Virologic microparticle fluid mechanics simulation: COVID-19 transmission inside an elevator space

2021 ◽  
pp. 2150007
Author(s):  
Zahra Nouri ◽  
Nima Norouzi ◽  
Neda Norouzi ◽  
Elham Ataei ◽  
Sania Azizi
Keyword(s):  
Fluid Mechanics ◽  
Respiratory Disease ◽  
Infectious Virus ◽  
Virus Transmission ◽  
Infected Person ◽  
Confined Space ◽  
Air Conditioners ◽  
Infected People ◽  
Global Epidemic ◽  
Transient Flows

COVID-19 is a serious respiratory disease caused by a devastating coronavirus family (2019-nCoV) that has become a global epidemic. It is an infectious virus transmitted by inhalation or contact with the droplet core produced by infected people when they sneeze, cough, and speak. SARS-COV-2 transmission in the air is possible even in a confined space near the infected person. This study examines air conditioners’ effect on the mixed virus and droplets with aerosol disinfectant and gets throughout the elevator to detect the SARS-COV-2, which helps protect passengers’ lives. This study uses fluent 2019R3 software to simulate the virus transmission to model the transient flows numerically. The analysis found that the ventilation system’s turbulent fields can be an effective method of protecting the space from being saturated by the coronavirus.

scholarly journals Rat Model of Borna Disease Virus Transmission: Epidemiological Implications

2003 ◽  
Vol 77 (23) ◽  
pp. 12886-12890 ◽  
Author(s):  
Christian Sauder ◽  
Peter Staeheli
Keyword(s):  
Disease Virus ◽  
Rat Model ◽  
Infectious Virus ◽  
Virus Transmission ◽  
Farm Animals ◽  
Borna Disease Virus ◽  
Persistently Infected ◽  
Rapid Transmission ◽  
Fresh Urine ◽  
Borna Disease

ABSTRACT Rapid transmission of Borna disease virus occurred upon cohabitation of persistently infected and naive rats. Infectious virus, which was abundantly present in fresh urine samples of carrier rats, entered the brains of recipient rats via the olfactory route. Thus, susceptible farm animals possibly acquire the virus from persistently infected rats.

scholarly journals UK B.1.1.7 variant exhibits increased respiratory replication and shedding in nonhuman primates

2021 ◽  
Author(s):  
Kyle Rosenke ◽  
Friederike Feldmann ◽  
Atsushi Okumura ◽  
Frederick Hansen ◽  
Tsing-Lee Tang-Huau ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Respiratory Tract ◽  
Respiratory Disease ◽  
Lower Respiratory Tract ◽  
Nonhuman Primates ◽  
Infectious Virus ◽  
Clinical Presentation ◽  
Viral Rna ◽  
The Uk ◽  
Green Monkeys

The continuing emergence of SARS-CoV-2 variants calls for regular assessment to identify differences in viral replication, shedding and associated disease. In this study, African green monkeys were infected intranasally with either a contemporary D614G or the UK B.1.1.7 variant. Both variants caused mild respiratory disease with no significant differences in clinical presentation. Significantly higher levels of viral RNA and infectious virus were found in upper and lower respiratory tract samples and tissues from B.1.1.7 infected animals. Interestingly, D614G infected animals showed significantly higher levels of viral RNA and infectious virus in rectal swabs and gastrointestinal tract tissues. Our results indicate that B.1.1.7 infection in African green monkeys is associated with increased respiratory replication and shedding but no disease enhancement similar to human B.1.1.7 cases.

scholarly journals Prediction of New Coronavirus Infection Based on a Modified SEIR Model

2020 ◽  
Author(s):  
Zhou Tang ◽  
Xianbin Li ◽  
Houqiang Li
Keyword(s):  
Incubation Period ◽  
Prevention And Control ◽  
Infected Person ◽  
Wuhan City ◽  
Seir Model ◽  
Infected People ◽  
Public Data ◽  
Coronavirus Infection ◽  
And Control ◽  
The City

