The virucidal spectrum of a high concentration alcohol mixture

Sensitivity Evaluation of Enveloped and Non-enveloped Viruses to Ethanol Using Machine Learning: A Systematic Review

Viral diseases are a severe public health issue worldwide. During the coronavirus pandemic, the use of alcohol-based sanitizers was recommended by WHO. Enveloped viruses are sensitive to ethanol, whereas non-enveloped viruses are considerably less sensitive. However, no quantitative analysis has been conducted to determine virus ethanol sensitivity and the important variables influencing the inactivation of viruses to ethanol. This study aimed to determine viruses' sensitivity to ethanol and the most important variables influencing the inactivation of viruses exposed to ethanol based on machine learning. We examined 37 peer-reviewed articles through a systematic search. Quantitative analysis was employed using a decision tree and random forest algorithms. Based on the decision tree, enveloped viruses required around ≥ 35% ethanol with an average contact time of at least 1 min, which reduced the average viral load by 4 log10. In non-enveloped viruses with and without organic matter, ≥ 77.50% and ≥ 65% ethanol with an extended contact time of ≥ 2 min were required for a 4 log10 viral reduction, respectively. Important variables were assessed using a random forest based on the percentage increases in mean square error (%IncMSE) and node purity (%IncNodePurity). Ethanol concentration was a more important variable with a higher %IncMSE and %IncNodePurity than contact time for the inactivation of enveloped and non-enveloped viruses with the available organic matter. Because specific guidelines for virus inactivation by ethanol are lacking, data analysis using machine learning is essential to gain insight from certain datasets. We provide new knowledge for determining guideline values related to the selection of ethanol concentration and contact time that effectively inactivate viruses.

Quantitative Risk Evaluation of Adventitious Agents in Heparin

Heparin is typically extracted from domestic pigs, which may carry zoonotic adventitious agents. Prion and viral safety cannot be assured by testing the active pharmaceutical ingredient itself; instead for the evaluation of the adventitious agent (i.e., viruses/prions) safety of heparin and heparinoid (e.g., Orgaran or Sulodexide) therapeutics, a risk assessment is required. An approach is presented which provides a quantitative estimation of the worst-case potential residual adventitious agent (i.e., GC/mL or ID ₅₀ ) present in a maximum daily dose of heparin. This estimation is based on the input (determined by prevalence, titer, and amount of starting material to prepare a maximum daily dose) and validated reduction by the manufacturing process, resulting in an estimation of the worst-case potential level of adventitious agent present in a maximum daily dose. The merits of this quantitative, worst-case approach are evaluated. The approach described in this review provides a tool for a quantitative risk evaluation of the viral and prion safety of heparin.

Comparative efficacy evaluation of disinfectants against severe acute respiratory syndrome coronavirus-2

BACKGROUND

Disinfection is one of the most effective ways to block the rapid transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Due to the prolonged coronavirus disease 2019 (COVID-19) pandemic, disinfectants have become crucial to prevent person-to-person transmission and decontaminate hands, clothes, facilities and equipment. However, there is a lack of accurate information on the virucidal activity of commercial disinfectants.

AIM

To evaluate the virucidal efficacy of 72 commercially available disinfectants constituting 16 types of ingredients against SARS-CoV-2.

METHODS

SARS-CoV-2 was tested with various concentrations of disinfectants at indicated exposure time points as recommended by the manufacturers. The 50% tissue culture infectious dose assay was used to calculate virus titre, and trypan blue staining and CCK-8 were used to assess cell viability after 3-5 days of SARS-CoV-2 infection.

FINDINGS

This study found that disinfectants based on 83% ethanol, 60% propanol/ethanol, 0.00108-0.0011% sodium dichloroisocyanurate and 0.497% potassium peroxymonosulfate inactivated SARS-CoV-2 effectively and safely. Although disinfectants based on 0.05-0.4% benzalkonium chloride (BAC), 0.02-0.07% quaternary ammonium compound (QAC; 1:1), 0.4% BAC/didecyldimethylammonium chloride (DDAC), 0.28% benzethonium chloride concentrate/2-propanol, 0.0205-0.14% DDAC/polyhexamethylene biguanide hydrochloride (PHMB) and 0.5% hydrogen peroxide inactivated SARS-CoV-2 effectively, they exhibited cytotoxicity. Conversely, disinfectants based on 0.04-4% QAC (2:3), 0.00625% BAC/DDAC/PHMB, and 0.0205-0.14% and 0.0173% peracetic acid showed approximately 50% virucidal efficacy with no cytotoxicity. Citric acid (0.4%) did not inactivate SARS-CoV-2.

