A comprehensive approach for evaluating the virucidal performance of domestic laundry detergents under practical conditions.

AIMS: We aimed to develop a method to assess the virucidal performance of domestic laundry in a lab-scale washing machine (Rotawash) based on EN 17658. METHODS AND RESULTS: For method development, virus recovery was investigated after drying on cotton carriers for three test viruses murine norovirus (MNV), modified vaccinia virus Ankara (MVA), and bovine coronavirus (BCoV), followed by washing simulations in flasks and Rotawash. MNV and MVA demonstrated sufficient recovery from carriers after drying and washing (up to 40°C and 60 min). BCoV exhibited lower recovery, indicating less relevance as a test virus. Rotawash efficacy tests conducted with MNV, a resistant, non-enveloped virus, showed limited efficacy of a bleach-free detergent, aligning with results from a domestic washing machine. Rotawash washes achieved higher reductions in infectious virus titers than suspension tests, indicating the role of washing mechanics in virus removal. CONCLUSIONS: This study established a practical method to test the virucidal efficacy of laundry detergents in Rotawash, simulating domestic washing.

Chatbot-Mediated Learning For Caregiving Relatives of People With Dementia: Empirical Findings and Didactical Implications For Mulitprofessional Health Care.

Purpose: Supporting family caregivers is a major challenge for the healthcare system. The first points of contact are physicians, nurses and social services, which are not easily accessible. For this reason, an information platform has been developed to provide information for family caregivers caring for people with dementia at home. The aim of this article is to provide an insight into the didactic design of this platform. Sample and Methods: A didactic concept was developed based on didactic target group analysis and interviews with caring relatives (n=6). Results: The didactic concept of the digital platform takes into account the characteristics of family caregivers as learners, such as time constraints and reciprocity. Therefore two different learning paths, a long and a short version, are offered. Reciprocity is supported by information which are related to individual characteristics of the caring relation. This is made possible by an adaptation of the didactic method "anchored instructions": Family caregivers experience a problematic caring situation. They use the platform and central concepts related to this situation are offered as anchors. In chatbot mediated learning, these concepts are identified and, ideally, relevant information is provided in a short version. These concepts are displayed as a learning map and must be proactively selected. Chatbot mediated learning has the advantage that matching concepts are offered as a pre-selection. Especially for inexperienced carers who are not familiar with the concepts, this learning path seems to be suitable. Conclusion: The combination of learning through the "Information for Relatives" website and CML seems to meet all needs. In order to promote learner motivation, the chatbot should not only offer the identified concept, but also those related to this concept, in order to link new knowledge in one's own knowledge network.

Impact of concentration, temperature and pH on the virucidal activity of alcohols against human adenovirus.

BACKGROUND: Adenoviruses belong to the stable nonenveloped viruses playing an important role in healthcare-associated infections mainly causing respiratory infections and epidemic keratoconjunctivitis. Hand disinfection with alcoholic preparations is therefore one of the most important measures to prevent such viral infections in hospitals and other medical settings. METHODS: The inactivation of adenovirus type 5 by ethanol, 1- and 2-propanol, and 2 commercially available hand disinfectants was examined at different concentrations, temperatures, and pH-values. RESULTS: For ethanol and 1-propanol the maximum virus-inactivating properties after 30 seconds exposure were found at a concentration of 60%-70% and 50%-60%, respectively, whereas with 2-propanol no activity was observed. The virucidal activity of all alcohols and the 2 hand disinfectants examined was increased when raising the temperature from 20°C to 25°C. By increasing the pH value to 9, a strong improvement of the activity of ethanol, 1-propanol and 1 hand disinfectant was observed, whereas pH lowering resulted in decrease of activity. CONCLUSIONS: These results demonstrate the importance of physical parameters in the inactivation of adenoviruses by alcohols and will help to improve measures to reduce adenovirus transmission in healthcare settings.

Hepatitis E virus is highly resistant to alcohol-based disinfectants.

