HVAC system requirements for protection against epidemics similar to Covid-19

2021 ◽  
Vol 1 (1) ◽  
pp. 001-013
Author(s):  
Ali Kemal CAKIR
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
Disease Transmission ◽  
Close Contact ◽  
Hvac Systems ◽  
Extensive Literature ◽  
Infectious Disease Transmission ◽  
Indirect Contact ◽  
Engineering Controls ◽  
Short Term Exposure

Tuberculosis and in some cases, flu, colds and other airborne diseases. Since research is one of the biggest concerns of causing influenza pandemics, most research surrounding aerosol contamination revolves around environmental influences on the influenza virus. Many literatures suggest that influenza is transmitted primarily through close contact, such as exposure to large respiratory droplets, direct mouth-to-mouth contact and short-term exposure to infectious aerosols. Diffusion can be accelerated or controlled by heating, ventilation and air conditioning (HVAC) systems. Researches continue that advances state of knowledge in the specific techniques that control airborne infectious disease transmission through HVAC systems, including ventilation rates, airflow regimes, filtration, and ultraviolet germicidal irradiation (UVGI). In this paper three methods of transmission of Airborne Infectious Diseases are discussed, namely through direct contact, large droplet contact, inhalation of droplet core. An extensive literature review of many papers was conducted infectious diseases spread in several different ways and the transmission of infectious viruses. This review targets direct and indirect contact as well as infectious viruses known to be transmitted from the air. And he focused on preventive ventilation systems for these targets. This paper will give idea to support further research on engineering controls to reduce infectious disease transmission.

scholarly journals Impact of Social Distancing on COVID-19 and Other Related Infectious Disease Transmission: A Systematic Review

2021 ◽  
Vol 9 (F) ◽  
pp. 601-607
Author(s):  
Nor Rumaizah Mohd Nordin ◽  
Fadly Syah Arsad ◽  
Puteri Sofia Nadira Megat Kamaruddin ◽  
Muhammad Hilmi ◽  
Mohd Faizal Madrim ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
South Korea ◽  
Disease Transmission ◽  
Research Question ◽  
Control Measures ◽  
Physical Contact ◽  
Infectious Disease Transmission ◽  
Social Distancing ◽  
The Impact

Background   Similar to other coronaviruses, COVID-19 is transmitted mainly by droplets and is highly transmissible through close proximity or physical contact with an infected person. Countries across the globe have implemented public health control measures to prevent onwards transmission and reduce burden on health care settings. Social or physical distancing was found to be one of appropriate measure based on previous experience with epidemic and pandemic contagious diseases. This study aims to review the latest evidence of the impact of social or physical distancing implemented during COVID-19 pandemic towards COVID-19 and other related infectious disease transmission.   Methodology   The study uses PRISMA review protocol and formulation of research question was based on PICO. The selected databases include Ovid MEDLINE and Scopus. Thorough identification, screening and eligibility process were done, revealed selected 8 articles. The articles then ranked in quality through MMAT.   Results   A total of eight papers included in this analysis. Five studies (USA, Canada, South Korea and the United Kingdom) showed physical distancing had resulted in a reduction in Covid-19 transmission. In comparison, three other studies (Australia, South Korea and Finland) showed a similar decline on other infectious diseases (Human Immunodeficiency Virus (HIV), other sexually transmitted infections (STI), Influenza, Respiratory Syncytial Virus (RSV) and Vaccine-Preventive Disease (VPD). The degree of the distancing policy implemented differ between strict and lenient, with both result in effectiveness in reducing transmission of infectious disease.   Conclusion   Physical or social distancing may come in the form of extreme or lenient measure in effectively containing contagious disease like COVID-19, however the stricter the measure will give more proportionate impact towards the economy, education, mental health issues, morbidity and mortality of non-COVID-19 diseases. Since we need this measure to ensure the reduction of infectious diseases transmission in order to help flattening the curve which allow much needed time for healthcare system to prepare adequately to response, ‘Precision physical distancing” can be implemented which will have more benefit towards the survival of the community as a whole.

scholarly journals Application of computer simulation in the study of infectious disease transmission mechanism

2021 ◽  
Vol 336 ◽  
pp. 06010
Author(s):  
Chengzhen Zhao ◽  
Hui Zhao ◽  
Xun liang
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
Disease Transmission ◽  
Transmission Mechanism ◽  
Dynamics Model ◽  
Infectious Disease Transmission ◽  
Testing Cost ◽  
Time Variables ◽  
And Control ◽  
Degree Of Isolation

