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1.
Advances in Natural Sciences. Nanoscience and Nanotechnology ; 13(3):035008, 2022.
Article in English | ProQuest Central | ID: covidwho-2001178

ABSTRACT

Over the last 10 years, the antiviral and antimicrobial activities of non-functionalised inorganic nanoparticles against different pathogens were experimentally shown. This effect has attracted the attention of scientists due to the COVID-19 pandemic;however, its mechanism is still unclear. For understanding the mechanism of nanoparticle’s action, it is important to know how this action depends on the parameters of nanoparticles and the properties of a pathogen. In the work, we have studied the action of gold nanoparticles on the viruses outside and inside the cell and compared this action with two sizes of nanoparticles and two types of viruses. The study has been conducted for adenovirus and H1N1 influenza virus, and gold nanoparticles of 5 nm and 20 nm diameter. Virucidal and antiviral actions were observed experimentally for both sizes of nanoparticles against both viruses. It has also been shown with the electron microscopy that the viruses may be destructed in 2 h after adsorption of 5 nm gold nanoparticles on their surface;and that the viruses may change their shape in 2 h after adsorption of 20 nm nanoparticles on their surface. The model of physical adsorption of nanoparticles on the virus surface due to near-field interaction was used to explain observed results.

2.
Lett Appl Microbiol ; 2022 Aug 15.
Article in English | MEDLINE | ID: covidwho-1992872

ABSTRACT

We previously reported a novel polymeric surface coating, namely HaloFilmTM , that can immobilize and extend the antimicrobial activity of chlorine on surfaces. In this study, we demonstrated the continuous antiviral efficacy of HaloFilmTM when applied on stainless steel and cotton gauze as two representative models for non-porous and porous surfaces against SARS-CoV-2. Forty-eight hours post HaloFilm application and chlorination, and 2 hours post the viral challenge, the inoculum titer was reduced by 2.25±0.33 and ≥4.36±0.23 log10 TCIDA50 on non-porous and porous surfaces, respectively. The half-life of the virus was shorter (13.86 min) on a HaloFilmTM -coated surface compared to what has been reported on copper (46.44 min).

3.
J Hosp Infect ; 116: 16-20, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1271690

ABSTRACT

Besides conventional prevention measures, no-touch technologies based on gaseous systems have been introduced in hospital hygiene for room disinfection. The whole-room disinfectant device Sterisafe Pro, which creates ozone as a biocidal agent, was tested for its virucidal efficacy based on Association Française de Normalisation Standard NF T 72-281:2014. All test virus titres were reduced after 150 and 300 min of decontamination, with mean reduction factors ranging from 2.63 (murine norovirus) to 3.94 (simian virus 40). These results will help to establish realistic conditions for virus inactivation, and assessment of the efficacy of ozone technology against non-enveloped and enveloped viruses.


Subject(s)
Disinfectants , Ozone , Animals , Disinfectants/pharmacology , Disinfection , Humans , Hygiene , Mice , Ozone/pharmacology , Virus Inactivation
4.
Gms Hygiene and Infection Control ; 17:14, 2022.
Article in English | Web of Science | ID: covidwho-1975986

ABSTRACT

The SARS-CoV-2 pandemic illustrates the necessity of effective preven-tive measures for existing and newly emerging pathogens. When con-fronted with pathogens or spoilage agents, especially if they are not yet well studied, effective hygiene protocols are needed immediately. In the medical field, effective preventive measures are key to prevent vulnerable patients from infections. In production areas, effective hy-giene measures are needed to protect goods from spoilage or microbial contamination. The European standardization framework established by the European Committee for Standardization (CEN) ensures that effective hygiene measures are available and can be immediately implemented when needed. Based on a broad portfolio of standards/laboratory tests, activity claims specifically addressing the special features of applications of antimicrobial formulations are substantiated. In this review, the concept of using standardized surrogate test organisms is explained, and the European standardized test approach to claim microbicidal and virucidal efficacy, the specificity of claims and their relevance for infec-tion prevention measures is illustrated. Furthermore, relevance of the European Norm test methods is elucidated in the light of legal require-ments. Finally, the review explains the systematics of the standardized meth-odological portfolio of CEN, Technical Committee 216, which is very useful when effective strategies for fighting or preventing microbial and viral induced infections, contaminations or spoilage are needed on an immediate basis.