BACKGROUND & AIMS: Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide and is mainly transmitted via the fecal-oral route or through consumption of contaminated food products. Due to the lack of efficient cell culture systems for the propagation of HEV, limited data regarding its sensitivity to chemical disinfectants are available. Consequently, preventive and evidence-based hygienic guidelines on HEV disinfection are lacking. METHODS: We used a robust HEV genotype 3 cell culture model which enables quantification of viral infection of quasi-enveloped and naked HEV particles. For HEV genotype 1 infections, we used the primary isolate Sar55 in a fecal suspension. Standardized quantitative suspension tests using end point dilution and large-volume plating were performed for the determination of virucidal activity of alcohols (1-propanol, 2-propanol, ethanol), WHO disinfectant formulations and 5 different commercial hand disinfectants against HEV. Iodixanol gradients were conducted to elucidate the influence of ethanol on quasi-enveloped viral particles. RESULTS: Naked and quasi-enveloped HEV was resistant to alcohols as well as alcohol-based formulations recommended by the WHO. Of the tested commercial hand disinfectants only 1 product displayed virucidal activity against HEV. This activity could be linked to phosphoric acid as an essential ingredient. Finally, we observed that ethanol and possibly non-active alcohol-based disinfectants disrupt the quasi-envelope structure of HEV particles, while leaving the highly transmissible and infectious naked virions intact. CONCLUSIONS: Different alcohols and alcohol-based hand disinfectants were insufficient to eliminate HEV infectivity with the exception of 1 commercial ethanol-based product that included phosphoric acid. These findings have major implications for the development of measures to reduce viral transmission in clinical practice. LAY SUMMARY: Hepatitis E virus (HEV) showed a high level of resistance to alcohols and alcohol-based hand disinfectants. The addition of phosphoric acid to alcohol was essential for virucidal activity against HEV. This information should be used to guide improved hygiene measures for the prevention of HEV transmission.

A realistic transfer method reveals low risk of SARS-CoV-2 transmission via contaminated euro coins and banknotes.

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has created a significant threat to global health. While respiratory aerosols or droplets are considered as the main route of human-to-human transmission, secretions expelled by infected individuals can also contaminate surfaces and objects, potentially creating the risk of fomite-based transmission. Consequently, frequently touched objects such as paper currency and coins have been suspected as potential transmission vehicle. To assess the risk of SARS-CoV-2 transmission by banknotes and coins, we examined the stability of SARS-CoV-2 and bovine coronavirus, as surrogate with lower biosafety restrictions, on these different means of payment and developed a touch transfer method to examine transfer efficiency from contaminated surfaces to fingertips. Although we observed prolonged virus stability, our results indicate that transmission of SARS-CoV-2 via contaminated coins and banknotes is unlikely and requires high viral loads and a timely order of specific events.

Virucidal efficacy of glutaraldehyde for instrument disinfection.

Aim: Glutaraldehyde (GDA) is an active ingredient in many instrument disinfectants and is effective against a broad spectrum of microorganisms. In the past, the virus-inactivating properties of these products were mainly claimed based on quantitative suspension tests with different test viruses. Recently, however, a European Norm EN 17111:2018 has been published which allows examination of instrument disinfectants in a surface carrier test, simulating practical conditions. Therefore, it is of interest to evaluate GDA for the ability to inactivate the viruses used in this European Norm as test viruses. Methods: The virucidal efficacy of GDA as the active ingredient in instrument disinfectants was evaluated with 4 different test viruses in a method simulating practical conditions (EN 17111:2018). Results: With a fixed exposure time of five minutes at 20°C, 100 ppm GDA were necessary to inactivate vaccinia virus, classifying it as a limited spectrum virucidal activity for pre-cleaning products. For adenovirus, 125 ppm GDA were required, whereas for murine norovirus as a surrogate for human norovirus, 4,000 ppm GDA were required for a significant reduction of viral titres. Both non-enveloped viruses must be tested to prove virucidal activity in EN 17111:2018. But even 4,000 ppm were not enough to yield a 4 log10 reduction of the murine parvovirus at 20°C. This virus is only required as a test virus using this method if temperatures ≥40°C are used. Conclusion: GDA, as the active ingredient of many instrument disinfectants, shows virucidal efficacy at 20°C. The necessary concentrations are strongly dependent on the stability of the test viruses. Due to the high stability of murine norovirus, GDA levels of 4,000 ppm were required to inactivate this virus within the 5-minute exposure time.