Major infectious diseases have exerted a serious influence on people's lives. Through quantifying the effect of prevention and control, we can deeply understand the transmission mechanism of infectious diseases. This paper estimates the intensity of detection, the degree of isolation and other indicators, and analyzes the influence mechanism of these indicators on the scale of the epidemic, using computer programming to simulate the extended dynamics model of infectious diseases, based on the infectious disease in Hubei. The mortality rate and recovery rate, according to the data of Hubei, in the model are set as time variables, and the threshold is set at the same time. As a result, the improved analysis mechanism of the model will get more realistic simulation prediction results. It is concluded that isolation measures can effectively control the scale of the epidemic, but there is a phenomenon of marginal utility degression with excessively strict isolation measures by analysing and comparing. The increasing detection efforts will reduce the epidemic duration of the later stage, accelerating the arrival of the epidemic peak, although the peak will be slightly larger. All in all, we can comprehensively consider the testing cost and maintain a moderate detection intensity.

scholarly journals An open-access database of infectious disease transmission trees to explore superspreader epidemiology

2021 ◽  
Author(s):  
Juliana C. Taube ◽  
Paige B. Miller ◽  
John M. Drake
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
Disease Transmission ◽  
Emerging Infectious Diseases ◽  
Dispersion Parameter ◽  
Infectious Disease Transmission ◽  
Secondary Infections ◽  
Open Access Database ◽  
Outbreak Investigations ◽  
Outbreak Size

AbstractHistorically, emerging and re-emerging infectious diseases have caused large, deadly, and expensive multi-national outbreaks. Often outbreak investigations aim to identify who infected whom by reconstructing the outbreak transmission tree, which visualizes transmission between individuals as a network with nodes representing individuals and branches representing transmission from person to person. We compiled a database of 383 published, standardized transmission trees consisting of 16 directly-transmitted diseases ranging in size from 2 to 286 cases. For each tree and disease we calculated several key statistics, such as outbreak size, average number of secondary infections, the dispersion parameter, and the number of superspreaders. We demonstrated the potential utility of the database through short analyses addressing questions about superspreader epidemiology for a variety of diseases, including COVID-19. First, we compared the frequency and contribution of superspreaders to onward transmission across diseases. COVID-19 outbreaks had significantly fewer superspreaders than outbreaks of SARS and MERS and a dispersion parameter between that of SARS and MERS. Across diseases the presence of more superspreaders was associated with greater outbreak size. Second, we further examined how early spread impacts tree size. Generally, trees sparked by a superspreader had larger outbreak sizes than those trees not sparked by a superspreader, and this trend was significant for COVID-19 trees. Third, we investigated patterns in how superspreaders are infected. Across trees with more than one superspreader, we found support for the theory that superspreaders generate other superspreaders, even when controlling for number of secondary infections. In sum, our findings put the role of superspreading to COVID-19 transmission in perspective with that of SARS and MERS and suggest an avenue for further research on the generation of superspreaders. These data have been made openly available to encourage reuse and further scientific inquiry.Author SummaryPublic health investigations often aim to identify who infected whom, or the transmission tree, during outbreaks of infectious diseases. These investigations tend to be resource intensive but valuable as they contain epidemiological information, including the average number of infections caused by each individual and the variation in this number. To date, there remains no standardized format nor comprehensive database of infectious disease transmission trees. To fill this gap, we standardized and compiled more than 350 published transmission trees for 16 directly-transmitted diseases into a database that is publicly available. In this paper, we give an overview of the database construction process, as well as a demonstration of the types of questions that the database can be used to answer related to superspreader epidemiology. For example, we show that COVID-19 outbreaks have fewer superspreaders than outbreaks of SARS and MERS. We also find support for the theory that superspreaders generate other superspreaders. In the future, this database can be used to answer other outstanding questions in the field of epidemiology.

Adapting Disease Prevention Protocols for Human Spaceflight During COVID-19

2021 ◽  
Vol 92 (7) ◽  
pp. 597-602
Author(s):  
Eric Petersen ◽  
James M. Pattarini ◽  
Robert A. Mulcahy ◽  
Samuel B. Beger ◽  
Matthew R. Mitchell ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Disease Prevention ◽  
Infectious Diseases ◽  
Disease Transmission ◽  
Descriptive Analysis ◽  
Commercial Application ◽  
Flight Crew ◽  
Rt Pcr ◽  
Infectious Disease Transmission ◽  
Human Spaceflight

