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1.
Viruses ; 13(2)2021 02 02.
Article in English | MEDLINE | ID: covidwho-1067781

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally. Although measures to control SARS-CoV-2, namely, vaccination, medication, and chemical disinfectants are being investigated, there is an increase in the demand for auxiliary antiviral approaches using natural compounds. Here we have focused on hydroxytyrosol (HT)-rich aqueous olive pulp extract (HIDROX®) and evaluated its SARS-CoV-2-inactivating activity in vitro. We showed that the HIDROX solution exhibits time- and concentration-dependent SARS-CoV-2-inactivating activities, and that HIDROX has more potent virucidal activity than pure HT. The evaluation of the mechanism of action suggested that both HIDROX and HT induced structural changes in SARS-CoV-2, which changed the molecular weight of the spike proteins. Even though the spike protein is highly glycosylated, this change was induced regardless of the glycosylation status. In addition, HIDROX or HT treatment disrupted the viral genome. Moreover, the HIDROX-containing cream applied on film showed time- and concentration-dependent SARS-CoV-2-inactivating activities. Thus, the HIDROX-containing cream can be applied topically as an antiviral hand cream. Our findings suggest that HIDROX contributes to improving SARS-CoV-2 control measures.


Subject(s)
Antiviral Agents/pharmacology , Olea , Phenylethyl Alcohol/analogs & derivatives , Plant Extracts/pharmacology , /drug effects , Administration, Topical , Animals , Antiviral Agents/chemistry , Carbohydrates/chemistry , Chlorocebus aethiops , Genome, Viral/drug effects , Glycosylation , Microbial Sensitivity Tests , Phenylethyl Alcohol/administration & dosage , Phenylethyl Alcohol/pharmacology , Phosphoproteins/chemistry , Plant Extracts/chemistry , /physiology , Skin Cream , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells , Virus Inactivation/drug effects
2.
Sci Rep ; 11(1): 1820, 2021 01 19.
Article in English | MEDLINE | ID: covidwho-1065931

ABSTRACT

RT-LAMP detection of SARS-CoV-2 has been shown to be a valuable approach to scale up COVID-19 diagnostics and thus contribute to limiting the spread of the disease. Here we present the optimization of highly cost-effective in-house produced enzymes, and we benchmark their performance against commercial alternatives. We explore the compatibility between multiple DNA polymerases with high strand-displacement activity and thermostable reverse transcriptases required for RT-LAMP. We optimize reaction conditions and demonstrate their applicability using both synthetic RNA and clinical patient samples. Finally, we validate the optimized RT-LAMP assay for the detection of SARS-CoV-2 in unextracted heat-inactivated nasopharyngeal samples from 184 patients. We anticipate that optimized and affordable reagents for RT-LAMP will facilitate the expansion of SARS-CoV-2 testing globally, especially in sites and settings where the need for large scale testing cannot be met by commercial alternatives.


Subject(s)
/diagnosis , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , /genetics , /virology , Hot Temperature , Humans , Nasopharynx/virology , RNA, Viral/metabolism , RNA-Directed DNA Polymerase/metabolism , Reagent Kits, Diagnostic , Sensitivity and Specificity , Virus Inactivation
3.
Environ Sci Technol ; 55(4): 2674-2683, 2021 02 16.
Article in English | MEDLINE | ID: covidwho-1060741

ABSTRACT

It is imperative to understand the behavior of enveloped viruses during water treatment to better protect public health, especially in the light of evidence of detection of coronaviruses in wastewater. We report bench-scale experiments evaluating the extent and mechanisms of removal and/or inactivation of a coronavirus surrogate (ϕ6 bacteriophage) in water by conventional FeCl3 coagulation and Fe(0) electrocoagulation. Both coagulation methods achieved ∼5-log removal/inactivation of ϕ6 in 20 min. Enhanced removal was attributed to the high hydrophobicity of ϕ6 imparted by its characteristic phospholipid envelope. ϕ6 adhesion to freshly precipitated iron (hydr)oxide also led to envelope damage causing inactivation in both coagulation techniques. Fourier transform infrared spectroscopy revealed oxidative damages to ϕ6 lipids only for electrocoagulation consistent with electro-Fenton reactions. Monitoring ϕ6 dsRNA by a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) method quantified significantly lower viral removal/inactivation in water compared with the plaque assay demonstrating that relying solely on RT-qPCR assays may overstate human health risks arising from viruses. Transmission electron microscopy and computationally generated electron density maps of ϕ6 showed severe morphological damages to virus' envelope and loss of capsid volume accompanying coagulation. Both conventional and electro- coagulation appear to be highly effective in controlling enveloped viruses during surface water treatment.


