Stability of SARS-CoV-2 and other coronaviruses in the environment and on common touch surfaces and the influence of climatic conditions: A review

SARS-CoV-2 Delta variant remains viable in environmental biofilms found in meat packaging plants

To determine why SARS-CoV-2 appears to thrive specifically well in meat packaging plants, we used SARS-CoV-2 Delta variant and meat packaging plant drain samples to develop mixed-species biofilms on materials commonly found within meat packaging plants (stainless steel (SS), PVC, and ceramic tile). Our data provides evidence that SARS-CoV-2 Delta variant remained viable on all the surfaces tested with and without an environmental biofilm after the virus was inoculated with the biofilm for 5 days at 7°C. We observed that SARS-CoV-2 Delta variant was able to remain infectious with each of the environmental biofilms by conducting plaque assay and qPCR experiments, however, we detected a significant reduction in viability post-exposure to Plant B biofilm on SS, PVC, and on ceramic tile chips, and to Plant C biofilm on SS and PVC chips. The numbers of viable SARS-CoV-2 Delta viral particles was 1.81-4.57-fold high than the viral inoculum incubated with the Plant B and Plant C environmental biofilm on SS, and PVC chips. We did not detect a significant difference in viability when SARS-CoV-2 Delta variant was incubated with the biofilm obtained from Plant A on any of the materials tested and SARS-CoV-2 Delta variant had higher plaque numbers when inoculated with Plant C biofilm on tile chips, with a 2.75-fold difference compared to SARS-CoV-2 Delta variant on tile chips by itself. In addition, we detected an increase in the biofilm biovolume in response to SARS-CoV-2 Delta variant which is also a concern for food safety due to the potential for foodborne pathogens to respond likewise when they come into contact with the virus. These results indicate a complex virus-environmental biofilm interaction which correlates to the different bacteria found in each biofilm. Our results also indicate that there is the potential for biofilms to protect SARS-CoV-2 from disinfecting agents and remaining prevalent in meat packaging plants.

Influence of storage solution, temperature, assay time and concentration on RT-qPCR nucleic acid detection for SARS-CoV-2 detection of SARS-CoV-2 by the RT-qPCR

Real-time reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is an important method for the early diagnosis of coronavirus disease 2019 (COVID-19). This study investigated the effects of storage solution, temperature and detection time on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid detection by RT-qPCR. Various concentrations of SARS-CoV-2 were added to inactive and non-inactive storage solution and the viral suspensions were stored at various temperatures (room temperature, 4, -20 and -80 °C). Then, at five different detection time points, the Ct values were determined by RT-qPCR. Active and inactive storage solutions and storage temperature have a great impact on the detection of N gene of SARS-CoV-2 at different concentration corridors but have little impact on the ORF gene. The storage time has a greater impact on the N gene and ORF gene at high concentrations but has no effect on the two genes at low concentrations. In conclusion, storage temperature, storage time and storage status (inactivated, non-inactivated) have no effect on the nucleic acid detection of SARS-CoV-2 at the same concentration. For different concentrations of SARS-CoV-2, the detection of N gene is mainly affected.

The Detection of Influenza Virus Before and During the COVID-19 Pandemic in Cameroon

BACKGROUND

Influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are both respiratory viruses with similar clinical manifestations and modes of transmission. This study describes influenza data before and during the coronavirus disease pandemic (COVID-19) in Cameroon and SARS-CoV-2 data during the pandemic period.

METHODS

The study ran from 2017 to 2022, and data were divided into two periods: before (2017-2019) and during (2020-2022) the COVID-19 pandemic. Nasopharyngeal samples collected from persons with respiratory illness were tested for influenza using the Centers for Disease Control and Prevention (CDC) typing and subtyping assays. During the COVID-19 pandemic, the respiratory specimens were simultaneously tested for SARS-CoV-2 using the DaAn gene protocol or the Abbott real-time SARS-CoV-2 assay. The WHO average curve method was used to compare influenza virus seasonality before and during the pandemic.

RESULTS

A total of 6246 samples were tested. Influenza virus detection rates were significantly higher in the pre-pandemic period compared to the pandemic period (30.8% vs. 15.5%; p < 0.001). Meanwhile, the SARS-CoV-2 detection rate was 2.5%. A change in the seasonality of influenza viruses was observed from a bi-annual peak before the pandemic to no clear seasonal pattern during the pandemic. The age groups 2-4 and 5-14 years were significantly associated with higher influenza positivity rates in both pre-pandemic and pandemic periods. For SARS-CoV-2, all age groups above 15 years were the most affected population.

CONCLUSION

The COVID-19 pandemic had a significant impact on the seasonal influenza by changing the seasonality of the virus and reducing its detection rates.

Persistence and free chlorine disinfection of human coronaviruses and their surrogates in water

The coronavirus disease 2019 pandemic illustrates the importance of understanding the behavior and control of human pathogenic viruses in the environment. Exposure via water (drinking, bathing, and recreation) is a known route of transmission of viruses to humans, but the literature is relatively void of studies on the persistence of many viruses, especially coronaviruses, in water and their susceptibility to chlorine disinfection. To fill that knowledge gap, we evaluated the persistence and free chlorine disinfection of human coronavirus OC43 (HCoV-OC43) and its surrogates, murine hepatitis virus (MHV) and porcine transmissible gastroenteritis virus (TGEV), in drinking water and laboratory buffer using cell culture methods. The decay rate constants of human coronavirus and its surrogates in water varied, depending on virus and water matrix. In drinking water without disinfectant addition, MHV showed the largest decay rate constant (estimate ± standard error, 2.25 ± 0.09 day-1) followed by HCoV-OC43 (0.99 ± 0.12 day-1) and TGEV (0.65 ± 0.06 day-1), while in phosphate buffer without disinfectant addition, HCoV-OC43 (0.51 ± 0.10 day-1) had a larger decay rate constant than MHV (0.28 ± 0.03 day-1) and TGEV (0.24 ± 0.02 day-1). Upon free chlorine disinfection, the inactivation rates of coronaviruses were independent of free chlorine concentration and were not affected by water matrix, though they still varied between viruses. TGEV showed the highest susceptibility to free chlorine disinfection with the inactivation rate constant of 113.50 ± 7.50 mg-1 min-1 L, followed by MHV (81.33 ± 4.90 mg-1 min-1 L) and HCoV-OC43 (59.42 ± 4.41 mg-1 min-1 L).

IMPORTANCE

This study addresses an important knowledge gap on enveloped virus persistence and disinfection in water. Results have immediate practical applications for shaping evidence-based water policies, particularly in the development of disinfection strategies for pathogenic virus control.

Nonthermal plasma air disinfection for the inactivation of airborne microorganisms in an experimental chamber and indoor air

AIMS

Airborne transmission of diseases presents a serious threat to human health, so effective air disinfection technology to eliminate microorganisms in indoor air is very important. This study evaluated the effectiveness of a non-thermal plasma (NTP) air disinfector in both laboratory experiments and real environments.

METHODS AND RESULTS

An experimental chamber was artificially polluted with a bioaerosol containing bacteria or viruses. Additionally, classroom environments with and without people present were used in field tests. Airborne microbial and particle concentrations were quantified. A 3.0 log10 reduction in the initial load was achieved when a virus-containing aerosol was disinfected for 60 min and a bacteria-containing aerosol was disinfected for 90 min. In the field test, when no people were present in the room, NTP disinfection decreased the airborne microbial and particle concentrations (P < 0.05). When people were present in the room, their constant activity continuously contaminated the indoor air, but all airborne indicators decreased (P < 0.05) except for planktonic bacteria (P = 0.094).

CONCLUSIONS

NTP effectively inactivated microorganisms and particles in indoor air.