5.
GMS Hyg Infect Control ; 17: Doc13, 2022.
Article in English | MEDLINE | ID: covidwho-1974608

ABSTRACT

The German Society of Hospital Hygiene develops guidelines, recommendations and standard operation procedures on a voluntary basis, published on the DGKH-website (https://www.krankenhaushygiene.de/). The original German version of this recommendation was published in April 2022 and has now been made available to the international professional public in English. Evaluating the current data on the efficacy of virucidal gargle/mouthwash solutions and nasal sprays against SARS-CoV-2 in vitro and in clinical trials, conducted with preventive or therapeutic objectives, recommendations are given for the prevention of COVID-19. The following areas are considered: Protection of the community when regional clusters or high incidences of infection become knownProtection of the community at low risk of infectionPre-exposure prophylaxis for the protection of healthcare workersPost-exposure prophylaxis.

6.
Zeitschrift fur Phytotherapie ; 43:S46, 2022.
Article in English | EMBASE | ID: covidwho-1967698

ABSTRACT

Introduction SARS-CoV-2 variants of concern (VOCs) represent an alarming threat as they may escape vaccination effectiveness. Broad-spectrum antivirals could complement and further enhance preventive benefits achieved through SARS-CoV-2 vaccination campaigns. Aim Testing the antiviral activity of Echinacea purpurea against VOCs and exploring underlying modes-of-action. Method A hydroethanolic extract of freshly harvested E. purpurea herb and roots (Echinaforce®, EF extract) was tested to inhibit infection of VOCs B1.1.7 (alpha), B.1.351.1 (beta), P.1 (gamma), B1.617.2 (delta), AV.1 (Scottish) and B1.525 (eta). Molecular dynamics (MD) were used to study interaction of EF phytochemical markers with known pharmacological viral and host cell targets. Results EF broadly inhibited propagation of all tested SARS-CoV-2 VOCs at EC50 < 12.0 ;jg/ml. Treatment of epithelial cells with 20 jg/ml EF prevented sequential infection with SARS-CoV-2 (Hu-1). MD analyses showed for alkylamides, caftaric acid and feruoyl-tartaric constant binding affinity to spike proteins of all VOCs and to TMPRSS-2, a serine protease required for virus endocytosis. Conclusion EF extract exhibits virucidal activity against all tested SARS-CoV-2 VOCs and protects epithelial cells from infection.

7.
Laryngo- Rhino- Otologie ; 101:S233, 2022.
Article in English | EMBASE | ID: covidwho-1967661

ABSTRACT

Introduction Reprocessing of medical devices becomes increasingly complex, due to higher hygiene requirements. Former studies revealed satisfactory bactericidal properties of UV-C light disinfection in otorhinolaryngological endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of high importance. In this study the virucidal efficacy of UV-C light disinfection was analyzed using a bacteriophage model. Materials and methods MS-2 bacteriophages were used as surrogate for stable viruses with high tenacity. The bacteriophage samples were irradiated for up to three cycles of 25 seconds by UV-C light (D25, UV-Smart Technologies B.V.). A dilution series of the irradiated test samples was mixed with 1x108 CFU of Escherichia coli. After incubation plaque formation of Escherichia coli were counted and hence the phage concentration was determined. Results The initial contamination of the test samples was 1.8x1012 plaque forming units (pfu). After 25 seconds of UV-C light irradiation, a non-significant Log reduction of 2.2 was found (p = 0,82). After 50 and 75 seconds of UV-exposure a significant Log reduction of 3.4 e.g. 5.1 (p = 0.05 e.g. p = 0.004) was found. The control sample showed a titer of 1.2 x 1010 pfu. Conclusion The tested UV system seems to provide a significant virucidal effect after a short time of exposure. In combination with the results of the bacteriological testing it appears suitable for clinical use as a substitute for current disinfection methods.