Evaluation of the virucidal efficacy of disinfectant wipes with a test method simulating practical conditions.

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 log10 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.

Virucidal efficacy of peracetic acid for instrument disinfection.

BACKGROUND: Various peracetic-acid (PAA)-based products for processing flexible endoscopes on the market are often based on a two-component system including a cleaning step before the addition of PAA as disinfectant. The peracetic acid concentrations in these formulations from different manufacturers are ranging from 400 to 1500 ppm (part per million). These products are used at temperatures between 20 °C and 37 °C. Since information on the virus-inactivating properties of peracetic acid at different concentrations and temperature is missing, it was the aim of the study to evaluate peracetic acid solutions against test viruses using the quantitative suspension test, EN 14476. In addition, further studies were performed with the recently established European pre norm (prEN 17111:2017) describing a carrier assay for simulating practical conditions using frosted glass. METHODS: In the first step of examination, different PAA solutions between 400 and 1500 ppm were tested at 20 °C, 25 °C, and 35 °C with three test viruses (adenovirus, murine norovirus and poliovirus) necessary for creating a virucidal action according to the European Norm, EN 14476. A second step for simulating practical conditions based on prEN 17111:2017 followed by spreading a test virus together with soil load onto a glass carrier which was immerged into a peracetic acid solution. A fixed exposure time of five minutes was used in all experiments. RESULTS: In the quantitative suspension test 1500 ppm PAA solution was needed at 35 °C for five minutes for the inactivation of poliovirus, whereas only 400 ppm at 20 °C for adeno- and murine norovirus were necessary. In the carrier assay 400 ppm peracetic acid at 20 °C were sufficient for adenovirus inactivation, whereas 600 ppm PAA were needed at 25 °C and 35 °C and 1000 ppm at 20 °C for murine norovirus. A PAA solution with 1000 ppm at 35 °C was required for complete inactivation of poliovirus. However, a dramatically decrease of titer after the drying and immerging could be observed. In consequence, a four log reduction of poliovirus titer could not be achieved in the carrier test. CONCLUSION: In summary, 1500 ppm PAA at 35 °C was necessary for a virucidal action in the quantitative suspension test. After passing the requirements of the suspension test, additional examinations with adeno- and murine norovirus on glass carriers based on prEN 17111:2017 will not additionally contribute to the final claim of an instrument disinfectant for virucidal efficacy. This is due to the great stability of poliovirus in the preceded quantitative suspension test and the fact that poliovirus could not serve as test virus in the following carrier assay.

Virucidal Activity of World Health Organization-Recommended Formulations Against Enveloped Viruses, Including Zika, Ebola, and Emerging Coronaviruses.

The World Health Organization (WHO) published 2 alcohol-based formulations to be used in healthcare settings and for outbreak-associated infections, but inactivation efficacies of these products have not been determined against (re-)emerging viruses. In this study, we evaluated the virucidal activity of these WHO products in a comparative analysis. Zika virus (ZIKV), Ebola virus (EBOV), severe acute respiratory syndrome coronavirus (SARS-CoV), and Middle East respiratory syndrome coronavirus (MERS-CoV) as (re-)emerging viral pathogens and other enveloped viruses could be efficiently inactivated by both WHO formulations, implicating their use in healthcare systems and viral outbreak situations.

Virucidal efficacy of a sonicated hydrogen peroxide system (trophon® EPR) following European and German test methods.

