Search

Ferrate (Fe(VI): HFeO 4 - /FeO 4 2- ), a potent oxidant, has been investigated as an alternative chemical disinfectant in water treatment due to its reduced production of disinfection by-products. In this study, we assessed the disinfecting ability of potassium ferrate against a variety of microorganisms, including waterborne pathogens, under varying pH and water temperature conditions. We presented CT values, a metric of ferrate concentrations (C) and contact time (T), to quantify microbial inactivation rates. Among the tested microorganisms, human adenovirus was the least resistant to ferrate, followed by waterborne bacteria such as Escherichia coli and Vibrio cholerae , and finally, the protozoan parasite Giardia duodenalis . We further investigated the impact of two pH values (7 and 8) and two temperatures (5 and 25 °C) on microbial inactivation rates, observing that inactivation rates increased with lower pH and higher temperature. In addition to showcasing ferrate's capacity to effectively inactivate a range of the tested microorganisms, we offer a ferrate CT table to facilitate the comparison of the effectiveness of various disinfection methods., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

Purpose: The aim of this study was to test the antiviral effectivity of potassium peroxymonosulfate (RUBYSTA ® , KYORIN) against five epidemic keratoconjunctivitis-related types of Human adenovirus D in vitro., Methods: Five types of Human adenovirus D (8, 37, 53, 54 and 56) were incubated with 1% potassium peroxymonosulfate, 0.1% sodium hypochlorite (NaClO) or alcohol-based disinfectant for 30 s or 1 min. These solutions were subjected to measurements of viral titres by infection assays in A549 cells. At day 6 post-infection, both, supernatants and cells, were collected and the viral genome was assessed by real-time polymerase chain reaction analysis., Results: Treatments with 1% potassium peroxymonosulfate led to significant reduction in all tested Human adenovirus D types comparable to disinfecting effects by 0.1% NaClO. Overall, potassium peroxymonosulfate demonstrated sufficient inactivation of the major epidemic keratoconjunctivitis-causing Human adenovirus D to be considered for disinfection and prevention purposes in ophthalmological clinics and hospitals., Conclusion: This study demonstrated that potassium peroxymonosulfate is a promising disinfectant for the prevention of epidemic keratoconjunctivitis nosocomial infections in ophthalmological clinics.

The new epidemiological scenario has so far focused on the environmental circulation of human viral pathogens. Owing to the side effects of chemical disinfectants, there is an increasing need for knowledge on the use of virucidal compounds, especially those of a natural origin. Climacostol is a molecule produced by a freshwater ciliate and it exhibits activity against bacterial and fungal pathogens. We thus also speculated that there might be an effect on viral viability, which has never been tested. To evaluate such activity, we chose human adenovirus (HAdV), which is representative of waterborne viruses. We conducted experiments using HAdV serotype 5, whose titer was determined by infecting HeLa cell cultures. HAdV5 was shown to be sensitive to climacostol at a concentration of 0.0002 mg/mL, with an approximate 3 Log 10 reduction when the initial titer of HAdV5 was approximately 10 4 and 10 3 TCID 50 /mL. These preliminary results could be an important starting point for further research aimed at improving the characterization of climacostol activity under different experimental conditions and against various viruses, including enveloped ones (i.e., the coronavirus). The production of climacostol by a protist living in fresh water also suggests a possible application in the activated sludge of wastewater treatment plants.