8.
Life (Basel) ; 12(7)2022 Jul 20.
Article in English | MEDLINE | ID: covidwho-1938893

ABSTRACT

Background: The use of various herbal therapists as part of traditional medicine in different parts of the world, including Bulgaria, is due to the knowledge accumulated over the centuries by people about their valuable biological activities. In this study, we investigate extracts from widely used Bulgarian medicinal plants for their ability to prevent the coronavirus infection of cells by testing different mechanisms of antiviral protection, their polyphenol content, and redox-modulating capacity. Methods: The influence on the stage of viral adsorption, the inhibition of extracellular virions, and the protective effect on uninfected cells of the plant's extracts were reported by the end-point dilution method, and virus titer (in Δ lgs) was determined as compared to the untreated controls. The total content of polyphenols and flavonoids was also determined. We tested the antioxidant power of the extracts by their ability to inhibit the generation of superoxide anionic radicals and to scavenge DPPH radicals. We determined their iron-reducing, copper-reducing, and metal-chelating antioxidant powers. Results: Most of the extracts tested suppress the extracellular virions of HCov. They also inhibit the stage of viral adsorption to the host cell to varying degrees and have a protective effect on healthy cells before being subjected to viral invasion. The examined extracts contained significant levels of polyphenols and quercetin-like flavonoids and showed remarkable antioxidant, radical, and redox-modulating effects. Conclusions: All of these 13 extracts from Bulgarian medicinal plants tested can act as antioxidants and antiviral and symptomatic drugs for the management of coronavirus infection.

9.
Plants (Basel) ; 11(13)2022 Jun 23.
Article in English | MEDLINE | ID: covidwho-1934187

ABSTRACT

BACKGROUND: Bulgaria is a country with a wide range of medicinal plants, with uses in traditional medicine dating back for centuries. METHODS: Disc diffusion assay was used to evaluate the antimicrobial activity of the plant extracts. A cytopathic effect inhibition test was used for the assessment of the antiviral activity of the extracts. The virucidal activity of the extracts, their influence on the stage of viral adsorption, and their protective effect on uninfected cells were reported using the end-point dilution method, and Δlgs was determined as compared to the untreated controls. RESULTS: The results of the study reveal that the antibacterial potential of G. glabra and H. perforatum extracts in Gram-positive bacteria is more effective than in Gram-negative bacteria. When applied during the replication of HSV-1 and HCov-OC-43, only some of the extracts showed weak activity, with SI between 2 to 8.5. Almost all tested extracts inhibited the extracellular virions of the studied enveloped viruses (HSV-1 and HCov-OC-43) to a greater extent than of the non-enveloped viruses (PV-1 and HAdV-5). They inhibited the stage of viral adsorption (HSV-1) in the host cell (MDBK) to varying degrees and showed a protective effect on healthy cells (MDBK) before they were subjected to viral invasion (HSV-1). CONCLUSION: The antipathogenic potential of extracts of H. perforatum and G. glabra suggests their effectiveness as antimicrobial agents. All 13 extracts of the Bulgarian medicinal plants studied can be used to reduce viral yield in a wide range of viral infections.

10.
Life (Basel) ; 12(7)2022 Jun 30.
Article in English | MEDLINE | ID: covidwho-1917599

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is evolving, with emergence of mutational variants due to the error-prone replication process of RNA viruses, in general. More recently, the Delta and Omicron variants (including sub-variants BA.1-5) predominate globally, and a Delta-Omicron recombinant termed Deltacron has emerged. The emergence of variants of concern (VOC) demonstrating immune evasion and potentially greater transmissibility and virulence naturally raises concern in both the infection control communities and the public at large, as to the continued suitability of interventions intended to mitigate the risk of viral dissemination and acquisition of the associated disease COVID-19. We evaluated the virucidal efficacy of targeted surface hygiene products (an ethanol/quaternary ammonium compound (QAC)-containing disinfectant spray, a QAC disinfectant wipe, a lactic acid disinfectant wipe, and a citric acid disinfectant wipe) through both theoretical arguments and empirical testing using international standard methodologies (ASTM E1053-20 hard surface test and EN14476:2013+A2:2019 suspension test) in the presence of soil loads simulating patients' bodily secretions/excretions containing shed virus. The results demonstrate, as expected, complete infectious viral inactivation (≥3.0 to ≥4.7 log10 reduction in infectious virus titer after as little as 15 s contact time at room temperature) by these surface hygiene agents of the original SARS-CoV-2 isolate and its Beta and Delta VOC. Through appropriate practices of targeted surface hygiene, it is expected that irrespective of the SARS-CoV-2 VOC encountered as the current pandemic unfolds (and, for that matter, any emerging and/or re-emerging enveloped virus), the chain of infection from virus-contaminated fomites to the hand and mucous membranes of a susceptible person may be disrupted.

