Microbial Risk Analysis最新文献

For thousands of years, medicine has made efforts to study and heal infectious diseases. For centuries, medicine and biology have attempted to study the mechanisms of development of infectious diseases. For 100 years, virology has tried to understand and describe different viruses and reveal the secrets of pathophysiology of infections. Several decades ago, the efforts of biomedical scientists were joined by chemists. Since then viruses have been explored not only as biological systems, but also as chemical systems. With the beginning of the COVID-19 pandemic, biothermodynamics has made its contribution to the research on driving forces and mechanisms of lifecycles of viruses, the virus-host interaction. Since then, viruses have been analyzed as biological, chemical and thermodynamic systems. After reporting of chemical and thermodynamic properties of SARS-CoV, MERS-CoV, SARS-CoV-2, Ebola, Mpox, West Nile virus and bacteriophages, this paper reports for the first time the empirical formulas (unit carbon formulas) of Rotavirus A, as well as its thermodynamic properties of virus-host interaction at the membrane (antigen-receptor binding) and virus-host interaction in the cytoplasm (virus multiplication). The virus-host interactions are essentially chemical reactions, the driving force of which is Gibbs energy (of binding and biosynthesis).

A question is often asked about what tomorrow brings. During the last 4 years of the COVID-19 pandemic, this question was asked with every appearance of a new SARS-CoV-2 variant. It seems that science has an ability to offer a relatively reliable answer. Theoretical and experimental research have allowed a deep insight into structure and function of SARS-CoV-2. Moreover, the developed mechanistic models allow prediction of virus-host interactions. In August 2023, the Omicron BA.2.86 Pirola variant was detected. Taught by the bad experience from 2019 to 2023, when every new variant that appeared during SARS-CoV-2 evolution has caused a new pandemic wave, the question was raised whether this will be the case with the new variant. Research presented in this paper shows that the driving force for antigen-receptor binding of the Omicron BA.2.86 variant is lower than that of the BN.1 and similar to that of the other variants. Based on the presented research, it seems that the new variant will not be more aggressive relative to the previous variants. The movement in the number of newly infected cases in USA in the period between August and mid-October 2023 is in favor of this prediction.

Airborne viral transmission in confined spaces, such as elevators, could lead to the spread of diseases such as COVID-19. A quantitative study of viral transmission in enclosed spaces, with a focus on assessing the efficacy of the present ventilation methods is hard to find. Additionally, there is a lack of guidelines for viral dispersion. The non-availability of such information reduces overall effectiveness in controlling the spread of the virus. A properly designed ventilation system for the elevator car will benefit in both pandemic situations as well as non-pandemic situations, especially for people using hospital elevators. For better control of the airborne viral transmission spread, it is essential to study the airflow in elevator cars. Exposure to high-emitter coughing for one minute by a SARS-CoV-2-infected person in an elevator can increase the risk of the virus reaching the lungs by generating a viral load that may remain airborne for a long time. There is little that has been considered for lessening the anticipated viral load in the elevator car. In this paper, we use a two-step approach. The first step is the risk assessment, and the second is risk mitigation. The risk is assessed by computing the probable viral load a healthy passenger will be subjected to during the typical travel in an elevator car contaminated by the ride of an infectious person. It is seen that the ventilation provided as per the minimum permissible requirements by various international codes is inadequate to maintain the viral load in the elevator car below the risky levels. To come up with the risk mitigation strategies, the required ventilation in the car was computed using a Computational Fluid Dynamics (CFD) model. Further, mathematical models are developed to enable quick calculations during the design of the elevator car ventilation system. Our CFD study shows that in the case of a 20-passenger capacity elevator car, with doors open, a 2000 Cubic Feet per Minute (CFM) airflow will disperse most of the viral load in less than one minute. In this paper, we give easy-to-follow design guidelines, and mathematical models to enable quick calculations during the design of the elevator car ventilation system. This study is useful for practicing engineers to achieve effective ventilation of the elevator car to curtail the spread of viral transmission.

