Virus In Air Research Articles

Detection of active SARS-CoV-2 in cough aerosols from COVID-19 patients

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an airborne pathogen, but detection of infectious SARS-CoV-2 in air and in particular the introduction of the virus into the environment by different human expiratory manoeuvres is not well studied. Objectives The aim of this study was to investigate the presence of SARS-CoV-2 in cough from coronavirus disease of 2019 (COVID-19) in-patients and to study contamination of the virus in the patient’s environment. Methods Detection of SARS-CoV-2 in cough was analyzed by PCR, culture and imaging. Detection in cough was compared to presence of the virus in air and on surfaces from patient rooms. Results Twenty-five patients in 21 rooms were included in the study. SARS-CoV-2 RNA was found in cough aerosols from 16 out of 22 patients that produced voluntary cough. As demonstrated by plaque-forming unit assays, active virus was isolated from 11 of these 16 patients. Using mainly molecular detection, the virus was also found in air, on high-contact surfaces, and no-touch surfaces from the room of the COVID-19 patients. Conclusions These results show that infectious SARS-CoV-2 circulating in air can originate from patient cough and should be considered against the risk of acquiring COVID-19 through inhalation.

Wearable MXene‐Graphene Sensing of Influenza and SARS‐CoV‐2 Virus in Air and Breath: From Lab to Clinic

AbstractThe rapidly expanding severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and its variants demand a continuous monitoring method through portable and wearable devices. Utilizing the rich surface chemistry and high chemical‐to‐electrical signal conversion of 2D MXene‐graphene heterostructure thin films, a field‐effect‐transistor (FET) sensor, which has a flexible substrate to be assembled onto the mask and combines with a Bluetooth system for wireless transmission is developed, to detect the influenza and SARS‐CoV‐2 viruses in air and breath. At first, the developed sensors are examined in the laboratory through direct contact with sensing targets in solution form. The results show a low limit of detection (LOD) of 1 fg mL−1 for recombinant SARS‐CoV‐2 spike protein and 125 copies mL−1 for inactivated influenza A (H1N1) virus with high specificity in differing recombinant SARS‐CoV‐2 spike protein and inactivated H1N1 virus. Then the sensors are tested under various simulated human breathing modes through controlled exposure to atomizer‐generated aerosols in an enclosed chamber and mask coverage. The results show the high sensitivity of the developed sensors under varying distances to the source, viral load, flow rate, and enclosed conditions. At last, clinical tests are carried out to demonstrate the robustness and potential field applications of the sensors.

Droplet digital PCR application for the detection of SARS-CoV-2 in air sample.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) may transmit through airborne route particularly when the aerosol particles remain in enclosed spaces with inadequate ventilation. There has been no standard recommended method of determining the virus in air due to limitations in pre-analytical and technical aspects. Furthermore, the presence of low virus loads in air samples could result in false negatives. Our study aims to explore the feasibility of detecting SARS-CoV-2 ribonucleic acid (RNA) in air samples using droplet digital polymerase chain reaction (ddPCR). Active and passive air sampling was conducted between December 2021 and February 2022 with the presence of COVID-19 confirmed cases in two hospitals and a quarantine center in Klang Valley, Malaysia. SARS-CoV-2 RNA in air was detected and quantified using ddPCR and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The comparability of two different digital PCR platforms (QX200 and QIAcuity) to RT-PCR were also investigated. Additionally negative staining transmission electron microscopy was performed to visualize virus ultrastructure. Detection rates of SARS-CoV-2 in air samples using ddPCR were higher compared to RT-PCR, which were 15.2% (22/145) and 3.4% (5/145), respectively. The sensitivity and specificity of ddPCR was 100 and 87%, respectively. After excluding 17 negative samples (50%) by both QX200 and QIAcuity, 15% samples (5/34) were found to be positive both ddPCR and dPCR. There were 23.5% (8/34) samples that were detected positive by ddPCR but negative by dPCR. In contrast, there were 11.7% (4/34) samples that were detected positive by dPCR but negative by ddPCR. The SARS-CoV-2 detection method by ddPCR is precise and has a high sensitivity for viral RNA detection. It could provide advances in determining low viral titter in air samples to reduce false negative reports, which could complement detection by RT-PCR.

Novel Virus Air Sampler Based on Electrostatic Precipitation and Air Sampling of SARS-CoV-2.