11.
Int J Mol Sci ; 23(12)2022 Jun 14.
Article in English | MEDLINE | ID: covidwho-1911401

ABSTRACT

The virucidal activity of a series of cationic surfactants differing in the length and number of hydrophobic tails (at the same hydrophilic head) and the structure of the hydrophilic head (at the same length of the hydrophobic n-alkyl tail) was compared. It was shown that an increase in the length and number of hydrophobic tails, as well as the presence of a benzene ring in the surfactant molecule, enhance the virucidal activity of the surfactant against SARS-CoV-2. This may be due to the more pronounced ability of such surfactants to penetrate and destroy the phospholipid membrane of the virus. Among the cationic surfactants studied, didodecyldimethylammonium bromide was shown to be the most efficient as a disinfectant, its 50% effective concentration (EC50) being equal to 0.016 mM. Two surfactants (didodecyldimethylammonium bromide and benzalkonium chloride) can deactivate SARS-CoV-2 in as little as 5 s.


Subject(s)
COVID-19 , Disinfectants , COVID-19/drug therapy , Disinfectants/chemistry , Disinfectants/pharmacology , Humans , Hydrophobic and Hydrophilic Interactions , SARS-CoV-2 , Surface-Active Agents/chemistry , Surface-Active Agents/pharmacology
12.
Int J Environ Res Public Health ; 19(13)2022 Jun 23.
Article in English | MEDLINE | ID: covidwho-1911343

ABSTRACT

With the arrival of the highly transmissible Omicron variants (BA.4 and BA.5), dentistry faces another seasonal challenge to preserve the biosafety of dental care and education. With the aim of protecting patients, students, teachers and healthcare professionals, this paper introduces a prospective sustainable biosafety setting for everyday dental care and education. The setting developed by dental clinicians, epidemiologists, and teachers of dentistry consists of a combination of modern technologies focused on the air-borne part of the viral pathway. The introduced biosafety setting has been clinically evaluated after 18 months of application in the real clinical environment. The protocol has three fundamental pillars: (1) UVC air disinfection; (2) air saturation with certified virucidal essences with nebulizing diffusers; (3) complementary solutions including telehealth and 3D printing. A pseudonymous online smart form was used as the evaluation method. The protocol operates on the premise that everybody is a hypothetical asymptomatic carrier. The results of a clinical evaluation of 115 patient feedbacks imply that no virus transmission from patient to patient or from doctor to nurse was observed or reported using this protocol, and vice versa, although nine patients retrospectively admitted that the clinic visit is likely to be infectious. Despite these promising results, a larger clinical sample and exposition to the current mutated strains are needed for reliable conclusions about protocol virucidal efficiency in current dental environments.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/prevention & control , Containment of Biohazards , Dental Care , Humans , Prospective Studies , Retrospective Studies , SARS-CoV-2/genetics
13.
Front Biosci (Schol Ed) ; 14(2): 12, 2022 May 06.
Article in English | MEDLINE | ID: covidwho-1904165

ABSTRACT

The COVID-19 pandemic has provided an opportunity for repurposing of drugs, including complex, natural drugs, to meet the global need for safe and effective antiviral medicines which do not promote multidrug resistance nor inflate medical costs. The author herein describes his own repurposing of herbal tinctures, previously prepared for oncology, into a possibly synergistic, anti-COVID 41 "herb" formula of extracts derived from 36 different plants and medicinal mushrooms. A method of multi-sample in vitro testing in green monkey kidney vero cells is proposed for testing the Hypothesis that even in such a large combination, antiviral potency may be preserved, along with therapeutic synergy, smoothness, and complexity. The possibility that the formula's potency may improve with age is considered, along with a suitable method for testing it. Collaborative research inquiries are welcome.