BACKGROUND: The National Aeronautics and Space Administration (NASA) Flight Crew Health Stabilization Program (HSP) was historically implemented to minimize infectious disease transmission to astronauts in the immediate prelaunch period. The first ever commercial application and adaptation of the NASA HSP was implemented during the Crew Demo-2 mission in the time of the Coronavirus disease 2019 (COVID-19) pandemic. This article details and discusses the first commercial implementation and adaptation of the HSP prior to the Crew Demo-2 launch.METHODS: This is a retrospective descriptive analysis of the application of NASA disease prevention protocols for human spaceflight during the COVID-19 pandemic. In the context of the pandemic, extra precautions added to the HSP included daily symptom surveys completed by Primary Contacts of the crew, COVID-19 RT-PCR testing, and improved quarantine protocols.RESULTS: Of the 91 SpaceX Primary Contacts who completed a total of 2720 daily symptom surveys prior to launch, 22 individuals (24.2) and 198 surveys (7.3) returned positive for potential symptoms of COVID-19. Two individuals were removed due to symptoms indistinguishable from COVID-19. Through this survey, systematic quarantine, and PCR testing, the Crew Demo-2 mission was successful with no known infectious diseases transmitted.CONCLUSIONS: Overall, the commercial implementation of the NASA Health Stabilization Program by SpaceX with adjustments required during the COVID-19 pandemic was a success, with protocols allowing identification and removal of potentially infectious persons from the program. The principles of the HSP may provide an adequate infectious disease playbook for commercial spaceflight operations going forward.Petersen E, Pattarini JM, Mulcahy RA, Beger SB, Mitchell MR, Hu YD, Middleton KN, Frazier W, Mormann B, Esparza H, Asadi A, Musk ER, Alter G, Nilles E, Menon AS. Adapting disease prevention protocols for human spaceflight during COVID-19. Aerosp Med Hum Perform. 2021; 92(7):597602.

scholarly journals Seasonal Variations and Immune Responses: Any Succor for COVID-19 Pandemic in Nigeria

2020 ◽  
Author(s):  
Adeleye Adeshakin ◽  
Oluwamuyiwa Ayanshina ◽  
Lukman Afolabi ◽  
Funmilayo Adeshakin ◽  
Ganiyu Alli-Balogun ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
Seasonal Variations ◽  
Disease Transmission ◽  
Weather Conditions ◽  
Transmission Dynamics ◽  
Infectious Disease Transmission ◽  
Healthcare Facilities ◽  
Weather Changes ◽  
The Impact

There is a global rise in the emergence of infectious diseases and the enigmatic coronavirus disease 2019 (COVID-19) being the most recent one. It is ravaging the world with little understanding of its etiology and factors affecting its transmission dynamics. Meanwhile, seasonal variations in weather are major factors impacting infectious disease transmission patterns. Developing countries are likely to be most affected by weather changes, largely because of challenges such as inadequate drainage and sewage management systems, healthcare facilities, education, and funding to efficiently mitigate infectious diseases. In Nigeria, weather conditions alternate between rainy and dry seasons. Conditions such as rainfall, flood, and humidity have been reported to influence infectious disease transmission. Thus, understanding the impact of weather changes in transmission dynamics and immune response to COVID 19 will help in preventive measures and policy making to curtail its spread most especially in Nigeria as the rainy season fully sets in.

Travel Connectivity and Infectious Disease Transmission Risks in Oceania

2020 ◽  
Author(s):  
Angela Maria Cadavid Restrepo ◽  
Luis Furuya-Kanamori ◽  
Helen Mayfield ◽  
Eric J. Nilles ◽  
Colleen L. Lau
Keyword(s):  
Infectious Disease ◽  
Disease Transmission ◽  
Infectious Disease Transmission

scholarly journals SPATIAL HETEROGENEITY IN SIMPLE DETERMINISTIC SIR MODELS ASSESSED ECOLOGICALLY

2012 ◽  
Vol 54 (1-2) ◽  
pp. 23-36 ◽  
Author(s):  
E. K. WATERS ◽  
H. S. SIDHU ◽  
G. N. MERCER
Keyword(s):  
Infectious Disease ◽  
Spatial Heterogeneity ◽  
Disease Transmission ◽  
Herd Immunity ◽  
Epidemic Models ◽  
Final Size ◽  
Infectious Disease Transmission ◽  
Epidemic Dynamics ◽  
Mean Crowding ◽  
Rate Of Movement

AbstractPatchy or divided populations can be important to infectious disease transmission. We first show that Lloyd’s mean crowding index, an index of patchiness from ecology, appears as a term in simple deterministic epidemic models of the SIR type. Using these models, we demonstrate that the rate of movement between patches is crucial for epidemic dynamics. In particular, there is a relationship between epidemic final size and epidemic duration in patchy habitats: controlling inter-patch movement will reduce epidemic duration, but also final size. This suggests that a strategy of quarantining infected areas during the initial phases of a virulent epidemic might reduce epidemic duration, but leave the population vulnerable to future epidemics by inhibiting the development of herd immunity.

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