Five tungsten carbide nanoparticle preparations (denoted WC1-WC5) were investigated for broad spectrum virucidal activity against four recommended model viruses. These are modified vaccinia virus Ankara (MVA), human adenovirus type 5 (HAdV-5), poliovirus type 1 (PV-1) and murine norovirus (MNV). All virucidal tests were performed two to five times using the quantitative suspension test, which is a highly standardized test method to evaluate the virucidal efficacy of disinfectants in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Quantitative detection of viruses was conducted by endpoint titration and quantitative real-time PCR. Results showed that three of the five tested compounds (WC1-WC3) were able to reduce the infectivity of all model viruses by at least four log 10 of tissue culture infective dose 50% per ml after 15 min, whereas the other two compounds exhibited only limited efficacy (WC4) or showed cytotoxicity (WC5). Virucidal activity of nanoparticles increased with incubation time and a dose-effect curve showed dependence of virucidal activity with particle concentration. Whereas WC1-WC4 showed little cytotoxicity, WC5 which was doped with copper exhibited a significant cytotoxic effect. These findings propose tungsten carbide nanoparticles to be very promising in terms of new disinfection techniques. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study investigates the virucidal activity of tungsten carbide nanoparticles using the quantitative suspension test in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Due to highly standardized assay conditions, results of this test are considered very reliable for evaluation of the virucidal activity of disinfectants. Broad-spectrum activity and high efficacy of three different tungsten carbide nanoparticles preparations is concluded., (© 2019 The Society for Applied Microbiology.)

Background: The use of disinfectant wipes in hospitals is increasing over the last years. These wipes should be able to inactivate microorganisms including viruses on environmental surfaces and to prevent their transfer to clean areas.The European norm (EN) 16615:2015 describes a wiping process over four fields starting on the contaminated field 1 followed by fields 2-4 and back to the starting point (4-field test). This test method exclusively describes killing and transfer of vegetative bacteria and fungi by disinfectant wipes without measuring virucidal activities. Therefore, it was the aim of this study to use the existing test methodology additionally to evaluate virus inactivation by wipes., Methods: The 4-field test was performed with four commercially available disinfectant wipes including the examination of the active solutions of these wipes with a reference wipe. Murine norovirus (MNV) as surrogate of human noroviruses, adenovirus (AdV) type 5 and polyomavirus SV40 (SV40) were chosen as test viruses., Results: The per acetic acid (PAA)-based wipe (wipe A) was able to inactivate all three test viruses resulting in a four log 10 reduction on test field 1, whereas the quaternary ammonium compound (QAC)-based products (wipes B and C) failed to reach such reduction. Both QAC-based wipes were able to inactivate SV40 and only the active solution of wipe B was effective against MNV. Another wipe with 2-propanol as active ingredient (wipe D) was not able to show a sufficient efficacy against all three test viruses. There was a good agreement between the results of the wipes and the corresponding fluids showing no influence of the material of wipes.Tests with the 2-propanol-based wipe D showed a transfer of all test viruses to the non-contaminated test fields 2-4. SV40 was additionally transferred by the QAC-based wipe C with 0.78% active ingredients to these additional fields. In all other cases no virus transfer to test fields 2-4 was observed. Finally, no virus could be detected in the PAA-based wipe A after usage in the 4-field test in contrast to the other wipes examined., Conclusions: The successful performance of a 4-field test with viruses demonstrated that the existing wiping method with bacteria and fungi can be used in addition for measuring virucidal efficacy. The virus-inactivating properties of surface disinfectants could be evaluated therefore with a test simulating practical conditions with mechanical action resulting in more reliable data than the existing quantitative suspension tests and/or a carrier test without any mechanical action., Competing Interests: Competing interestsThe authors declare that they have no competing interests.

Millions of people use contaminated water sources for direct consumption. Chlorine is the most widely disinfection product but can produce toxic by-products. In this context, natural and synthetic compounds can be an alternative to water disinfection. Therefore, the aim of this study was to assess the inactivation of human adenovirus by N-chlorotaurine (NCT), bromamine-T (BAT) and Grape seed extract (GSE) in water. Distilled water artificially contaminated with recombinant human adenovirus type 5 (rAdV-GFP) was treated with different concentrations of each compound for up to 120 min, and viral infectivity was assessed by fluorescence microscopy. The decrease in activity of the compounds in the presence of organic matter was evaluated in water supplemented with peptone. As results, NCT and GSE inactivated approximately 2.5 log 10 of adenovirus after 120 min. With BAT, more than 4.0 log 10 decrease was observed within 10 min. The oxidative activity of 1% BAT decreased by 50% in 0.5% peptone within a few minutes, while the reduction was only 30% for 1% NCT in 5% peptone after 60 min. Organic matter had no effect on the activity of GSE. Moreover, the minimal concentration of BAT and GSE to kill viruses was lower than that known to kill human cells. It was concluded that the three compounds have potential to be used for water disinfection for drinking or reuse purposes.

