BACKGROUND: Pseudorabies virus (PRV), a member of the family Herpesviridae, is responsible for significant economic losses in the pig industry and has recently been associated with human viral encephalitis, leading to severe neurological symptoms post-recovery. Despite the widespread impact of PRV, there are currently no approved effective drugs for treating PRV-related diseases in humans or pigs. Therefore, the exploration and discovery of safe and effective drugs for the prevention and treatment of PRV infection is of paramount importance.
OBJECTIVE: The objective of this study is to screen and identify natural compounds with antiviral activity against PRV.
METHODS: First, we used a strain of PRV with green fluorescent protein (PRV-GFP) to screen a natural product chemical library to identify potential antiviral drugs. Next, we assessed the antiviral abilities of salvianolic acid A (SAA) in vitro using virus titer assay, qPCR, and IFA. We investigated the mechanisms of SAA\'s antiviral activity through viral attachment, internalization, inactivation, and nuclease digestion assay. Finally, we evaluated the efficacy of SAA in inactivating PRV using mice as the experimental subjects.
RESULTS: This study screened 206 natural compounds for anti-PRV activity in vitro, resulting in the identification of seven potential antiviral agents. Notably, SAA emerged as a promising candidate with significant anti-PRV activity. The mechanism of action may be that SAA can directly inactivate the virus by disrupting viral envelope. In vivo experiments have shown that pre-incubation of SAA and PRV can effectively inhibit the infectivity and pathogenicity of PRV in mice.
CONCLUSIONS: This study offers valuable insights into the antiviral properties of SAA, potentially informing strategies for controlling PRV epidemics and treating related diseases in both humans and animals.

Human norovirus (HuNoV), the leading cause of foodborne acute gastroenteritis, poses a serious threat to public health. Traditional disinfection methods lead to destructions of food properties and functions, and/or environmental contaminations. Green and efficient approaches are urgently needed to disinfect HuNoV. Plasma-activated water (PAW) containing amounts of reactive species is an emerging nonthermal and eco-friendly disinfectant towards the pathogenic microorganisms. However, the disinfection efficacy and mechanism of PAW on HuNoV has not yet been studied. Murine norovirus 1 (MNV-1) is one of the most commonly used HuNoV surrogates to evaluate the efficacy of disinfectants. In the current study, the inactivation efficacy of MNV-1 by PAW was investigated. The results demonstrated that PAW significantly inactivated MNV-1, reducing the viral titer from approximately 6 log10 TCID50/mL to non-detectable level. The decreased pH, increased oxidation-reduction potential (ORP) and conductivity of PAW were observed compared with that of deionized water. Compositional analysis revealed that hydrogen peroxide (H2O2), nitrate (NO3-) and hydroxyl radical (OH) were the functional reactive species in MNV-1 inactivation. L-histidine could scavenge most of the inactivation effect in a concentration-dependent manner. Moreover, PAW could induce damage to viral proteins. Part of MNV-1 particles was destroyed, while others were structurally intact without infectiousness. After 45 days of storage at 4 °C, PAW generated with 80 % O2 and 100 % O2 could still reduce over 4 log10 TCID50/mL of the viral titer. In addition, PAW prepared using hard water induced approximately 6 log10 TCID50/mL reduction of MNV-1. PAW treatment of MNV-1-inoculated blueberries reduced the viral titer from 3.79 log10 TCID50/mL to non-detectable level. Together, findings of the current study uncovered the crucial reactive species in PAW inactivate MNV-1 and provided a potential disinfection strategy to combat HuNoV in foods, water, and environment.

The accuracy of predictive microbial models used in quantitative microbial risk assessment (QMRA) relies on the relevancy of conditions influencing growth or inactivation. The continued use of log-linear models in studies remains widespread, despite evidence that they fail to accurately account for biphasic kinetics or include parameters to account for the effect of environmental conditions within the model equation. Although many experimental studies detail conditions of interest, studies that do not do so lead to uncertainty in QMRA modeling because the applicability of the predictive microbial models to the conditions in the risk scenarios is questionable or must be extrapolated. The current study systematically reviewed 65 articles that provided quantitative data and documented the conditions influencing the inactivation or growth of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in leafy greens. The conditions were identified and categorized as environmental, biological, chemical, and/or processing. Our study found that temperature (n = 37 studies) and sanitizing and washing procedures (n = 12 studies) were the most studied conditions in the farm-to-table continuum of leafy greens. In addition, relative humidity was also established to affect growth and inactivation in more than one stage in the continuum. This study proposes the evaluation of the interactive effects of multiple conditions in processing and storage stages from controlled experiments as they relate to the fate of STEC O157:H7 in leafy greens for future quantitative analysis.