SARS-CoV-2 infection in animals: Patterns, transmission routes, and drivers

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is more widespread in animals than previously thought, and it may be able to infect a wider range of domestic and wild species. To effectively control the spread of the virus and protect animal health, it is crucial to understand the cross-species transmission mechanisms and risk factors of SARS-CoV-2. This article collects published literature on SARS-CoV-2 in animals and examines the distribution, transmission routes, biophysical, and anthropogenic drivers of infected animals. The reported cases of infection in animals are mainly concentrated in South America, North America, and Europe, and species affected include lions, white-tailed deer, pangolins, minks, and cats. Biophysical factors influencing infection of animals with SARS-CoV-2 include environmental determinants, high-risk landscapes, air quality, and susceptibility of different animal species, while anthropogenic factors comprise human behavior, intensive livestock farming, animal markets, and land management. Due to current research gaps and surveillance capacity shortcomings, future mitigation strategies need to be designed from a One Health perspective, with research focused on key regions with significant data gaps in Asia and Africa to understand the drivers, pathways, and spatiotemporal dynamics of interspecies transmission.

Assessing the impact of the COVID-19 pandemic on latex glove usage and latex allergy complaints among nurses: A descriptive study

BACKGROUND

The coronavirus 2019 (COVID-19) pandemic has led to a significant increase in the use of latex gloves among nurses. However, concerns about the rise in latex allergies and related complaints due to this increase remain uncertain.OBJECTİVE: This study aims to assess the rates of latex glove usage and allergy-related complaints among nurses working in hospitals during the COVID-19 pandemic.

METHODS

Between May 15 and June 15, 2021, ethical approvals were obtained for a cross-sectional study involving 448 volunteer nurses. Descriptive statistics were used to represent categorical values as counts (n) and percentages (%), while continuous values were represented as mean±standard deviation. The normal distribution of the data was assessed using the Kolmogorov-Smirnov and Shapiro-Wilk tests. Comparative analyses were conducted using paired sample t-test, Pearson's chi-squared (x2) test, McNemar's chi-squared (x2) test, and Spearman correlation analysis.

RESULTS

Before the pandemic, the average number of invasive procedures was 45.13±26.48, whereas during the pandemic, this rate increased to 50.23±29.14. The average glove usage duration went from 7.69±3.13 hours to 14.73±3.68 hours during the pandemic. Among nurses, the rate of allergic symptoms, which was previously at 31.5%, rose to 33.3% during the pandemic.CONCLUSİON: This study revealed a significant increase in daily invasive procedures and the use of latex gloves among nurses during the pandemic period. Simultaneously, the frequency of allergic symptoms also rose. These findings underscore the importance of awareness and preventive measures, particularly regarding latex allergies, in the healthcare field.

A high-performance polymer composite column for coronavirus nucleic acid purification

Here, we report the development of a novel polymer composite (PC) purification column and kit. The performance of the PC columns was compared to conventional silica gel (SG) columns for the purification of nucleic acids from coronaviruses, including SARS-CoV-2, in 82 clinical samples. The results shows that PC-based purification outperforms silica gel (SG)-based purification by enabling a higher sensitivity (94%), accuracy (97%), and by eliminating false positives (100% specificity). The high specificity is critical for efficient patient triage and resource management during pandemics. Furthermore, PC-based purification exhibits three times higher analytical precision than a commonly used SG-based nucleic acid purification thereby enabling a more accurate quantification of viral loads and higher reproducibility.

Stability of Feline Coronavirus in aerosols and dried in organic matrices on surfaces at various environmental conditions

Enveloped respiratory viruses, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can be transmitted through aerosols and contact with contaminated surfaces. The stability of these viruses outside the host significantly impacts their transmission dynamics and the spread of diseases. In this study, we investigated the tenacity of Feline Coronavirus (FCoV) in aerosols and on surfaces under varying environmental conditions. We found that airborne FCoV showed different stability depending on relative humidity (RH), with higher stability observed at low and high RH. Medium RH conditions (50-60%) were associated with increased loss of infectivity. Furthermore, FCoV remained infectious in the airborne state over 7 h. On stainless-steel surfaces, FCoV remained infectious for several months, with stability influenced by organic material and temperature. The presence of yeast extract and a temperature of 4 °C resulted in the longest maintenance of infectivity, with a 5 log10 reduction of the initial concentration after 167 days. At 20 °C, this reduction was achieved after 19 days. These findings highlight the potential risk of aerosol and contact transmission of respiratory viruses, especially in enclosed environments, over extended periods. Studying surrogate viruses like FCoV provides important insights into the behavior of zoonotic viruses like SARS-CoV-2 in the environment.

Climate-dependent effectiveness of nonpharmaceutical interventions on COVID-19 mitigation

Environmental factors have a significant impact on the transmission of infectious diseases. Existing results show that the novel coronavirus can persist outside the host. We propose a susceptible-exposed-presymptomatic-infectious-asymptomatic-recovered-susceptible (SEPIARS) model with a vaccination compartment and indirect incidence to explore the effect of environmental conditions, temperature and humidity, on the transmission of the SARS-CoV-2 virus. Using climate data and daily confirmed cases data in two Canadian cities with different atmospheric conditions, we evaluate the mortality rates of the SARS-CoV-2 virus and further estimate the transmission rates by the inverse method, respectively. The numerical results show that high temperature or humidity can be helpful in mitigating the spread of COVID-19 during the warm summer months. Our findings verify that nonpharmaceutical interventions are less effective if the virus can persist for a long time on surfaces. Based on climate data, we can forecast the transmission rate and the infection cases up to four weeks in the future by a generalized boosting machine learning model.

Building parameters linked with indoor transmission of SARS-CoV-2

The rapid spread of Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emphasized the importance of understanding and adapting to the indoor remediation of transmissible diseases to decrease the risk for future pandemic threats. While there were many precautions in place to hinder the spread of COVID-19, there has also been a substantial increase of new research on SARS-CoV-2 that can be utilized to further mitigate the transmission risk of this novel virus. This review paper aims to identify the building parameters of indoor spaces that could have considerable influence on the transmission of SARS-CoV-2. The following building parameters have been identified and analyzed, emphasizing their link with the indoor transmission of SARS-CoV-2: temperature and relative humidity, temperature differences between rooms, ventilation rate and access to natural ventilation, occupant density, surface type and finish, airflow direction and speed, air stability, indoor air pollution, central air conditioning systems, capacity of air handling system and HVAC filter efficiency, edge sealing of air filters, room layout and interior design, and compartmentalization of interior space. This paper also explains the interactions of SARS-CoV-2 with indoor environments and its persistence. Furthermore, the modifications of the key building parameters have been discussed for controlling the transmission of SARS-CoV-2 in indoor spaces. Understanding the information provided in this paper is crucial to develop effective health and safety measures that will aid in infection prevention.

Stability of pathogens on banknotes and coins: A narrative review

For the prevention of infectious diseases, knowledge about potential transmission routes is essential. Pathogens can be transmitted directly (i.e. respiratory droplets, hand-to-hand contact) or indirectly via contaminated surfaces (fomites). In particular, frequently touched objects/surfaces may serve as transmission vehicles for different clinically relevant bacterial, fungal, and viral pathogens. Banknotes and coins offer ample surface area and are frequently exchanged between individuals. Consequently, many concerns have been raised in the recent past, that banknotes and coins could serve as vectors for the transmission of disease-causing microorganisms. This review summarizes the latest research on the potential of paper currency and coins to serve as sources of pathogenic viral, bacterial, and fungal agents. In contrast to the current perception of banknotes and coins as important transmission vehicles, current evidence suggests, that banknotes and coins do not pose a particular risk of pathogen infection for the public.