Subject(s)
Iron , Water Purification , Electrocoagulation , Humans , Virus Inactivation , Waste Water
4.
Sci Rep ; 11(1): 2418, 2021 01 28.
Article in English | MEDLINE | ID: covidwho-1054060

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is currently a global pandemic, and there are limited laboratory studies targeting pathogen resistance. This study aimed to investigate the effect of selected disinfection products and methods on the inactivation of SARS-CoV-2 in the laboratory. We used quantitative suspension testing to evaluate the effectiveness of the disinfectant/method. Available chlorine of 250 mg/L, 500 mg/L, and 1000 mg/L required 20 min, 5 min, and 0.5 min to inactivate SARS-CoV-2, respectively. A 600-fold dilution of 17% concentration of di-N-decyl dimethyl ammonium bromide (283 mg/L) and the same concentration of di-N-decyl dimethyl ammonium chloride required only 0.5 min to inactivate the virus efficiently. At 30% concentration for 1 min and 40% and above for 0.5 min, ethanol could efficiently inactivate SARS-CoV-2. Heat takes approximately 30 min at 56 °C, 10 min above 70 °C, or 5 min above 90 °C to inactivate the virus. The chlorinated disinfectants, Di-N-decyl dimethyl ammonium bromide/chloride, ethanol, and heat could effectively inactivate SARS-CoV-2 in the laboratory test. The response of SARS-CoV-2 to disinfectants is very similar to that of SARS-CoV.


Subject(s)
Disinfectants/pharmacology , Disinfection/methods , Virus Inactivation/drug effects , /prevention & control , Chlorine/chemistry , Chlorine/pharmacology , Disinfectants/chemistry , Ethanol/chemistry , Ethanol/pharmacology , Humans , Pandemics/prevention & control , Quaternary Ammonium Compounds/chemistry , Quaternary Ammonium Compounds/pharmacology
5.
Viruses ; 13(1)2020 12 24.
Article in English | MEDLINE | ID: covidwho-1042658

ABSTRACT

The newly identified pathogenic human coronavirus, SARS-CoV-2, led to an atypical pneumonia-like severe acute respiratory syndrome (SARS) outbreak called coronavirus disease 2019 (abbreviated as COVID-19). Currently, nearly 77 million cases have been confirmed worldwide with the highest numbers of COVID-19 cases in the United States. Individuals are getting vaccinated with recently approved vaccines, which are highly protective in suppressing COVID-19 symptoms but there will be a long way before the majority of individuals get vaccinated. In the meantime, safety precautions and effective disease control strategies appear to be vital for preventing the virus spread in public places. Due to the longevity of the virus on smooth surfaces, photocatalytic properties of "self-disinfecting/cleaning" surfaces appear to be a promising tool to help guide disinfection policies for controlling SARS-CoV-2 spread in high-traffic areas such as hospitals, grocery stores, airports, schools, and stadiums. Here, we explored the photocatalytic properties of nanosized TiO2 (TNPs) as induced by the UV radiation, towards virus deactivation. Our preliminary results using a close genetic relative of SAR-CoV-2, HCoV-NL63, showed the virucidal efficacy of photoactive TNPs deposited on glass coverslips, as examined by quantitative RT-qPCR and virus infectivity assays. Efforts to extrapolate the underlying concepts described in this study to SARS-CoV-2 are currently underway.


Subject(s)
Disinfection/methods , Metal Nanoparticles/chemistry , /radiation effects , Titanium/pharmacology , Animals , Antiviral Agents/pharmacology , /virology , Chlorocebus aethiops , Disease Outbreaks/prevention & control , HEK293 Cells , Humans , Titanium/chemistry , Ultraviolet Rays , Vero Cells , Virus Inactivation/drug effects , Virus Inactivation/radiation effects
6.
ACS Appl Mater Interfaces ; 13(5): 5919-5928, 2021 Feb 10.
Article in English | MEDLINE | ID: covidwho-1042382

