Search for New AntiphytovirucidesⅣ.Synthesis of 2-(2'-Hydroxyphenyl)-5(6)-substituted benzimidazole Derivatives

A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylenediamine in the presence pyridine POCl 3 . Three compounds were tested as plant virucide against tobacco mosaic virus and they exhibited some activities.

Deep-ultraviolet photonics for the disinfection of SARS-CoV-2 and its variants(Delta and Omicron)in the cryogenic environment

Deep-ultraviolet(DUV)disinfection technology provides an expeditious and efficient way to suppress the transmission of coronavirus disease 2019(COVID-19).However,the influences of viral variants(Delta and Omicron)and low temperatures on the DUV virucidal efficacy are still unknown.Here,we developed a reliable and uniform planar light source comprised of 275-nm light-emitting diodes(LEDs)to investigate the effects of these two unknown factors and delineated the principle behind different disinfection performances.We found the lethal effect of DUV at the same radiation dose was reduced by the cryogenic environment,and a negative-U large-relaxation model was used to explain the difference in view of the photoelectronic nature.The chances were higher in the cryogenic environment for the capture of excited electrons within active genetic molecules back to the initial photo-ionised positions.Additionally,the variant of Omicron required a significantly higher DUV dose to achieve the same virucidal efficacy,and this was thanks to the genetic and proteinic characteristics of the Omicron.The findings in this study are important for human society using DUV disinfection in cold conditions(e.g.,the food cold chain logistics and the open air in winter),and the relevant DUV disinfection suggestion against COVID-19 is provided.

The bactericidal spectrum and virucidal effects of silver nanoparticles against the pathogens in sericulture

Silver nanoparticles have mainly been studied for their antimicrobial potential against bacteria, but have also proven to be active against several types of viruses, even against pebrine as well. Methods: Petri dishes and transmission electronic microscope were applied to observe silver nanoparticles against bacteria strains and nuclear polyhedral viruses (NPV) and cytoplasmic polyhedral viruses (CPV). For biological test, 108 CFU/mL NPV with strong pathogenicity, and the NPV samples treated with 1:100 ratio of “Sumerian Silver” for 8 hrs were sprayed on the mulberry leaves, respectively, for silkworm rearing. Conclusion: Silver nanoparticle solution showed a strong bactericidal effect against both G+ and G﹣bacterial pathogenic strains from Bombyx mori and mulberry. Under transmission electronic microscope (TEM), Bacillus sp. Samples showed light particles in the cells when treated with silver nanoparticles, in contrast, untreated samples showed homogeneity contents. Further, NPV particles showed no significant differences between treated and untreated samples, but CPV showed strong effects that almost all CPV were collapsed. For biological test, “Sumerian Silver” treated NPV showed no diseased silkworm but nearly all silkworms were dead with no treatment. It seems like that silver nanoparticles were proved to be more effective against CPV than that of NPV. The significant differences between two antivirus or virucidal mechanism should be greatly aroused the scientific interest.

Virucidal Activity of Chlorine Dioxide Gas for Reduction of Coronavirus on Surfaces and PPE

A coronavirus (SARS-CoV-2) has caused a global pandemic and associated morbidity and mortality resultant from COVID-19. As a result of efforts to control direct (person to person) and indirect (contaminated objects, surfaces, indoor air) transmission of the virus, various interventions have been evaluated. Studies were conducted to evaluate the efficacy of commercially available chlorine dioxide (CD) products to reduce viral loads on PPE (face masks) and surfaces using a novel dry gas release intervention. The efficacy of CD slow release 30-day sachets was tested on N95 face masks inoculated with human coronavirus OC43 in suspension. One sachet was placed with an inoculated mask in plastic resealable bags. Three trials were completed using the original sachet where a mask and sachet were placed into a plastic bag for 13 hours per sachet age of 1 day, 14 days, and 30 days. The amount of CD generated during a 13-hour treatment period was 0.30 mg. The nominal concentration of CD was estimated to be 317 mg/m3. All three tests demonstrated at least a 99.91% reduction of viral loading in the mask versus a non-treated control. Efficacy of CD dry gas fast releasing pods (Ultrashok) for fumigation was also tested in a 1344 ft3 closed room. Two pods were placed in the space and CD surface virucidal efficacy was tested in three locations of the room after 1 hour and 2 hours of dwell time. The estimated nominal peak concentration was 15 ppmv in the room. The one-hour exposure saw a >99.91% OC43 reduction on surfaces and the two-hour exposure resulted in a >99.997% OC43 reduction on surfaces versus a non-treated control. These results indicate dry CD is highly effective against human coronavirus. CD was 99.91% effective for eliminating human coronavirus OC43 in both sachet and capsule fumigant form using both fast and slow release mechanisms. Rapid fumigant application is suitable for contaminated rooms, ambulances, emergency vehicles, and many types of PPE, most particularly porous PPE materials. The gaseous state of CD allows for rapid diffusion and transfer of the virucidal stable free radical to all surfaces of PPE and indoor areas that would favor virus survival. Additionally, this work suggests CD can be effective at levels with significant margins of safety (little to no exposure and rapid degradation of residuals) providing minimal public health risks associated with the use of CD.

Is hepatitis B-virucidal validation of biocides possible with the use of surrogates?