Potential airborne human pathogens: A relevant inhabitant in built environments but not considered in indoor air quality standards

Potential airborne human pathogens (PAHPs) may be a relevant component of the air microbiome in built environments. Despite that PAHPs can cause infections, particularly in immunosuppressed patients at medical centers, they are scarcely considered in standards of indoor air quality (IAQ) worldwide. Here, we reviewed the current information on microbial aerosols (bacteria, fungal and viruses) and PAHPs in different types of built environments (e.g., medical center, industrial and non-industrial), including the main factors involved in their dispersion, the methodologies used in their study and their associated biological risks. Our analysis identified the human occupancy and ventilation systems as the primary sources of dispersal of microbial aerosols indoors. We also observed temperature and relative humidity as relevant physicochemical factors regulating the dispersion and viability of some PAHPs. Our analysis revealed that some PAHPs can survive and coexist in different environments while other PAHPs are limited or specific for an environment. In relation to the methodologies (conventional or molecular) the nature of PAHPs and sampling type are pivotal. In this context, indoors air-borne viruses are the less studies because their small size, environmental lability, and absence of efficient sampling techniques and universal molecular markers for their study. Finally, it is noteworthy that PAHPs are not commonly considered and included in IAQ standards worldwide, and when they are included, the total abundance is the single parameter considered and biological risks is excluded. Therefore, we propose a revision, design and establishment of public health policies, regulations and IAQ standards, considering the interactions of diverse factors, such as nature of PAHPs, human occupancy and type of built environments where they develop.

Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization

During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.

Virus Dynamics and Decay in Evaporating Human Saliva Droplets on Fomites

The transmission of most respiratory pathogens, including SARS-CoV-2, occurs via virus-containing respiratory droplets, and thus, factors that affect virus viability in droplet residues on surfaces are of critical medical and public health importance. Relative humidity (RH) is known to play a role in virus survival, with a U-shaped relationship between RH and virus viability. The mechanisms affecting virus viability in droplet residues, however, are unclear. This study examines the structure and evaporation dynamics of virus-containing saliva droplets on fomites and their impact on virus viability using four model viruses: vesicular stomatitis virus, herpes simplex virus 1, Newcastle disease virus, and coronavirus HCoV-OC43. The results support the hypothesis that the direct contact of antiviral proteins and virions within the "coffee ring" region of the droplet residue gives rise to the observed U-shaped relationship between virus viability and RH. Viruses survive much better at low and high RH, and their viability is substantially reduced at intermediate RH. A phenomenological theory explaining this phenomenon and a quantitative model analyzing and correlating the experimentally measured virus survivability are developed on the basis of the observations. The mechanisms by which RH affects virus viability are explored. At intermediate RH, antiviral proteins have optimal influence on virions because of their largest contact time and overlap area, which leads to the lowest level of virus activity.

SARS-CoV-2 transmission via maritime cold chains: A statistical analysis of nucleic acid detection results of cold chain food imported from Fuzhou ports

Numerous epidemic outbreaks related to cold chains have occurred since the coronavirus disease 2019 (COVID-19) outbreak, suggesting the potential danger of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission through cold chain foods (CCFs). By analyzing SARS-CoV-2 RNA contamination of CCFs imported from Fuzhou ports, this study evaluated the contamination and transmission of SARS-CoV-2 RNA via maritime cold chains, with the aim of provide suggestions for CCFs supervision and public health management. The statistical analysis included 131,385 samples. The majority of the CCFs imported into Fuzhou ports was aquatic raw food that originated in Southeast Asia (57.08 %), South America (19.87 %), and South Asia (11.22 %). South Asia had the highest positivity rate of 0.37 %, followed by Southeast Asia (0.21 %) and South America (0.08 %). The positivity rate showed that the outer packaging of CCFs was the most easily contaminated, accounting for 81.33 % of all positive samples. This suggested that CCFs storage and loading processes were the weak links vulnerable to SARS-CoV-2 contamination. The positivity rates in outer packaging, inner packaging, and content of raw food were 0.48 %, 0.08 %, and 0.05 %, respectively, which were obviously higher than those of processed and refined food. This indicated that increasing the mechanization of factories and implementing sensible worker management practices may decrease viral contamination. The monthly positivity rates varied widely from 0 % (March 2021) to 0.40 % (January 2021), with an average of 0.19 %. The positivity rates in outer packaging, inner packaging and content of crustaceans from Southeast Asia were 2.47 %, 0.41 %, and 0.69 %, which were approximately 5-14 times higher than those of fish and cephalopods. Meanwhile, the monthly detection number show that SARS-CoV-2 epidemic prevention strategies affected the trade of imported CCFs.

Lesson learned from COVID-19 pandemic for the future of food industry

With WHO announcing COVID-19 no longer as a public health emergency of international concern (PHEIC) on May 5, 2023, coupled with the fact that the majority of the countries of the world have dropped strict city lockdown or border closure, this perhaps signals the end of the COVID-19 crisis caused by the SARS-CoV-2 virus. However, the COVID-19 pandemic has resulted in far-reaching effects affecting nearly every aspect of our lives and society. Notably, the food industry including agriculture, food manufacturers, food logistics, distributors and retailers have all felt the profound impact and had experienced significant stress during the pandemic. Therefore, it is essential to retrospect the lessons that can be learned from this pandemic for the food industry. This short review aims to address the food safety issues related to the COVID-19 pandemic by focusing on its foodborne transmission potential, innovations of virus detection strategies suitable for food industry; development of phathogenicaidal methods and devices to inactivate SARS-CoV-2 virus (particularly in industrial scale); and the set-up of related food regulations and guidelines as preventive and control measures for preventing the spread of SARS-CoV-2 virus through the food supply chain during the pandemic. This article may provide useful references for the food industry to minimize the food safety impact of COVID-19 (as well as other respiratory virus) and allows them to better prepare for similar future challenges.

High-Titer Recombinant Adenovirus 26 Vector GMP Manufacturing in HEK 293 Cells with a Stirred Single-Use Bioreactor for COVID-19 Vaccination Purposes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus) pandemic has shown the importance of pursuing various vaccine manufacturing strategies. In the present study, the HEK 293 cells were infected with recombinant adenovirus serotype 26 (rAd26), and the effects of critical process parameters (CPPs) including viable cell density (VCD) at infection time (0.5 × 106, 0.8 × 106, 1.4 × 106, 1.8 × 106, and 2.5 × 106 cells/mL), the multiplicity of infection (MOI) = 3, 6, 9, 12, and 15, and two aeration strategies (high-speed agitation with a sparging system and low-speed agitation with an overlay system) were investigated experimentally. The results of small-scale experiments in 2 L shake flasks (SF 2L) demonstrated that the initial VCD and MOI could affect the cell proliferation and viability. The results at these experiments showed that VCD = 1.4 × 106 cells/mL and MOI = 9 yielded TCID50 /mL = 108.9, at 72 h post-infection (hpi), while the virus titer at VCD = 0.5 × 106 and 0.8 × 106 cells/mL was lower compared to that of VCD = 1.4 × 106 cells/mL. Moreover, our findings showed that VCDs > 1.8 × 106 cells/m with MOI = 9 did not have a positive effect on TCID50 /mL and MOI = 3 and 6 were less efficient, whereas MOI > 12 decreased the viability drastically. In the next step, the optimized CPPs in a small scale were exploited in a 200 L single-use bioreactor (SUB), with good manufacturing practice (GMP) conditions, at RPM = 25 with an overlay system, yielding high-titer rAd26 manufacturing, i.e., TCID50/mL = 108.9, at 72 hpi.