Subject(s)
COVID-19 , Peganum , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Chlorocebus aethiops , Humans , Pandemics , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Seeds , Vero Cells
14.
Adv Exp Med Biol ; 2022 Jun 15.
Article in English | MEDLINE | ID: covidwho-1888836

ABSTRACT

The availability of virucidal compounds to reduce the impact of respiratory viruses is a relevant topic for public health, especially during the recent coronavirus disease (COVID-19) pandemic. Antimicrobial properties of Xibornol are known since the 1970s, but its activity on viruses is currently little explored. In this study, Xibornol activity at a fixed concentration of 0.03 mg/100 ml has been evaluated on five respiratory viruses (Human Adenovirus 5, Human Rhinovirus type 13, Human Coronavirus 229E, Human Parainfluenza Virus type 1, and Human Respiratory Syncytial Virus) through in vitro experiments based on adapted European standard UNI EN 14476-20019. The experiments were carried out under two different environmental conditions, one with the addition of fetal bovine serum to simulate an in vivo condition (dirty condition) and the other without the addition of any organic substances (clean condition). The viral abatement of Xibornol (expressed as Log10 reduction - LR) was statistically significant under both clean and dirty environmental conditions. Namely, in clean condition, LR ranged from 2.67 to 3.84, while in the dirty one the abatement was slightly lower (from 1.75 to 3.03). Parainfluenza Virus and Human Adenovirus were most resistant compared to the other viruses. The obtained data confirmed Xibornol activity and its use as topic substance for viral inactivation to prevent upper respiratory tract disease.

15.
Wiley Interdiscip Rev Nanomed Nanobiotechnol ; : e1823, 2022 Jun 13.
Article in English | MEDLINE | ID: covidwho-1888822

ABSTRACT

The COVID-19 pandemic has inspired large research investments from the global scientific community in the study of viral properties and antiviral technologies (e.g., self-cleaning surfaces, virucides, antiviral drugs, and vaccines). Emerging viruses are a constant threat due to the substantial variation in viral structures, limiting the potential for expanded broad-spectrum antiviral agent development, and the complexity of targeting multiple and diverse viral species with unique characteristics involving their virulence. Multiple, more infectious variants of SARS-CoV2 (e.g., Delta, Omicron) have already appeared, necessitating research into versatile, robust control strategies in response to the looming threat of future viruses. Nanotechnology and nanomaterials have played a vital role in addressing current viral threats, from mRNA-based vaccines to nanoparticle-based drugs and nanotechnology enhanced disinfection methods. Rapid progress in the field has prompted a review of the current literature primarily focused on nanotechnology-based virucides and antivirals. In this review, a brief description of antiviral drugs is provided first as background with most of the discussion focused on key design considerations for high-efficacy antiviral nanomaterials (e.g., nanopharmaceuticals) as determined from published studies as well as related modes of biological activity. Insights into potential future research directions are also provided with a section devoted specifically to the SARS-CoV2 virus. This article is categorized under: Toxicology and Regulatory Issues in Nanomediciney > Toxicology of Nanomaterials Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease.

