Review of Infective Dose, Routes of Transmission, and Outcome of COVID-19 Caused by the SARS-CoV-2 Virus: Comparison with Other Respiratory Viruses

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pandemic. Prevention and control strategies require an improved understanding of SARS-CoV-2 dynamics. We did a rapid review of the literature on SARS-CoV-2 viral dynamics with a focus on infective dose. We sought comparisons of SARS-CoV-2 with other respiratory viruses including SARS-CoV-1 and MERS-CoV. We examined laboratory animal, and human studies. The literature on infective dose, transmission, and routes of exposure was limited specially in humans, and varying endpoints were used for measurement of infection. We propose the minimum infective dose of COVID-19 in humans, is higher than 100 particles, possibly slightly lower than the 700 particles estimated for H1N1 influenza. Despite variability in animal studies, there was some evidence that increased dose at exposure correlated with higher viral load clinically, and severer symptoms. Higher viral load measures did not reflect COVID-19 severity. Aerosol transmission seemed to raise the risk of more severe respiratory complications in animals. An accurate quantitative estimate of the infective dose of SARS-CoV-2 in humans is not currently feasible and needs further research. Further work is also required on the relationship between routes of transmission, infective dose, co-infection, and outcomes.

Download Full-text

Management in the paediatric wards facing novel coronavirus infection: a rapid review of guidelines and consensuses

BMJ Open ◽

10.1136/bmjopen-2020-039897 ◽

2020 ◽

Vol 10 (8) ◽

pp. e039897

Author(s):

Wen-Yi Luo ◽

Ji-Wen Sun ◽

Wen-Lan Zhang ◽

Qian Li ◽

Ping Ni ◽

...

Keyword(s):

Control Strategies ◽

Stakeholder Involvement ◽

Rapid Review ◽

Cochrane Library ◽

China National Knowledge Infrastructure ◽

Agree Ii ◽

Relevant Evidence ◽

And Control ◽

Agree Ii Tool

ObjectivesRelevant guidelines and consensuses for COVID-19 contain recommendations aimed at optimising the management in paediatric wards. The goal of this study was to determine the quality of those recommendations and provide suggestions to hospital managers for the adjustment of existing hospital prevention and control strategies, and also to offer recommendations for further research.DesignA rapid review of the guidelines and consensuses for the management in paediatric wards facing COVID-19.MethodsPubMed, EMBASE, the Cochrane Library, UpToDate, China National Knowledge Infrastructure, the Wanfang database and relevant websites such as medlive.cn, dxy.cn, the National Health and Health Commission and the China Center for Disease Control and Prevention were systematically searched through late May 2020. The Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool was then used to assess the quality of the selected articles and summarise the relevant evidence concerning management in paediatric wards.ResultsA total of 35 articles were included, composed of 3 consensus guidelines, 25 expert consensuses and 7 expert opinions. Of the 35 papers, 24 were from China, 2 from the USA, 1 from Spain, 1 from Brazil, 1 from Saudi Arabia and 6 from multinational cooperative studies. Scores for the six domains of the AGREE II tool (scope and purpose, stakeholder involvement, rigour of development, clarity of presentation, applicability and editorial independence) were 98.57%, 53.57%, 17.92%, 69.62%, 26.96% and 50.35%, respectively. Recommendations for nosocomial infection and control, human resource management as well as management of paediatric patients and their families were summarised.ConclusionsDue to the outbreak of COVID-19, the quality of rapid guidelines and consensuses for the management in paediatric wards affected by COVID-19 is unsatisfactory. In the future, it will be necessary to develop more high-quality guidelines or consensuses for the management in paediatric wards to deal with nosocomial outbreaks in order to fully prepare for emergency medical and health problems.

Download Full-text

The relationship between microfilaraemic and amicrofilaraemic loiasis involving co-infection with Mansonella perstans and clinical symptoms in an exposed population from Gabon

Journal of Helminthology ◽

10.1017/s0022149x15000607 ◽

2015 ◽

Vol 90 (4) ◽

pp. 469-475 ◽

Cited By ~ 5

Author(s):

M.K. Bouyou Akotet ◽

M. Owono-Medang ◽

D.P. Mawili-Mboumba ◽

M.N. Moussavou-Boussougou ◽

S. Nzenze Afène ◽

...