CONCLUSION

These results indicate that most commercially available disinfectants exert a disinfectant effect against SARS-CoV-2. However, re-evaluation of the effective concentration and exposure time of certain disinfectants is needed, especially citric acid and peracetic acid.

Viral Coinfections

In nature, viral coinfection is as widespread as viral infection alone. Viral coinfections often cause altered viral pathogenicity, disrupted host defense, and mixed-up clinical symptoms, all of which result in more difficult diagnosis and treatment of a disease. There are three major virus-virus interactions in coinfection cases: viral interference, viral synergy, and viral noninterference. We analyzed virus-virus interactions in both aspects of viruses and hosts and elucidated their possible mechanisms. Finally, we summarized the protocol of viral coinfection studies and key points in the process of virus separation and purification.

Volatile Chemical Profile of Ethanol-Based Hand Sanitizer marketed in Brazil by HS-SPME/GC-MS

Aim:

This study aims to determine the volatile chemical profile of ethanol-based hand sanitizer marketed in Brazil by HS-SPME/GC-MS.

Background:

Ethanol-based hand sanitizer has been used to protect against coronavirus disease (COVID-19). In general, these formulations are prepared using a carbomer. In 2020 and 2021, the production of hand sanitizer has increased due to the COVID-19 epidemic. Therefore, it is important to know the composition of this formulation because certain molecules present in some alcoholic mixtures can cause health problems

Method:

Ethanol-based hand sanitizer, AL1, AL2, BL1, CL1, DL1, EL1, FL1, and GL1 (ethanol derivative of fuel station), was purchased from manufacturers commercialized in Araguaína-TO and analyzed by HS-SPME/GC-MS for determining volatile chemical profile.

Results:

The analyses showed different compositions for the ethanol-based hand sanitizers. Samples AL1 and AL2 contained isopropyl alcohol, ethyl acetate, benzene, ethane-1,1-diethoxy, limonene, and other compounds. Linear alkanes were also detected. Only ethyl acetate and ethane-1,1-diethoxy were detected in CL1, in addition to ethanol. Thus, it is the most suitable sample among those analyzed. The presence of benzene, alkanes, and other hydrocarbons may be associated with the use of fuel ethanol to prepare these sanitizers, as shown in the sample GL1. Benzene, xylene, and toluene were found in FL1. This sample is the most contaminated among those analyzed.

Conclusion:

The chemical profile of commercial ethanol-based hand sanitizer from eight different samples sold in Araguaína-Brazil was established by GC-MS. Compounds like benzene and other alkanes were found in some samples. These results suggested possible contamination by alcohols unqualified in producing pharmaceutical substances. These analyzes are particularly relevant due to the pandemic situation to avoid COVID-19 proliferation. Benzene and other alkanes are harmful to human health and should be avoided in hand sanitizer production.

Inactivation Activities of Ozonated Water, Slightly Acidic Electrolyzed Water and Ethanol against SARS-CoV-2

This study aimed to compare the SARS-CoV-2-inactivation activity and virucidal mechanisms of ozonated water (OW) with those of slightly acidic electrolyzed water (SAEW) and 70% ethanol (EtOH). SARS-CoV-2-inactivation activity was evaluated in a virus solution containing 1%, 20% or 40% fetal bovine serum (FBS) with OW, SAEW or EtOH at a virus-to-test solution ratio of 1:9, 1:19 or 1:99 for a reaction time of 20 s. EtOH showed the strongest virucidal activity, followed by SAEW and OW. Even though EtOH potently inactivated the virus despite the 40% FBS concentration, virus inactivation by OW and SAEW decreased in proportion to the increase in FBS concentration. Nevertheless, OW and SAEW showed potent virucidal activity with 40% FBS at a virus-to-test solution ratio of 1:99. Real-time PCR targeting the viral genome revealed that cycle threshold values in the OW and SAEW groups were significantly higher than those in the control group, suggesting that OW and SAEW disrupted the viral genome. Western blotting analysis targeting the recombinant viral spike protein S1 subunit showed a change in the specific band into a ladder upon treatment with OW and SAEW. OW and SAEW may cause conformational changes in the S1 subunit of the SARS-CoV-2 spike protein.