16.
Topics in Antiviral Medicine ; 30(1 SUPPL):181-182, 2022.
Article in English | EMBASE | ID: covidwho-1880616

ABSTRACT

Background: SARS-CoV-2 is spread via airborne transmission. Mouthwashes containing virucidal compounds can help reduce viral spread. Here we show that cetylpyridinium chloride (CPC), a quaternary ammonium present in many oral mouthwashes, reduces SARS-CoV-2 infectivity by disrupting viral membranes both in vitro and in vivo. Methods: We tested the capacity of CPC-containing mouthwashes to inhibit SARS-CoV-2 entry into target cells by using a luciferase-based assay with a reporter lentivirus pseudotyped with the SARS-CoV-2 spike protein. The replication-competent SARS-CoV-2 B.1.1.7 and D614G variants were also assayed. Viral envelope disruption by CPC's virucidal effect was measured by dynamic light-scattering analyses (DSL). We confirmed these results by modifying an ELISA that detects the SARS-CoV-2 nucleocapsid (NC), which was used in the absence of its own lysis buffer. The effect of CPC in the saliva of individuals with CoVID-19 was assessed in a double-blind, placebo-controlled, randomized clinical trial. SARS-CoV-2 positive patients were randomized to gargle either water or 0.07% CPC mouthwash. The study outcomes were the SARS-CoV-2 log10 viral RNA load by RT-PCR and the NC protein levels by ELISA, both in saliva at 1h and 3h post-intervention. Results: CPC-containing mouthwashes inhibited SARS-CoV-2 viral fusion in vitro in a dose-dependent manner and decreased more than a 1000 times the viral TCID50 in target cells, regardless of the variant tested. The ELISA and the DSL analyses pointed to the effective disruption of the integrity of viral membranes after treatment with CPC. The clinical study performed with 105 patients showed no significant differences in viral RNA load at 1h and 3h post-treatment in saliva between placebo and CPC-treated groups. However, the levels of SARS-CoV-2 NC protein of lysed viruses were significantly higher in the CPC group at 1h and 3h post-intervention. Conclusion: CPC decreased more than a 1000 times the infectivity of SARS-CoV-2 in vitro and was effective against different SARS-CoV-2 variants. In CoVID-19 patients, the use of a 0.07% CPC mouthwash correlated with a statistically significant increase of NC protein levels in saliva, indicating enhanced disruption of viral particles. CPC-containing mouth rinses can represent a cost-effective measure to reduce SARS-CoV-2 infectivity in saliva, aiding to reduce viral transmission from infected individuals regardless of the variants they are infected with.

17.
Topics in Antiviral Medicine ; 30(1 SUPPL):182-183, 2022.
Article in English | EMBASE | ID: covidwho-1880240

ABSTRACT

Background: The dominance of SARS-CoV-2 Variants of Concern (VOC) and Interest (VOI) has challenged the efficacy of public health strategies to control the current pandemic. Astodrimer sodium is a broad-spectrum antiviral dendrimer that has been formulated as a topical nasal spray to help reduce exposure to infectious viral load in the nasal cavity. Astodrimer sodium showed antiviral and virucidal activity against early pandemic isolates of SARS-CoV-2 in vitro and after nasal administration in vivo. The current studies assessed the spectrum of activity of astodrimer sodium against emerging variants of SARS-CoV-2 and other pandemic viruses. Methods: Assays utilized hACE2+ and hTMPRSS2+ HEK-293T cells, Calu-3 and Vero E6 cells. Time of addition studies involved adding astodrimer sodium 1 hour prior to, at the time of, or 1-hour post-infection. Coronavirus spike receptor binding domain (RBD) or S1 binding studies were analysed by ELISA or confocal microscopy. Virucidal studies involved exposing 105 SARS-CoV-2 PFU to 10mg/mL astodrimer sodium for 0.5, 1, 5, 15 and 30 mins. Results: Astodrimer sodium demonstrated potent antiviral and virucidal activity against SARS-CoV-2 VOC α, β, δ and γ, and VOI κ in Vero E6 and Calu-3 cells. Astodrimer sodium reduced infectious viral load of all variants by >99.9% vs virus control. The pan-SARS-CoV-2 activity of astodrimer sodium occurred despite multiple mutations and deletions in the viral spike protein of each variant. The attachment of SARS-CoV-2 early pandemic virus isolates, Wuhan-Hu-1 and USA-WA-1/2020, and SARS-CoV-1 Spike binding to ACE2, as well as attachment of Middle Eastern respiratory syndrome (MERS) coronavirus spike protein to its cellular receptor, was inhibited by astodrimer sodium. Astodrimer sodium did not prevent attachment of the SARS-CoV-2 VOC α and β spike S1, or γ RBD spike protein, to the ACE2 receptor in vitro. Conclusion: Astodrimer sodium mimics negatively charged glycosaminoglycans and provides a potent antiviral and virucidal barrier to viral attachment and entry. The potent broad-spectrum anti-pandemic coronavirus and virucidal efficacy of astodrimer sodium against whole virus is likely due to blocking multiple electrostatic interactions of the spike protein that are not negated by minor or major changes to the isolated RBD of SARS-CoV-2 VOC α, β and γ alone. Astodrimer sodium has the potential to block the binding of pan-SARS-CoV-2, thus reducing the potential for the development of COVID-19.