Aim: The virucidal efficacy of an automated ultrasound probe disinfector (trophon® EPR) was evaluated in a three step procedure according to European and German test methods. This system uses sonicated hydrogen peroxide mist (35%) at elevated temperature (50°C) in a closed chamber with control of all parameters within a 7 minute cycle. Methods: In the first step of examination, the peroxide solution was tested in a quantitative suspension assay according to the Guideline of Deutsche Vereinigung zur Bekämpfung der Viruskrankheiten (DVV) e.V. and Robert Koch-Institute (RKI) and in parallel with the European Norm EN 14476 with all test viruses creating a virucidal claim. In the second step, the virucidal efficacy of the hydrogen peroxide solution was evaluated in a hard surface carrier test according to the Guideline of DVV with adenovirus, murine norovirus and parvovirus simulating practical conditions. Finally, the efficacy was evaluated by the automated system using stainless steel carriers inoculated with test virus and positioned at different levels inside the chamber. Results: A ≥4 log10 reduction of virus titre was demonstrated with all methods including carrier tests with murine norovirus, adenovirus, and parvovirus using the automated device. Conclusion: The automated device is able to inactivate test viruses of German and European norms and can therefore claim efficacy against human pathogenic enveloped and non-enveloped viruses. This includes human papillomaviruses which form part of the complete virucidal claim.

Development and virucidal activity of a novel alcohol-based hand disinfectant supplemented with urea and citric acid.

BACKGROUND: Hand disinfectants are important for the prevention of virus transmission in the health care system and environment. The development of broad antiviral spectrum hand disinfectants with activity against enveloped and non-enveloped viruses is limited due to a small number of permissible active ingredients able to inactivate viruses. METHODS: A new hand disinfectant was developed based upon 69.39 % w/w ethanol and 3.69 % w/w 2-propanol. Different amounts of citric acid and urea were added in order to create a virucidal claim against poliovirus (PV), adenovirus type 5 (AdV) and polyomavirus SV40 (SV40) as non-enveloped test viruses in the presence of fetal calf serum (FCS) as soil load. The exposure time was fixed to 60 s. RESULTS: With the addition of 2.0 % citric acid and 2.0 % urea an activity against the three test viruses was achieved demonstrating a four log10 reduction of viral titers. Furthermore, this formulation was able to inactivate PV, AdV, SV40 and murine norovirus (MNV) in quantitative suspension assays according to German and European Guidelines within 60 s creating a virucidal claim. For inactivation of vaccinia virus and bovine viral diarrhea virus 15 s exposure time were needed to demonstrate a 4 log10 reduction resulting in a claim against enveloped viruses. Additionally, it is the first hand disinfectant passing a carrier test with AdV and MNV. CONCLUSIONS: In conclusion, this new formulation with a low alcohol content, citric acid and urea is capable of inactivating all enveloped and non-enveloped viruses as indicated in current guidelines and thereby contributing as valuable addition to the hand disinfection portfolio.

Virucidal activity of Formulation I of the World Health Organization's alcohol-based handrubs: impact of changes in key ingredient levels and test parameters.

BACKGROUND: A recently modified World Health Organization (WHO) Formulation I was examined as 80% and 97% solutions against poliovirus type 1, adenovirus type 5 and murine norovirus according to the new European Norm prEN 14476:2011. In a previous study the unmodified WHO Formulation I had failed to demonstrate a sufficient activity against poliovirus type 1 according to the European Norm EN 14476-2007 whereas a sufficient activity was seen with adeno- and norovirus. FINDINGS: The modified WHO Formulation I demonstrated a virucidal activity against all 3 test viruses of the European Norm prEN 14476:2011 under clean conditions. This was achieved as 80% solution against adeno- and norovirus within 30 seconds and as 97% solution against poliovirus within 60 seconds. Testing the unmodified WHO Formulation I against poliovirus type 1 in the 97% assay of the European Norm prEN 14476:2011 an identical activity could be demonstrated. When comparing the 80% and the 97% assay of the European Norm prEN 14476:2011 the modified WHO Formulation I as 80% solution was active against adenovirus type 5 within 30 seconds whereas the 97% solution failed within 2 minutes exposure time. CONCLUSIONS: The technical possibility in the new European Norm prEN 14476:2011 allows testing a ready-to-use disinfectant as 97% solution and is responsible for the new virucidal claim of the modified WHO Formulation I. In contrast to the improvements with poliovirus type 1 the activity against adenovirus type 5 decreased when increasing the test concentration from 80% to 97%.

