Solar heating to inactivate thermal-sensitive pathogenic microorganisms in vehicles: application to COVID-19

Unanswered questions on the airborne transmission of COVID-19

Policies and measures to control pandemics are often failing. While biological factors controlling transmission are usually well explored, little is known about the environmental drivers of transmission and infection. For instance, respiratory droplets and aerosol particles are crucial vectors for the airborne transmission of the severe acute respiratory syndrome coronavirus 2, the causation agent of the coronavirus 2019 pandemic (COVID-19). Once expectorated, respiratory droplets interact with atmospheric particulates that influence the viability and transmission of the novel coronavirus, yet there is little knowledge on this process or its consequences on virus transmission and infection. Here we review the effects of atmospheric particulate properties, vortex zones, and air pollution on virus survivability and transmission. We found that particle size, chemical constituents, electrostatic charges, and the moisture content of airborne particles can have notable effects on virus transmission, with higher survival generally associated with larger particles, yet some viruses are better preserved on small particles. Some chemical constituents and surface-adsorbed chemical species may damage peptide bonds in viral proteins and impair virus stability. Electrostatic charges and water content of atmospheric particulates may affect the adherence of virion particles and possibly their viability. In addition, vortex zones and human thermal plumes are major environmental factors altering the aerodynamics of buoyant particles in air, which can strongly influence the transport of airborne particles and the transmission of associated viruses. Insights into these factors may provide explanations for the widely observed positive correlations between COVID-19 infection and mortality with air pollution, of which particulate matter is a common constituent that may have a central role in the airborne transmission of the novel coronavirus.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10311-022-01557-z.

Evaluation of the impact of pre-analytical conditions on sample stability for the detection of SARS-CoV-2 RNA

Demand for accurate SARS-CoV-2 diagnostics is high. Most samples in the UK are collected in the community and rely on the postal service for delivery to the laboratories. The current recommendation remains that swabs should be collected in Viral Transport Media (VTM) and transported with a cold chain to the laboratory for RNA extraction and RT-qPCR. This is not always possible. We aimed to test the stability of SARS-CoV-2 RNA subjected to different pre-analytical conditions. Swabs were dipped into PBS containing cultured SARS-CoV-2 and placed in either a dry tube or a tube containing either normal saline or VTM. The tubes were then stored at different temperatures (20-50 °C) for variable periods (8 h to 5 days). Samples were tested by RT-qPCR targeting SARS-CoV-2 E gene. VTM outperformed swabs in saline and dry swabs in all conditions. Samples in VTM were stable, independent of a cold chain, for 5 days, with a maximum increase in cycle threshold (Ct) of 1.34 when held at 40 °C. Using normal saline as the transport media resulted in a loss of sensitivity (increased Ct) over time and with increasing temperature (up to 7.8 cycles compared to VTM). SARS-CoV-2 was not detected in 3/9 samples in normal saline when tested after 120 h incubation. Transportation of samples in VTM provides a high level of confidence in the results despite the potential for considerable, uncontrolled variation in temperature and longer transportation periods. False negative results may be seen after 96 h in saline and viral loads will appear lower.

Municipal solid waste, an overlooked route of transmission for the severe acute respiratory syndrome coronavirus 2: a review

Municipal solid waste could potentially transmit human pathogens during the collection, transport, handling, and disposal of waste. Workers and residents living in the vicinity of municipal solid waste collection or disposal sites are particularly susceptible, especially unprotected workers and waste pickers. Recent evidence suggests that municipal solid waste-mediated transmission can spread the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans. Such risks, however, have received little attention from public health authorities so far and may present an under-investigated transmission route for SARS-CoV-2 and other infectious agents during pandemics. In this review, we provide a retrospective analysis of the challenges, practices, and policies on municipal solid waste management during the current pandemic, and scrutinize the recent case reports on the municipal solid waste-mediated transmission of the coronavirus disease 2019 (COVID-19). We found abrupt changes in quantity and composition of municipal solid wastes during the COVID-19. We detail pathways of exposure to SARS-CoV-2 and other pathogens carried on municipal solid wastes. We disclose evidence of pathogenic transmission by municipal solid waste to humans and animals. Assessments of current policies, gaps, and voluntary actions taken on municipal solid waste handling and disposal in the current pandemic are presented. We propose risk mitigation strategies and research priorities to alleviate the risk for humans and vectors exposed to municipal solid wastes.

