruses are dispersed and suspended in the air when an infected individual coughs or sneezes. These viruses spread easily, and inhalation by unsuspecting susceptible individuals may result in new infections, which are highly dependent on the host's immunity, inoculation dose, and duration of exposure. They do not exclusively infect humans as animals are also susceptible and control of these infections remains a huge public health concern. There has been an astronomic increase in the number and types of airborne viruses either as an emerging or a reemerging agent with the ability to mutate. Thus, the airborne viruses—measles, rhinovirus, hantavirus, influenza, mumps, varicella–zoster virus viral meningitis, and the coronaviruses—discussed herein comprise some of the medically important common airborne viral diseases. © 2023 Elsevier Inc. All rights reserved.

Early detection of recurrent HPV+ hypopharyngeal squamous cell carcinoma by circulating tumor DNA

Circulating tumor DNA is a liquid biomarker that offers a highly specific method to assess HPV-associated tumor burden via a blood draw. It has the potential for many clinical applications in cancer care, including prognostication, monitoring treatment response, and surveillance for disease recurrence. In this case report, we present a case of recurrent HPV-associated hypopharyngeal squamous cell carcinoma first detected by circulating tumor HPV DNA that demonstrates the role of circulating tumor HPV DNA tests in posttreatment surveillance and the utility of HPV testing in all HPV-mediated tumors, regardless of subsite.Copyright © 2023 Elsevier Inc.