Brazilian sheep farming is an ancient socioeconomic activity of great importance for maintaining income and generating family employment. Brazil is the largest producer of sheep in South America, making it a strategic country for the control of infectious diseases such as scrapie. In the present study, scrapie was officially reported in 74 cases in nine Brazilian states between 2005 and 2021. Among all Brazilian regions, the South with 54.06 % (40/74), the Midwest with 28.38 % (21/74), and the Southeast with 16.21 % (12/74) stood out with higher relative frequencies in the number of cases of the disease. Among the states, Santa Catarina presented 35.14 % of the notified cases, and the risk of incidence (IR) was 91.9 per 100,000 sheep. The years with the highest reported cases were 2012 (17 cases and IR = 2.11) and 2017 (16 cases and IR = 6.17). There was the formation of a primary cluster in the year 2017, formed only by the state of Santa Catarina, with relative risk (RRs) = 313.97, and a secondary cluster formed by the states of Mato Grosso, Mato Grosso do Sul, Goiás, Tocantins, Minas Gerais, and São Paulo in the period from 2006 to 2009, with RRs = 27.92. All of the states with reported cases shared borders, demonstrating the disease's ability to spread across state lines. Scrapie must be prevented from spreading in Brazil by implementing active surveillance measures.

Since 2019, when it appeared in Wuhan, in the wild type form later labeled Hu-1, SARS-CoV-2 mutated dozens of times and evolved towards increase in infectivity and decrease or maintenance of constant pathogenicity through dozens of variants. The last of them are Omicron EG.5 and EG.5.1. Until 2019, an empirical formula was known only for the poliovirus. Until now empirical formulas and thermodynamic properties were reported for all variants of SARS-CoV-2 and some other viruses. Also, models were developed that describe the biothermodynamic background of SARS-CoV-2 interaction with its human host. With every new mutation in SARS-CoV-2, the question is raised about the further evolution of the virus. This paper reports for the first time empirical formulas and molar masses of Omicron EG.5 and EG.5.1 variants, as well as thermodynamic properties (enthalpy, entropy and Gibbs energy) of formation and biosynthesis. Moreover, the driving force of virus multiplication was analyzed, as well as multiplication rate and pathogenicity of Omicron EG.5 and EG.5.1.

From July to October, West Nile virus is the leading cause of mosquito born disease in Europe and North America. This paper reports for the first time a chemical and thermodynamic analysis of the West Nile virus particles, genome and proteins, as well as interactions with its host organism. The empirical formula of mature West Nile virus particles was found through the atom counting method. Based on the empirical formula, biosynthesis reactions were formulated, which describe the formation of new virus live matter. Based on the biosynthesis reactions, Gibbs energy of biosynthesis was determined, which represents the physical driving force for the production of viral and host cell components. Gibbs energy of biosynthesis of the West Nile virus was found to be several times more negative than that of its host tissues. Due to the more negative Gibbs energy of biosynthesis, the West Nile virus components are produced much faster than those of its host cells. This allows the virus to hijack the host cell metabolism. Therefore, the virus-host interactions of the West Nile virus were explained through chemical and thermodynamic analysis.

In this study, the heat resistance of S. aureus in goats’ raw milk subjected to thermisation temperatures was characterised through tests at various temperatures and modelling the survival curves using the Weibull model, through a two-step and an omnibus approach, which can model a full dataset covering all experimental conditions in one step. The fitting capacity of the secondary models obtained from the two-step approach was reasonable (adj. R² > 0.639) and both demonstrated the negative linear effects of temperature on $\sqrt{\chi }$ (p = 0.0004) and $\sqrt{\beta }$ (p = 0.017). The fitting capacity of the omnibus model was more satisfactory (adj. R² = 0.996) and also hinted at the negative linear effect of temperature on $\sqrt{\chi }$ (p < 0.0001), with the added advantage that, in this model, random effects can be used to account for the variability in the parameters. Our study estimated the significant inactivation parameters and established a model capable of predicting S. aureus behaviour at various temperatures. This information is useful to create time-temperature tables to reach target log reductions of S. aureus in goats’ raw milk to be used by artisanal cheesemakers; hence providing an opportunity to increase the microbiological safety of cheeses made from unpasteurised milk.