ABSTRACT

The ongoing COVID-19 pandemic has created a need for coatings that reduce infection from SARS-CoV-2 via surfaces. Such a coating could be used on common touch surfaces (e.g., door handles and railings) to reduce both disease transmission and fear of touching objects. Herein, we describe the design, fabrication, and testing of a cupric oxide anti-SARS-CoV-2 coating. Rapid loss of infectivity is an important design criterion, so a porous hydrophilic coating was created to allow rapid infiltration of aqueous solutions into the coating where diffusion distances to the cupric oxide surface are short and the surface area is large. The coating was deposited onto glass from a dispersion of cuprous oxide in ethanol and then thermally treated at 700 °C for 2 h to produce a CuO coating that is ≈30 µm thick. The heat treatment oxidized the cuprous oxide to cupric oxide and sintered the particles into a robust film. The SARS-CoV-2 infectivity from the CuO film was reduced by 99.8% in 30 min and 99.9% in 1 h compared to that from glass. The coating remained hydrophilic for at least 5 months, and there was no significant change in the cross-hatch test of robustness after exposure to 70% ethanol or 3 wt % bleach.


Subject(s)
/prevention & control , Copper/pharmacology , /physiology , Animals , Chlorocebus aethiops , Humans , Photoelectron Spectroscopy , Surface Properties , Vero Cells , Virus Inactivation/drug effects , X-Ray Diffraction
7.
Anal Chem ; 93(5): 2950-2958, 2021 02 09.
Article in English | MEDLINE | ID: covidwho-1041144

ABSTRACT

There is an urgent need for ultrarapid testing regimens to detect the severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] infections in real-time within seconds to stop its spread. Current testing approaches for this RNA virus focus primarily on diagnosis by RT-qPCR, which is time-consuming, costly, often inaccurate, and impractical for general population rollout due to the need for laboratory processing. The latency until the test result arrives with the patient has led to further virus spread. Furthermore, latest antigen rapid tests still require 15-30 min processing time and are challenging to handle. Despite increased polymerase chain reaction (PCR)-test and antigen-test efforts, the pandemic continues to evolve worldwide. Herein, we developed a superfast, reagent-free, and nondestructive approach of attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy with subsequent chemometric analysis toward the prescreening of virus-infected samples. Contrived saliva samples spiked with inactivated γ-irradiated COVID-19 virus particles at levels down to 1582 copies/mL generated infrared (IR) spectra with a good signal-to-noise ratio. Predominant virus spectral peaks are tentatively associated with nucleic acid bands, including RNA. At low copy numbers, the presence of a virus particle was found to be capable of modifying the IR spectral signature of saliva, again with discriminating wavenumbers primarily associated with RNA. Discrimination was also achievable following ATR-FTIR spectral analysis of swabs immersed in saliva variously spiked with virus. Next, we nested our test system in a clinical setting wherein participants were recruited to provide demographic details, symptoms, parallel RT-qPCR testing, and the acquisition of pharyngeal swabs for ATR-FTIR spectral analysis. Initial categorization of swab samples into negative versus positive COVID-19 infection was based on symptoms and PCR results (n = 111 negatives and 70 positives). Following training and validation (using n = 61 negatives and 20 positives) of a genetic algorithm-linear discriminant analysis (GA-LDA) algorithm, a blind sensitivity of 95% and specificity of 89% was achieved. This prompt approach generates results within 2 min and is applicable in areas with increased people traffic that require sudden test results such as airports, events, or gate controls.


Subject(s)
Algorithms , /physiology , Spectroscopy, Fourier Transform Infrared/methods , Virion/chemistry , /virology , Discriminant Analysis , Gamma Rays , Humans , Point-of-Care Testing , Principal Component Analysis , Saliva/virology , Sensitivity and Specificity , Signal-To-Noise Ratio , Virion/radiation effects , Virus Inactivation
8.
Anal Chem ; 93(5): 2767-2775, 2021 02 09.
Article in English | MEDLINE | ID: covidwho-1039622

ABSTRACT

Clinical tissue specimens are often unscreened, and preparation of tissue sections for analysis by mass spectrometry imaging (MSI) can cause aerosolization of particles potentially carrying an infectious load. We here present a decontamination approach based on ultraviolet-C (UV-C) light to inactivate clinically relevant pathogens such as herpesviridae, papovaviridae human immunodeficiency virus, or SARS-CoV-2, which may be present in human tissue samples while preserving the biodistributions of analytes within the tissue. High doses of UV-C required for high-level disinfection were found to cause oxidation and photodegradation of endogenous species. Lower UV-C doses maintaining inactivation of clinically relevant pathogens to a level of increased operator safety were found to be less destructive to the tissue metabolome and xenobiotics. These doses caused less alterations of the tissue metabolome and allowed elucidation of the biodistribution of the endogenous metabolites. Additionally, we were able to determine the spatially integrated abundances of the ATR inhibitor ceralasertib from decontaminated human biopsies using desorption electrospray ionization-MSI (DESI-MSI).