Background: Hand antiseptics are of great importance in the prevention of nosocomial infections. Due to the frequent occurrence of adenoviral epidemic keratoconjunctivitis outbreaks in the study hospital, it was necessary to investigate the efficiency of alcohol-based solutions on adenoviruses., Aim: To investigate the efficacy of alcohol-based solutions commonly found in hand antiseptics against adenovirus serotypes 8, 19 and 37., Methods: The efficacy of ethanol, isopropanol, chlorhexidine-digluconate, n-butanol and different combinations of these antiseptics on adenovirus serotypes that typically cause epidemic keratoconjunctivitis was investigated. The effect of antiseptic substances was investigated using a quantitative suspension test technique according to EN-14476. Antiseptics were prepared as follows: 70% ethanol, 70% isopropanol, 70% ethanol+0.5% chlorhexidine-digluconate, 70% isopropanol+0.5% chlorhexidine-digluconate, 60% ethanol+10% isopropanol, 60% ethanol+10% isopropanol+0.5% chlorhexidine-digluconate and 60% ethanol+10% isopropanol+1% n-butanol. The effect of antiseptics was evaluated at 30, 60 and 120 s., Findings: The highest reduction in virus titre was detected with 60% ethanol+10% isopropanol+1% n-butanol. This caused a reduction of 2.5log 10 , 3 log 10 and 2.5log 10 in adenovirus serotypes 8, 19 and 37, respectively. The lowest reduction in virus titre was detected with 70% ethanol+0.5% chlorhexidine-digluconate and 70% isopropanol+0.5% chlorhexidine-digluconate. These combinations caused a reduction of 1.62log 10 in adenovirus serotypes 19 and 37. All antiseptics showed efficacy levels below 4log 10 which is regarded as the efficiency limit by EN-14476., Conclusion: The alcohol-based solutions tested in this study were not found to be sufficiently effective against adenovirus serotypes. Further studies to investigate the efficiency of different alcohol-based solutions are required., (Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

It is generally accepted that viral particles in source water are likely to be found as aggregates attached to other particles. For this reason, it is important to investigate the disinfection efficacy of chlorine on aggregated viruses. A method to produce adenovirus particle aggregation was developed for this study. Negative stain electron microscopy was used to measure aggregation before and after addition of virus particles to surface water at different pH and specific conductance levels. The impact of aggregation on the efficacy of chlorine disinfection was also examined. Disinfection experiments with human adenovirus 2 (HAdV2) in source water were conducted using 0.2 mg/L free chlorine at 5 °C. Aggregation of HAdV2 in source water (≥3 aggregated particles) remained higher at higher specific conductance and pH levels. However, aggregation was highly variable, with the percentage of particles present in aggregates ranging from 43 to 71 %. Upon addition into source water, the aggregation percentage dropped dramatically. On average, chlorination CT values (chlorine concentration in mg/L × time in min) for 3-log10 inactivation of aggregated HAdV2 were up to three times higher than those for dispersed HAdV2, indicating that aggregation reduced the disinfection rate. This information can be used by water utilities and regulators to guide decision making regarding disinfection of viruses in water.

Free chlorine is effective at inactivating a wide range of waterborne viral pathogens including human adenovirus (HAdV), but the mechanisms by which free chlorine inactivates HAdV and other human viruses remain to be elucidated. Such advances in fundamental knowledge are key for development of new disinfection technologies and novel sensors to detect infectious viruses in drinking water. We developed and tested a quantitative assay to analyze several steps in the HAdV replication cycle upon increasing free chlorine exposure. We used quantitative polymerase chain reaction (qPCR) to detect HAdV genomic DNA as a means to quantify attachment and genome replication of untreated and treated virions. Also, we used quantitative reverse-transcription PCR (RT-qPCR) to quantify the transcription of E1A (first early protein) and hexon mRNA. We compared these replication cycle events to virus inactivation kinetics to determine what stage of the virus replication cycle was inhibited as a function of free chlorine exposure. We observed that adenovirus inactivated at levels up to 99.99% by free chlorine still attached to host cells; however, viral DNA synthesis and early E1A and late hexon gene transcription were inhibited. We conclude that free chlorine exposure interferes with a replication cycle event occurring postbinding but prior to early viral protein synthesis.