The Impact of Mobility on Shopping Preferences during the COVID-19 Pandemic: The Evidence from the Slovak Republic

The COVID-19 global pandemic has affected normal human behaviour in day-to-day activities. As a result of various restrictions, people have significantly changed their shopping and mobility to limit the spread of the pandemic. This article aims to determine the association between consumers’ shopping preferences and the frequency of selected daily activities during and before the COVID-19 pandemic using correspondence analysis. The total sample consists of 407 respondents from Slovakia. The data are obtained from an online questionnaire divided into several sections such as socio-demographic factors, shopping preferences, and frequency of selected activities per week. The results show that there is an association between consumers’ preference for shopping in supermarkets and the frequency of family visits per week during the pandemic, among other factors. These findings follow up on previous studies on the consequences of changing mobility as a result of the global crisis.

Barcoding drug information to recycle unwanted household pharmaceuticals: a review

Huge quantities of unwanted pharmaceuticals are left in households, notably as a consequence of the rising drug demand caused by improved healthcare and the aging population. Unwanted pharmaceuticals may thus easily end up polluting ecosystems upon disposal. This pharmaceutical waste issue has been aggravated during the coronavirus disease pandemic (COVID-19) by excess prescription and panic buying. Unwanted household pharmaceuticals are normally collected by owners and volunteers, then incinerated in centralized facilities, yet with low efficiency during the COVID-19 lockdowns. Most pharmaceuticals could be recycled because they are rather stable, however there is actually no sustainable strategy to manage unwanted pharmaceuticals in a pandemic. Here I review the management of unwanted pharmaceuticals in households during the pandemic, with emphasis on drug take-back programs, waste minimization and recycling efforts. Reducing pharamaceutical waste could be done by informing people on what to do with unwanted pharmaceutical products; using machine-readable codes for automatic sorting; and applying existing techniques for recovery of active pharmaceutical ingredients for reuse. I propose a new strategy where owners sort their unwanted pharmaceuticals and submit information online. This will generate coded mailing labels that allow the owner to separate pharmaceuticals into categories such as opened, unused, expired, and non-expired. Once collected by recycling facilities and manufacturers, active ingredients will be extracted to create new pharmaceuticals which will be recycled to other patients.

Environmental factors influencing the transmission of the coronavirus 2019: a review

The coronavirus 2019 pandemic, induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has strongly altered healthcare systems and the economy worldwide. The lack of knowledge on this virus has led to the implementation of uncertain strategies and measures to fight the pandemic. Here, we review environmental factors that control viral transmission, such as air, temperature, humidity, food, water and sewage, insects, inanimate surfaces, hand hygiene, and social distancing. The main route of viral transmission is the respiratory tract through aerosols. Masks and social distancing are effective in ceasing air transmission. Proper cleaning of surfaces and hand disinfection are required, especially in healthcare units. Food should be handled properly, and food handlers should work based on hygienic protocols. Water and sewage transmission, and transmission through insects appear less important than other environmental factors.

Less COVID-19 deaths in southern and insular Italy explained by forest bathing, Mediterranean environment, and antiviral plant volatile organic compounds

The coronavirus disease 2019 (COVID-19) is causing major sanitary and socioeconomic issues, yet some locations are less impacted than others. While densely populated areas are likely to favor viral transmission, we hypothesize that other environmental factors could explain lower cases in some areas. We studied COVID-19 impact and population statistics in highly forested Mediterranean Italian regions versus some northern regions where the amount of trees per capita is much lower. We also evaluated the affinity of Mediterranean plant-emitted volatile organic compounds (VOCs) isoprene, α-pinene, linalool and limonene for COVID-19 protein targets by molecular docking modeling. Results show that while mean death number increased about 4 times from 2020 to 2021, the percentage of deaths per population (0.06-0.10%) was lower in the greener Mediterranean regions such as Sardinia, Calabria and Basilica versus northern regions with low forest coverage, such as Lombardy (0.33%) and Emilia Romagna (0.29%). Data also show that the pandemic severity cannot be explained solely by population density. Modeling reveals that plant organic compounds could bind and interfere with the complex formed by the receptor binding domain of the coronavirus spike protein with the human cell receptor. Overall, our findings are likely explained by sea proximity and mild climate, Mediterranean diet and the abundance of non-deciduous Mediterranean plants which emit immunomodulatory and antiviral compounds. Potential implications include 'forest bathing' as a therapeutic practice, designing nasal sprays containing plant volatile organic compounds, and preserving and increasing forest coverage.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10311-021-01309-5.