Virus on surfaces: Chemical mechanism, influence factors, disinfection strategies, and implications for virus repelling surface design

While SARS-CoV-2 is generally under control, the question of variants and infections still persists. Fundamental information on how the virus interacts with inanimate surfaces commonly found in our daily life and when in contact with the skin will be helpful in developing strategies to inhibit the spread of the virus. Here in, a critically important review of current understanding of the interaction between virus and surface is summarized from chemistry point-of-view. The Derjaguin-Landau-Verwey-Overbeek and extended Derjaguin-Landau-Verwey-Overbeek theories to model virus attachments on surfaces are introduced, along with the interaction type and strength, and quantification of each component. The virus survival and transfer are affected by a combination of biological, physical, and chemical parameters, as well as environmental parameters. The surface properties for virus and virus survival on typical surfaces such as metals, plastics, and glass are summarized. Attention is also paid to the transfer of virus to/from surfaces and skin. Typical virus disinfection strategies utilizing heat, light, chemicals, and ozone are discussed together with their disinfection mechanism. In the last section, design principles for virus repelling surface chemistry such as surperhydrophobic or surperhydrophilic surfaces are also introduced, to demonstrate how the integration of surface property control and advanced material fabrication can lead to the development of functional surfaces for mitigating the effect of viral infection upon contact.

Probing nanomechanical interactions of SARS-CoV-2 variants Omicron and XBB with common surfaces

The emergence of SARS-CoV-2 variants has further raised concerns about viral transmission. A fundamental understanding of the intermolecular interactions between the coronavirus and different surfaces is needed to address the transmission of SARS-CoV-2 through respiratory droplet-contaminated surfaces or fomites. The receptor-binding domain (RBD) of the spike protein is a key target for the adhesion of SARS-CoV-2 on the surface. To understand the effect of mutations on adhesion, atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) was used to quantify the interactions between wild-type, Omicron, and XBB with several surfaces. The measurement revealed that RBD exhibits relatively higher forces on paper and gold surfaces, with the average force being 1.5 times greater compared to that on plastic surface. In addition, the force elevation on paper and gold surfaces for the variants can reach ∼28% relative to the wild type. These findings enhance our understanding of the nanomechanical interactions of the virus on common surfaces.

Exploring the spatial pattern of community urban green spaces and COVID-19 risk in Wuhan based on a random forest model

Since 2019, COVID-19 has triggered a renewed investigation of the urban environment and disease outbreak. While the results have been inconsistent, it has been observed that the quantity of urban green spaces (UGS) is correlated with the risk of COVID-19. However, the spatial pattern has largely been ignored, especially on the community scale. In high-density communities where it is difficult to increase UGS quantity, UGS spatial pattern could be a crucial predictive variable. Thus, this study investigated the relative contribution of quantity and spatial patterns of UGS on COVID-19 risk at the community scale using a random forest (RF) regression model based on (n = 44) communities in Wuhan. Findings suggested that 8 UGS indicators can explain 35% of the risk of COVID-19, and the four spatial pattern metrics that contributed most were core, edge, loop, and branch whereas UGS quantity contributed least. The potential mechanisms between UGS and COVID-19 are discussed, including the influence of UGS on residents' social distance and environmental factors in the community. This study offers a new perspective on optimizing UGS for public health and sustainable city design to combat pandemics and inspire future research on the specific relationship between UGS spatial patterns and pandemics and therefore help establish mechanisms of UGS and pandemics.

Development and efficacy assessment of hand sanitizers and polylactic acid films incorporating caffeic acid and vanillin for enhanced antiviral properties against HCoV-229E

BACKGROUND

Although three years after the outbreak of SARS-CoV-2, the virus is still having a significant impact on human health and the global economy. Infection through respiratory droplets is the main transmission route, but the transmission of the virus by surface contact cannot be ignored. Hand sanitizers and antiviral films can be applied to control SARS-CoV-2, but sanitizers and films show drawbacks such as resistance of the virus against ethanol and environmental problems including the overuse of plastics. Therefore, this study suggested applying natural substrates to hand sanitizers and antiviral films made of biodegradable plastic (PLA). This approach is expected to provide advantages for the easy control of SARS-CoV-2 through the application of natural substances.

METHODS

Antiviral disinfectants and films were manufactured by adding caffeic acid and vanillin to ethanol, isopropyl alcohol, benzalkonium chloride, and PLA. Antiviral efficacies were evaluated with slightly modified international standard testing methods EN 14,476 and ISO 21,702.

RESULTS

In suspension, all the hand sanitizers evaluated in this study showed a reduction of more than 4 log within 2 min against HCoV-229E. After natural substances were added to the hand sanitizers, the time needed to reach the detection limit of the viral titer was shortened both in suspension and porcine skin. However, no difference in the time needed to reach the detection limit of the viral titer was observed in benzalkonium chloride. In the case of antiviral films, those made using both PLA and natural substances showed a 1 log reduction of HCoV-229E compared to the neat PLA film for all treatment groups. Furthermore, the influence of the organic load was evaluated according to the number of contacts of the antiviral products with porcine skin. Ten rubs on the skin resulted in slightly higher antiviral activity than 50 rubs.

CONCLUSION

This study revealed that caffeic acid and vanillin can be effectively used to control HCoV-229E for hand sanitizers and antiviral films. In addition, it is recommended to remove organic matter from the skin for maintaining the antiviral activity of hand sanitizer and antiviral film as the antiviral activity decreased as the organic load increased in this study.

Toxicity Mechanisms of Copper Nanoparticles and Copper Surfaces on Bacterial Cells and Viruses

Copper is a metal historically used to prevent infections. One of the most relevant challenges in modern society are infectious disease outbreaks, where copper-based technologies can play a significant role. Currently, copper nanoparticles and surfaces are the most common antimicrobial copper-based technologies. Despite the widespread use of copper on nanoparticles and surfaces, the toxicity mechanism(s) explaining their unique antimicrobial properties are not entirely known. In general, toxicity effects described in bacteria and fungi involve the rupture of membranes, accumulation of ions inside the cell, protein inactivation, and DNA damage. A few studies have associated Cu-toxicity with ROS production and genetic material degradation in viruses. Therefore, understanding the mechanisms of the toxicity of copper nanoparticles and surfaces will contribute to developing and implementing efficient antimicrobial technologies to combat old and new infectious agents that can lead to disease outbreaks such as COVID-19. This review summarizes the current knowledge regarding the microbial toxicity of copper nanoparticles and surfaces and the gaps in this knowledge. In addition, we discuss potential applications derived from discovering new elements of copper toxicity, such as using different molecules or modifications to potentiate toxicity or antimicrobial specificity.

Understanding how different surfaces and environmental biofilms found in food processing plants affect the spread of COVID-19

Meat processing plants have been at the center of the SARS-CoV-2 pandemic, with a recent report citing 90% of US facilities having multiple outbreaks during 2020 and 2021. We explored the potential for biofilms to act as a reservoir in protecting, harboring, and dispersing SARS-CoV-2 throughout the meat processing facility environment. To do this, we used Murine Hepatitis Virus (MHV), as a surrogate for SARS-CoV-2, and meat processing facility drain samples to develop mixed-species biofilms on materials found in meat processing facilities (stainless steel (SS), PVC, and ceramic tiles). After exposure to the biofilm organisms for five days post-inoculation at 7°C we conducted quantitative PCR (qPCR) and plaque assays to determine whether MHV could remain both detectable and viable. Our data provides evidence that coronaviruses can remain viable on all the surfaces tested and are also able to integrate within an environmental biofilm. Although a portion of MHV was able to remain infectious after incubation with the environmental biofilm, a large reduction in plaque numbers was identified when compared with the viral inoculum incubated without biofilm on all test surfaces, which ranged from 6.45-9.27-fold higher. Interestingly, we observed a 2-fold increase in the virus-environmental biofilm biovolume when compared to biofilm without virus, indicating that the biofilm bacteria both detected and reacted to the virus. These results indicate a complex virus-environmental biofilm interaction. Although we observed better survival of MHV on a variety of surfaces commonly found in meat processing plants alone than with the biofilm, there is the potential for biofilms to protect virions from disinfecting agents, which has implications for the potential of SARS-CoV-2 prevalence within the meat processing plant environment. Also given the highly infectious nature of SARS-CoV-2, particularly for some of the variant strains such as omicron, having even a residual level of virus present represents a serious health hazard. The increase in biofilm biovolume in response to virus is also a concern for food safety due to the potential of the same being seen with organisms associated with food poisoning and food spoilage.