Subject(s)
Decontamination/methods , Ultraviolet Rays , Animals , Azetidines/analysis , Azetidines/therapeutic use , /virology , Head and Neck Neoplasms/chemistry , Head and Neck Neoplasms/drug therapy , Head and Neck Neoplasms/pathology , Humans , Male , Metabolome , Naphthalenes/analysis , Naphthalenes/therapeutic use , Photolysis/radiation effects , Rats , Rats, Wistar , /radiation effects , Spectrometry, Mass, Electrospray Ionization/methods , Terfenadine/chemistry , Virus Inactivation/radiation effects
9.
Emerg Microbes Infect ; 10(1): 206-210, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1007445

ABSTRACT

The extremely rapid spread of the SARS-CoV-2 has already resulted in more than 1 million reported deaths of coronavirus disease 2019 (COVID-19). The ability of infectious particles to persist on environmental surfaces is potentially considered a factor for viral spreading. Therefore, limiting viral diffusion in public environments should be achieved with correct disinfection of objects, tissues, and clothes. This study proves how two widespread disinfection systems, short-wavelength ultraviolet light (UV-C) and ozone (O3), are active in vitro on different commonly used materials. The development of devices equipped with UV-C, or ozone generators, may prevent the virus from spreading in public places.


Subject(s)
/prevention & control , Disinfection/methods , Ozone/pharmacology , Ultraviolet Rays , Virus Inactivation/drug effects , Virus Inactivation/radiation effects , Humans , /isolation & purification , /radiation effects
10.
Sci Rep ; 10(1): 22421, 2020 12 30.
Article in English | MEDLINE | ID: covidwho-1003313

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has devastated global public health systems and economies, with over 52 million people infected, millions of jobs and businesses lost, and more than 1 million deaths recorded to date. Contact with surfaces contaminated with droplets generated by infected persons through exhaling, talking, coughing and sneezing is a major driver of SARS-CoV-2 transmission, with the virus being able to survive on surfaces for extended periods of time. To interrupt these chains of transmission, there is an urgent need for devices that can be deployed to inactivate the virus on both recently and existing contaminated surfaces. Here, we describe the inactivation of SARS-CoV-2 in both wet and dry format using radiation generated by a commercially available Signify ultraviolet (UV)-C light source at 254 nm. We show that for contaminated surfaces, only seconds of exposure is required for complete inactivation, allowing for easy implementation in decontamination workflows.


Subject(s)
/prevention & control , Decontamination/methods , Ultraviolet Rays , Virus Inactivation/radiation effects , /transmission , Humans
11.
Cornea ; 40(1): 121-122, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-998522

ABSTRACT

PURPOSE: To report the germicidal range ultraviolet (UV) irradiation-induced phototoxicity because of unprotected exposure to the UV lamps for presumed household disinfection of SARS-CoV-2 in a domestic setting. METHODS: We report on a family of 3 adults who experienced photophobia, intense eye pain, epiphora, blurred vision, and a burning sensation over the face and neck area after a short period of unprotected exposure to the UV germicidal lamps. RESULTS: An initial examination revealed erythema and tenderness over the face and neck area, reduced visual acuity of 6/12, and conjunctival injections bilaterally in all 3 patients. Further assessment at the ophthalmology department 3 days later revealed gradual improvement of visual acuity to 6/6 bilaterally. Slit-lamp examinations revealed few punctate epithelial erosions. Fundal examinations were normal without evidence of solar retinopathy. The patients were diagnosed with germicidal range UV irradiation-induced photokeratitis and epidermal phototoxicity. Lubricants and emollients were prescribed for symptom relief, and the patients were warned against using a UV germicidal lamp for disinfection purposes without appropriate protection. CONCLUSIONS: Although SARS-CoV-2 is structurally akin to SARS-CoV-1 and MERS-CoV, and previous studies demonstrated high levels of inactivation of beta-coronavirus with germicidal-range UV, evidence for its efficacy to inactivate SARS-CoV-2 is lacking. This case report serves to emphasize the potential consequences of phototoxicity from the improper use of UV germicidal lamps for household disinfection and to highlight the fact that UV germicidal lamps currently have no established role in household disinfection of SARS-CoV-2.