Aflatoxin B1 (AFB1), is among the most carcinogenic and genotoxic food and feed contaminants and there is no acceptable level of their intake. An analysis of the top 10 countries of origin notifications on aflatoxins (AFs) involved in the EU RASFF database over the last 26 years was undertaken. A risk assessment was estimated for simulating the worst-case scenario for the serious notifications of the mostly notified products as well. Out of 12,400 notifications on AFs over the period between 1997 and 2022, of which 10,340 (83.39 %) concerned Iran which was the most frequently notified country (21.56 %), followed by Turkey (20.48), China (9.99 %), India (7.88 %), the USA (7.74 %), Argentina (5.82 %), Egypt (3.94 %), Brazil (3.05 %), Pakistan (1.52 %), and Nigeria (1.41 %). Germany was the most notifying country, followed by the Netherlands. Among all notifications, 53.3 % have been border rejected. Nuts, nuts products, and seeds were the highest notified product category followed by fruits and vegetables. The highest serious risk decision in terms of notification number was taken for contaminated dried fig from Turkey, followed by pistachio from Iran. The estimated margin of exposure (MOE) values for the mostly notified products i.e., pistachio, dried fig, and peanut were <10,000 which is not safe and represents a health concern.

Objectives

In this research, we aimed to find potential factors which are rapidly obtained for the risk of the coming new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when their genetic substitutions were detected in late 2022.

Methods

We first performed molecular docking simulation analyses of the spike proteins with human angiotensin-converting enzyme 2 (ACE2) by using ZDOCK program to determine the binding affinities to human cells of three new variants of SARS-CoV-2: Omicron BQ.1, XBB, and XBB.1.5. We then investigated the three variants to determine the relative evolutionary distance of the spike protein gene (S gene) from the Wuhan, Omicron BA.1, and Omicron BA.4/5 variants.

Results

The results indicated that Omicron BQ.1. had a highest binding affinity but had the shortest evolutionary distance from BA.4/5. The XBB variant had a lower binding affinity and long evolutionary distances from all the three variants. However, the XBB.1.5 variant had the highest binding affinity of the spike protein with ACE2 and the longest evolutionary distance of the S gene.

Conclusion

This result suggested that in silico binding affinity of the spike protein with ACE2 and the relative evolutionary distance of S gene may be potential factors for the risk of SARS-CoV-2 variants based on the comparison of infectivity of BQ.1, XBB, and XBB.1.5.

After the first introduction of African swine fever (ASF) in the European Union in 2014, the ASF virus (ASFV) has steadily spread in the European Union. The virus has occasionally been transmitted over unexpectedly large distances that are believed to be related to human-mediated spread. Hunting tourism has been mentioned as a potential contributor to these long-distance jumps, although evidence is lacking. In this study, the possible role of hunters carrying ASFV-contaminated wild boar products (WBP) from hunting trips in affected countries was evaluated. A quantitative risk model was developed to estimate the expected annual number of ASF exposures of wild boar and domestic pigs in the Netherlands via this introduction route. Main input data into the model were the ASF prevalence in hunted wild boar, the number and destination of hunting trips of Dutch hunters, and the probabilities that hunters take WBP home and dispose leftovers such that wild boar or domestic pigs have access. The model indicated that the total expected annual number of exposures (wild boar and domestic pigs together) in the Netherlands is 0.048 (95% uncertainty interval 7.5 × 10⁻³ – 0.15). Model results were most sensitive to uncertainty on leftovers fed to domestic pigs (swill feeding), which is an illegal practice. Uncertainties on the ASF prevalence of hunted wild boar and the probabilities that hunters take WBP home also impacted model results. Default model results were based on the 2019 situation. Alternative scenarios were run with the model to account for the change of ASF status of Belgium (recovery of ASF-free status) and Germany (ASF-infected) in 2020. Results indicated that especially the presence of ASF in Germany increased the incursion risk. However, this increase might be counteracted by a change in travel behavior of hunters.