SARS-CoV-2 Surveillance between 2020 and 2021 of All Mammalian Species in Two Flemish Zoos (Antwerp Zoo and Planckendael Zoo)

The COVID-19 pandemic has led to millions of human infections and deaths worldwide. Several other mammal species are also susceptible to SARS-CoV-2, and multiple instances of transmission from humans to pets, farmed mink, wildlife and zoo animals have been recorded. We conducted a systematic surveillance of SARS-CoV-2 in all mammal species in two zoos in Belgium between September and December 2020 and July 2021, in four sessions, and a targeted surveillance of selected mammal enclosures following SARS-CoV-2 infection in hippopotamuses in December 2021. A total of 1523 faecal samples from 103 mammal species were tested for SARS-CoV-2 via real-time PCR. None of the samples tested positive for SARS-CoV-2. Additional surrogate virus neutralisation tests conducted on 50 routinely collected serum samples from 26 mammal species were all negative. This study is the first to our knowledge to conduct active SARS-CoV-2 surveillance for several months in all mammal species of a zoo. We conclude that at the time of our investigation, none of the screened animals were excreting SARS-CoV-2.

Decay rate estimation of respiratory viruses in aerosols and on surfaces under different environmental conditions

Majority of the viral outbreaks are super-spreading events established within 2-10 h, dependent on a critical time interval for successful transmission between humans, which is governed by the decay rates of viruses. To evaluate the decay rates of respiratory viruses over a short span, we calculated their decay rate values for various surfaces and aerosols. We applied Bayesian regression and ridge regression and determined the best estimation for respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), severe acute respiratory syndrome coronavirus (SARS-CoV), middle east respiratory syndrome coronavirus (MERS-CoV), influenza viruses, and respiratory syncytial virus (RSV); the decay rate values in aerosols for these viruses were 4.83 ± 5.70, 0.40 ± 0.24, 0.11 ± 0.04, 2.43 ± 5.94, and 1.00 ± 0.50 h^-1, respectively. The highest decay rate values for each virus type differed according to the surface type. According to the model performance criteria, the Bayesian regression model was better for SARS-CoV-2 and influenza viruses, whereas ridge regression was better for SARS-CoV and MERS-CoV. A simulation using a better estimation will help us find effective non-pharmaceutical interventions to control virus transmissions.

Antibacterial, antiviral, and biodegradable collagen network mask for effective particulate removal and wireless breath monitoring

Functional face masks that can effectively remove particulate matter and pathogens are critical to addressing the urgent health needs arising from industrial air pollution and the COVID-19 pandemic. However, most commercial masks are manufactured by tedious and complicated network-forming procedures (e.g., meltblowing and electrospinning). In addition, the materials used (e.g., polypropylene) have significant limitations such as a lack of pathogen inactivation and degradability, which can cause secondary infection and serious environmental concerns if discarded. Here, we present a facile and straightforward method for creating biodegradable and self-disinfecting masks based on collagen fiber networks. These masks not only provide superior protection against a wide range of hazardous substances in polluted air, but also address environmental concerns associated with waste disposal. Importantly, collagen fiber networks with naturally existing hierarchical microporous structures can be easily modified by tannic acid to improve its mechanical characteristics and enable the in situ production of silver nanoparticles. The resulting masks exhibit excellent antibacterial (>99.99%, 15 min) and antiviral (>99.999%, 15 min) capabilities, as well as high PM_2.5 removal efficiency (>99.9%, 30 s). We further demonstrate the integration of the mask into a wireless platform for respiratory monitoring. Therefore, the smart mask has enormous promise for combating air pollution and contagious viruses, managing personal health, and alleviating waste issues caused by commercial masks.

Influence of meteorological factors on the severity of COVID-19 in Spain: Observational ecological study

Objectives

Evaluating whether meteorological and geographical variables could be associated with the severity of COVID-19 in Spain.

Methods

An ecological study was performed to analyze the influence of meteorological and geographical factors in hospital admissions and deaths due to COVID-19 in the 52 provinces of Spain (24 coastal and 28 inland regions), during the first three pandemic waves. Medical and mortality data were collected from the Carlos III Health Institute (ISCIII) and meteorological variables were requested to the Spanish State Meteorological Agency (AEMET).

Results

Regarding the diagnosed cases it is remarkable that the percentage of patients hospitalized for COVID-19 was lower in the coastal provinces than in the inland ones (8.7 ± 2.6% vs. 11.5 ± 2.6%; p = 9.9 × 10^-5). Furthermore, coastal regions registered a lower percentage of mortality than inland regions (2.0 ± 0.6% vs. 3.1 ± 0.8%; p = 1.7 × 10^-5). Mean air temperature was inversely correlated both with COVID-19 hospitalizations (Rho: -0.59; p = 3.0 × 10^-6) and mortality (Rho: -0.70; p = 5.3 × 10^-9). In those provinces with a mean air temperature <10 °C mortality by COVID-19 was twice that of those with >16 °C. Finally, we found an association between mortality and the location of the province (coastal/inland), altitude, patient age and the average air temperature; the latter was inversely and independently correlated with mortality (non standardised B coeff.: -0.24; IC 95%: -0.31 to -0.16; p = 2.38 × 10^-8).

Conclusions

The average air temperature was inversely associated with COVID-19 mortality in our country during the first three waves of the pandemic.

Stability of SARS-CoV-2 on inanimate surfaces: A review

The stability of SARS-CoV-2 for varying periods on a wide range of inanimate surfaces has raised concerns about surface transmission; however, there is still no evidence to confirm this route. In the present review, three variables affecting virus stability, namely temperature, relative humidity (RH), and initial virus titer, were considered from different experimental studies. The stability of SARS-CoV-2 on the surfaces of six different contact materials, namely plastic, metal, glass, protective equipment, paper, and fabric, and the factors affecting half-life period was systematically reviewed. The results showed that the half-life of SARS-CoV-2 on different contact materials was generally 2-10 h, up to 5 d, and as short as 30 min at 22 °C, whereas the half-life of SARS-CoV-2 on non-porous surfaces was generally 5-9 h d, up to 3 d, and as short as 4 min at 22 ℃. The half-life on porous surfaces was generally 1-5 h, up to 2 d, and as short as 13 min at 22 °C. Therefore, the half-life period of SARS-CoV-2 on non-porous surfaces is longer than that on porous surfaces, and thehalf-life of the virus decreases with increasing temperature, whereas RH produces a stable negative inhibitory effect only in a specific humidity range. Various disinfection precautions can be implemented in daily life depending on the stability of SARS-CoV-2 on different surfaces to interrupt virus transmission, prevent COVID-19 infections, and avoid over-disinfection. Owing to the more stringent control of conditions in laboratory studies and the lack of evidence of transmission through surfaces in the real world, it is difficult to provide strong evidence for the efficiency of transmission of the contaminant from the surface to the human body. Therefore, we suggest that future research should focus on exploring the systematic study of the entire transmission process of the virus, which will provide a theoretical basis for optimizing global outbreak prevention and control measures.

A Comprehensive Sampling Study on SARS-CoV-2 Contamination of Air and Surfaces in a Large Meat Processing Plant Experiencing COVID-19 Clusters in June 2020

OBJECTIVE

We aimed to assess SARS-CoV-2 contamination of air and surfaces to gain insight into potential occupational exposure in a large meat processing plant experiencing COVID-19 clusters. Methods: Oro-nasopharyngeal SARS-CoV-2 screening was performed in 76 workers. Environmental samples ( n = 275) including air, ventilation systems, sewage, and swabs of high-touch surfaces and workers' hands were tested for SARS-CoV-2 RNA by real-time quantitative polymerase chain reaction. Results: Twenty-seven (35.5%) of the (predominantly asymptomatic) workers tested positive with modest to low viral loads (cycle threshold ≥ 29.7). Six of 203 surface swabs, 1 of 12 personal air samples, and one of four sewage samples tested positive; other samples tested negative. Conclusions: Although one third of workers tested positive, environmental contamination was limited. Widespread SARS-CoV-2 transmission via air and surfaces was considered unlikely within this plant at the time of investigation while strict COVID-19 control measures were already implemented.

