scholarly journals The Effectiveness of Far-Ultraviolet (UVC) Light Prototype Devices with Different Wavelengths on Disinfecting SARS-CoV-2

2021 ◽  
Vol 11 (22) ◽  
pp. 10661
Author(s):  
Jian-Jong Liang ◽  
Chun-Che Liao ◽  
Chih-Shin Chang ◽  
Chih-Yin Lee ◽  
Si-Yu Chen ◽  
...  
Keyword(s):  
Indoor Air ◽  
Mercury Lamp ◽  
Virucidal Activity ◽  
African Green Monkey Kidney ◽  
Infectious Dose ◽  
Excimer Lamp ◽  
Log Reduction ◽  
Far Ultraviolet ◽  
Uvc Radiation ◽  
Tissue Culture Infectious Dose

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a serious threat to human health worldwide. The inactivation of SARS-CoV-2 on object surfaces and in the indoor air might help to halt the COVID-19 pandemic. Far-ultraviolet light (UVC) disinfection has been proven to be highly effective against viruses and bacteria. To understand the wavelength and duration of UVC radiation required for SARS-CoV-2 inactivation, we examined the efficacy of UVC light prototype devices with the wavelengths of 275, 254, and 222 nm. The disinfection effectiveness was determined by cell-based assays including the median tissue culture infectious dose (TCID50) and an immunofluorescent assay on African green monkey kidney epithelial Vero E6 cells. Among the three prototypes, the UVC LED (275 nm) had the best virucidal activity with a log-reduction value (LRV) >6 after 10 s of exposure. The mercury lamp (254 nm) reached similar virucidal activity after 20 s of exposure. However, the excimer lamp (222 nm) showed limited anti-SARS-CoV-2 activity with a LRV < 2 after 40 s of exposure. Overall, in comparison, the UVC LED (275 nm) exhibited superior SARS-CoV-2 disinfection activity than the mercury lamp (254 nm) and the excimer lamp (222 nm).

Ozone Inactivation of Norovirus Surrogates on Fresh Produce

2011 ◽  
Vol 74 (5) ◽  
pp. 836-839 ◽  
Author(s):  
K. A. HIRNEISEN ◽  
S. M. MARKLAND ◽  
K. E. KNIEL
Keyword(s):  
Fresh Produce ◽  
Plaque Assay ◽  
Ozone Treatment ◽  
Great Promise ◽  
Murine Norovirus ◽  
Time Intervals ◽  
Infectious Dose ◽  
Log Reduction ◽  
Soil Irrigation ◽  
Tissue Culture Infectious Dose

Preharvest contamination of produce by foodborne viruses can occur through a variety of agents, including animal feces/manures, soil, irrigation water, animals, and human handling. Problems of contamination are magnified by potential countrywide distribution. Postharvest processing of produce can involve spraying, washing, or immersion into water with disinfectants; however, disinfectants, including chlorine, have varying effects on viruses and harmful by-products pose a concern. The use of ozone as a disinfectant in produce washes has shown great promise for bacterial pathogens, but limited research exists on its efficacy on viruses. This study compares ozone inactivation of human norovirus surrogates (feline calicivirus [FCV] and murine norovirus [MNV]) on produce (green onions and lettuce) and in sterile water. Green onions and lettuce inoculated with FCV or MNV were treated with ozone (6.25 ppm) for 0.5- to 10-min time intervals. Infectivity was determined by 50% tissue culture infectious dose (TCID50) and plaque assay for FCV and MNV, respectively. After 5 min of ozone treatment, &gt;6 log TCID50/ml of FCV was inactivated in water and ~2-log TCID50/ml on lettuce and green onions. MNV inoculated onto green onions and lettuce showed a &gt;2-log reduction after 1 min of ozone treatment. The food matrix played the largest role in protection against ozone inactivation. These results indicate that ozone is an alternative method to reduce viral contamination on the surface of fresh produce.

scholarly journals Optimized Hepatitis E Virus (HEV) Culture and Its Application to Measurements of HEV Infectivity

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 139 ◽  
Author(s):  
Nicolas Capelli ◽  
Martine Dubois ◽  
Mélanie Pucelle ◽  
Isabelle Da Silva ◽  
Sébastien Lhomme ◽  
...  
Keyword(s):  
Hepatitis E Virus ◽  
Fetal Bovine Serum ◽  
Hepatitis E ◽  
Chronic Liver Diseases ◽  
Infectious Dose ◽  
Clinical Strains ◽  
Fetal Bovine ◽  
Culture Supernatants ◽  
Tissue Culture Infectious Dose

Hepatitis E virus (HEV) is a major concern in public health worldwide. Infections with HEV genotypes 3, 4, or 7 can lead to chronic hepatitis while genotype 1 infections can trigger severe hepatitis in pregnant women. Infections with all genotypes can worsen chronic liver diseases. As virions are lipid-associated in blood and naked in feces, efficient methods of propagating HEV clinical strains in vitro and evaluating the infectivity of both HEV forms are needed. We evaluated the spread of clinical strains of HEV genotypes 1 (HEV1) and 3 (HEV3) by quantifying viral RNA in culture supernatants and cell lysates. Infectivity was determined by endpoint dilution and calculation of the tissue culture infectious dose 50 (TCID50). An enhanced HEV production could be obtained varying the composition of the medium, including fetal bovine serum (FBS) and dimethylsulfoxide (DMSO) content. This increased TCID50 from 10 to 100-fold and allowed us to quantify HEV1 infectivity. These optimized methods for propagating and measuring HEV infectivity could be applied to health safety processes and will be useful for testing new antiviral drugs.