Keyword(s):

Clinical Symptoms ◽

Control Strategies ◽

Strong Predictor ◽

Loa Loa ◽

Exposed Population ◽

Specific Objective ◽

Mansonella Perstans ◽

Worm Migration ◽

And Control ◽

The Relationship

AbstractThe relationship between the frequency of loiasis objective symptoms and microfilaraemic or amicrofilaraemic infection was assessed in 1148 exposed patients also infected, or not, with Mansonella perstans. Filarial infections were detected by direct microscopy, leucoconcentration and serology, with prevalence values of 39.5% Loa loa, 5.6% M. perstans and 3.4% co-infection with both filarial species. Amicrofilaraemic or occult loiasis (OL) predominated among L. loa-infected individuals, with a prevalence of 58.2%. Hypermicrofilaraemia (>8000 microfilariae (mf)/ml) was found in 18.4% of L. loa microfilaraemic patients, with 25.7% of them harbouring more than 30,000 mf/ml. Up to 34% of patients with OL showed evidence of Calabar swelling, compared with 26.3% of microfilaraemic patients (P= 0.03). Overall 5.3% of patients presented with adult worm migration across the eye, representing 16.3% of microfilaraemic individuals and 11.4% of amicrofilaraemic patients (P= 0.13). This symptom was similarly found in patients with more than 30,000 mf/ml (22%), those with microfilaraemia between 8 and 30,000 mf/ml (15.4%) and also in individuals with low or without microfilaraemia (16.1%) (P= 0.7). Five (14.3%) hypermicrofilaraemic patients did not present any L. loa-specific objective symptoms, as well as all the patients with single M. perstans infection. The presence of adult eye worm migration as a strong predictor of high microfilaraemia density would obscure the real burden of L. loa hypermicrofilaraemia in exposed individuals. For epidemiological purposes and control strategies, the mapping of L. loa in endemic areas should also take into account the group of patients with occult loiasis.

Download Full-text

Analysis on Electronic Differential Control Strategies of Electric Vehicle

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.562-564.1602 ◽

2012 ◽

Vol 562-564 ◽

pp. 1602-1605

Author(s):

Cheng Qun Li ◽

Cui Yu Zhou

Keyword(s):

Detailed Analysis ◽

Electric Current ◽

Electric Vehicle ◽

Control Strategies ◽

Control Process ◽

Control Torque ◽

Control Scheme ◽

Differential Control ◽

And Control ◽

The Relationship

Based on the relationship between the motor torque of each side and electric current when the electric vehicle turns, this article puts forward a control scheme of electronic differential which is used to regulate current and control torque, according to the micro electric vehicle with a double-wheel motor driven. In addition, the article makes detailed analysis for the electronic differential control process.

Download Full-text

Neural structure of a sensory decoder for motor control

10.1101/2020.10.22.350371 ◽

2020 ◽

Author(s):

Seth W. Egger ◽

Stephen G. Lisberger

Keyword(s):

Motor Control ◽

Motor Behavior ◽

Control Strategies ◽

Surprising Result ◽

Neural Responses ◽

Multiple Sources ◽

Neural Structure ◽

Sources Of Variation ◽

And Control ◽

The Relationship

ABSTRACTWe seek to understand the neural mechanisms that perform sensory decoding for motor behavior, advancing the field by designing decoders based on neural circuits. A simple experiment produced a surprising result that shapes our approach. Changing the size of a target for smooth pursuit eye movements changes the relationship between the variance and mean of the evoked behavior in a way that contradicts the regime of “signal-dependent noise” and defies traditional decoding approaches. A theoretical analysis leads us to conclude that sensory decoding circuits for pursuit include multiple parallel pathways and multiple sources of variation. Behavioral and neural responses with biomimetic statistics emerge from a biologically-motivated circuit model with noise in the pathway that is dedicated to flexibly adjusting the strength of visual-motor transmission. Flexible adjustment of transmission strength applies much more broadly to issues in sensory-motor control such as Bayesian integration and control strategies to optimize motor behavior.

Download Full-text

Initial Analysis of Viral Dynamics and Circulating Viral Variants During the mRNA-1273 Phase 3 COVE Trial

10.1101/2021.09.28.21264252 ◽

2021 ◽

Author(s):

Rolando Pajon ◽

Yamuna Paila ◽

Bethany Girard ◽

Groves Dixon ◽

Katherine Kacena ◽

...