Virucidal Action Mechanism of Alcohol and Divalent Cations Against Human Adenovirus

Hygiene and disinfection practices play an important role at preventing spread of viral infections in household, industrial and clinical settings. Although formulations based on >70% ethanol are virucidal, there is a currently a need to reformulate products with much lower alcohol concentrations. It has been reported that zinc can increase the virucidal activity of alcohols, although the reasons for such potentiation is unclear. One approach in developing virucidal formulations is to understand the mechanisms of action of active ingredients and formulation excipients. Here, we investigated the virucidal activity of alcohol (40% w/v) and zinc sulfate (0.1% w/v) combinations and their impact on a human adenovirus (HAdV) using, nucleic acid integrity assays, atomic force microscopy (AFM) and transmission electron microscopy (TEM). We observed no difference in virucidal activity (5 log₁₀ reduction in 60 min) against between an ethanol only based formulation and a formulation combining ethanol and zinc salt. Furthermore, TEM imaging showed that the ethanol only formulation produced gross capsid damage, whilst zinc-based formulation or formulation combining both ethanol and zinc did not affect HAdV DNA. Unexpectedly, the addition of nickel salt (5 mM NiCl₂) to the ethanol-zinc formulation contributed to a weakening of the capsid and alteration of the capsid mechanics exemplified by AFM imaging, together with structural capsid damage. The addition of zinc sulfate to the ethanol formulation did not add the formulation efficacy, but the unexpected mechanistic synergy between NiCl₂ and the ethanol formulation opens an interesting perspective for the possible potentiation of an alcohol-based formulation. Furthermore, we show that AFM can be an important tool for understanding the mechanistic impact of virucidal formulation.

Modification of adsorption, aggregation and wetting properties of surfactants by short chain alcohols

The adsorption of methanol, ethanol and propan-1-ol at the solution-air and solid-solution interfaces, their aggregation in the aqueous media as well as wetting properties regarding their applications as additives or co-surfactants in the surfactants aqueous solution were discussed based on the literature data. Mutual influence of alcohols and surfactants on the solution-air and solid-solution interface tension was considered. For this purpose there were used different methods allowing to describe or predict changes of water surface tension as a function of alcohols concentration. These, in turn, as a function of alcohol and/or surfactant concentration were also analyzed by means of the methods applied for prediction of surface tension of aqueous solution of the classical surfactants mixture. The same considerations related to the behaviour of alcohol and surfactant at the solid-solution and solution-air interfaces were made. To explain the behaviour of alcohols and surfactants mixture at the solution-air and solid-solution interfaces the components and parameters of water, alcohols, surfactants and solids surface tension as well as the Gibbs free energy changes during the adsorption process were taken into account. It was proved that wettability of some solids can be predicted based on alcohol and surfactants adsorption as well as surface tension components and parameters. As follows the mutual influence of alcohol and surfactant on their adsorption at the solution-air and solid-solution interfaces as well as on the wetting properties at the alcohol concentration from zero to its critical aggregation concentration (CAC) is different from that at its concentration higher than CAC.

Electron beam irradiation on novel coronavirus (COVID-19): A Monte-Carlo simulation

The novel coronavirus pneumonia triggered by COVID-19 is now raging the whole world. As a rapid and reliable killing COVID-19 method in industry, electron beam irradiation can interact with virus molecules and destroy their activity. With the unexpected appearance and quickly spreading of the virus, it is urgently necessary to figure out the mechanism of electron beam irradiation on COVID-19. In this study, we establish a virus structure and molecule model based on the detected gene sequence of Wuhan patient, and calculate irradiated electron interaction with virus atoms via a Monte Carlo simulation that track each elastic and inelastic collision of all electrons. The characteristics of irradiation damage on COVID-19, atoms' ionizations and electron energy losses are calculated and analyzed with regions. We simulate the different situations of incident electron energy for evaluating the influence of incident energy on virus damage. It is found that under the major protecting of an envelope protein layer, the inner RNA suffers the minimal damage. The damage for a ∼100-nm-diameter virus molecule is not always enhanced by irradiation energy monotonicity, for COVID-19, the irradiation electron energy of the strongest energy loss damage is 2 keV.