Lessons learned from the SARS-CoV-2 pandemic; from nucleic acid nanomedicines, to clinical trials, herd immunity, and the vaccination divide

INTRODUCTION

In November 2019, the idea of a zoonotic virus crossing over to human transmission in a seafood market in Wuhan, China, and then soaring across the globe to claim over 6.3 million lives and persisting to date, seemed more like wild science fiction than a future reality. As the SARS-CoV-2 pandemic continues, it is important to hallmark the imprints the pandemic has made on science.

AREAS COVERED

This review covers the biology of SARS-CoV-2, vaccine formulations and trials, the concept of 'herd resistance,' and the vaccination divide.

EXPERT OPINION

The SARS-CoV-2 pandemic has changed the landscape of medicine. The rapid approval of SARS-CoV-2 vaccines has changed the culture of drug development and clinical approvals. This change is already leading to more accelerated trials. The RNA vaccines have opened the market for nucleic acid therapies and the applications are limitless - from cancer to influenza. A phenomenon that has occurred is that the low efficacy of current vaccines and the rapid mutation rate of the virus is preventing herd immunity from being attained. Instead, herd resistance is being acquired. Even with future, more effective vaccines, anti-vaccination attitudes will continue to challenge the quest for SARS-CoV-2 herd immunity.

Factors associated with changes in healthy lifestyle behaviors among hematological cancer patients during the COVID-19 pandemic

Background

There is a paucity of research examining the effects of the COVID-19 pandemic on the healthy lifestyle behaviors of hematological cancer patients. We examined changes in healthy lifestyle behaviors since the pandemic and identified factors associated with these changes among members of this high-risk population.

Methods

Hematological cancer patients (n = 394) completed a self-report online survey from July to August 2020. The survey assessed pandemic-related changes in exercise, alcohol consumption, and consumption of fruit, vegetables, and wholegrains. Information relating to several demographic, clinical, and psychological factors was also collected. Factors associated with changes in healthy lifestyle behaviors were analyzed using logistic regression.

Results

Just 14% of patients surveyed reported exercising more during the pandemic (39% exercised less). Only a quarter (24%) improved their diet, while nearly half (45%) reported eating less fruit, vegetables, and wholegrains. Just over a quarter (28%) consumed less alcohol (17% consumed more alcohol). Fear of contracting COVID-19 and psychological distress were significantly associated with reduced exercise. Younger age was significantly associated with both increased alcohol consumption and increased exercise. Being a woman was significantly associated with unfavorable changes in diet and being married was significantly associated with decreased alcohol consumption.

Conclusion

A substantial proportion of hematological cancer patients reported unfavorable changes in healthy lifestyle behaviors during the pandemic. Results highlight the importance of supporting healthy lifestyle practices among this particularly vulnerable group to ensure health is optimized while undergoing treatment and when in remission, particularly during crisis times like the COVID-19 pandemic.

Antimicrobial Nanomaterials as Advanced Coatings for Self-Sanitizing of Textile Clothing and Personal Protective Equipment

Controlling bioaerosols has become increasingly critical in affecting human health. Natural product treatment in the nano form is a potential method since it has lower toxicity than inorganic nanomaterials like silver nanoparticles. This research is important for the creation of a bioaerosol control system that is effective. Nanoparticles (NPs) are gradually being employed to use bacteria as a nonantibiotic substitute for treating bacterial infections. The present study looks at nanoparticles' antimicrobial properties, their method of action, their impact on drug-opposing bacteria, and the hazards connected with their operation as antimicrobial agents. The aspects that influence nanoparticle conduct in clinical settings, as well as their distinctive features and mode of action as antibacterial assistants, are thoroughly examined. Nanoparticles' action on bacterial cells is presently accepted by way of the introduction of oxidative stress induction, metal-ion release, and nonoxidative methods. Because many concurrent mechanisms of action against germs would necessitate multiple simultaneous gene modifications in the same bacterial cell for antibacterial protection to evolve, bacterial cells developing resistance to NPs is difficult. This review discusses the antimicrobial function of NPs against microbes and presents a comprehensive discussion of the bioaerosols: their origin, hazards, and their prevention. This state of the art method is dependent upon the use of personal protective gear against these bioaerosols. The benefit of the utmost significant categories of metal nanoparticles as antibacterial agents is given important consideration. The novelty of this review depends upon the antimicrobial properties of (a) silver (Ag), (b) zinc oxide (ZnO), and (c) copper oxide (CuO) nanoparticles. The value-added features of these nanoparticles are discussed, as well as their physicochemical characterization and pharmacokinetics, including the toxicological danger they pose to people. Lastly, the effective role of nanomaterials and their future in human wellness is discussed.

Number of COVID-19 cases required in a population to detect SARS-CoV-2 RNA in wastewater in the province of Alberta, Canada: Sensitivity assessment

With a unique and large size of testing results of 1,842 samples collected from 12 wastewater treatment plants (WWTP) for 14 months through from low to high prevalence of COVID-19, the sensitivity of RT-qPCR detection of SARS-CoV-2 RNA in wastewater that correspond to the communities was computed by using Probit analysis. This study determined the number of new COVID-19 cases per 100,000 population required to detect SARS-CoV-2 RNA in wastewater at defined probabilities and provided an evidence-based framework of wastewater-based epidemiology surveillance (WBE). Input data were positive and negative test results of SARS-CoV-2 RNA in wastewater samples and the corresponding new COVID-19 case rates per 100,000 population served by each WWTP. The analyses determined that RT-qPCR-based SARS-CoV-2 RNA detection threshold at 50%, 80% and 99% probability required a median of 8 (range: 4-19), 18 (9-43), and 38 (17-97) of new COVID-19 cases /100,000, respectively. Namely, the positive detection rate at 50%, 80% and 99% probability were 0.01%, 0.02%, and 0.04% averagely for new cases in the population. This study improves understanding of the performance of WBE SARS-CoV-2 RNA detection using the large datasets and prolonged study period. Estimated COVID-19 burden at a community level that would result in a positive detection of SARS-CoV-2 in wastewater is critical to support WBE application as a supplementary warning/monitoring system for COVID-19 prevention and control.

Mechanisms controlling the transport and evaporation of human exhaled respiratory droplets containing the severe acute respiratory syndrome coronavirus: a review

Transmission of the coronavirus disease 2019 is still ongoing despite mass vaccination, lockdowns, and other drastic measures to control the pandemic. This is due partly to our lack of understanding on the multiphase flow mechanics that control droplet transport and viral transmission dynamics. Various models of droplet evaporation have been reported, yet there is still limited knowledge about the influence of physicochemical parameters on the transport of respiratory droplets carrying the severe acute respiratory syndrome coronavirus 2. Here we review the effects of initial droplet size, environmental conditions, virus mutation, and non-volatile components on droplet evaporation and dispersion, and on virus stability. We present experimental and computational methods to analyze droplet transport, and factors controlling transport and evaporation. Methods include thermal manikins, flow techniques, aerosol-generating techniques, nucleic acid-based assays, antibody-based assays, polymerase chain reaction, loop-mediated isothermal amplification, field-effect transistor-based assay, and discrete and gas-phase modeling. Controlling factors include environmental conditions, turbulence, ventilation, ambient temperature, relative humidity, droplet size distribution, non-volatile components, evaporation and mutation. Current results show that medium-sized droplets, e.g., 50 µm, are sensitive to relative humidity. Medium-sized droplets experience delayed evaporation at high relative humidity, and increase airborne lifetime and travel distance. By contrast, at low relative humidity, medium-sized droplets quickly shrink to droplet nuclei and follow the cough jet. Virus inactivation within a few hours generally occurs at temperatures above 40 °C, and the presence of viral particles in aerosols impedes droplet evaporation.