The assessment of airborne viruses in air is a critical step in the design of appropriate prevention and control measures. Hence, herein, we developed a novel wet-type electrostatic air sampler using a viral dissolution buffer containing a radical scavenging agent, and verified the concentration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in the air of hospital rooms inhabiting coronavirus disease 2019 (COVID-19) patients and public areas. RNA damage caused by corona discharge was negligible when Buffer AVL was used as the collecting electrode. The viral RNA concentration in the air of the room varied by patient: 3.9 × 103 copy/m3 on the 10th day after onset in a mild case and 1.3 × 103 copy/m3 on the 18th day in a severe case. Viral RNA levels were 7.8 × 102 and 1.9 × 102 copy/m3 in the air of the office and food court, respectively, where people removed their masks when eating and talking, but it remained undetected in the station corridor where all the people were wearing masks. The assessment of airborne SARS-CoV-2 RNA using the proposed sampler can serve as a basis for the safe discontinuation of COVID-19 isolation precautions to identify exposure hotspots and alert individuals at increased infection risks.

Characteristics of collection and inactivation of virus in air flowing inside a winding conduit equipped with 280 nm deep UV-LEDs

A general-purpose virus inactivation unit that can inactivate viruses was developed using deep ultraviolet (DUV) LEDs that emit DUV rays with a wavelength of 280 nm. The inside of the virus inactivation unit is a rectangular conduit with a sharp turn of 180° (sharp-turned rectangular conduit). Virus inactivation is attempted by directly irradiating the air passing through the conduit with DUV rays. The flow characteristics of air and virus particles inside the virus inactivation unit were investigated using numerical simulations. The air was locally accelerated at the sharp turn parts and flowed along the partition plate in the sharp-turned rectangular conduit. The aerosol particles moving in the sharp-turned rectangular conduit were greatly bent in orbit at the sharp turn parts, and then rapidly approached the partition plate at the lower part of the conduit. Consequently, many particles collided with the partition plates behind the sharp-turn parts. SARS-CoV-2 virus was nebulized in the virus inactivation unit, and the RNA concentration and virus inactivation rate with and without the emission of DUV-LEDs were measured in the experiment. The concentration of SARS-CoV-2 RNA was reduced to 60% through DUV-LED irradiation. In addition, SARS-CoV-2 passing through the virus inactivation unit was inactivated below the detection limit by the emission of DUV-LEDs. The virus inactivation rate and the value of the detection limit corresponded to 99.38% and 35.36 TCID50/mL, respectively.

Assessment of rotavirus and norovirus emitted from water spray park: QMRA, diseases burden and sensitivity analysis

A quantitative model on exposure to pathogenic viruses in air of recreational area and their corresponding health effects is necessary to provide mitigation actions in content of emergency response plans (ERP). Here, the health risk associated with exposure to two pathogenic viruses of concern: Rotavirus (RoV) and Norovirus (NoV) in air of water spray park were estimated using a quantitative microbial risk assessment (QMRA) model. To this end, real-time Reverse Transcriptase polymerase chain reaction (real-time RT-PCR) was employed to measure the concentration levels of RoV and NoV over a twelve-month period. The probability of infection, illness and diseases burden of gastrointestinal illness (GI) caused by RoV and NoV for both workers and visitors were estimated using QMRA and Monto-Carlo simulation technique. The annual mean concentration for RoV and NoV in sampling air of water spray park were 20and 1754, respectively. The %95 confidence interval (CI) calculated annual DALY indicator for RoV (Workers: 2.62 × 10−4–2.62 × 10−1, Visitors: 1.50 × 10−5–2.42 × 10−1) and NoV (Workers: 5.54 × 10−3–2.53 × 10−1; Visitors: 5.18 × 10−4–2.54 × 10−1) were significantly higher the recommended values by WHO and US EPA (10−6–10−4 DALY pppy). According to sensitivity analysis, exposure dose and disease burden per case (DBPC) were found as the most influencing factors on disease burden as a consequences of exposure to RoV and NoV, respectively. The comprehensive information on DALY and QMRA can aid authorities involved in risk assessment and recreational actions to adopt proper approach and mitigation actions to minimize the health risk.