Sustainability of Coronavirus on Different Surfaces

Coronavirus disease 2019 (COVID-19) is the name of the disease supposedly manifested in December 2019 from Wuhan, from the virus named SARS-CoV-2. Now, this disease has spread to almost all other parts of the world. COVID-19 pandemic has various reasons for its dramatic worldwide increase. Here, we have studied coronavirus sustainability on various surfaces. Various disinfectants and their roles are discussed from the available literature. The infection capabilities of SARS-CoV-1 and SARS-CoV-2 for different materials and finally studies on infection decay for SARS-CoV-1 and SARS-CoV-2 are discussed.

Virological and Immunological Outcomes of Coinfections

Coinfections involving viruses are being recognized to influence the disease pattern that occurs relative to that with single infection. Classically, we usually think of a clinical syndrome as the consequence of infection by a single virus that is isolated from clinical specimens. However, this biased laboratory approach omits detection of additional agents that could be contributing to the clinical outcome, including novel agents not usually considered pathogens. The presence of an additional agent may also interfere with the targeted isolation of a known virus. Viral interference, a phenomenon where one virus competitively suppresses replication of other coinfecting viruses, is the most common outcome of viral coinfections. In addition, coinfections can modulate virus virulence and cell death, thereby altering disease severity and epidemiology. Immunity to primary virus infection can also modulate immune responses to subsequent secondary infections. In this review, various virological mechanisms that determine viral persistence/exclusion during coinfections are discussed, and insights into the isolation/detection of multiple viruses are provided. We also discuss features of heterologous infections that impact the pattern of immune responsiveness that develops.

Efficacy of ethanol against viruses in hand disinfection

Ethanol is used worldwide in healthcare facilities for hand rubbing. It has been reported to have a stronger and broader virucidal activity compared with propanols. The aim of this review was to describe the spectrum of virucidal activity of ethanol in solution or as commercially available products. A systematic search was conducted. Studies were selected when they contained original data on reduction of viral infectivity from suspension tests (49 studies) and contaminated hands (17 studies). Ethanol at 80% was highly effective against all 21 tested, enveloped viruses within 30 s. Murine norovirus and adenovirus type 5 are usually inactivated by ethanol between 70% and 90% in 30 s whereas poliovirus type 1 was often found to be too resistant except for ethanol at 95% (all test viruses of EN 14476). Ethanol at 80% is unlikely to be sufficiently effective against poliovirus, calicivirus (FCV), polyomavirus, hepatitis A virus (HAV) and foot-and-mouth disease virus (FMDV). The spectrum of virucidal activity of ethanol at 95%, however, covers the majority of clinically relevant viruses. Additional acids can substantially improve the virucidal activity of ethanol at lower concentrations against, e.g. poliovirus, FCV, polyomavirus and FMDV although selected viruses such as HAV may still be too resistant. The selection of a suitable virucidal hand rub should be based on the viruses most prevalent in a unit and on the user acceptability of the product under frequent-use conditions.

Biocidal Inactivation of Lactococcus lactis Bacteriophages: Efficacy and Targets of Commonly Used Sanitizers

Lactococcus lactis strains, being intensely used in the dairy industry, are particularly vulnerable to members of the so-called 936 group of phages. Sanitization and disinfection using purpose-made biocidal solutions is a critical step in controlling phage contamination in such dairy processing plants. The susceptibility of 36 936 group phages to biocidal treatments was examined using 14 biocides and commercially available sanitizers. The targets of a number of these biocides were investigated by means of electron microscopic and proteomic analyses. The results from this study highlight significant variations in phage resistance to biocides among 936 phages. Furthermore, rather than possessing resistance to specific biocides or biocide types, biocide-resistant phages tend to possess a broad tolerance to multiple classes of antimicrobial compounds.