Background: In Brazil, ordinance no. 2,914/2011 of the Ministry of Health requires the absence of total coliforms and Escherichia coli (E. coli) in treated water. However it is essential that water treatment is effective against all pathogens. Disinfection in Water Treatment Plants (WTP) is commonly performed with chlorine., Methods: The recombinant adenovirus (rAdV), which expresses green fluorescent protein (GFP) when cultivated in HEK 293A cells, was chosen as a model to evaluate the efficiency of chlorine for human adenovirus (HAdV) inactivation in filtered water samples from two WTPs: Lagoa do Peri (pH 6.9) and Morro dos Quadros (pH 6.5). Buffered demand free (BDF) water (pH 6.9 and 8.0) was used as control. The samples were previously submitted to physicochemical characterization, and bacteriological analysis. Two free chlorine concentrations and two temperatures were assayed for all samples (0.2 mg/L, 0.5 mg/L, and 15°C, and 20°C). Fluorescence microscopy (FM) was used to check viral infectivity in vitro and qPCR as a molecular method to determine viral genome copies. Real treated water samples from the WTP (at the output of WTP and the distribution network) were also evaluated for total coliforms, E. coli and HAdV., Results: The time required to inactivate 4log₁₀ of rAdV was less than 1 min, when analyzed by FM, except for BDF pH 8.0 (up to 2.5 min for 4log₁₀). The pH had a significant influence on the efficiency of disinfection. The qPCR assay was not able to provide information regarding rAdV inactivation. The data were modeled (Chick-Watson), and the observed Ct values were comparable with the values reported in the literature and smaller than the values recommended by the EPA. In the treated water samples, HAdV was detected in the distribution network of the WTP Morro dos Quadros (2.75 × 10(3) PFU/L)., Conclusion: The Chick-Watson model proved to have adjusted well to the experimental conditions used, and it was possible to prove that the adenoviruses were rapidly inactivated in the surface water treated with chlorine and that the recombinant adenovirus expressing GFP is a good model for this evaluation.

Hepatitis E virus (HEV) is transmitted via the fecal-oral route and has been recognized as a common source of large waterborne outbreaks involving contaminated water in developing countries. Thus, there is the need to produce experimental data on the disinfection kinetics of HEV by chlorine in water samples with diverse levels of fecal contamination. Here, the inactivation of HEV and human adenovirus C serotype 2 (HAdV2), used as a reference virus, was monitored using immunofluorescence and quantitative reverse transcription polymerase chain reaction (RT-qPCR) assays. HEV has been shown to be susceptible to chlorine disinfection and presented equivalent kinetics to human adenoviruses. The C(t) values observed for a 2-log reduction of HEV were 0.41 in buffered demand-free water and 11.21 mg/L × min in the presence of 1% sewage. The results indicate that the inactivation kinetics of HEV and HAdV2 are equivalent and support the use of chlorine disinfection as an effective strategy to control HEV waterborne transmission.