BACKGROUNDThe outbreak of the new coronavirus infection in Wuhan City, Hubei Province in December 2019, poses a huge threat to China and even global public health security. Respiratory droplets and contact transmission are the main routes of transmission of new coronaviruses. Compared with SARS and Ebola viruses, new coronavirus infections are infectious during the incubation period. Traditional SEIR (susceptibility-exposure-infection-Removal) There are some differences in conditions for the prediction of the epidemic trend of new coronavirus infection. The outbreak of the new coronavirus infection coincided with the Spring Festival before and after the Chinese Spring Festival.It is necessary to make appropriate optimization and amendments to the traditional model to meet the actual evolution of the epidemic situation.METHODSThe traditional SEIR model assumes that the virus-infected person is not infectious during the incubation period and that the infected person did not take isolation measures during the illness. The transmission of the new coronavirus no longer meets the basic assumptions of the classical kinetic system. Therefore, this article first establishes a modified SEIR model. Predict and analyze the changing trend of the epidemic situation, then estimate the parameters involved in the infection dynamics model, and then use Matlab to simulate the established dynamic equations based on public data and analyze the results. Recommendations for universal prevention and control of infectious diseases.RESULTSThe first case of new coronavirus infection was confirmed in Wuhan on December 8, 2019. When Wuhan City took no action, assuming the average daily number of contacts per infected person k = 5, the number of infected persons will reach about 2,384,803 people; If wuhan adopts the measures of sealing the city on January 22, 2020, under the premise of k=2, the number of infected people decreases by 19,773 compared with that on January 23, and there is no significant change in the time when the number of infected people reaches the peak. Under the premise of k = 1, the number of infected persons was reduced by 14,330 compared with the closure on January 23, and the time to reach the peak of the number of infected persons was reduced by 2 days. If Wuhan City is closed for one day, the number of infected persons will increase from 106,145 to 130,626 under the premise of k = 2; the number of infected persons will increase from 74,369 to 92,010 under the premise of k = 1.CONCLUSIONSComparing the number of confirmed diagnoses actually notified by the department with the number of infected people obtained from the simulation of the model, it can be seen that the city closure measures adopted by the Wuhan Municipal Government on January 23 and the first-level response measures adopted by the country are effective for the epidemic Prevention and control play a vital role. Wearing a mask when going out and avoiding close contact with people can effectively reduce the infection rate.

scholarly journals Protective Effects of Astodrimer Sodium 1% Nasal Spray Formulation against SARS-CoV-2 Nasal Challenge in K18-hACE2 Mice

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1656
Author(s):  
Jeremy R. A. Paull ◽  
Carolyn A. Luscombe ◽  
Alex Castellarnau ◽  
Graham P. Heery ◽  
Michael D. Bobardt ◽  
...  
Keyword(s):  
Nasal Cavity ◽  
Nasal Spray ◽  
Viral Genome ◽  
Infectious Virus ◽  
Virus Transmission ◽  
Protective Effects ◽  
Viral Shedding ◽  
Nasal Secretions ◽  
Spray Formulation ◽  
The Brain

Strategies to combat COVID-19 require multiple ways to protect vulnerable people from infection. SARS-CoV-2 is an airborne pathogen and the nasal cavity is a primary target of infection. The K18-hACE2 mouse model was used to investigate the anti-SARS-CoV-2 efficacy of astodrimer sodium formulated in a mucoadhesive nasal spray. Animals received astodrimer sodium 1% nasal spray or PBS intranasally, or intranasally and intratracheally, for 7 days, and they were infected intranasally with SARS-CoV-2 after the first product administration on Day 0. Another group was infected intranasally with SARS-CoV-2 that had been pre-incubated with astodrimer sodium 1% nasal spray or PBS for 60 min before the neutralisation of test product activity. Astodrimer sodium 1% significantly reduced the viral genome copies (>99.9%) and the infectious virus (~95%) in the lung and trachea vs. PBS. The pre-incubation of SARS-CoV-2 with astodrimer sodium 1% resulted in a significant reduction in the viral genome copies (>99.9%) and the infectious virus (>99%) in the lung and trachea, and the infectious virus was not detected in the brain or liver. Astodrimer sodium 1% resulted in a significant reduction of viral genome copies in nasal secretions vs. PBS on Day 7 post-infection. A reduction in the viral shedding from the nasal cavity may result in lower virus transmission rates. Viraemia was low or undetectable in animals treated with astodrimer sodium 1% or infected with treated virus, correlating with the lack of detectable viral replication in the liver. Similarly, low virus replication in the nasal cavity after treatment with astodrimer sodium 1% potentially protected the brain from infection. Astodrimer sodium 1% significantly reduced the pro-inflammatory cytokines IL-6, IL-1α, IL-1β, TNFα and TGFβ and the chemokine MCP-1 in the serum, lung and trachea vs. PBS. Astodrimer sodium 1% nasal spray blocked or reduced SARS-CoV-2 replication and its sequelae in K18-hACE2 mice. These data indicate a potential role for the product in preventing SARS-CoV-2 infection or for reducing the severity of COVID-19.