Complexities in Isolation and Purification of Multiple Viruses from Mixed Viral Infections: Viral Interference, Persistence and Exclusion

Successful purification of multiple viruses from mixed infections remains a challenge. In this study, we investigated peste des petits ruminants virus (PPRV) and foot-and-mouth disease virus (FMDV) mixed infection in goats. Rather than in a single cell type, cytopathic effect (CPE) of the virus was observed in cocultured Vero/BHK-21 cells at 6^th blind passage (BP). PPRV, but not FMDV could be purified from the virus mixture by plaque assay. Viral RNA (mixture) transfection in BHK-21 cells produced FMDV but not PPRV virions, a strategy which we have successfully employed for the first time to eliminate the negative-stranded RNA virus from the virus mixture. FMDV phenotypes, such as replication competent but noncytolytic, cytolytic but defective in plaque formation and, cytolytic but defective in both plaque formation and standard FMDV genome were observed respectively, at passage level BP8, BP15 and BP19 and hence complicated virus isolation in the cell culture system. Mixed infection was not found to induce any significant antigenic and genetic diversity in both PPRV and FMDV. Further, we for the first time demonstrated the viral interference between PPRV and FMDV. Prior transfection of PPRV RNA, but not Newcastle disease virus (NDV) and rotavirus RNA resulted in reduced FMDV replication in BHK-21 cells suggesting that the PPRV RNA-induced interference was specifically directed against FMDV. On long-term coinfection of some acute pathogenic viruses (all possible combinations of PPRV, FMDV, NDV and buffalopox virus) in Vero cells, in most cases, one of the coinfecting viruses was excluded at passage level 5 suggesting that the long-term coinfection may modify viral persistence. To the best of our knowledge, this is the first documented evidence describing a natural mixed infection of FMDV and PPRV. The study not only provides simple and reliable methodologies for isolation and purification of two epidemiologically and economically important groups of viruses, but could also help in establishing better guidelines for trading animals that could transmit further infections and epidemics in disease free nations.

Safety of snake antivenom immunoglobulins: efficacy of viral inactivation in a complete downstream process

Viral safety remains a challenge when processing a plasma-derived product. A variety of pathogens might be present in the starting material, which requires a downstream process capable of broad viral reduction. In this article, we used a wide panel of viruses to assess viral removal/inactivation of our downstream process for Snake Antivenom Immunoglobulin (SAI). First, we screened and excluded equine plasma that cross-reacted with any model virus, a procedure not published before for antivenoms. In addition, we evaluated for the first time the virucidal capacity of phenol applied to SAI products. Among the steps analyzed in the process, phenol addition was the most effective one, followed by heat, caprylic acid, and pepsin. All viruses were fully inactivated only by phenol treatment; heat, the second most effective step, did not inactivate the rotavirus and the adenovirus used. We therefore present a SAI downstream method that is cost-effective and eliminates viruses to the extent required by WHO for a safe product.

Inactivation of influenza A virus H1N1 by disinfection process

BACKGROUND

Because any patient, health care worker, or visitor is capable of transmitting influenza to susceptible persons within hospitals, hospital-acquired influenza has been a clinical concern. Disinfection and cleaning of medical equipment, surgical instruments, and hospital environment are important measures to prevent transmission of influenza virus from hospitals to individuals. This study was conducted to evaluate the efficacy of disinfection processes, which can be easily operated at hospitals, in inactivating influenza A virus H1N1 (H1N1).

METHODS

The effects of 0.1 mol/L NaOH, 70% ethanol, 70% 1-propanol, solvent/detergent (S/D) using 0.3% tri (n-butyl)-phosphate and 1.0% Triton X-100, heat, and ethylene oxide (EO) treatments in inactivating H1N1 were determined. Inactivation of H1N1 was kinetically determined by the treatment of disinfectants to virus solution. Also, a surface test method, which involved drying an amount of virus on a surface and then applying the inactivation methods for 1 minute of contact time, was used to determine the virucidal activity.

RESULTS

H1N1 was completely inactivated to undetectable levels in 1 minute of 70% ethanol, 70% 1-propanol, and solvent/detergent treatments in the surface tests as well as in the suspension tests. H1N1 was completely inactivated in 1 minute of 0.1 mol/L NaOH treatment in the suspension tests and also effectively inactivated in the surface tests with the log reduction factor of 3.7. H1N1 was inactivated to undetectable levels within 5 minutes, 2.5 minutes, and 1 minute of heat treatment at 70, 80, and 90 degrees C, respectively in the suspension tests. Also, H1N1 was completely inactivated by EO treatment in the surface tests.