Conversational head movement decreases close-contact exposure to expired respiratory droplets

People constantly move their heads during conversation, as such movement is an important non-verbal mode of communication. Head movement alters the direction of people's expired air flow, therefore affecting their conversational partners' level of exposure. Nevertheless, there is a lack of understanding of the mechanism whereby head movement affects people's exposure. In this study, a dynamic meshing method in computational fluid dynamics was used to simulate the head movement of a human-shaped thermal manikin. Droplets were released during the oral expiration periods of the source manikin, during which it was either motionless, was shaking its head or was nodding its head, while the head of a face-to-face target manikin remained motionless. The results indicate that the target manikin had a high level of exposure to respiratory droplets when the source manikin was motionless, whereas the target manikin's level of exposure was significantly reduced when the source manikin was shaking or nodding its head. The source manikin had the highest level of self-exposure when it was nodding its head and the lowest level of self-exposure when its head was motionless. People's level of exposure during close contact is highly variable, highlighting the need for further investigations in more realistic conversational scenarios.

Interactions between Humans and Dogs during the COVID-19 Pandemic: Recent Updates and Future Perspectives

COVID-19 is one of the deadliest epidemics. This pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the role of dogs in spreading the disease in human society is poorly understood. This review sheds light on the limited susceptibility of dogs to COVID-19 infections which is likely attributed to the relatively low levels of angiotensin-converting enzyme 2 (ACE2) in the respiratory tract and the phylogenetic distance of ACE2 in dogs from the human ACE2 receptor. The low levels of ACE2 affect the binding affinity between spike and ACE2 proteins resulting in it being uncommon for dogs to spread the disease. To demonstrate the role of dogs in spreading COVID-19, we reviewed the epidemiological studies and prevalence of SARS-CoV-2 in dogs. Additionally, we discussed the use of detection dogs as a rapid and reliable method for effectively discriminating between SARS-CoV-2 infected and non-infected individuals using different types of samples (secretions, saliva, and sweat). We considered the available information on COVID-19 in the human-dog interfaces involving the possibility of transmission of COVID-19 to dogs by infected individuals and vice versa, the human-dog behavior changes, and the importance of preventive measures because the risk of transmission by domestic dogs remains a concern.

Municipal wastewater viral pollution in Saudi Arabia: effect of hot climate on COVID-19 disease spreading

The viral RNA of SARS-Coronavirus-2 is known to be contaminating municipal wastewater. We aimed to assess if COVID-19 disease is spreading through wastewater. We studied the amount of viral RNA in raw sewage and the efficiency of the sewage treatment to remove the virus. Sewage water was collected before and after the activated sludge process three times during summer 2020 from three different sewage treatment plants. The sewage treatment was efficient in removing SARS-CoV-2 viral RNA. Each sewage treatment plant gathered wastewater from one hospital, of which COVID-19 admissions were used to describe the level of disease occurrence in the area. The presence of SARS-CoV-2 viral RNA-specific target genes (N1, N2, and E) was confirmed using RT-qPCR analysis. However, hospital admission did not correlate significantly with viral RNA. Moreover, viral RNA loads were relatively low, suggesting that sewage might preserve viral RNA in a hot climate only for a short time.

Sewage surveillance system using urological wastewater: Key to COVID-19 monitoring?

Since December 2019, the emergence of a new Severe Acute Respiratory Syndrome- coronavirus (SARS-CoV-2) has led to a global coronavirus pandemic disease (COVID-19), with devastating consequences for all healthcare worldwide, including urological care. COVID-19 has led to concern among urological healthcare workers about viral presence, detection and routes of transmission during routine clinical practice. The potential presence of (active) virus in bodily fluids of COVID-19 patients remains a continuing topic of debate. Therefore, we highlight viral detection methods and review the presence of SARS-CoV-2 in urine, feces, and semen. Finally, we discuss how excretion of virus particles through urological bodily fluids might be pivotal to epidemiologic monitoring and control of the disease.

Bioinformatic modelling of SARS-CoV-2 pandemic with a focus on country-specific dynamics

BACKGROUND

One of the seminal events since 2019 has been the outbreak of the SARS-CoV-2 pandemic. Countries have adopted various policies to deal with it, but they also differ in their socio-geographical characteristics and public health care facilities. Our study aimed to investigate differences between epidemiological parameters across countries.

METHOD

The analysed data represents SARS-CoV-2 repository provided by the Johns Hopkins University. Separately for each country, we estimated recovery and mortality rates using the SIRD model applied to the first 30, 60, 150, and 300 days of the pandemic. Moreover, a mixture of normal distributions was fitted to the number of confirmed cases and deaths during the first 300 days. The estimates of peaks' means and variances were used to identify countries with outlying parameters.

RESULTS

For 300 days Belgium, Cyprus, France, the Netherlands, Serbia, and the UK were classified as outliers by all three outlier detection methods. Yemen was classified as an outlier for each of the four considered timeframes, due to high mortality rates. During the first 300 days of the pandemic, the majority of countries underwent three peaks in the number of confirmed cases, except Australia and Kazakhstan with two peaks.

CONCLUSIONS

Considering recovery and mortality rates we observed heterogeneity between countries. Liechtenstein was the "positive" outlier with low mortality rates and high recovery rates, at the opposite, Yemen represented a "negative" outlier with high mortality for all four considered periods and low recovery for 30 and 60 days.

Nature-Inspired Surface Structures Design for Antimicrobial Applications

Surface contamination by microorganisms such as viruses and bacteria may simultaneously aggravate the biofouling of surfaces and infection of wounds and promote cross-species transmission and the rapid evolution of microbes in emerging diseases. In addition, natural surface structures with unique anti-biofouling properties may be used as guide templates for the development of functional antimicrobial surfaces. Further, these structure-related antimicrobial surfaces can be categorized into microbicidal and anti-biofouling surfaces. This review introduces the recent advances in the development of microbicidal and anti-biofouling surfaces inspired by natural structures and discusses the related antimicrobial mechanisms, surface topography design, material application, manufacturing techniques, and antimicrobial efficiencies.

An excimer lamp to provide far-ultraviolet C irradiation for dining-table disinfection

Dining tables may present a risk to diners by transmitting bacteria and/or viruses. Currently, there is a lack of an environmental-friendly and convenient means to protect diners when they are sitting together. This investigation constructed far-UVC excimer lamps to disinfect dining-table surfaces. The lamps were mounted at different heights and orientations, and the irradiance on table surfaces was measured. The irradiation doses to obtain different inactivation efficiencies for Escherichia coli (E. coli) were provided. In addition, numerical modeling was conducted for irradiance and the resulting inactivation efficiency. The surface-to-surface (S2S) model was validated with the measured irradiance. The germicidal performance of far-UVC irradiation, the far-UVC doses to which diners were exposed, and the risk of exposure to the generated ozone were evaluated. The results revealed that an irradiation dose of 12.8 mJ/cm2 can disinfect 99.9% of E. coli on surfaces. By varying the lamp irradiance output, the number and positions of the lamps, the far-UVC irradiation can achieve a 3-log reduction for a dining duration of 5 min. Besides, the far-UVC lamp has a low damage risk to diners when achieving an effective inactivation rate. Moreover, there is virtually no ozone exposure risk in a mechanically ventilated dining hall.