Correlation of serostatus and viraemia levels among Indian dengue patients at the time of first diagnosis

2020 ◽  
Vol 114 (7) ◽  
pp. 513-520
Author(s):  
Ruta Kulkarni ◽  
Shubham Shrivastava ◽  
Harshad P Patil ◽  
Divya Tiraki ◽  
Akhilesh Chandra Mishra ◽  
...  
Keyword(s):  
Public Health Problem ◽  
Vero Cells ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Markers ◽  
Serum Samples ◽  
Infectious Dose ◽  
Therapeutic Monoclonal Antibodies ◽  
Tissue Culture Infectious Dose ◽  
First Diagnosis

Abstract Background Dengue is a public health problem worldwide. Therapeutic monoclonal antibodies (MAbs) against dengue virus (DENV) are likely to be available soon. In view of the feasibility issues pertaining to pretreatment viraemia quantitation for therapy decisions, we conducted this study for investigation of a correlation between patient serostatus (NS1/immunoglobulin M [IgM]/IgG) and viraemia levels among Indian dengue patients at the time of first diagnosis. Methods The study included 297 serum samples from dengue patients in Pune, India. The samples were tested for NS1, IgM and IgG (capture enzyme-linked immunosorbent assay [ELISA] for identifying secondary dengue) using Panbio ELISAs. Quantitation of viraemia was conducted using an NS1 ELISA-based 50% tissue culture infectious dose (TCID50) test in Vero cells. Results Viraemia was detectable only among NS1-positive patients (n = 229, range 0.5–8.3 logTCID50/ml) with a mean titre of 1.9 logTCID50/ml. Among the NS1-positive patients, DENV titres were higher in IgM-negative than IgM-positive patients (p &lt; 0.0001) and in primary (IgG &lt; 18 Panbio units) versus secondary (IgG &gt; 22 Panbio units) dengue patients (p = 0.002). Virus titres were higher during the first 3 days of illness and decreased later (p = 0.005). Conclusions The study provides a range of infectious DENV titres in relation to serologic status among dengue patients in India. The data suggest the possibility of using serological markers (NS1/IgM) as a basis for treatment decisions.

Evaluating the Antimicrobial Efficacy of White Mustard Essential Oil Alone and in Combination with Thymol and Carvacrol Against Salmonella

2019 ◽  
Vol 82 (12) ◽  
pp. 2038-2043 ◽  
Author(s):  
JOHN ADAM PORTER ◽  
EMEFA ANGELICA MONU
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Food Products ◽  
The United States ◽  
Positive Control ◽  
Antimicrobial Efficacy ◽  
White Mustard ◽  
Infectious Dose ◽  
Log Reduction ◽  
Mustard Essential Oil

ABSTRACT It is estimated that nontyphoidal Salmonella causes approximately 1 million illnesses and 378 deaths per year in the United States. Reduction of Salmonella-related foodborne infections can be achieved through application of food antimicrobials. Essential oils in combination with other antimicrobials can be added to food products to reduce the levels of the organism below the infectious dose for healthy individuals. The purpose of this study was to investigate the antimicrobial efficacy of white mustard essential oil (WMEO) against serovars of Salmonella and its potential to be used with carvacrol or thymol to control Salmonella. Results showed that WMEO at the highest concentration of 0.84% (v/v) compared with the positive control had approximately a 6- to 7-log reduction for all serovars. It was found that no difference in susceptibility existed among the serovars tested (P &gt; 0.05). In addition, the MICs were determined to be 0.5, 0.02, and 0.02% for WMEO, carvacrol, and thymol, respectively, against Salmonella Typhimurium. The fractional inhibitory concentration index was calculated. A score of 1 indicated an additive effect occurred when WMEO was combined with thymol or carvacrol. Combining WMEO with carvacrol or thymol indicated that the concentration of individual essential oils needed to inhibit Salmonella can be reduced using these combinations and warrants further study to determine potential use in controlling Salmonella in commercial food products. HIGHLIGHTS

scholarly journals Prolonged Viability of Senecavirus A in Exposed House Flies (Musca domestica)