CONCLUSION

Common disinfectants, heat, and EO tested in this study were effective at inactivating H1N1. These results would be helpful in implementing effective disinfecting measures to prevent hospital-acquired infections.

2008 American Association of Feline Practitioners' feline retrovirus management guidelines

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are among the most common infectious diseases of cats. Although vaccines are available for both viruses, identification and segregation of infected cats form the cornerstone for preventing new infections. Guidelines in this report have been developed for diagnosis, prevention, treatment, and management of FeLV and FIV infections. All cats should be tested for FeLV and FIV infections at appropriate intervals based on individual risk assessments. This includes testing at the time of acquisition, following exposure to an infected cat or a cat of unknown infection status, prior to vaccination against FeLV or FIV, prior to entering group housing, and when cats become sick. No test is 100% accurate at all times under all conditions; results should be interpreted along with the patient's health and risk factors. Retroviral tests can diagnose only infection, not clinical disease, and cats infected with FeLV or FIV may live for many years. A decision for euthanasia should never be based solely on whether or not the cat is infected. Vaccination against FeLV is highly recommended in kittens. In adult cats, antiretroviral vaccines are considered non-core and should be administered only if a risk assessment indicates they are appropriate. Few large controlled studies have been performed using antiviral or immunomodulating drugs for the treatment of naturally infected cats. More research is needed to identify best practices to improve long-term outcomes following retroviral infections in cats.

Resistance of surface-dried virus to common disinfection procedures

It is believed that surface-dried viruses can remain infectious and may therefore pose a threat to public health. To help address this issue, we studied 0.1 N NaOH and 0.1% hypochlorite for their capacity to inactivate surface-dried lipid-enveloped (LE) [human immunodeficiency virus (HIV), bovine viral diarrhoea virus (BVDV) and pseudorabies virus (PRV)] and non-lipid-enveloped [NLE; canine parvovirus (CPV) and hepatitis A virus (HAV)] viruses in a background of either plasma or culture medium. In addition, 80% ethanol was tested on surface-dried LE viruses. Without treatment, surface-dried LE viruses remained infectious for at least one week and NLE viruses for more than one month. Irrespective of the disinfectant, inactivation decreased for viruses dried in plasma, which is more representative of viral contaminated blood than virus in culture medium. Inactivation by all disinfectants improved when preceded by rehydration, although the infectivity of CPV actually increased after rehydration and disinfection may thus be overestimated in the absence of rehydration. This is the first comprehensive study of five important (model) viruses in a surface-dried state showing persistence of infectivity, resistance to three commonly used disinfectants and restoration of susceptibility after rehydration. Our results may have implications for hygiene measurements in the prevention of virus transmission.

Effect of dietary lipoic acid on metabolic hormones and acute-phase proteins during challenge with infectious bovine rhinotracheitis virus in cattle

OBJECTIVE

To determine the effect of dietary supplemental lipoic acid (LA) on serum concentrations of metabolic hormones and acute-phase proteins of steers challenged with infectious bovine rhinotracheitis virus (IBRV).

ANIMALS

32 steers.

PROCEDURES

Steers were randomly assigned to 4 treatments: negative control (NC; no LA, no IBRV challenge), control (CON; no LA, IBRV challenge), 16 mg of LA/kg of body weight (BW)/d plus IBRV challenge (LA16), and 32 mg of LA/kg of BW/d plus IBRV challenge (LA32). Following a 21-day adaptation period, CON, LA16, and LA32 steers received IBRV (2 mL/nostril [day 0]); NC steers received saline (0.9% NaCl) solution. Blood samples, nasal swab specimens, BW, and rectal temperatures were obtained 0, 1, 3, 5, 7, 14, and 21 days after challenge. Serum was analyzed for concentrations of haptoglobin, amyloid-A, leptin, and anti-IBRV antibodies.

RESULTS

Steers fed LA32 began gaining BW by day 7, whereas BW of CON and LA16 steers declined. Serum haptoglobin concentration of LA32 steers was lower than that of CON and LA16 steers on day 7. Serum neutralization titers for 30 of 32 steers were negative for anti-IBRV antibodies before challenge; however, all steers (including NCs) had antibodies on day 21.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that LA supplementation augmented certain aspects of the immune response; LA32 steers had a more rapid recovery from IBRV viral challenge than did others.