Keyword(s):

Viral Load ◽

Severe Acute Respiratory Syndrome ◽

Copy Number ◽

Respiratory Viruses ◽

Viral Dynamics ◽

Phase 3 ◽

Viral Copy Number ◽

The Us ◽

Viral Copy ◽

The Impact

This analysis assessed the impact of mRNA-1273 vaccination on the viral dynamics of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in the ongoing Coronavirus Efficacy (COVE) trial. mRNA-1273 vaccination significantly reduced SARS-CoV-2 viral copy number (95% confidence interval [CI]) by 100-fold on the day of diagnosis (4.1 [3.4-4.8] versus placebo (6.2 [6.0-6.4] log10 copies/ml). Median times to undetectable viral copies were 4 days for mRNA-1273 and 7 for placebo. Vaccination also reduced the burden of disease and infection scores. Vaccine efficacies (95% CI) during the trial against SARS-CoV-2 variants circulating in the US were 82.4% (40.4%-94.8%) for Epsilon and Gamma, and 81.2% (36.1%-94.5%) for the Epsilon variants. The detection of other respiratory viruses during the trial was similar between groups. In those who became SARS-CoV-2 infected, the reduction of viral load after mRNA-1273 vaccination is potentially correlated to the risk of transmission, which has not been assessed in this study.

Download Full-text

Lessons Learned and Recent Advances in Dengue Research

Dengue Fever in a One Health Perspective ◽

10.5772/intechopen.92076 ◽

2020 ◽

Author(s):

Juan Samuel Sulca Herencia

Keyword(s):

Climate Change ◽

Viral Load ◽

Antiviral Activity ◽

Prevention And Control ◽

Lessons Learned ◽

New Drugs ◽

Diagnostic Assays ◽

And Control ◽

Relationship Of ◽

The Relationship

Dengue is the most important arbovirus, many research have contributed to the diagnosis, management, prevention and control of this disease, which will be described in this chapter, for example: the importance of serotypes and genotypes for the development of the disease, the relationship of the viral load between symptomatic and asymptomatic people, the influence of antibodies on the development of the disease, co-infections with microorganisms and chronic diseases, possible reservoirs, the diagnostic assays, cross-reactions in the diagnosis, the influence of climate change on the disease and the vector, mechanisms of transmission of the disease, new drugs and plant extracts with antiviral activity, the dengue vaccine, the results of immunizations, etc. This information gives a concrete idea of the advances and challenges against this disease.

Download Full-text

The Increased Densities, But Different Distributions, of Both C3 and S100A10 Immunopositive Astrocyte-Like Cells in Alzheimer’s Disease Brains Suggest Possible Roles for Both A1 and A2 Astrocytes in the Disease Pathogenesis

Brain Sciences ◽

10.3390/brainsci10080503 ◽

2020 ◽

Vol 10 (8) ◽

pp. 503

Author(s):

Andrew King ◽

Boglarka Szekely ◽

Eda Calapkulu ◽

Hanan Ali ◽

Francesca Rios ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cerebral Cortex ◽

White Matter ◽

Cell Density ◽

Animal Studies ◽

Post Mortem ◽

Disease Pathogenesis ◽

And Control ◽

The Relationship

There is increasing evidence of astrocyte dysfunction in the pathogenesis of Alzheimer’s disease (AD). Animal studies supported by human post-mortem work have demonstrated two main astrocyte types: the C3 immunopositive neurotoxic A1 astrocytes and the S100A10 immunopositive neuroprotective A2 astrocytes. A1 astrocytes predominate in AD, but the number of cases has been relatively small. We examined post-mortem brains from a larger cohort of AD cases and controls employing C3 and S100 immunohistochemistry to identify the astrocytic subtypes. There were a number of C3 immunopositive astrocyte-like cells (ASLCs) in the control cases, especially in the lower cerebral cortex and white matter. In AD this cell density appeared to be increased in the upper cerebral cortex but was similar to controls in other regions. The S100A10 showed minimal immunopositivity in the control cases in the cortex and white matter, but there was increased ASLC density in upper/lower cortex and white matter in AD compared to controls. In AD and control cases the numbers of C3 immunopositive ASLCs were greater than those for S100A10 ASLCs in all areas studied. It would appear that the relationship between A1 and A2 astrocytes and their possible role in the pathogenesis of AD is complex and requires more research.