Subject(s)
/prevention & control , Dermatitis, Phototoxic/etiology , Disinfection/instrumentation , Photophobia/etiology , Radiation Injuries/etiology , Ultraviolet Rays/adverse effects , Adolescent , Dermatitis, Phototoxic/diagnosis , Eye Pain/diagnosis , Eye Pain/etiology , Female , Humans , Infection Control/instrumentation , Photophobia/diagnosis , Radiation Injuries/diagnosis , Virus Inactivation/radiation effects
12.
Sci Rep ; 10(1): 22419, 2020 12 29.
Article in English | MEDLINE | ID: covidwho-997947

ABSTRACT

Survival of respiratory viral pathogens in expelled saliva microdroplets is central to their transmission, yet the factors that determine survival in such microdroplets are not well understood. Here we combine microscopy imaging with virus viability assays to study survival of three bacteriophages suggested as good models for respiratory pathogens: the enveloped Phi6 (a surrogate for SARS-CoV-2), and the non-enveloped PhiX174 and MS2. We measured virus viability in human saliva microdroplets, SM buffer, and water following deposition on glass surfaces at various relative humidities (RH). Saliva and water microdroplets dried out rapidly, within minutes, at all tested RH levels (23%, 43%, 57%, and 78%), while SM microdroplets remained hydrated at RH ≥ 57%. Generally, the survival of all three viruses in dry saliva microdroplets was significantly greater than those in SM buffer and water under all RH (except PhiX174 in water under 57% RH survived the best among 3 media). Thus, atmosphere RH and microdroplet hydration state are not sufficient to explain virus survival, indicating that the virus-suspended medium, and association with saliva components in particular, likely play a role in virus survival. Uncovering the exact properties and components that make saliva a favorable environment for the survival of viruses, in particular enveloped ones like Phi6, is thus of great importance for reducing transmission of viral respiratory pathogens including SARS-CoV-2.


Subject(s)
Bacteriophage phi X 174/metabolism , Levivirus/metabolism , Microbial Viability , Saliva/virology , Bacteriophage phi 6/metabolism , Environmental Microbiology , Humans , Viral Plaque Assay , Virus Inactivation
13.
F1000Res ; 9: 674, 2020.
Article in English | MEDLINE | ID: covidwho-902997

ABSTRACT

Background: The ability to protect workers and healthcare professionals from infection by SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is of great concern. Hospitals, nursing homes and employers are adopting infection control strategies based on guidance from leading public health organizations such as the CDC, OSHA, FDA, and other government bodies. Certain hard surface disinfectants are effective against SARS-CoV-2 but are not suitable for use on skin or personal protective equipment (PPE) that comes into contact with skin. Furthermore, near-ubiquitous alcohol-based hand sanitizers are acceptable for use on skin, but they are not suitable for use on PPE. PPE, especially masks, are also commonly being used for longer durations than normal. There is a need for new products and techniques that can effectively disinfect PPE during wear time without having detrimental effects on surrounding skin. Clyraguard spray is a novel copper iodine complex designed to be used on non-critical PPE. Methods: In this study, the Clyraguard copper iodine complex was tested for its ability to inactivate SARS-CoV-2 in solution. Results: These data indicate the product to be effective in reducing SARS-CoV-2 titers in a time-dependent manner, with the virus being reduced below the detection limits within 30 minutes. Conclusions: These results suggest that Clyraguard may be an effective tool for mitigating cross-contamination of non-critical PPE that may come into contact with SARS-CoV-2.