SARS-CoV-2 Aerosol and Surface Detections in COVID-19 Testing Centers and Implications for Transmission Risk in Public Facing Workers

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and resulting COVID-19 (coronavirus disease 2019) pandemic have required mass diagnostic testing, often taking place in testing sites within hospitals, clinics, or at satellite locations. To establish the potential of SARS-CoV-2 aerosol transmission and to identify junctures during testing that result in increased viral exposure, aerosol and surface samples were examined for the presence of SARS-CoV-2 RNA from locations within Nebraska Medicine COVID-19 testing and vaccine clinics. Aerosols containing SARS-CoV-2 RNA detected within clinics suggest viral shedding from infected individuals. SARS-CoV-2 RNA detection in aerosol samples was shown to correlate with clinic operation and patient infection, as well as with community infection findings. Additionally, SARS-CoV-2 RNA was detected in surface samples collected from clinics. The presence of SARS-CoV-2 RNA in aerosols in these clinics supports the continued use of respiratory protection and sanitization practices for healthcare workers, and other workers with public facing occupations.

The association of COVID-19 incidence with temperature, humidity, and UV radiation - A global multi-city analysis

BACKGROUND AND AIM

The associations between COVID-19 transmission and meteorological factors are scientifically debated. Several studies have been conducted worldwide, with inconsistent findings. However, often these studies had methodological issues, e.g., did not exclude important confounding factors, or had limited geographic or temporal resolution. Our aim was to quantify associations between temporal variations in COVID-19 incidence and meteorological variables globally.

METHODS

We analysed data from 455 cities across 20 countries from 3 February to 31 October 2020. We used a time-series analysis that assumes a quasi-Poisson distribution of the cases and incorporates distributed lag non-linear modelling for the exposure associations at the city-level while considering effects of autocorrelation, long-term trends, and day of the week. The confounding by governmental measures was accounted for by incorporating the Oxford Governmental Stringency Index. The effects of daily mean air temperature, relative and absolute humidity, and UV radiation were estimated by applying a meta-regression of local estimates with multi-level random effects for location, country, and climatic zone.

RESULTS

We found that air temperature and absolute humidity influenced the spread of COVID-19 over a lag period of 15 days. Pooling the estimates globally showed that overall low temperatures (7.5 °C compared to 17.0 °C) and low absolute humidity (6.0 g/m3 compared to 11.0 g/m3) were associated with higher COVID-19 incidence (RR temp =1.33 with 95%CI: 1.08; 1.64 and RR AH =1.33 with 95%CI: 1.12; 1.57). RH revealed no significant trend and for UV some evidence of a positive association was found. These results were robust to sensitivity analysis. However, the study results also emphasise the heterogeneity of these associations in different countries.

CONCLUSION

Globally, our results suggest that comparatively low temperatures and low absolute humidity were associated with increased risks of COVID-19 incidence. However, this study underlines regional heterogeneity of weather-related effects on COVID-19 transmission.

Stability of SARS-CoV-2 in cold-chain transportation environments and the efficacy of disinfection measures

Background

Low temperature is conducive to the survival of COVID-19. Some studies suggest that cold-chain environment may prolong the survival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and increase the risk of transmission. However, the effect of cold-chain environmental factors and packaging materials on SARS-CoV-2 stability remains unclear.

Methods

This study aimed to reveal cold-chain environmental factors that preserve the stability of SARS-CoV-2 and further explore effective disinfection measures for SARS-CoV-2 in the cold-chain environment. The decay rate of SARS-CoV-2 pseudovirus in the cold-chain environment, on various types of packaging material surfaces, i.e., polyethylene plastic, stainless steel, Teflon and cardboard, and in frozen seawater was investigated. The influence of visible light (wavelength 450 nm-780 nm) and airflow on the stability of SARS-CoV-2 pseudovirus at -18°C was subsequently assessed.

Results

Experimental data show that SARS-CoV-2 pseudovirus decayed more rapidly on porous cardboard surfaces than on nonporous surfaces, including polyethylene (PE) plastic, stainless steel, and Teflon. Compared with that at 25°C, the decay rate of SARS-CoV-2 pseudovirus was significantly lower at low temperatures. Seawater preserved viral stability both at -18°C and with repeated freeze-thaw cycles compared with that in deionized water. Visible light from light-emitting diode (LED) illumination and airflow at -18°C reduced SARS-CoV-2 pseudovirus stability.

Conclusion

Our studies indicate that temperature and seawater in the cold chain are risk factors for SARS-CoV-2 transmission, and LED visible light irradiation and increased airflow may be used as disinfection measures for SARS-CoV-2 in the cold-chain environment.

Various advanced wastewater treatment methods to remove microplastics and prevent transmission of SARS-CoV-2 to airborne microplastics

Microplastics (MPs) and SARS-CoV-2 interact due to their widespread presence in our environment and affect the virus' behaviour indoors and outdoors. Therefore, it is necessary to study the interaction between MPs and SARS-CoV-2. The environmental damage caused by MPs is increasing globally. Emerging pollutants may adversely affect organisms, especially sewage, posing a threat to human health, animal health, and the ecological system. A significant concern with MPs in the air is that they are a vital component of MPs in the other environmental compartments, such as water and soil, which may affect human health through ingesting or inhaling. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membrane bioreactors, advanced oxidation processes, adsorption, etc., are highly effective in removing MPs; they can still serve as an entrance route due to their constantly being discharged into aquatic environments. Following that, an analysis of each process for MPs' removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, an airborne microplastic has been reported in urban areas, raising health concerns since aerosols are considered a possible route of SARS-CoV-2 disease transmission and bind to airborne MP surfaces. The MPs can be removed from wastewater through conventional treatment processes with physical processes such as screening, grit chambers, and pre-sedimentation.

Assessment of SARS-CoV-2 Stability in human and environmental matrices, and potential hazards

In the context of the ongoing pandemic of COVID-19, SARS-CoV-2 was detected in human excreta and environmental matrices. The occurrence of SARS-CoV-2 in environmental compartments raises questions on its fate and stability in these matrices and its potential to spread in the exposed communities. This review focused on the stability of the SARS-CoV-2 in human excreta, wastewater, soils, crops, and other environmental matrices, that may be reached through human excreta and sewage products spreading. Little is known about the persistence and survival of SARS-CoV-2 in the environment. Up to now sewage sludge, soil and crops are seldom investigated implying the convenience of considering future researches focusing on SARS-CoV-2 in soils receiving wastewater and sewage sludge, as well as on grown crops. Information regarding SARS-CoV-2 persistence in environmental media is crucial to establish and implement effective policies and measures for mitigating the transmission of COVID-19 and tackling eventual future outbreaks.

Efficacy of copper blend coatings in reducing SARS-CoV-2 contamination

SARS-CoV-2 is a highly infectious virus and etiologic agent of COVID-19, which is spread by respiratory droplets, aerosols, and contaminated surfaces. Copper is a known antiviral agent, and has resulted in successful reduction of pathogens and infections by 83-99.9% when coated on surfaces in intensive care units. Additionally, copper has been shown to inactivate pathogens such as Coronavirus 226E, a close relative of SARS-CoV-2. Here, we examine the ability of two copper blends with differing compositions to inactivate SARS-CoV-2 virus at different time points. Copper Blend 2 (75.07% pure copper) was found to significantly reduce (over 50%) the viability of SARS-CoV-2 at 5 min of contact, with at least 98% reduction in recovered virus at 20 min (vs. plastic control). However, Copper Blend 1 (48.26% pure copper), was not found to significantly reduce viability of SARS-CoV-2 at any time point when compared to plastic. This may indicate that there is an important percentage of copper content in materials that is needed to effectively inactivate SARS-CoV-2. Overall, this study shows that over the course of 20 min, coatings made of copper materials can significantly reduce the recovery of infectious SARS-CoV-2 compared to uncoated controls, indicating the effective use of copper for viral inactivation on surfaces. Furthermore, it may suggest higher copper content has stronger antiviral properties. This could have important implications when short turnaround times are needed for cleaning and disinfecting rooms or equipment, especially in strained healthcare settings which are struggling to keep up with demand.