Download Full-text

Novel Respiratory Viruses in the Context of Mass-Gathering Events: A Systematic Review to Inform Event Planning from a Health Perspective

Prehospital and Disaster Medicine ◽

10.1017/s1049023x21000662 ◽

2021 ◽

pp. 1-12

Author(s):

Jamie Ranse ◽

Deborah Beckwith ◽

Anas Khan ◽

Saber Yezli ◽

Attila J. Hertelendy ◽

...

Keyword(s):

Literature Review ◽

Prevention And Control ◽

Infection Prevention ◽

Respiratory Virus ◽

Control Strategies ◽

Respiratory Viruses ◽

Mitigation Strategies ◽

Infection Prevention And Control ◽

Mass Gathering ◽

And Control

Abstract Background: Mass-gathering events (MGEs) occur regularly throughout the world. As people congregate at MGEs, there is an increased risk of transmission of communicable diseases. Novel respiratory viruses, such as Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1), Influenza A Virus Subtype H1N1 Strain 2009 (H1N1pdm09), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), or Coronavirus Disease 2019 (COVID-19), may require specific infection prevention and control strategies to minimize the risk of transmission when planning MGEs. This literature review aimed to identify and analyze papers relating to novel respiratory viruses with pandemic potential and to inform MGE planning. Method: This paper used a systematic literature review method. Various health care databases were searched using keywords relating to MGEs and novel respiratory viruses. Information was extracted from identified papers into various tables for analysis. The analysis identified infection prevention and control strategies used at MGEs to inform planning before, during, and following events. Results: In total, 27 papers met the criteria for inclusion. No papers were identified regarding SARS-CoV-1, while the remainder reported on H1N1pdm09 (n = 9), MERS-CoV (n = 15), and SARS-CoV-2 (n = 3). Various before, during, and after event mitigation strategies were identified that can be implemented for future events. Conclusions: This literature review provided an overview of the novel respiratory virus epidemiology at MGEs alongside related public health mitigation strategies that have been implemented at these events. This paper also discusses the health security of event participants and host communities in the context of cancelling, postponing, and modifying events due to a novel respiratory virus. In particular, ways to recommence events incorporating various mitigation strategies are outlined.

Download Full-text

Knowledge, attitude and practices pertaining to healthy lifestyle in prevention and control of chronic diseases: a rapid review

International Journal of Community Medicine and Public Health ◽

10.18203/2394-6040.ijcmph20213822 ◽

2021 ◽

Vol 8 (10) ◽

pp. 5106

Author(s):

Saba Naaz

Keyword(s):

Behaviour Change ◽

Positive Attitude ◽

Healthy Lifestyle ◽

Rapid Review ◽

Change Strategies ◽

Awareness Campaigns ◽

Unhealthy Diet ◽

Epistemological Analysis ◽

And Control ◽

The Relationship

With the emergence of non-communicable diseases (NCDs), healthy lifestyle has become critical to not only reduce the burden of NCDs, but also to prevent complications and severity of these diseases. Knowledge, attitude and practices (KAP) pertaining to healthy lifestyle play an important role in determining the occurrence and progress of NCDs. KAP elements are interrelated and dependent on each other. While awareness campaigns provide necessary information to people on healthy lifestyle, how well this information is utilised is a grey area. The objective of this rapid review is to understand the relationship between KAP elements pertaining to healthy lifestyle among individuals who are at risk of developing NCDs and those who are living with NCDs. For this purpose, a rapid review of articles available on Google scholar and Pubmed was conducted. Articles focusing on KAP elements pertaining to healthy lifestyle from the year 2015-2021 were reviewed. Findings from the reviewed studies suggested that people have knowledge about the harmful effects of unhealthy diet, physical inactivity, tobacco and alcohol. People have a positive attitude towards healthy lifestyle, however, being knowledgeable and having a positive attitude did not translate into practicing healthy lifestyle due to multiple barriers to translate existing knowledge into practice. Since practice scores are poor among people, existing behaviour change strategies must be re-examined. An epistemological analysis of existing human behaviour with identified barriers and facilitators to adopt healthy lifestyle can help in formulating sustainable and effective social and behaviour change interventions.

Download Full-text