Implication of cell culture methods and biases on UV inactivation of viruses

Inactivation of human respiratory viruses in air and on surfaces is important to control their spread. Exposure to germicidal ultraviolet (UV-C) light damages viral nucleic acid rendering them non-infectious. Most of the recent viral inactivation studies have not considered potential artifacts caused by interactions between UV-C light and culture media used to suspend and deposit virus on surfaces. We show that the reactive oxygen and nitrogen species (ROS and RNS) form when commonly used virus culture media is exposed to 265 nm irradiation from light emitting diodes (LEDs) at UV-C doses (4 or 40 mJ/cm2) commonly considered to achieve multiple log-inactivation of virus. Surface viral inactivation values were enhanced from 0.49 to 2.92 log10 of viruses in DMEM, EMEM or EMEM-F as compared to absence of culture media (only suspended in Tris-buffer). The mechanisms responsible for the enhanced surface inactivate is hypothesized to involve photo-activation of vitamins and dyes present in the culture media, deposited with the virus on surfaces to be disinfected, which produce ROS and RNS. Given the rapidly growing research and commercial markets for UV-C disinfecting devices, there is a need to establish surface disinfecting protocols that avoid viral inactivation enhancement artifacts associated with selection and use of common cell culture media in the presence of UV-C light. This study addresses this weak link in the literature and highlights that inadequate selection of virus suspension media may cause a bias (i.e., over-estimation) for the UV-C dosages required for virus inactivation on surfaces.

SARS-CoV-2 computer simulation of sterilization via electrical resistance in air conditioning

In search of reinvention in the middle of the pandemic, an equipment adapted from a system that controls morph for indoor environments that have air conditioners is proposed. This paper presents a study via computational modeling to test the effect of electrical resistance as an air filter against SARS-CoV-2. The mode of transmission of SARS-CoV-2 includes, for example, transmission via contact, droplets, and aerosols present in indoor humidity. Therefore, aerosol spread of SARS-CoV-2 is similar to the indoor spread of the morph. The result shows that the system works by eliminating the humidity in the air containing SARS-CoV-2. What we are trying to demonstrate is that an electrically resistive filter controls the spread of the virus in air up to 10 cubic meters in size indoors. This system does not replace existing filters, but is a piece of equipment to help control SARS-CoV-2.

Green aspects of photocatalysts during corona pandemic: a promising role for the deactivation of COVID-19 virus.

The selection of a facile, eco-friendly, and effective methodology is the need of the hour for efficient curing of the COVID-19 virus in air, water, and many food products. Recently, semiconductor-based photocatalytic methodologies have provided promising, green, and sustainable approaches to battle against viral activation via the oxidative capabilities of various photocatalysts with excellent performance under moderate conditions and negligible by-products generation as well. Considering this, recent advances in photocatalysis for combating the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are inclusively highlighted. Starting from the origin to the introduction of the coronavirus, the significant potential of photocatalysis against viral prevention and -disinfection is discussed thoroughly. Various photocatalytic material-based systems including metal-oxides, metal-free and advanced 2D materials (MXenes, MOFs and COFs) are systematically examined to understand the mechanistic insights of virus-disinfection in the human body to fight against COVID-19 disease. Also, a roadmap toward sustainable solutions for ongoing COVID-19 contagion is also presented. Finally, the challenges in this field and future perspectives are comprehensively discussed involving the bottlenecks of current photocatalytic systems along with potential recommendations to deal with upcoming pandemic situations in the future.

Method of photodynamic inactivation of viruses in air

The photodynamic inactivation of viruses by a microporous photocatalytic element made of copper or copper alloy is the very method of ensuring biosafety that the article is about. Based on this method, encouraging results of virological studies (using the influenza virus as a test) were obtained as well as the equipment solving the strategic task of antiviral (influenza, COVID-19, etc.) disinfecting and sterilizing of confined spaces air, including air of medical premises, was developed. Keywords: air sterilization, copper, microporous membrane, influenza virus, singlet oxigen.

A review on the transmission of COVID-19 based on cough/sneeze/breath flows.

COVID-19 pandemic has recently had a dramatic impact on society. The understanding of the disease transmission is of high importance to limit its spread between humans. The spread of the virus in air strongly depends on the flow dynamics of the human airflows. It is, however, known that predicting the flow dynamics of the human airflows can be challenging due to different particles sizes and the turbulent aspect of the flow regime. It is thus recommended to present a deep analysis of different human airflows based on the existing experimental investigations. A validation of the existing numerical predictions of such flows would be of high interest to further develop the existing numerical model for different flow configurations. This paper presents a literature review of the experimental and numerical studies on human airflows, including sneezing, coughing and breathing. The dynamics of these airflows for different droplet sizes is discussed. The influence of other parameters, such as the viscosity and relative humidity, on the germs transmission is also presented. Finally, the efficacy of using a facemask in limiting the transmission of COVID-19 is investigated.