18.
Pathogens ; 11(5)2022 May 02.
Article in English | MEDLINE | ID: covidwho-1875721

ABSTRACT

Using an effective natural virucidal substance may be a feasible approach for preventing food-borne viral contamination. Here, the virucidal efficacy of theaflavins (TFs)-enriched tea leaf extract (TY-1) against feline calicivirus (FCV) and murine norovirus (MNV), surrogates of human norovirus (HuNoV), was evaluated. The virus solutions were mixed with various dosages of TY-1 and incubated at 25 °C for different contact times. TY-1 reduced the viral titer of both surrogate viruses in a time- and dosage-dependent manner. A statistically significant reduction in the viral titer of FCV by 5.0 mg/mL TY-1 and MNV by 25.0 mg/mL TY-1 was observed in 10 s and 1 min, respectively. Furthermore, TY-1 reduced the viral titer of FCV and MNV on the dry surface in 10 min. The multiple compounds in TY-1, including TFs and catechins, contributed to its overall virucidal activity. Furthermore, the effect of TY-1 on viral proteins and genome was analyzed using Western blotting, RT-PCR, and transmission electron microscopy. TY-1 was found to promote the profound disruption of virion structures, including the capsid proteins and genome. Our finding demonstrates the potential of using TY-1 as a nature-derived disinfectant in food processing facilities and healthcare settings to reduce viral load and HuNoV transmission.

19.
Viruses ; 14(6)2022 05 27.
Article in English | MEDLINE | ID: covidwho-1869816

ABSTRACT

Pyridobenzothiazolone derivatives are a promising class of broad-spectrum antivirals. However, the mode of action of these compounds remains poorly understood. The HeE1-17Y derivative has already been shown to be a potent compound against a variety of flaviviruses of global relevance. In this work, the mode of action of HeE1-17Y has been studied for West Nile virus taking advantage of reporter replication particles (RRPs). Viral infectivity was drastically reduced by incubating the compound with the virus before infection, thus suggesting a direct interaction with the viral particles. Indeed, RRPs incubated with the inhibitor appeared to be severely compromised in electron microscopy analysis. HeE1-17Y is active against other enveloped viruses, including SARS-CoV-2, but not against two non-enveloped viruses, suggesting a virucidal mechanism that involves the alteration of the viral membrane.


Subject(s)
COVID-19 , Flavivirus , RNA Viruses , Viruses , Antiviral Agents/pharmacology , Humans , SARS-CoV-2
20.
B-ENT ; 16(4):202-208, 2020.
Article in English | EMBASE | ID: covidwho-1863155

ABSTRACT

Objective: Allograft tympano-ossicular systems (ATOS) can provide superior outcomes in particular circumstances, for example, in case of a need for total reconstruction of the eardrum and chain. ATOS are preserved in a 2.7%–4% formaldehyde solution after procurement at room temperature (15-25°C) for 2–5 days, followed by 4 °C for a total storage of at least 14 days. This study aimed to review the literature on the virucidal effect of formaldehyde on viruses such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Narrative review of the literature available on the virucidal effect of formaldehyde, as searched in the scientific database PubMed. Results: Both free and intracellular HIV as well as HBV and HCV are significantly reduced at low concentrations of formaldehyde and short exposure time. Factors increasing the effectivity of formaldehyde solutions are high concentration, long exposure time, and high temperature. It has been demonstrated that HIV-infected allografts are disinfected by formaldehyde preservation. No case of HIV, HBV, or HCV transmission through ATOS has been reported. Coronaviruses closely related to SARS-CoV-2, such as SARS-CoV and MERS-CoV, are inactivated by low concentrations of formaldehyde solution, even at short exposure times. Conclusion: These findings indicate that formaldehyde is effective in inactivating HIV, HBV, HCV, and coronaviruses. ATOS are stored in a high concentration formaldehyde solution for a long period. The applied preservation method of ATOS, including temporary storage at room temperature, should be maintained for effective inactivation. The formaldehyde preservation method in combination with donor screening and serological and nucleotide amplification testing make ATOS a very safe reconstruction material.

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