Inactivation of the enveloped virus phi6 with hydrodynamic cavitation.

The COVID -19 pandemic reminded us that we need better contingency plans to prevent the spread of infectious agents and the occurrence of epidemics or pandemics. Although the transmissibility of SARS-CoV-2 in water has not been confirmed, there are studies that have reported on the presence of infectious coronaviruses in water and wastewater samples. Since standard water treatments are not designed to eliminate viruses, it is of utmost importance to explore advanced treatment processes that can improve water treatment and help inactivate viruses when needed. This is the first study to investigate the effects of hydrodynamic cavitation on the inactivation of bacteriophage phi6, an enveloped virus used as a SARS-CoV-2 surrogate in many studies. In two series of experiments with increasing and constant sample temperature, virus reduction of up to 6.3 logs was achieved. Inactivation of phi6 at temperatures of 10 and 20 °C occurs predominantly by the mechanical effect of cavitation and results in a reduction of up to 4.5 logs. At 30 °C, the reduction increases to up to 6 logs, where the temperature-induced increased susceptibility of the viral lipid envelope makes the virus more prone to inactivation. Furthermore, the control experiments without cavitation showed that the increased temperature alone is not sufficient to cause inactivation, but that additional mechanical stress is still required. The RNA degradation results confirmed that virus inactivation was due to the disrupted lipid bilayer and not to RNA damage. Hydrodynamic cavitation, therefore, has the potential to inactivate current and potentially emerging enveloped pathogenic viruses in water at lower, environmentally relevant temperatures.

Efficacy of water-only or soap and water skin decontamination of chemical warfare agents or simulants using in vitro human models: A systematic review.

Water-only or water and soap are widely recommended as preferred solutions for dermal decontamination. However, limited efficacy data exist. We summarized experimental studies evaluating in vitro efficacy of water-only or soap and water in decontaminating chemical warfare agents (CWA) or their simulants from human skin models. Embase, Covidence®, MEDLINE, PubMed, Web of Science, and Google Scholar were searched for articles using water-only or soap and water decontamination methods for removal of CWA/CWA simulants in in vitro human skin models. Data extraction was completed from seven studies, yielding seven contaminants. Water-only decontamination led to partial decontamination in all skin samples (100%, n = 81/81). Soap and water decontamination led to partial decontamination in all skin samples (100%, n = 143/143). Four studies found decontamination to either paradoxically enhance absorption of contaminants or their penetration rates, known as the "wash-in" effect. Despite recommendations, water-only or water and soap decontamination were found to yield partial decontamination of CWA or their simulants in all human in vitro studies. Thus, more effective decontaminating agents are needed. Some studies demonstrated increased or faster penetration of chemicals following decontamination, which could prove deadly for agents such as VX, although these findings require in vivo validation. Heterogeneity in experimental setups limits interstudy comparison, and it remains unclear when water-only or water and soap are ideal decontaminants, which requires more studies. Pending manuscripts will summarize in vivo human and animal efficacy data. International harmonized efficacy protocol should enable more efficient public health decisions for evidence-based public health decisions.

Efficacy of soap and water based skin decontamination using in vivo animal models: a systematic review.

Water-only or soap and water solutions are considered a gold standard for skin decontamination. However, there is lack of conclusive data regarding their efficacy. The aim of this study was to summarize in vivo animal model data on skin decontamination using water-only, and/or soap and water. Covidence, Embase, MEDLINE, PubMed, Web of Science, and Google Scholar were searched to identify relevant articles using water-only or soap and water decontamination methods in in vivo animals. Data extraction was completed from studies, representing three animal models, and 11 contaminants. Results demonstrated water-only decontamination solutions led to complete decontamination in 3.1% (n = 16/524) protocols, incomplete decontamination in 90.6% (n = 475/524) of protocols, and mortality in 6.3% (n = 33/524) of protocols. Soap and water decontamination solutions resulted in complete decontamination in 6.9% (n = 8/116) protocols, incomplete decontamination in 92.2% (n = 107/116) of protocols, and mortality in 6.9% (n = 8/116) of protocols. Although water only, or soap and water is considered a gold standard for skin decontamination, most papers investigated found that water only, and soap and water provided incomplete decontamination. Due to the insufficient data, and limitations that hinder the applicability of available data, evidence indicates that more contemporary studies investigating skin decontamination are needed, and compared to other model species, including humans, when practical.