Can imported cold food cause COVID-19 recurrent outbreaks? A review

The coronavirus disease 2019 (COVID-19) pandemic is still spreading all over the world. Although China quickly brought the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) under control in 2020, sporadic outbreaks have recurred from time to time. Outbreaks since June 2020 have suggested that the imported cold food supply chain is a major cause for the recurrence and spread of COVID-19. Here we review recurrent outbreaks in China from June 2020 to March 2021, and we analyse the main causes for recurrence and transmission by the supply of imported cold food from port to fork. Contaminated cold food or food packaging material can transmit the virus through 'person-to-thing-to-person', by contrast with the classical 'person-to-person' pathway. We decribe safety precautions for the food system, operating environment and people along the cold chain logistics. Surface disinfection and nucleic acid inspection are needed in each stage of the logistics of imported cold food supply.

Emerging contaminants, SARS-COV-2 and wastewater treatment plants, new challenges to confront: A short review

The current pandemic caused by SARS-CoV-2 has put public health at risk, being wastewater-based epidemiology (WBE) a potential tool in the detection, prevention, and treatment of present and possible future outbreaks, since this virus enters wastewater through various sources such as feces, vomit, and sputum. Thus, advanced technologies such as advanced oxidation processes (AOP), membrane technology (MT) are identified through a systematic literature review as an alternative option for the destruction and removal of emerging contaminants (drugs and personal care products) released mainly by infected patients. The objectives of this review are to know the implications that the new COVID-19 outbreak is generating and will generate in water compartments, as well as the new challenges faced by wastewater treatment plants due to the change in a load of contaminants and the solutions proposed based on the aforementioned technologies to be applied to preserve public health and the environment.

COVID-19 and sunlight: Impact on SARS-CoV-2 transmissibility, morbidity, and mortality

Coronavirus disease 2019 (COVID-19) has already affected millions of people worldwide. There are reports of SARS-CoV-2 transmission as a consequence of environmental contamination. The SARS-CoV-2 laden infective droplets can actively persist on the surface of different materials for several hours to days. Sunlight can affect the stability of SARS-CoV-2 in these aerosols and thereby have an impact on the decay rate of the virus. Solar radiation might play an important role in inactivating SARS-CoV-2 that persists in different surfaces and the environment. Among the different climatological factors, ultraviolet radiation was found to have an important role in determining the spread of SARS-CoV-2. Although ultraviolet radiation C (UVC), UVB, UVA, visible light, and infrared radiation possess germicidal properties, human CoVs including the recently emerged SARS-CoV-2 are inherently sensitive to UVC. However, the successful decontamination using other wavebands requires higher dosages and longer administration times. Furthermore, studies have also identified association between COVID-19 fatalities and the latitude. The intensity of sunlight is highest near the equator, and therefore populations in these regions with more regular exposure to sunlight are less susceptible to vitamin D deficiency. This article has analyzed the potential impact of sunlight in reducing SARS-CoV-2 transmissibility, morbidity, and mortality. It is evident that there exists an interesting link between sunlight exposure, latitude, and vitamin D status with COVID-19 incidence, fatality and recovery rates that requires further investigation.

COVID-19 transmission, vulnerability, persistence and nanotherapy: a review

End 2019, the zoonotic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), named COVID-19 for coronavirus disease 2019, is the third adaptation of a contagious virus following the severe acute respiratory syndrome coronavirus in 2002, SARS-CoV, and the Middle East respiratory syndrome virus in 2012, MERS-CoV. COVID-19 is highly infectious and virulent compared to previous outbreaks. We review sources, contagious routes, preventive measures, pandemic, outbreak, epidemiology of SARS-CoV, MERS-CoV and SARS-CoV-2 from 2002 to 2020 using a Medline search. We discuss the chronology of the three coronaviruses, the vulnerability of healthcare workers, coronaviruses on surface and in wastewater, diagnostics and cures, and measures to prevent spreading.