Importance: Swimming pools can be a vector for transmission of adenovirus ocular infections. Polyhexamethylene biguanide (PHMB) is a disinfectant used in swimming pools and hot tubs., Objective: To determine whether PHMB is an effective disinfectant against ocular adenovirus serotypes at a concentration used to disinfect swimming pools and hot tubs., Design: In vitro laboratory study., Interventions: The direct disinfecting activity of PHMB was determined in triplicate assays by incubating 9 human adenovirus types (1, 2, 3, 4, 5, 7a, 8, 19, and 37) with PHMB concentrations of 50 and 0 ppm (micrograms per milliliter) for 24 hours at room temperature to simulate swimming pool temperatures or 40oC to simulate hot tub temperatures., Main Outcome Measures: Plaque assays were performed to determine adenovirus titers after incubation. Titers were log10 converted and mean (SD) log10 reductions relative to controls were calculated. Virucidal (>99.9%) decreases in mean adenovirus titers after PHMB treatment were determined for each adenovirus type and temperature tested. RESULTS At room temperature, 50 ppm of PHMB produced mean reductions in titers less than 1 log10 for all adenovirus types tested. At 40°C, 50 ppm of PHMB produced mean reductions in titers less than 1 log10 for 2 adenovirus types and greater than 1 but less than 3 log10 for 7 of 9 adenovirus types., Conclusions and Relevance: At a concentration of 50 ppm, PHMB was not virucidal against adenovirus at temperatures consistent with swimming pools or hot tubs. Recreational water maintained and sanitized with PHMB can serve as a vector for the transmission of ocular adenovirus infections.

Viruses excreted by humans affect the commercial and recreational use of coastal water. Shellfish produced in contaminated waters have been linked to many episodes and outbreaks of viral gastroenteritis, as well as other food-borne diseases worldwide. The risk can be reduced by appropriate treatment following harvesting and by depuration. The kinetics of inactivation of murine norovirus 1 and human adenovirus 2 in natural and artificial seawater by free available chlorine was studied by quantifying genomic copies (GC) using quantitative PCR and infectious viral particles (PFU). Human JC polyomavirus Mad4 kinetics were evaluated by quantitative PCR. DNase or RNase were used to eliminate free genomes and assess potential viral infectivity when molecular detection was performed. At 30 min of assay, human adenovirus 2 showed 2.6- and 2.7-log(10) GC reductions and a 2.3- and 2.4-log(10) PFU reductions in natural and artificial seawater, respectively, and infectious viral particles were still observed at the end of the assay. When DNase was used prior to the nucleic acid extraction the kinetic of inactivation obtained by quantitative PCR was statistically equivalent to the one observed by infectivity assays. For murine norovirus 1, 2.5, and 3.5-log(10) GC reductions were observed in natural and artificial seawater, respectively, while no viruses remained infectious after 30 min of contact with chlorine. Regarding JC polyomavirus Mad4, 1.5- and 1.1-log(10) GC reductions were observed after 30 min of contact time. No infectivity assays were conducted for this virus. The results obtained provide data that might be applicable to seawater used in shellfish depuration.

We investigated the virucidal activity of commercially available alcohol-based hand rub products against coxsackievirus A7, B5, feline calicivirus F9, and human adenovirus type 3, type 7, type 8 using susceptible cell lines, Vero cells, CRFK cells, and A549 cells. Fifteen tested hand rub products were ethanol (EtOH) for disinfection (Japanese Pharmacopoeia Grade), two EtOH-based products, one povidone iode-containing product, one alkyldiaminoethylglycine hydrochloride-containing product, six benzalkonium chloride (BAK)-containing products, and four chlorohexidine gluconate (CHG)-containing products. Some active ingredients (BAK, benzetonium chloride, and CHG) were diluted with EtOH to make 0.5% and 0.2% solutions. Virus inactivation rates were calculated after contact with each hand rub product for 10 or 60 seconds. Of the hand rub products tested, only the povidone iode-based product showed antiviral activity superior to that of EtOH against all the strains. EtOH solutions of active ingredients (0.2% and 0.5%) also showed decreased antiviral activity. In conclusion, antiviral activity of all the commercially available alcohol-based hand rub products except that containing povidone idode was dependent on their active ingredients. The povidone idode-containing hand rub product kept its effectiveness even after the dilution with EtOH. Although alcohol-based hand rub products are convenient and suitable for the control of some microbes, they are not generally recommended for the control of viral infections.