scholarly journals Evaluation of Aircraft Boarding Scenarios Considering Reduced Transmissions Risks

2020 ◽  
Vol 12 (13) ◽  
pp. 5329 ◽  
Author(s):  
Michael Schultz ◽  
Jörg Fuchte
Keyword(s):  
Physical Distance ◽  
Air Travel ◽  
Transmission Model ◽  
Confined Space ◽  
Infected People ◽  
Transmission Potential ◽  
Remote Locations ◽  
The Individual ◽  
Space Conditions ◽  
Sample Case

Air travel appears as particularly hazardous in a pandemic situation, since infected people can travel worldwide and could cause new breakouts in remote locations. The confined space conditions in the aircraft cabin necessitate a small physical distance between passengers and hence may boost virus transmissions. In our contribution, we implemented a transmission model in a virtual aircraft environment to evaluate the individual interactions between passengers during aircraft boarding and deboarding. Since no data for the transmission is currently available, we reasonably calibrated our model using a sample case from 2003. The simulation results show that standard boarding procedures create a substantial number of possible transmissions if a contagious passenger is present. The introduction of physical distances between passengers decreases the number of possible transmissions by approx. 75% for random boarding sequences, and could further decreased by more strict reduction of hand luggage items (less time for storage, compartment space is always available). If a second door is used for boarding and deboarding, the standard boarding times could be reached. Individual boarding strategies (by seat) could reduce the transmission potential to a minimum, but demand for complex pre-sorting of passengers. Our results also exhibit that deboarding consists of the highest transmission potential and only minor benefits from distance rules and hand luggage regulations.

scholarly journals Wrong person, place and time: viral load and contact network structure predict SARS-CoV-2 transmission and super-spreading events

2020 ◽  
Author(s):  
Ashish Goyal ◽  
Daniel B Reeves ◽  
E. Fabian Cardozo-Ojeda ◽  
Joshua T Schiffer ◽  
Bryan T. Mayer
Keyword(s):  
Viral Load ◽  
High Viral Load ◽  
Physical Contact ◽  
Therapeutic Interventions ◽  
Contact Network ◽  
Infected Person ◽  
Infected People ◽  
Viral Shedding ◽  
Secondary Infections ◽  
Peak Viral Load

SARS-CoV-2 is difficult to contain because many transmissions occur during the pre-symptomatic phase of infection. Moreover, in contrast to influenza, while most SARS-CoV-2 infected people do not transmit the virus to anybody, a small percentage secondarily infect large numbers of people. We designed mathematical models of SARS-CoV-2 and influenza which link observed viral shedding patterns with key epidemiologic features of each virus, including distributions of the number of secondary cases attributed to each infected person (individual R0) and the duration between symptom onset in the transmitter and secondarily infected person (serial interval). We identify that people with SARS-CoV-2 or influenza infections are usually contagious for fewer than one day congruent with peak viral load several days after infection, and that transmission is unlikely below a certain viral load. SARS-CoV-2 super-spreader events with over 10 secondary infections occur when an infected person is briefly shedding at a very high viral load and has a high concurrent number of exposed contacts. The higher predisposition of SARS-CoV-2 towards super-spreading events is not due to its 1-2 additional weeks of viral shedding relative to influenza. Rather, a person infected with SARS-CoV-2 exposes more people within equivalent physical contact networks than a person infected with influenza, likely due to aerosolization of virus. Our results support policies that limit crowd size in indoor spaces and provide viral load benchmarks for infection control and therapeutic interventions intended to prevent secondary transmission.

scholarly journals Not all wavelengths are created equal: disinfection of SARS-CoV-2 using UVC radiation is wavelength-dependent

2021 ◽  
Vol 3 (11) ◽  
Author(s):  
Richard M. Mariita ◽  
James W. Peterson
Keyword(s):  
Light Emitting Diodes ◽  
Irradiation Time ◽  
Close Contact ◽  
Virus Transmission ◽  
Disease Outbreak ◽  
Subtype C ◽  
Light Emitting ◽  
Infected People ◽  
Transmission Chain ◽  
Uvc Radiation