Comparative efficacy of ethanol and isopropanol against feline calicivirus, a norovirus surrogate

BACKGROUND

Improper disinfection of environmental surfaces contaminated by the feces or vomitus of infected patients is believed to be a major cause of the spread of noroviruses (NoV) in close institutional settings. Although several disinfectants are available, the search for safe and effective disinfectant continues. Because alcohol and alcohol-based products have been used as antiseptics and their efficacy against several enveloped viruses has been documented, we wanted to determine their efficacy against nonenveloped calicivirus.

METHODS

Feline calicivirus (FCV) was used as a surrogate for NoVs, using the carrier test. We evaluated the virucidal efficacy of various concentrations of ethanol and isopropanol against FCV, dried on an inanimate, nonporous contact surface for contact times of 1, 3, and 10 minutes. The virus was eluted after alcohol treatment and titrated in feline kidney cells. Percentage virus inactivation was calculated by comparing these titers with those obtained with virus eluted from controls.

RESULTS

Ethanol at 70% and 90% and isopropanol at 40% to 60% concentrations were found to be the most effective, killing 99% of FCV within a short contact time of 1 minute.

CONCLUSION

Isopropanol was more efficacious than ethanol at 40% to 60% concentrations, suggesting that the use of an appropriate concentration of isopropanol or ethanol would help in controlling the transmission of NoVs from environmental contact surfaces.

Contact inactivation of orthopoxviruses by household disinfectants

AIMS

The aim of this study is to identify common household disinfectants that combine significant activity against the type orthopoxvirus, vaccinia virus with minimal impact in terms of potential toxicity and/or damage to household or personal items.

METHODS AND RESULTS

Laboratory scale experiments assessed common disinfectants containing anionic and nonionic detergents, oxygen-based bleach, potassium peroxomonosulfate, chloroxylenol or halogenated phenols. Disinfectants were assessed for their ability to inactivate the virus on contact or after a short incubation period in the presence and absence of foetal bovine serum as a potential interferant. Significant differences were observed ranging from negligible effect of detergents to complete inactivation on contact with chloroxylenol.

CONCLUSIONS

At least one chloroxylenol-based household disinfectant is available, which inactivates vaccinia virus on contact.

SIGNIFICANCE AND IMPACT OF THE STUDY

In the event of a release or major outbreak of a pathogenic orthopoxvirus there is likely to be significant public demand for disinfectants with activity against these viruses. The identification of common household disinfectants with such activity obviates any requirement to stockpile or distribute laboratory/industrial disinfectants for this purpose.

Antiviral activity of alcohol for surface disinfection

Bacteria and viruses from the patient's mouth travel with dental splatter and spills. A surface disinfectant should possess antiviral activity as well as antibacterial action. Because of frequent and 'open' application in the dental office, such a disinfectant should be non-toxic, non-allergenic and safe for the hygienist. It now appears that high-concentration alcohol mixtures (i.e. 80% ethanol + 5% isopropanol) are not only excellent antibacterials, but quickly inactivate HIV as well as hepatitis B and hepatitis C viruses. Compared to alternative surface disinfectants, use of high-concentration alcohol for the spray-wipe-spray method of surface disinfection in dentistry appears safe and efficient. However, dried matter should be wiped and hydrated first.

Virucidal activity of a new hand disinfectant with reduced ethanol content: comparison with other alcohol-based formulations

A new formula with reduced ethanol content (55%) in combination with 10% propan-1-ol, 5.9% propan-1.2-diol, 5.7% butan-1.3-diol and 0.7% phosphoric acid exhibited a broad spectrum of virucidal activity. In quantitative suspension tests, with and without protein load, this formulation reduced the infectivity titre of seven enveloped (influenza A and B, herpes simplex 1 and 2, bovine corona, respiratory syncytial, vaccinia, hepatitis B, bovine viral diarrhoea) and four non-enveloped (hepatitis A, polio, rota, feline calici) viruses >10(3)-fold within 30s. In comparative testing, only 95% ethanol showed similar levels of activity. In fingerpad tests, the formulation produced a log10 reduction factor of the titre of poliovirus type 1 (Sabin) of 3.04 in 30s compared with 1.32 by 60% propan-2-ol. Testing against feline calicivirus produced a log10 reduction factor of 2.38 by the test formulation; in contrast, the log10 reduction factors with 70% ethanol and 70% propan-1-ol were 0.68 and 0.70, respectively.