Continuous and Ultra-Fast Sars-Cov-2 Monitoring of Indoor Air

With the COVID-19 pandemic extending over a year now, it has become even more important to detect the SARS-CoV-2 virus as early as possible. Detecting the virus is of utmost importance to ensure safe return to schools, offices, public places, etc. Continuous monitoring of classrooms, workspaces has thus become the need of the hour. For this purpose, there is a pressing need for real-time sensors that can detect and warn the presence of SARS-CoV-2 virus in air. As a remedy to this problem, we have developed an ultra-fast electrochemical sensor device that detects the SARS-CoV-2 virus present in air. The SARS-CoV-2 viral proteins interact with a Ni-based electrode at an alkaline pH to produce a positive current difference compared to a baseline solution devoid of any viral proteins. The mechanism of detection is hypothesized to be analogous to the binding mechanism of SARS-CoV-2 on human body surfaces. As a result of such a mechanism, it is believed that local pH changes occur at the electric double layer and are captured as current signatures by the sensor. Our sensor device has selectively detected SARS-CoV-2 when tested in the presence of H1N1 Influenza A, SARS-CoV, and Human CoV OC43. Moreover, the use of electrochemical technique has rendered a very low detection limit for the sensor. Using continuous monitoring devices such as this ultra-fast COVID-19 diagnostic sensor for monitoring the air surrounding us would be the way forward for ensuring safe return to normalcy post-pandemic. Acknowledgment: This material is based upon work supported by the Defense Advanced Research Projects Agency (DARPA) under Agreement No. HR00112190063. Keywords: SARS-CoV-2 detection; Electrochemical viral sensor; COVID-19 diagnostic test

Improved estimates of 222 nm far-UVC susceptibility for aerosolized human coronavirus via a validated high-fidelity coupled radiation-CFD code

Transmission of SARS-CoV-2 by aerosols has played a significant role in the rapid spread of COVID-19 across the globe. Indoor environments with inadequate ventilation pose a serious infection risk. Whilst vaccines suppress transmission, they are not 100% effective and the risk from variants and new viruses always remains. Consequently, many efforts have focused on ways to disinfect air. One such method involves use of minimally hazardous 222 nm far-UVC light. Whilst a small number of controlled experimental studies have been conducted, determining the efficacy of this approach is difficult because chamber or room geometry, and the air flow within them, influences both far-UVC illumination and aerosol dwell times. Fortunately, computational multiphysics modelling allows the inadequacy of dose-averaged assessment of viral inactivation to be overcome in these complex situations. This article presents the first validation of the WYVERN radiation-CFD code for far-UVC air-disinfection against survival fraction measurements, and the first measurement-informed modelling approach to estimating far-UVC susceptibility of viruses in air. As well as demonstrating the reliability of the code, at circa 70% higher, our findings indicate that aerosolized human coronaviruses are significantly more susceptible to far-UVC than previously thought.

Why Does the SARS-CoV-2 Delta VOC Spread So Rapidly? Universal Conditions for the Rapid Spread of Respiratory Viruses, Minimum Viral Loads for Viral Aerosol Generation, Effects of Vaccination on Viral Aerosol Generation, and Viral Aerosol Clouds.

This study analyzes the reasons the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant of concern (VOC) spreads so rapidly. Novel topics such as universal conditions for the rapid spread of respiratory viruses, minimum viral loads for viral aerosol generation, effects of vaccination on viral aerosol generation, and viral aerosol clouds were studied. The analyses were based on experimental results and analytic model studies. Four universal conditions, namely asymptomatic host, high viral load, stability of viruses in air, and binding affinity of viruses to human cells, need to be satisfied for the rapid spread of respiratory viruses. SARS-CoV-2 and its variants such as the Alpha VOC and Delta VOC satisfy the four fundamental conditions. In addition, there is an original principle of aerosol generation of respiratory viruses. Assuming that the aerosol–droplet cutoff particle diameter for distinguishing potential aerosols from earthbound respiratory particles is 100 μm, the minimum viral load required in respiratory fluids to generate viral aerosols is ~106 copies mL−1, which is within the range of the reported viral loads in the Alpha VOC cases and the Delta VOC cases. The daily average viral loads of the Delta VOC in hosts have been reported to be between ~109 copies mL−1 and ~1010 copies mL−1 during the four days after symptom onset in 1848 cases of the Delta VOC infection. Owing to the high viral load, the SARS-CoV-2 Delta VOC has the potential to effectively spread through aerosols. COVID-19 vaccination can decrease aerosol transmission of the SARS-CoV-2 Alpha VOC by reducing the viral load. The viral load can explain the conundrum of viral aerosol spreading. The SARS-CoV-2 Delta VOC aerosol clouds have been assumed to be formed in restricted environments, resulting in a massive numbers of infected people in a very short period with a high spreading speed. Strong control methods against bioaerosols should be considered in this SARS-CoV-2 Delta VOC pandemic. Large-scale environmental monitoring campaigns of SARS-CoV-2 Delta VOC aerosols in public places in many countries are necessary, and these activities could contribute to controlling the coronavirus disease pandemic.