SARS-CoV-2 is mostly transmitted through close contact with infected people by infected aerosols and fomites. Ultraviolet subtype C (UVC) lamps and light-emitting diodes can be used to disrupt the transmission chain by disinfecting fomites, thus managing the disease outbreak progression. Here, we assess the ultraviolet wavelengths that are most effective in inactivation of SARS-CoV-2 on fomites. Variations in UVC wavelengths impact the dose required for disinfection of SARS-CoV-2 and alter how rapidly and effectively disruption of the virus transmission chain can be achieved. This study reveals that shorter wavelengths (254–268 nm) take a maximum of 6.25 mJ/cm2 over 5 s to obtain a target SARS-CoV-2 reduction of 99.9%. Longer wavelengths, like 280 nm, take longer irradiation time and higher dose to inactivate SARS-CoV-2. These observations emphasize that SARS-CoV-2 inactivation is wavelength-dependent.

scholarly journals Mathematical Modeling and Simulation of Development of the Fires in Confined Spaces

2020 ◽  
Author(s):  
Ivan Antonov ◽  
Rositsa Velichkova ◽  
Svetlin Antonov ◽  
Kamen Grozdanov
Keyword(s):  
Mathematical Modeling ◽  
Fluid Mechanics ◽  
Dynamic Simulation ◽  
Turbulence Models ◽  
Solution Model ◽  
Computational Fluid Mechanics ◽  
Confined Space ◽  
Confined Spaces ◽  
Story Building ◽  
Over Time

The mathematical models of fire distribution in a confined space–in underground garages and in buildings—are described. Integral and computational fluid mechanics methods are used. The chapter presents the results of a fire simulation using the software Fluent. It uses Reynolds-type turbulence models of the Fire Dynamic Simulation or PyroSim graphical interface with a solution model describing a turbulence. For both cases, the pictures of the spread of fire and smoke over time in an atrium of an administrative building and a five-story building of the TUS were presented.

scholarly journals Estimation SARS-CoV-2 viability in time on experimental surfaces over

2021 ◽  
Author(s):  
MA Nikiforova ◽  
AE Siniavin ◽  
EV Shidlovskaya ◽  
NA Kuznetsova ◽  
VA Guschin
Keyword(s):  
Tissue Culture ◽  
Infectious Virus ◽  
Aluminum Foil ◽  
Infected Person ◽  
Rt Pcr ◽  
Ceramic Tiles ◽  
Model Surfaces ◽  
Experimental Surface ◽  
Metal Aluminum ◽  
Over Time

Infected SARS-CoV-2 virus occurs not only through contact with an infected person, but also through surfaces with wich the illnes has contacted. The problem of preserving an infectious virus over time capable of infecting remains actual. We evaluated the SARS-CoV-2 viability preservation on different model surfaces over time. Ceramic tiles, metal (aluminum foil), wood (chipboard), plastic and cloth (towel) were used as model materials. Assessment of the presence of SARS-CoV-2 RNA was carried out by quantitative RT-PCR. Viable virus was determined by tissue culture assay on 293T/ACE2 cells. It was found that the SARS-CoV-2 RNA was detected on all studied surfaces for 360 minutes, but a significant decrease RNA by 1 log10 copies/ml was detected after contact of the virus with cloth (towel). While the viability of the virus was completely lost after 120 minutes. Type of experimental surface significantly affects viability preservation.

scholarly journals Intervention strategies with 2D cellular automata for testing SARS-CoV-2 and reopening the economy

2020 ◽  
Author(s):  
Igor Lugo ◽  
Martha G. Alatriste-Contreras
Keyword(s):  
Large Scale ◽  
Systems Approach ◽  
Virus Transmission ◽  
Disease Outbreaks ◽  
Urban Environments ◽  
Model Parameters ◽  
Infected People ◽  
Testing Frequency ◽  
Short Period ◽  
Asymptomatic Individuals

Abstract During the period of time between a new disease outbreaks and its vaccine is deployed, the health and the economic systems have to find a testing strategy for reopening activities. In particular, asymptomatic individuals, who transmit locally the covid-19 indoors, have to be identified and isolated. We proposed a 2D cellular automaton based on the SI epidemic model for selecting the most desirable testing frequency and identifying the best fitting size of random trails on local urban environments to diagnose SARS-CoV-2 and isolate infected people. We used the complex systems approach to face the challenge of a large-scale test strategy based on urban interventions, starting with first responders and essential workers. We used the case of Mexico to exemplify a credible and intelligent intervention that reduces the virus transmission and detects economic and health costs. Findings suggest that controlling and stopping the virus transmission in a short period of time are possible if the frequency of testing is daily and the percentage of random samples to be tested is at least 90%. This combination of model parameters represents the least expensive intervention compared to others. Therefore, the key for a national testing-isolating strategy is local interventions.

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