BACKGROUND: Experimental studies in animals have yielded conflicting results on the role of Tumor Necrosis Factor (TNF) in sepsis and endotoxemia, with some reporting adaptive and others inappropriate effects. A meta-analysis of the available literature was performed to determine the factors explaining this discrepancy.
METHODS: The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The protocol was registered with PROSPERO (CRD42020167384) prior to data collection. PubMed and Embase were the databases queried. Risk of bias was evaluated using the SYRCLE Risk of Bias Tool. All animal studies investigating sepsis-related mortality and modified TNF signaling were considered eligible. The exclusion criteria were: lack of mortality data, 7-day mortality rates below 10% in both wild type and TNF-altered pathway animals, and absence of an English abstract. To determine the role of TNF according to the experimental protocol, three approaches were used: first an approach based on the statistical significance of each experiment, then the pooled mortality was calculated, and finally the weighted risk ratio for mortality was assessed.
RESULTS: A total of 175 studies were included in the analysis, comprising a total of 760 experiments and involving 19,899 animals. The main species used were mice (77%) and rats (21%). The most common method of TNF pathway modulation was TNF pathway inactivation that was primarily associated with an inappropriate secretion of TNF. At the opposite, TNF injection was associated with an adaptive role of TNF. Lipopolysaccharide (LPS) injection was the most used stimulus to establish an infectious model (42%) and was strongly associated with an inappropriate role of TNF. Conversely, live bacterial models, especially the cecal ligation and puncture (CLP) model, pneumonia, meningitis, and gastrointestinal infection, were associated with an adaptive role. This was particularly evident for Listeria monocytogenes, Streptococcus pneumoniae.
CONCLUSIONS: The role of TNF during infection varies depending on the experimental model used. Models that mimic clinical conditions, based on virulent bacteria that cause high mortality even at low inocula, demonstrated an adaptive role of TNF. Conversely, models based on LPS or low-pathogenic live bacteria, administered at doses well above physiological thresholds and combined with early antibiotic therapy, were associated with an inappropriate role.

Viruses impose a significant public health burden globally, and one of the key elements in controlling their transmission is the ability to inactivate them using disinfectants. However, numerous challenges to inactivating foodborne viruses exist due to inherent viral characteristics (such as recalcitrance to commonly used inactivation agents) and external factors (such as improper cleaning before application of inactivation agent, improper contact time, etc.). Given the potential for improper application of disinfectants (such as shorter than recommended contact time, improper disinfectant concentration, etc.), understanding the performance of a disinfectant in the presence of an organic load is important. To accomplish this, the introduction of simulated organic loads is often used when studying the efficacy of a disinfectant against different viruses. However, the different types of simulated organic loads used in foodborne virus inactivation studies or their relative effects on inactivation have not been reviewed. The purpose of this review is to survey different simulated organic load formulations used in studying foodborne virus inactivation, as well as present and compare the influence of these different formulations on viral inactivation. The findings included in this review suggest that many simulated organic load formulations can reduce disinfectants\' efficacy against viruses. Based on the findings in this review, blood, particularly serum or feces, are among the most commonly used and efficacious forms of simulated organic load in many tests.

The opening of the Torpedo CLC-0 chloride (Cl-) channel is known to be regulated by two gating mechanisms: fast gating and slow (common) gating. The structural basis underlying the fast-gating mechanism is better understood than that of the slow-gating mechanism, which is still largely a mystery. Our previous study on the intracellular proton (H+i)-induced inhibition of the CLC-0 anionic current led to the conclusion that the inhibition results from the slow-gate closure (also called inactivation). The conclusion was made based on substantial evidence such as a large temperature dependence of the H+i inhibition similar to that of the channel inactivation, a resistance to the H+i inhibition in the inactivation-suppressed C212S mutant, and a similar voltage dependence between the current recovery from the H+i inhibition and the recovery from the channel inactivation. In this work, we further examine the mechanism of the H+i inhibition of wild-type CLC-0 and several mutants. We observe that an anion efflux through the pore of CLC-0 accelerates the recovery from the H+i-induced inhibition, a process corresponding to the slow-gate opening. Furthermore, various inactivation-suppressed mutants exhibit different current recovery kinetics, suggesting the existence of multiple inactivated states (namely, slow-gate closed states). We speculate that protonation of the pore of CLC-0 increases the binding affinity of permeant anions in the pore, thereby generating a pore blockage of ion flow as the first step of inactivation. Subsequent complex protein conformational changes further transition the CLC-0 channel to deeper inactivated states.