Determination of the Efficacy of the Cold Atmospheric Plasma with Nano Tio2 Covered in Cathode Towards Enveloped Viruses such as Covid 19 and Influenza in Room Air

In this research, Medwave air and surface disinfection system (model:Klin20)selected to investigation effect , towards aerosolised enveloped viruses in room air. Phi6Pseudomonas syringae phage, a surrogate for coronavirus and influenza, was used in the trials Viral suspensions of Phi6 were aerosolised within the ukas accreditation Campden BRI aerobiology laboratory to achieve initial levels of ~106PFU/m3, representing very heavily contaminated air . Air samples were taken at 15 minute intervals and analysed to determine levels of Phi6 in the room air over a total test period of 135 minutes. On 3 separate days, paired trials were carried out with the Medwave switched onand with the units witched off as a control to determine baseline levels of virus in the air overtime. Trials carried out on the first two test days showed no reduction in viral titre compared with the control. Further investigation revealed that a wiring loom within the test unit had become disconnected during transport and the instrument was therefore not functioning correctly. Results from the trial showed that the level of Phi6 in the room air decreased rapidly from an initial titre of 6.12 log PFU/m3to undetectable levels (<1.78 log PFU/m3) after 45 minutes of operation, representing a log reduction of ≥4.00 logs compared with the control run with the unit switched off. Log reductions of 2.21, 3.30and ≥4.00 logs were observed after 15, 30 and 45 minutes respective to the log PFU/m3countsin the control run Keywords: Bioaerosols nano-titanium atmospheric cold plasma, covid19

Evidence of the presence of SARS-CoV-2 virus in atmospheric air and surfaces of a dedicated COVID hospital.

The present study was conducted from July 1, 2020 to September 25, 2020 in a dedicated coronavirus disease 2019 (COVID‐19) hospital in Delhi, India to provide evidence for the presence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) virus in atmospheric air and surfaces of the hospital wards. Swabs from hospital surfaces (patient's bed, ward floor, and nursing stations area) and suspended particulate matter in ambient air were collected by a portable air sampler from the medicine ward, intensive care unit, and emergency ward admitting COVID‐19 patients. By performing reverse‐transcriptase polymerase chain reaction (RT‐PCR) for E‐gene and RdRp gene, SARS‐CoV‐2 virus was detected from hospital surfaces and particulate matters from the ambient air of various wards collected at 1 and 3‐m distance from active COVID‐19 patients. The presence of the virus in the air beyond a 1‐m distance from the patients and surfaces of the hospital indicates that the SARS‐CoV‐2 virus has the potential to be transmitted by airborne and surface routes from COVID‐19 patients to health‐care workers working in COVID‐19 dedicated hospital. This warrants that precautions against airborne and surface transmission of COVID‐19 in the community should be taken when markets, industries, educational institutions, and so on, reopen for normal activities.

Real-time monitoring and controlling strategies of indoor environment in the frontline hospitals during COVID-19 pandemic