Subject(s)
Betacoronavirus/drug effects , Copper/pharmacology , Disinfectants/pharmacology , Iodine/pharmacology , Virus Inactivation/drug effects , Coronavirus Infections , Humans , Pandemics , Pneumonia, Viral
14.
Viruses ; 12(11)2020 10 23.
Article in English | MEDLINE | ID: covidwho-895403

ABSTRACT

Critical to facilitating SARS-CoV-2 point-of-care (POC) testing is assurance that viruses present in specimens are inactivated onsite prior to processing. Here, we conducted experiments to determine the virucidal activity of commercially available Viral Transport Mediums (VTMs) to inactivate SARS-CoV-2. Independent testing methods for viral inactivation testing were applied, including a previously described World Health Organization (WHO) protocol, in addition to a buffer exchange method where the virus is physically separated from the VTM post exposure. The latter method enables sensitive detection of viral viability at higher viral titre when incubated with VTM. We demonstrate that VTM formulations, Primestore® Molecular Transport Medium (MTM) and COPAN eNAT™ completely inactivate high-titre SARS-CoV-2 virus (>1 × 107 copies/mL) and are compatible with POC processing. Furthermore, full viral inactivation was rapidly achieved in as little as 2 min of VTM exposure. We conclude that adding certain VTM formulations as a first step post specimen collection will render SARS-CoV-2 non-infectious for transport, or for further in-field POC molecular testing using rapid turnaround GeneXpert platforms or equivalent.


Subject(s)
Betacoronavirus/isolation & purification , Point-of-Care Testing , Specimen Handling , Virus Inactivation , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Culture Media/analysis , Culture Media/pharmacology , Humans , Point-of-Care Testing/standards , Specimen Handling/methods , Specimen Handling/standards , Viral Load/drug effects , Virus Inactivation/drug effects
15.
J Virol Methods ; 287: 113996, 2021 01.
Article in English | MEDLINE | ID: covidwho-894099

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) pandemic caused by infection with severe acute respiratory syndrome - coronavirus-2 (SARS-CoV-2) continues to affect many countries and large populations. Serologic assays for antibody detection aid patient diagnosis and seroepidemiologic investigations. METHODS: An indirect IgG ELISA was developed indigenously using ß-propiolactone (BPL) inactivated SARS-CoV-2. This assay was used for screening 200 healthy donor sera collected prior to COVID-19 emergence (2017-2019), 185 serum/plasma samples of confirmed COVID-19 patients (n = 137) and 57 samples of viral RNA positive asymptomatic contacts (n = 51). The IgG response was studied in relation to duration and severity of illness. RESULTS: The ELISA demonstrated 97 % specificity and IgG detection in >50 %, 80 %, 93.8 % and 100 % of the patients respectively during the first, second, third and fourth week of illness. IgG detection rate was higher in patients with severe disease (SD, 90.9 %) than those with mild disease (MD, 68.8 %) during the second week of illness (P = 0.027). IgG seropositivity among asymptomatic contacts was 64.7 %. IgG ELISA absorbance values were higher in SD than MD patients during the first 2 weeks of illness (P < 0.05). No significant difference was observed between the absorbance values of asymptomatic subjects and MD patients (P = 0.94). CONCLUSION: The BPL inactivated virus-based ELISA could detect IgG antibodies early and in a significant proportion of COVID-19 patients suggesting its potential utility as a supplement to the currently used viral RNA detection tests in patient diagnosis and contact screening algorithms.


Subject(s)
/methods , Immunoglobulin G/blood , Propiolactone/pharmacology , /immunology , Antibodies, Viral/blood , /pathology , Enzyme-Linked Immunosorbent Assay , Humans , Sensitivity and Specificity , Seroepidemiologic Studies , Virus Inactivation/drug effects
16.
mSphere ; 5(5)2020 10 21.
Article in English | MEDLINE | ID: covidwho-889854