Glabridin is an antimicrobial compound which can be extracted from plants, such as liquorice (Glycyrrhiza glabra) roots. Although its activity against foodborne pathogens and spoilage microorganisms has already been reported, the investigation of potential applications as a surface disinfectant is still largely unexplored. Hence, this study evaluated the disinfectant efficacy of glabridin against Listeria monocytogenes. The activity of glabridin was first tested in vitro in a nutrient-rich medium against eight strains of L. monocytogenes, including food isolates and the model strain EGDe. The tested strains showed similar susceptibility with minimal inhibitory and bactericidal concentrations of 12.5 µg/mL and 25 µg/mL, respectively. Subsequently, L. monocytogenes L6, FBR17 and EGDe were selected to assess the efficacy of glabridin against dried cells (according to the European standard EN 13697:2015 + A1:2019) and biofilm cells on stainless steel surfaces. Moreover, the impact of food residual organic matter was investigated using skim milk, cantaloupe and smoked salmon solution as soiling components. Our results showed that applying 200 µg/mL of glabridin resulted in a substantial reduction (>3 log10) of dried and biofilm cells of L. monocytogenes in standard conditions (i.e. low level of residual organic matter). Cantaloupe soiling components slightly reduced the activity of glabridin, while the efficacy of glabridin when tested with salmon and skim milk residuals was substantially affected. Comparative analysis using standardized protein contents provided evidence that the type of food matrices and type of proteins may impact the activity of glabridin as a disinfectant. Overall, this study showed low strain variability for the activity of glabridin against L. monocytogenes and shed light on the possible application of this natural antimicrobial compound as a surface disinfectant.

The Rift Valley fever virus (RVFV) is an arthropod-borne, zoonotic, hemorrhagic fever virus that can cause severe diseases both in livestock and humans. The spread of RVFV in areas previously considered as non-endemic together with the absence of licensed vaccines for use in humans and animals poses a major health and economic threat worldwide. It is therefore crucial to make major progresses in our understanding and management of this virus and its zoonosis. RVFV is considered a bioterrorism pathogen, and, thus, only a few institutes, facilities, and personnel are legally authorized to detain it and handle it. Moreover, this virus must be manipulated in a biosafety level 3 (BSL3) laboratory following strict biosafety protocols to ensure that biosecurity\'s highest standards are met. Only certain attenuated strains such as the MP12 strain can be handled in BSL2 laboratories, depending on the country considered. To assist researchers in working with RVFV in the safest possible conditions, this chapter presents validated methods for effective RVFV decontamination and inactivation.

Solar disinfection (SODIS) is an affordable and sustainable Household Water Treatment (HWT) method endorsed by WHO. However, its limitations include longer sunlight exposure requirements, incomplete microbial inactivation, and post-SODIS microbial regrowth during monsoon and winter seasons in subtropical climates. To address these limitations, the performance of SODIS with H2O2 for microbial inactivation during the monsoon and winter seasons in Bangladesh was evaluated following the WHO HWT protocols. Moreover, the process was verified using drinking water samples collected from restaurants, households, and slums. All SODIS experiments were conducted using reflective reactors with PET bottles and plastic bags, adding 10 mg/L of H2O2, and exposing them to sunlight for 6 h. The results showed that E. coli was completely inactivated within 2 h in plastic bags and within 3 h in PET bottles during the monsoon season, achieving an LRV of > 5. In winter, both achieved an LRV > 5 within 3 h and plastic bags showed more efficient in microbial inactivation than PET bottles. The microbial inactivation rates were 5 times higher than those of conventional SODIS. No regrowth of microorganisms was observed during the subsequent post-SODIS period of 12 h and 24 h at room temperature. The study findings suggest that SODIS with H2O2 has the potential for complete microorganism inactivation with shorter sunlight exposure in subtropical climates with moderate to low solar irradiation and can be adopted as a reliable disinfection option for rural and urban communities with unsafe drinking water supply.

Epidemics caused by pathogenic viruses are a severe threat to public health worldwide. Electromagnetic waves are a type of noncontact and nonionizing radiation technology that has emerged as an effective tool for inactivating bacterial pathogens. In this study, we used a 9.375 GHz electromagnetic wave to study the inactivation effect and mechanism of electromagnetic waves on MHV-A59, a substitute virus for pathogenic human coronavirus, and to evaluate the inactivation efficiency on different surface materials. We showed that 9.375 GHz electromagnetic waves inactivate MHV-A59 by destroying viral particles, envelopes, or genomes. We also found that 9.375 GHz electromagnetic waves can decrease the infectivity of viruses on the surface of inanimate materials such as plastic, glass, cloth, and wood. In conclusion, our results suggested that the 9.375 GHz electromagnetic wave is a promising disinfection technique for preventing the spread and infection of pathogenic viruses.