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Environmental Role of Open Space in Infection and Disease Control
Published in AnnaMarie Bliss, Dak Kopec, Architectural Factors for Infection and Disease Control, 2023
Respiratory droplets include large droplets (measuring ≥5 µm in diameter). Therefore, they do not remain suspended in the air for long periods but fall rapidly near the source to the ground or other surfaces by force of gravity within <1 m radius on release. Fine-particle aerosols (measuring ≤5 µm in measuring) can remain suspended for long periods in the air and can be inhaled into the respiratory tract of susceptible individuals (Leung, 2021; Wong & Leung, 2004; Bourouiba, 2020).
Introduction to Coronaviruses and COVID-19
Published in Joystu Dutta, Srijan Goswami, Abhijit Mitra, COVID-19 and Emerging Environmental Trends, 2020
Joystu Dutta, Srijan Goswami, Abhijit Mitra
There are two basic ways by which an individual can get infected by SARS-CoV-2: one is through the “respiratory droplets,” and the other is through “droplet nuclei” (WHO, 2020a). Respiratory droplets are droplet particles that are >5–10 μm in diameter, whereas droplet particles of size <5μm in diameter are called droplet nuclei (WHO, 2014). Several researchers have reported that respiratory droplets and contact routes are the primary modes of transmission between individuals (Liu et al., 2020; Chan et al., 2020; Li et al., 2020; Burke et al., 2020; WHO, 2020a). Transmission through droplets is possible when an individual is in close contact (generally within 1 m) with the infected person (See Figure 1.6). The infected person may transmit the virus through a cough or sneeze or sometimes just by talking (without protective masks), and as a result, the mucosa (nose and mouth) and conjunctiva (eyes) of the healthy person may get exposed to potentially infective respiratory droplets (Ong et al., 2020). The virus can also get transmitted through fomites (Ong et al., 2020). Fomites are the objects contaminated with infectious agents (in this case the SARS-CoV-2) and serve in their transmission. Therefore, direct contact with an infected individual and indirect contact with fomites are the major ways by which SARS-CoV-2 can get transmitted (See Figures 1.5 and 1.6). Sometimes, the droplet nuclei (containing the pathogen) remains in the air for a long period of time and gets transmitted to individuals over distances greater than 1 meter. This phenomenon is called airborne transmission. Airborne transmission of COVID-19 is possible under specific circumstances in which aerosol production is facilitated. Endotracheal intubation, noninvasive positive pressure ventilation, and disconnecting a patient from the ventilators are some of the situations (among many) that can lead to airborne transmission (WHO, 2020a). A group of researchers from China reported that COVID-19 may give rise to intestinal symptoms and that the viral particles may be present in the feces of the patient (Zhang et al., 2020). According to WHO, no report of fecal–oral transmission of COVID-19 has been reported until June 30, 2020 (WHO, 2020). Figure 1.5 represents the sequence of transmission of COVID-19.
Silver nanoparticles against SARS-CoV-2 and its potential application in medical protective clothing – a review
Published in The Journal of The Textile Institute, 2022
Toufique Ahmed, R. Tugrul Ogulata, Sabiha Sezgin Bozok
Silver nanoparticles (AgNPs) incorporated PPEs could be an effective tool in combating respiratory viruses such as Covid-19. The SARS-CoV-2 and all other surrogates have the same proteins-components: Glycine, Alanine, Glycoprotein, Hemagglutinin, Neucleocapsid, etc. AgNPs can effectively inhibit all the protein components. The toxicity of silver is also comparatively lower than that of other antiviral agents. Respiratory droplets primarily transmit the Covid-19 virus. Hence PPEs are probably the most effective preventive measure against this pandemic. The PPEs in health care must be antiviral and comfortable. In this context, AgNPs coated PPEs can inhibit the SARS-CoV-2 virus effectively within a few minutes. Moreover, it prepares the PPEs for reuse without any physical or chemical intervention. The AgNPs can be impregnated in textile by various means; however, for cotton fiber in-situ is quite promising. The silver treatment on PPEs should be done in such a way that prevents or minimize the AgNPs leaching at a significant scale. The hybrid nanocomposite might be an excellent antiviral agent to combat respiratory viruses, including ongoing Covid-19. Extensive research works are needed to nullify the toxicity and adverse effect of AgNPs on the environment.
Evaluating the filtration efficiency of commercial facemasks’ materials against respiratory aerosol droplets
Published in Journal of the Air & Waste Management Association, 2022
Satya S. Patra, Jyotishree Nath, Subhasmita Panda, Trupti Das, Boopathy Ramasamy
Human-to-human transmission of respiratory viruses and other pathogens (measles virus, Mycobacterium tuberculosis, etc.) via respiratory droplets has been widely documented in the epidemiology literature (Dbouk and Drikakis 2020; Manjarrez-Zavala 2013; Richard et al. 2020; Stadnytskyi et al. 2020). Speaking, coughing, breathing, or sneezing activities are the primary sources of human respiratory droplets (Dbouk and Drikakis 2020; Johnson et al. 2011). Facemasks are commonly used to minimize the risk of transmission of pathogens through these droplet particles. For instance, to limit the spread of the SARS-CoV-2 (widely referred to as COVID-19) virus during the ongoing pandemic, several government authorities made the use of facemasks mandatory in public areas.
Influence of nanotechnology in polymeric textiles, applications, and fight against COVID-19
Published in The Journal of The Textile Institute, 2021
As at December 2019, there was outbreak of the severe pneumonically alike disease in Wuhan, China referred as novel coronavirus (SARS-CoV-2 or coronavirus-disease-2019 or COVID-19) which rapidly spread across the globe (Santarpia et al,. 2020). The World Health Organization (WHO) situation report 58 revealed that, as of 18 March 2020, there were 191,127 confirmed cases and 7,807 deaths across the globe (WHO, 2020). Therefore, as a result of its critical impact, the novel coronavirus was officially declared a pandemic (WHO, 2020). Moreso, as at 9 May 2020, the COVID-19 virus was confirmed in 4,080,426 individuals globally with 279,286 deaths (“Worldometer - Real time world statistics”), causing greater mortality rate in comparison with influenza (Lai et al., 2020). As an extremely infectious disease, infected individuals mainly displayed dry cough, fatigue, and fever, although a huge percentage of carriers were asymptomatic. The viral transmission is perceived to occur via respiratory droplets which result in sneezing and coughing (Wang & Du, 2020; Workman et al., 2020). Respiratory droplets conform to varying sizes (Cook, 2020; Callaway, 2020), while aerosols are composed of droplet sizes of sub-5 µm (Cucinotta & Vanelli, 2020). Moreover, lighter and smaller aerosols continually maintain air floatage for prolonged duration, thereby rapidly escalating distribution of the virus (Morawska & Cao, 2020; Zheng et al., 2020; Zhou et al., 2020). Therefore, it becomes essentially imperative to utilize facial masks as a physical protection/barrier to hinder getting exposed to the respiratory droplets (Wang & Du, 2020). Figure 9 depicts strategies for combating Covid-19 via NMs and nanomedicine.