How stable is the hepatitis C virus (HCV)? Environmental stability of HCV and its susceptibility to chemical biocides.

BACKGROUND: In the absence of a cell culture system for propagation of the hepatitis C virus (HCV), the antiviral activity of disinfectants against HCV was extrapolated from studies with the bovine viral diarrhea virus. The recent development of an HCV infection system allowed the direct assessment of environmental stability and susceptibility to chemical disinfectants. METHODS: Studies were performed using cell-culture grown HCV. Infectivity was determined by limiting dilutions. HCV RNA levels were analyzed by quantitative real-time polymerase chain reaction. Genome stability was determined by transfection of recovered RNA into Huh7.5 cells and immunostaining. RESULTS: HCV infectivity in a liquid environment was detectable for up to 5 month at lower temperatures. The risk of HCV infections may not accurately be reflected by determination of HCV RNA levels, because viral infectivity and HCV RNA copy numbers did not directly correlate. Different alcohols and commercially available antiseptics reduced the infectivity of HCV to undetectable levels. However, diluting the hand disinfectants abrogated the virucidal activity. CONCLUSIONS: This study assessed the environmental stability and susceptibility to chemical biocides of HCV. The results should be useful in defining rigorous disinfection protocols to prevent nosocomial transmission of HCV.

Virucidal activity of 2 alcohol-based formulations proposed as hand rubs by the World Health Organization.

The virucidal activity of 2 hand rubs proposed by the World Health Organization was studied in a quantitative suspension test for chemical disinfectants and antiseptics in human medicine (EN 14476). These formulations are recommended if no hand rubs with declared microbiological activity are available in health care settings. Formulation I, based on ethanol, inactivated bovine viral diarrhea virus (BVDV), hepatitis C virus (HCV), adenovirus, and murine norovirus as a surrogate for human norovirus. Formulation II, based on isopropyl alcohol, was active only against adenovirus and enveloped viruses, such as BVDV and HCV. Both formulations failed to inactivate poliovirus by 4 log(10) steps within 300 seconds.

Inactivation of murine norovirus by chemical biocides on stainless steel.

BACKGROUND: Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. METHODS: The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. RESULTS: PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by > or = 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes). CONCLUSION: Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces.

Hepatitis A virus suppresses monocyte-to-macrophage maturation in vitro.

To analyze the pathogenetic mechanism of hematopoietic dysregulation associated with hepatitis A virus (HAV) infections, we studied the influence of HAV on monocyte (MO)-to-macrophage (MAC) maturation in vitro. Exposure of peripheral blood-derived mononuclear cells (MNC) to HAV led to diminished adherence of MO to plastic. Furthermore, HAV inhibited the ability of peripheral blood MO to differentiate toward MAC. Freshly isolated and 14-day-old MO cultures demonstrated reduced differentiation and decreased phagocytic capacity after challenge with HAV. Viral replication in MO/MAC cultures was confirmed by titration of infectious virus. We also determined the influence of HAV on the MO/MAC population in human long-term bone marrow cultures (LTBMCs). Inoculation of bone marrow MNC with HAV suppressed the establishment of an adherent stromal layer containing a reduced number of MAC. Furthermore, increased MO numbers in the nonadherent fraction of HAV-challenged LTBMCs are indicative of the disturbance of MO adherence. These findings suggest that HAV infection leads to a disorder of the mononuclear phagocytic system which may contribute to functional abnormalities of the bone marrow stroma.