The hepatitis B virus(HBV)is considered to be a major public health problem worldwide,and a significant number of reports on nosocomial outbreaks of HBV infections have been reported.Prevention of indirect HBV transmission by contaminated objects is only possible through the use of infection-control principles,including the use of chemical biocides,which are proven to render the virus non-infectious.The virucidal activity of biocides against HBV cannot be predicted;therefore,validation of the virucidal action of disinfectants against HBV is essential.However,feasible HBV infectivity assays have not yet been established.Thus,surrogate models have been proposed for testing the efficacy of biocides against HBV.Most of these assays do not correlate with HBV infectivity.Currently,the most promising and feasible assay is the use of the taxonomically related duck hepatitis B virus(DHBV),which belongs to the same Hepadnaviridae virus family.This paper reviews the application of DHBV,which can be propagated in vitro in primary duck embryonic hepatocytes,for the testing of biocides and describes why this model can be used as reliable method to evaluate disinfectants for efficacy against HBV.The susceptibility levels of important biocides,which are often used as ingredients for commercially available disinfectants,are also described.

Viricidal activity of several disinfectants against African swine fever virus

Prevention of African swine fever,a disease caused by African swine fever virus(ASFV),requires maintenance of high biosecurity standards,which principally relies on disinfection.Finding the perfect disinfectant against ASFV is difficult because of the lack of relevant data.Therefore,we aimed to find the most effective disinfectant and to optimise its concentration as well as contact time to confirm the viricidal effect against ASFV in vitro.We evaluated the viricidal activity of three concentrations each of six common disinfectants against ASFV using immersion disinfection assay(IDA)and spray disinfection assay(SDA);the concentrations of these disinfectants at which complete viral inactivation occurred were almost same as the manufacturer-recommended concentrations,but the exposure times for viral inactivation are different.The following disinfectants(assay:concentration,exposure time)showed complete inactivation:iodine and acid mixed solution(IDA/SDA:0.5%,10 min);compound potassium peroxymonosulfate(IDA:0.25%,30 min;SDA:0.25%,60 min);citric acid(IDA:0.25%,60 min;SDA:0.5%,60 min);sodium dichloroisocyanurate(IDA:0.125%,60 min;SDA:0.25%,60 min);and glutaral ang deciquam(IDA/SDA:0.2%,60 min);and deciquam(IDA/SDA:0.5%,60 min).However,in the presence of organic material contamination,disinfectants did not show a marked inactivation effect.Therefore,disinfection procedures should be performed in two steps:thorough mechanical cleaning followed by application of disinfectant.In conclusion,all the tested disinfectants can inactivate ASFV;these can be used as alternative disinfectants to enhance biosecurity.

Virucidal Efficacy of Chlorine Dioxide Interventions on MS2 Phage Bioaerosol in a Laboratory Chamber

The ongoing SARS-CoV-2 outbreak has rapidly increased the desire to manage bioaerosol exposures in indoor settings. Studies using chlorine dioxide gas (ClO2) at low concentrations have shown this intervention to be an effective mitigation strategy against viral, bacterial, and fungal elements in ambient air. There is an array of available products for generating ClO2 gas however most involve the use of expensive or sophisticated technology that makes their applicability limited to specialized consumers. The purpose of this study was to determine the virucidal efficacy of three pragmatic and affordable, ClO2 generating products using an aerosolized MS2 surrogate in a sealed chamber room under five different scenarios. The products tested included: Ultrashock—a ClO2 releasing pod (30 ppmv), Filter Media—a ClO2 impregnated zeolite media made to fit into an air blower housing (<0.01 ppmv) and Flow Stick—a smaller ClO2 impregnated media filled air reactor tube (<0.01 ppmv). Testing scenarios included product deployment post MS2 bioaerosol introduction (Ultrashock and Filter Media), during MS2 bioaerosol introduction (Filter Media and Flow Stick) and prior to MS2 bioaerosol introduction (Filter Media). MS2 surface samples were collected using sterile petri-dishes and MS2 and ClO2 air samples were collected from sampling ports on the outer chamber wall at 0, 90 and 180 minutes. The Ultrashock and Filter Media with air flow in the rapid sweep scenario showed the greatest reduction in air MS2 (T180 = 99.992% and T180 = 99.996% respectively) compared to the control (T180 = 99.6%). When compared to the control results, the filter media with air flow engaged prior to the introduction of MS2 yielded reductions of 99.87% and 99.93% in air and on surfaces respectively at T0, demonstrating the protective effect residual ClO2 has against air and surface contamination. These product formats have potential uses as remedial and preventative interventions against viral constituents in air and should undergo further evaluation to determine efficacy and human health risk.

Antiviral adsorption activity of porous silicon nanoparticles against different pathogenic human viruses

New viral infections,due to their rapid spread,lack of effective antiviral drugs and vaccines,kill millions of people every year.The global pandemic SARS-CoV-2 in 2019-2021 has shown that new strains of viruses can widespread very quickly,causing disease and death,with significant socio-economic consequences.Therefore,the search for new methods of combating different pathogenic viruses is an urgent task,and strategies based on nanoparticles are of significant interest.This work demonstrates the antiviral adsorption(virucidal)efficacy of nanoparticles of porous silicon(PSi NPs)against various enveloped and non-enveloped pathogenic human viruses,such as Influenza A virus,Poliovirus,Human immunodeficiency virus,West Nile virus,and Hepatitis virus.PSi NPs sized 60 nm with the average pore diameter of 2 nm and specific surface area of 200 m^(2)/g were obtained by ball-milling of electrochemically-etched microporous silicon films.After interaction with PSi NPs,a strong suppression of the infectious activity of the virus-contaminated fluid was observed,which was manifested in a decrease in the infectious titer of all studied types of viruses by approximately 104 times,and corresponded to an inactivation of 99.99%viruses in vitro.This sorption capacity of PSi NPs is possible due to their microporous structure and huge specific surface area,which ensures efficient capture of virions,as confirmed by ELISA analysis,dynamic light scattering measurements and transmission electron microscopy images.The results obtained indicate the great potential of using PSi NPs as universal viral sorbents and disinfectants for the detection and treatment of viral diseases.