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 127
Author(s):  
Justin Heath Turner ◽  
Willian Pinto Paim ◽  
Mayara Fernanda Maggioli ◽  
Cristina Mendes Peter ◽  
Robert Miknis ◽  
...  
Keyword(s):  
Musca Domestica ◽  
Female Group ◽  
Infectious Dose ◽  
House Flies ◽  
Environmental Resistance ◽  
Successful Isolation ◽  
Swinepox Virus ◽  
High Virus ◽  
Tissue Culture Infectious Dose

House flies (Musca domestica) are often present in swine farms worldwide. These flies utilize animal secretions and waste as a food source. House flies may harbor and transport microbes and pathogens acting as mechanical vectors for diseases. Senecavirus A (SVA) infection in pigs occurs via oronasal route, and animals shed high virus titers to the environment. Additionally, SVA possesses increased environmental resistance. Due to these reasons, we investigated the tenacity of SVA in house flies. Five groups of flies, each composed of ten females and ten males, were exposed to SVA, titer of 109.3 tissue culture infectious dose (TCID50/mL). Groups of male and female flies were collected at 0, 6, 12, 24, and 48 h post-exposure. For comparison purposes, groups of flies were exposed to Swinepox virus (SwPV). Infectious SVA was identified in all tested groups. Successful isolation of SVA demonstrated the titers varied between 106.8 and 102.8 TCID50/mL in female groups and varied from 105.85 to 103.8 TCID50/mL in male groups. In contrast, infectious SwPV was only detected in the female group at 6 h. The significant SVA infectious titer for prolonged periods of time, up to 48 h, indicates a potential role of flies in SVA transmission.

Inactivation of Avirulent Yersinia pestis in Butterfield's Phosphate Buffer and Frankfurters by UVC (254 nm) and Gamma Radiation†

2009 ◽  
Vol 72 (4) ◽  
pp. 755-759 ◽  
Author(s):  
CHRISTOPHER H. SOMMERS ◽  
PETER H. COOKE
Keyword(s):  
Radiation Dose ◽  
Gamma Radiation ◽  
Yersinia Pestis ◽  
Phosphate Buffer ◽  
Radiation Doses ◽  
Refrigerated Storage ◽  
Log Reduction ◽  
Contaminated Food ◽  
Gamma Radiation Dose ◽  
Uvc Radiation

Yersinia pestis is the causative agent of plague. Although rare, pharyngeal plague in humans has been associated with consumption or handling of meat prepared from infected animals. The risks of contracting plague from consumption of deliberately contaminated food are currently unknown. Gamma radiation is a penetrating form of electromagnetic radiation, and UVC radiation is used for decontamination of liquids or food surfaces. Gamma radiation D10-values (the radiation dose needed to inactivate 1 log unit pathogen) were 0.23 (±0.01) and 0.31 (±0.03) kGy for avirulent Y. pestis inoculated into Butterfield's phosphate buffer and onto frankfurter surfaces, respectively, at 0°C. A UVC radiation dose of 0.25 J/cm2 inactivated avirulent Y. pestis suspended in Butterfield's phosphate buffer. UVC radiation doses of 0.5 to 4.0 J/cm2 inactivated 0.97 to 1.20 log units of the Y. pestis surface inoculated onto frankfurters. A low gamma radiation dose of 1.6 kGy could provide a 5-log reduction and a UVC radiation dose of 1 to 4 J/cm2 would provide a 1-log reduction of Y. pestis surface inoculated onto frankfurters. Y. pestis was capable of growth on frankfurters during refrigerated storage (10°C). Gamma radiation of frankfurters inhibited the growth of Y. pestis during refrigerated storage, and UVC radiation delayed the growth of Y. pestis.

Bovine viral diarrhoea(BVD) virus antiviral activity of Korean Tung Tree (Aleurites fordii) extracts in vivo

2015 ◽  
Author(s):  
Youn-Jin Park ◽  
Yeong-ho Choe ◽  
Byeung-Soo Kim
Keyword(s):  
Antiviral Activity ◽  
Ethyl Acetate ◽  
Antiviral Effect ◽  
Cytotoxicity Test ◽  
Tung Tree ◽  
Bovine Viral Diarrhoea ◽  
Infectious Dose ◽  
Tissue Culture Infectious Dose ◽  
Ethyl Acetate Extracts

This study investigated the Bovine viral diarrhoea(BVD) virus antiviral effect of Aleurites fordii (tung tree) extract. . First, a cytotoxicity test on MDBK (Madin-Darby bovine kidney) cells took place at various n-Hexane and ethyl acetate extract concentrations. Each of the extracts’ cytotoxicity test results had 0.03mg/ml of n-Hexane and 0.06 mg/ml of ethyl acetate. In the tissue culture infectious dose (TCID50) assay, 0.03 mg/ml of the ethyl acetate extracts decreased the BVD virus by 1.4 log, whereas the other extracts did not show any antiviral activity. The results suggest that ethyl acetate extracts and fractions of Aleurites fordii can replace chemical antivirus substances.

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