More information is needed on the disinfection efficacy of chlorine for viruses in source water. In this study, chlorine disinfection efficacy was investigated for USEPA Contaminant Candidate List viruses coxsackievirus B5 (CVB5), echovirus 1 (E1), murine norovirus (MNV), and human adenovirus 2 (HAdV2) in one untreated groundwater source and two partially treated surface waters. Disinfection experiments using pH 7 and 8 source water were carried out in duplicate, using 0.2 and 1 mg/liter free chlorine at 5 and 15 degrees C. The efficiency factor Hom (EFH) model was used to calculate disinfectant concentration x contact time (CT) values (mg x min/liter) required to achieve 2-, 3-, and 4-log(10) reductions in viral titers. In all water types, chlorine disinfection was most effective for MNV, with 3-log(10) CT values at 5 degrees C ranging from < or = 0.020 to 0.034. Chlorine disinfection was least effective for CVB5 in all water types, with 3-log(10) CT values at 5 degrees C ranging from 2.3 to 7.9. Overall, disinfection proceeded faster at 15 degrees C and pH 7 for all water types. Inactivation of the study viruses was significantly different between water types, but no single source water had consistently different inactivation rates than another. CT values for CVB5 in one type of source water exceeded the recommended CT values set forth by USEPA's Guidance Manual for Compliance with the Filtration and Disinfection Requirements for Public Water Systems using Surface Water Sources. The results of this study demonstrate that water quality plays a substantial role in the inactivation of viruses and should be considered when developing chlorination plans.

Throughout the pharmaceutical industry, adenovirus-based products are being developed for human use as vaccine vectors and gene therapy delivery vehicles. The implementation of effective decontamination procedures is critical to the successful manufacture of these products to minimize the risk of personnel exposure and prevent product cross-contamination in the manufacturing facility. In this investigation, we have conducted small-scale decontamination studies to determine the efficacy of Virkon S on the inactivation of adenovirus types 5 and 6 in suspension. Virkon S is a commercially available oxidative disinfectant used against a variety of bacteria, spores, fungi, and viruses. A cytotoxicity-based endpoint dilution assay was used to quantify adenovirus potency before and after Virkon S treatment. We show that the level of organic content in the inactivation sample matrix has a significant impact on Virkon S activity. The potency of adenovirus types 5 and 6 was reduced by greater than six logs upon a five minute exposure to the appropriate concentration of Virkon S. Based on these results, we propose that Virkon S liquid decontamination procedures for adenovirus types 5 and 6 use 0.9% Virkon S for contact times greater than five minutes.

Human adenoviruses are model viruses for testing the virucidal efficacy of disinfectants. However, a recent study has shown that the chemical sensitivity of adenovirus serotypes varies significantly, possibly due to the composition of the viral capsid and/or the resistance of nucleic acids. We have investigated the effect of molecular changes in the viral genome of the human adenovirus subgenera C and D. A common oligonucleotide fragment within the hexon gene was amplified by polymerase chain reaction (PCR) after exposure to liposomal povidone-iodine (PVP-I), peracetic acid (PAA), and formaldehyde. The findings were compared with infectivity in cell cultures. PVP-I (0.125%) destroyed the infectivity of most serotypes within 60 min. However, PCR revealed no destruction of the adenoviral genome in most serotypes, even after exposure to higher PVP-I concentrations. PAA (0.5%) failed to inactivate the hexon gene of adenovirus types 22 and 44. Furthermore, the hexon gene of adenovirus type 22 was not altered by 0.7% formaldehyde. In conclusion, the genomes of human adenoviruses show considerably more chemical resistance than the complete viral particle. The molecular resistance of individual serotypes also varies. However, there was no clear correlation between the differences in the effect of disinfectants on infectivity of the complete viral particle and destruction of the viral genome.

As it is no longer readily permissible to propagate polioviruses, adenoviruses will probably become more frequently used for virucidal testing of broad-spectrum disinfectants. We tested prototype strains of different adenovirus serotypes belonging to the subgenera C and D for sensitivity to liposomal povidone-iodine (PVP-I), peracetic acid (PAA) and formaldehyde. Virucidal assays were performed as suspension tests in accordance with the German guidelines for testing the effectiveness of chemical disinfectants against viruses. The sensitivity of the adenovirus serotypes to test disinfectants varied greatly. Prototype strains of adenovirus 5 and 44 statistically selected as 'little sensitive' to PVP-I, PAA and formaldehyde were found to be the most resistant. These might be suitable as model viruses for testing the broad-spectrum virucidal activity of disinfectants and might even replace the resistant poliovirus type 1. The main reason for the different chemical sensitivity of adenovirus serotypes may be the composition of the viral capsid proteins. Alternatively a different chemical inactivation of the viral genome could be involved.