Epidemiologic background of hand hygiene and evaluation of the most important agents for scrubs and rubs

The etiology of nosocomial infections, the frequency of contaminated hands with the different nosocomial pathogens, and the role of health care workers' hands during outbreaks suggest that a hand hygiene preparation should at least have activity against bacteria, yeasts, and coated viruses. The importance of efficacy in choosing the right hand hygiene product is reflected in the new Centers for Disease Control and Prevention guideline on hand hygiene (J. M. Boyce and D. Pittet, Morb. Mortal. Wkly. Rep. 51:1-45, 2002). The best antimicrobial efficacy can be achieved with ethanol (60 to 85%), isopropanol (60 to 80%), and n-propanol (60 to 80%). The activity is broad and immediate. Ethanol at high concentrations (e.g., 95%) is the most effective treatment against naked viruses, whereas n-propanol seems to be more effective against the resident bacterial flora. The combination of alcohols may have a synergistic effect. The antimicrobial efficacy of chlorhexidine (2 to 4%) and triclosan (1 to 2%) is both lower and slower. Additionally, both agents have a risk of bacterial resistance, which is higher for chlorhexidine than triclosan. Their activity is often supported by the mechanical removal of pathogens during hand washing. Taking the antimicrobial efficacy and the mechanical removal together, they are still less effective than the alcohols. Plain soap and water has the lowest efficacy of all. In the new Centers for Disease Control and Prevention guideline, promotion of alcohol-based hand rubs containing various emollients instead of irritating soaps and detergents is one strategy to reduce skin damage, dryness, and irritation. Irritant contact dermatitis is highest with preparations containing 4% chlorhexidine gluconate, less frequent with nonantimicrobial soaps and preparations containing lower concentrations of chlorhexidine gluconate, and lowest with well-formulated alcohol-based hand rubs containing emollients and other skin conditioners. Too few published data from comparative trials are available to reliably rank triclosan. Personnel should be reminded that it is neither necessary nor recommended to routinely wash hands after each application of an alcohol-based hand rub. Long-lasting improvement of compliance with hand hygiene protocols can be successful if an effective and accessible alcohol-based hand rub with a proven dermal tolerance and an excellent user acceptability is supplied, accompanied by education of health care workers and promotion of the use of the product.

Inactivation of feline calicivirus, a surrogate of norovirus (formerly Norwalk-like viruses), by different types of alcohol in vitro and in vivo

Hand disinfection is an important measure to prevent transmission of norovirus (formerly called Norwalk-like viruses) from hands or environmental surfaces to other objects. Therefore, three types of alcohol (ethanol, 1- and 2-propanol) were examined for their virus-inactivating properties against feline calicivirus (FCV) as a surrogate for norovirus. Tests were performed as quantitative suspension assays or as in vivo experiments with artificially contaminated fingertips. The in vitro experiments showed that 1-propanol was more effective than ethanol and 2-propanol for the inactivation of FCV: in tests with the 50 and 70% solutions of the different alcohols, a 10(4)-fold reduction was observed with 1-propanol after 30 s, whereas the other alcohols were effective only after 3 min contact time. The greatest efficacy did not occur at the highest concentrations (80%). The following concentrations (extrapolated data) showed the greatest virus-inactivating properties in the suspension test: ethanol 67%, 2-propanol 58% (exposure times of 1 min) and 1-propanol 60% (exposure time of 30 s). The results from fingertips experiments with 70 and 90% solutions and an application time of 30 s confirmed these findings: the 70% alcoholic solutions were more effective than the 90% solutions. In contrast to the suspension tests, 70% ethanol showed the greatest efficacy in vivo with a log(10) reduction factor (RF) of 3.78 compared with 70% 1-propanol (RF 3.58), 70% 2-propanol (RF 2.15) and hard water (RF 1.23). Ethanol and 1-propanol-based solutions with a high alcohol content thus appear most effective.