Classical and alternative disinfection strategies to control the COVID-19 virus in healthcare facilities: a review

The coronavirus disease COVID-19 has spread throughout the world and has been declared as a pandemic by the World Health Organization on March 11th, 2020. The COVID-19 is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). One possible mode of virus transmission is through surfaces in the healthcare settings. This paper reviews currently used disinfection strategies to control SARS-CoV-2 at the healthcare facilities. Chemical disinfectants include hypochlorite, peroxymonosulfate, alcohols, quaternary ammonium compounds, and hydrogen peroxide. Advanced strategies include no-touch techniques such as engineered antimicrobial surfaces and automated room disinfection systems using hydrogen peroxide vapor or ultraviolet light.

How human thermal plume influences near-human transport of respiratory droplets and airborne particles: a review

With mounting evidence and notable cases of large clustered infections, airborne transmission via droplets and particles has been recently acknowledged as an effective mode of transmission for COVID-19. How droplets and aerosol particles disperse are being transported into the human breathing zone-the last few inches for airborne transmission to effectuate-remains a key question which has been widely overlooked. Human thermal plume refers to the constantly rising airflows around the boundary layer of human body due to persisting temperature gradients between the body surfaces and the ambient air. Ample evidence indicated that the thermal plume controls the dispersion and transport of aerosols in the human microenvironment. Given that in calm indoor environments most air inhaled by human comes from the boundary layer where thermal plume flows through constantly, the role of thermal plume needs to be scrutinized to predict the diffusion of droplets, aerosols and other airborne carriers of the novel coronavirus around the human body for prioritizing infection control strategies. Here, we assessed the potential influences of the thermal plume on the transmission of COVID-19 and other airborne pathogens by reviewing the most pertinent evidence and analyzing key variables in the formation of thermal plume in indoor environments, e.g., ambient temperature, human posture and type of clothing. Our reviewed evidence and data indicate that the human thermal plume should facilitate the airborne transmission of COVID-19 in enclosed spaces by elevating small droplets and airborne particles into the breathing zone from lower regions and ascending respiratory droplets from the sources into the upper atmosphere. By drawing attention to aerosol transport dynamics in the human microenvironment, these insights may be useful for understanding COVID-19 transmission in enclosed spaces, especially those intended for public use.

Locked on salt? Excessive consumption of high-sodium foods during COVID-19 presents an underappreciated public health risk: a review

Abrupt changes in food preferences and eating habits have induced an overlooked health risk during the coronavirus disease pandemic (COVID-19). Indeed, emerging evidence points to a major shift to consumption of high-sodium foods during the pandemic lockdowns in the population from different countries and cultures. High-sodium foods have sodium contents exceeding 500 mg per 100 g, and many processed and preserved foods fall into this category. Excessive dietary sodium intake is associated with chronic diseases including hypertension, cardiovascular diseases, and kidney diseases, and thus poses confounding risks during the pandemic. Here, we review food categories in consumers' shopping lists and food parcels delivered to people who needed assistance during the pandemic, when frozen meals, canned foods, instant foods, snacks, and other high-sodium foods gained substantial popularity. Such change in consumers' behavior is driven by several factors: the perceived risk of viral infection in grocery shopping trips, limited supplies and inflated prices of fresh produce, preference on foods with long shelf lives, and emotional eating. Moreover, the general low awareness of sodium contents in food has contributed to the increased consumption of high-sodium foods during the pandemic. We also discuss the possible effects on COVID-19 infection and severity caused by excessive sodium intake. We conclude that the public should be educated to maintain a healthy sodium intake during the pandemic, and measures should be adopted by governments and private donors in procuring food parcels with more balanced sodium contents to lower the risks of prolonged and excessive sodium intakes in the vulnerable population.

SARS-CoV-2 is rapidly inactivated at high temperature

In the absence of a vaccine, preventing the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the primary means to reduce the impact of the 2019 coronavirus disease (COVID-19). Multiple studies have reported the presence of SARS-CoV-2 genetic material on surfaces suggesting that fomite transmission of SARS-CoV-2 is feasible. High temperature inactivation of virus has been previously suggested, but not shown. In the present study, we investigated the environmental stability of SARS-CoV-2 in a clinically relevant matrix dried onto stainless steel at a high temperature. The results show that at 54.5 °C, the virus half-life was 10.8 ± 3.0 min and the time for a 90% decrease in infectivity was 35.4 ± 9.0 min. These findings suggest that in instances where the environment can reach temperatures of at least 54.5 °C, such as in vehicle interior cabins when parked in warmer ambient air, that the potential for exposure to infectious virus on surfaces could be decreased substantially in under an hour.