The formulation PAA-ethanol, consisting of 0.2% paracetic acid (PAA) and 80% ethanol, was tested for its virucidal activity on the enveloped vaccinia virus and papova virus SV 40 and the non-enveloped adenovirus type 2 and poliovirus type 1. All test viruses were inactivated by PAA-ethanol within an exposure time of 1 minute, as measured by a log(10)reduction of 4 in virus titres. It was shown that poliovirus type 1 can be inactivated by PAA-ethanol within 1 min, whilst for the aqueous 0.2% PAA solution, an exposure time of 5 min is necessary. As shown by electron microscopic observation, the structure of virus particles was completely destroyed by 0.2% PAA within 15 min. The broad antimicrobial spectrum including a high virucidal activity, short exposure time and no toxic or allergenic decomposition products are favourable prerequisites for the medical use of PAA-ethanol and it warrants further investigation as a hand disinfectant., (Copyright 2000 The Hospital Infection Society.)

First, four disinfectants were tested for virucidal activity on viruses coated upon materials. Disinfectants of the aldehyde and halogen groups had a destructive effect on both enveloped and non-enveloped DNA and RNA viruses coated on a cotton gauze, stainless chips, wood shavings, polyplopylene resin chips and latex resin chips, respectively. Disinfectant of the biguanide group had a virucidal activity on both enveloped DNA and RNA viruses. Secondary, five disinfectants were tested for the durability of their virucidal activity on two DNA and RNA viruses after preparing working solutions. The disinfectants of the aldehyde group maintained their virucidal efficiency for 2 to 3 days. Disinfectants of the invert and amphoteric soap groups, the biguanide group and the halogen group maintained their virucidal efficiency for 1 to 2 days. In the presence of bovine serum, the virucidal activity of the aldehyde group and the halogen group were not influenced but that of the invert and amphoteric soap groups were strongly influenced and lost their effect.

Various members of the picornavirus family, adenovirus 2, papovavirus SV40, as well as rotaviruses were tested for inactivation of infectivity by hand disinfectants formulated on the basis of ethanol. The inactivating effect of povidine-iodine (Betaisodona) on enteroviruses and rotaviruses was also investigated. The degree of inactivation by these disinfectants on the various non-enveloped viruses studied, however, was found unpredictable. In fact, striking differences with the very same disinfectant existed even for members of one virus family. Isopropanol was inactive against enteroviruses. These findings are discussed from a theoretical point of view and practical implications are considered. Disinfection of poliovirus 1-contaminated hands by 80% (v/v) ethanol proved not very effective, despite encouraging results obtained in the suspension test. The load of rotavirus-contaminated hands, however, was substantially reduced by treatment with Desderman. A practical regimen can be proposed.

A commercial alcoholic disinfectant (Welpas) was tested for its activity against adenovirus type 3 (Ad 3) by using two procedures, the in vitro suspension test and the in vivo fingertip test. Other available techniques for the sterilization of fingers were also evaluated for removal of Ad by using the fingertip test. In the suspension tests, the infectivity of Ad 3 was reduced to undetectable levels within 30-60 seconds. This results suggest the effectiveness of this disinfectant in reducing Ad infectivity. In the fingertip tests, the viruses were recovered from fingertips in varying titers after using one of the following techniques: wiping with tissue papers, washing with running water, washing with soap and rinsing with water, rubbing with Welpas, wiping with cotton soaked in 70% alcohol, or washing with a brush under running water. However, the viruses were not recovered when the fingertip was washed with water, wiped with paper, and rubbed with Welpas successively. This technique was found to be the most effective method currently available.