Many emergent measures on mitigating and controlling the COVID-19 pandemic have been unprecedented in China, one of which is the urgent construction of isolation wards in Huoshenshan Hospital and Leishenshan Hospital, as well as in sixteen Fangcang shelter hospitals. These hospitals, built or reconstructed within a remarkably short period, have treated a large number of COVID-19 patients in time and successfully mitigated disease spread in population. One of the many challenges during the hospitals’ functioning period is the precaution of potential airborne transmission. Airborne transmission could occur during medical procedures including tracheotomy, intubation, extubation, etc., and several surveillance studies have detected SARS-CoV-2 virus in air by polymerase chain reaction (PCR), but direct methods on monitoring airborne SARS-CoV-2 in real-time have not been developed so far. Though it is yet to know whether these airborne viruses are viable and able to cause person-to-person infection, airborne precautions such as negative-pressure wards and N95 respirators have already been recommended and implemented in China. In order to protect the healthcare workers (HCWs) and reduce the demand of high-level protection gear, this study proposed an indirect method to identify and alert the airborne infection risk. We deployed numerous sensors to monitor CO₂ concentration, PM_2.5 mass concentration, air temperature and relative humidity, and illumination at ICUs (intensive care units), general wards, nurse stations, buffer rooms, etc. in real-time. Online CO₂ concentration reflects the dilution of occupants’ exhalation substances by the ventilation and air distribution system. High CO₂ concentrations indicate either the fresh air supply fails or the room is overcrowded at the moment. The readings of CO₂ concentration across adjacent zones with known functions can also help identify whether the airflow direction is consistent with the designed requirement. PM_2.5 mass concentration indicates the air cleanness of the measured zones, which could be crucial for patient recovery and reduction of symptom complication. Air temperature and relative humidity are key parameters that influence the evaporation of expiratory droplets and the thermal comfort of patients, while illumination indicates the intake of ultraviolet from outdoor. The sensors could keep quiet during the sampling process, so they would not disturb the HCWs and patients. Moreover, they are integrated with 3G SIM cards and powered just by a DC 5V/3A power adapter with a USB Type-C line, so they could be easily installed at target locations, and adapt for multi-scene, multi-demand, and long-term online and offline monitoring. When integrated with online meta-analysis and computer fluid dynamics (CFD) simulation, this method can send alarms to the HCWs about the locations where the ventilation against potential pathogen-laden aerosols fails. This study introduces the principle of the method in detail as well as its application at Huoshenshan Hospital, Leishenshan Hospital and Jiangxia Dahuashan Fangcang shelter hospital, etc., in Wuhan, China, during February and March of 2020. As the society gradually steps into post-pandemic phase, the proposed method could help optimize the ventilation and filtration strategies in public buildings and transportations.

Controversies in airway management of COVID-19 patients: updated information and international expert consensus recommendations

Controversies in airway management of COVID-19 patients: updated information and international expert consensus recommendations

Rapid Airborne Influenza Virus Quantification Using an Antibody-Based Electrochemical Paper Sensor and Electrostatic Particle Concentrator.

Airborne influenza viruses are responsible for serious respiratory diseases, and most detection methods for airborne viruses are based on extraction of nucleic acids. Herein, vertical-flow-assay-based electrochemical paper immunosensors were fabricated to rapidly quantify the influenza H1N1 viruses in air after sampling with a portable electrostatic particle concentrator (EPC). The effects of antibodies, anti-influenza nucleoprotein antibodies (NP-Abs) and anti-influenza hemagglutinin antibodies (HA-Abs), on the paper sensors as well as nonpulsed high electrostatic fields with and without corona charging on the virus measurement were investigated. The antigenicity losses of the surface (HA) proteins were caused by H2O2 via lipid oxidation-derived radicals and 1O2 via direct protein peroxidation upon exposure of a high electrostatic field. However, minimal losses in antigenicity of NP of the influenza viruses were observed, and the concentration of the H1N1 viruses was more than 160 times higher in the EPC than the BioSampler upon using NP-Ab based paper sensors after 60 min collection. This NP-Ab-based paper sensors with the EPC provided measurements comparable to quantitative polymerase chain reaction (qPCR) but much quicker, specific to the influenza H1N1 viruses in the presence of other airborne microorganisms and beads, and more cost-effective than enzyme-linked immunosorbent assay and qPCR.

Sampling and detection of corona viruses in air: A mini review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a strain of coronaviruses that causes coronavirus disease 2019 (COVID-19). In these days, the spread of the SARS-CoV-2 virus through the air has become a controversial topic among scientists. Various organizations provide standard methods for monitoring biological agents in the air. Nevertheless, there has been no standard recommended method for sampling and determination of viruses in air. This manuscript aimed at reviewing published papers for sampling and detection of corona viruses, especially SARS-Cov-2 as a global health concern. It was found that SARS-Cov 2 was present in some air samples that were collected from patient's rooms in hospitals. This result warrants its airborne transmission potential. However, due to the fact that in the most reviewed studies, sampling was performed in the patient's room, it seems difficult to discriminate whether it is airborne or is transmitted through respiratory droplets. Moreover, some other disrupting factors such as patient distance from the sampler, using protective or oxygen masks by patients, patient activities, coughing and sneezing during sampling time, air movement, air conditioning, sampler type, sampling conditions, storage and transferring conditions, can affect the results. About the sampling methods, most of the used samplers such as PTFE filters, gelatin filers and cyclones showed suitable performance for trapping SARS-Co and MERS-Cov viruses followed by PCR analysis.