ABSTRACT

Supply shortages of N95 respirators during the coronavirus disease 2019 (COVID-19) pandemic have motivated institutions to develop feasible and effective N95 respirator reuse strategies. In particular, heat decontamination is a treatment method that scales well and can be implemented in settings with variable or limited resources. Prior studies using multiple inactivation methods, however, have often focused on a single virus under narrowly defined conditions, making it difficult to develop guiding principles for inactivating emerging or difficult-to-culture viruses. We systematically explored how temperature, humidity, and virus deposition solutions impact the inactivation of viruses deposited and dried on N95 respirator coupons. We exposed four virus surrogates across a range of structures and phylogenies, including two bacteriophages (MS2 and phi6), a mouse coronavirus (murine hepatitis virus [MHV]), and a recombinant human influenza A virus subtype H3N2 (IAV), to heat treatment for 30 min in multiple deposition solutions across several temperatures and relative humidities (RHs). We observed that elevated RH was essential for effective heat inactivation of all four viruses tested. For heat treatments between 72°C and 82°C, RHs greater than 50% resulted in a >6-log10 inactivation of bacteriophages, and RHs greater than 25% resulted in a >3.5-log10 inactivation of MHV and IAV. Furthermore, deposition of viruses in host cell culture media greatly enhanced virus inactivation by heat and humidity compared to other deposition solutions, such as phosphate-buffered saline, phosphate-buffered saline with bovine serum albumin, and human saliva. Past and future heat treatment methods must therefore explicitly account for deposition solutions as a factor that will strongly influence observed virus inactivation rates. Overall, our data set can inform the design and validation of effective heat-based decontamination strategies for N95 respirators and other porous surfaces, especially for emerging viruses that may be of immediate and future public health concern.IMPORTANCE Shortages of personal protective equipment, including N95 respirators, during the coronavirus (CoV) disease 2019 (COVID-19) pandemic have highlighted the need to develop effective decontamination strategies for their reuse. This is particularly important in health care settings for reducing exposure to respiratory viruses, like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Although several treatment methods are available, a widely accessible strategy will be necessary to combat shortages on a global scale. We demonstrate that the combination of heat and humidity inactivates a range of RNA viruses, including both viral pathogens and common viral pathogen surrogates, after deposition on N95 respirators and achieves the necessary virus inactivation detailed by the U.S. Food and Drug Administration guidelines to validate N95 respirator decontamination technologies. We further demonstrate that depositing viruses onto surfaces when suspended in culture media can greatly enhance observed inactivation, adding caution to how heat and humidity treatment methods are validated.


Subject(s)
Decontamination/methods , Hot Temperature , Humidity , Ventilators, Mechanical , Virus Diseases/prevention & control , Virus Inactivation , Virus Physiological Phenomena , Betacoronavirus , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Saline Solution , Saliva , Serum Albumin, Bovine
17.
J Microbiol ; 58(10): 886-891, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-807667

ABSTRACT

Various treatments and agents had been reported to inactivate RNA viruses. Of these, thermal inactivation is generally considered an effective and cheap method of sample preparation for downstream assays. The purpose of this study is to establish a safe inactivation method for SARS-CoV-2 without compromising the amount of amplifiable viral genome necessary for clinical diagnoses. In this study, we demonstrate the infectivity and genomic stability of SARSCoV- 2 by thermal inactivation at both 56°C and 65°C. The results substantiate that viable SARS-CoV-2 is readily inactivated when incubated at 56°C for 30 min or at 65°C for 10 min. qRT-PCR of specimens heat-inactivated at 56°C for 30 min or 65°C for 15 min revealed similar genomic RNA stability compared with non-heat inactivated specimens. Further, we demonstrate that 30 min of thermal inactivation at 56°C could inactivate viable viruses from clinical COVID-19 specimens without attenuating the qRT-PCR diagnostic sensitivity. Heat treatment of clinical specimens from COVID-19 patients at 56°C for 30 min or 65°C for 15 min could be a useful method for the inactivation of a highly contagious agent, SARS-CoV-2. Use of this method would reduce the potential for secondary infections in BSL2 conditions during diagnostic procedures. Importantly, infectious virus can be inactivated in clinical specimens without compromising the sensitivity of the diagnostic RT-PCR assay.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/diagnosis , Pneumonia, Viral/virology , Specimen Handling/methods , Virus Inactivation , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , Clinical Laboratory Techniques , Coronavirus Infections/virology , Genome, Viral , Genomic Instability , Hot Temperature , Humans , Pandemics , Pneumonia, Viral/diagnosis , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction
18.
J Photochem Photobiol B ; 212: 112044, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-799262

ABSTRACT

UV light-emitting diodes (UV LEDs) are an emerging technology and a UV source for pathogen inactivation, however low UV-LED wavelengths are costly and have low fluence rate. Our results suggest that the sensitivity of human Coronavirus (HCoV-OC43 used as SARS-CoV-2 surrogate) was wavelength dependent with 267 nm ~ 279 nm > 286 nm > 297 nm. Other viruses showed similar results, suggesting UV LED with peak emission at ~286 nm could serve as an effective tool in the fight against human Coronaviruses.


Subject(s)
Betacoronavirus/radiation effects , Ultraviolet Rays , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , Coronavirus Infections/pathology , Coronavirus Infections/virology , Humans , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , RNA, Viral/metabolism , Radiation Dosage , Real-Time Polymerase Chain Reaction , Virus Inactivation/radiation effects
19.
Appl Environ Microbiol ; 86(18)2020 09 01.
Article in English | MEDLINE | ID: covidwho-788000

ABSTRACT

Temperature and relative humidity are major factors determining virus inactivation in the environment. This article reviews inactivation data regarding coronaviruses on surfaces and in liquids from published studies and develops secondary models to predict coronaviruses inactivation as a function of temperature and relative humidity. A total of 102 D values (i.e., the time to obtain a log10 reduction of virus infectivity), including values for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were collected from 26 published studies. The values obtained from the different coronaviruses and studies were found to be generally consistent. Five different models were fitted to the global data set of D values. The most appropriate model considered temperature and relative humidity. A spreadsheet predicting the inactivation of coronaviruses and the associated uncertainty is presented and can be used to predict virus inactivation for untested temperatures, time points, or any coronavirus strains belonging to Alphacoronavirus and Betacoronavirus genera.IMPORTANCE The prediction of the persistence of SARS-CoV-2 on fomites is essential in investigating the importance of contact transmission. This study collects available information on inactivation kinetics of coronaviruses in both solid and liquid fomites and creates a mathematical model for the impact of temperature and relative humidity on virus persistence. The predictions of the model can support more robust decision-making and could be useful in various public health contexts. A calculator for the natural clearance of SARS-CoV-2 depending on temperature and relative humidity could be a valuable operational tool for public authorities.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/virology , Models, Biological , Pneumonia, Viral/virology , Virus Inactivation , Fomites/virology , Humans , Humidity , Pandemics , Public Health , Suspensions , Temperature
20.
Appl Environ Microbiol ; 86(17)2020 08 18.
Article in English | MEDLINE | ID: covidwho-767717

ABSTRACT

The infection of health care workers during the 2013 to 2016 Ebola outbreak raised concerns about fomite transmission. In the wake of the coronavirus disease 2019 (COVID-19) pandemic, investigations are ongoing to determine the role of fomites in coronavirus transmission as well. The bacteriophage phi 6 has a phospholipid envelope and is commonly used in environmental studies as a surrogate for human enveloped viruses. The persistence of phi 6 was evaluated as a surrogate for Ebola virus (EBOV) and coronaviruses on porous and nonporous hospital surfaces. Phi 6 was suspended in a body fluid simulant and inoculated onto 1-cm2 coupons of steel, plastic, and two fabric curtain types. The coupons were placed at two controlled absolute humidity (AH) levels: a low AH of 3.0 g/m3 and a high AH of 14.4 g/m3 Phi 6 declined at a lower rate on all materials under low-AH conditions, with a decay rate of 0.06-log10 PFU/day to 0.11-log10 PFU/day, than under the higher AH conditions, with a decay rate of 0.65-log10 PFU/h to 1.42-log10 PFU/day. There was a significant difference in decay rates between porous and nonporous surfaces at both low AH (P < 0.0001) and high AH (P < 0.0001). Under these laboratory-simulated conditions, phi 6 was found to be a conservative surrogate for EBOV under low-AH conditions in that it persisted longer than Ebola virus in similar AH conditions. Additionally, some coronaviruses persist longer than phi 6 under similar conditions; therefore, phi 6 may not be a suitable surrogate for coronaviruses.IMPORTANCE Understanding the persistence of enveloped viruses helps inform infection control practices and procedures in health care facilities and community settings. These data convey to public health investigators that enveloped viruses can persist and remain infective on surfaces, thus demonstrating a potential risk for transmission. Under these laboratory-simulated Western indoor hospital conditions, we assessed the suitability of phi 6 as a surrogate for environmental persistence research related to enveloped viruses, including EBOV and coronaviruses.


Subject(s)
Bacteriophage phi 6/isolation & purification , Bacteriophage phi 6/physiology , Coronavirus/physiology , Ebolavirus/physiology , Environmental Microbiology , Fomites/virology , Virus Inactivation , Betacoronavirus/physiology , Coronavirus/isolation & purification , Coronavirus Infections/transmission , Coronavirus Infections/virology , Ebolavirus/isolation & purification , Hemorrhagic Fever, Ebola/transmission , Hemorrhagic Fever, Ebola/virology , Hospitals , Humans , Humidity , Pandemics , Pneumonia, Viral/transmission , Porosity , Temperature
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