scholarly journals Simulating social distancing measures in household and close contact transmission of SARS-CoV-2

2020 ◽  
Vol 36 (5) ◽  
Author(s):  
Carlos Garcia Filho
Keyword(s):  
Close Contact ◽  
Contact Rate ◽  
Rate Reduction ◽  
Agent Based ◽  
Social Distancing ◽  
Infected People ◽  
Contact Transmission ◽  
Close Contact Transmission ◽  
The Relationship ◽  
Close Contacts

We sought to evaluate contact rate reduction goals for household and close contacts and to provide preventive recommendations during the coronavirus pandemic. We applied an agent-based model to simulate the transmission dynamics of SARS-CoV-2 within household or close contacts through a social network of 150 nodes. there is no great difference in total infected people within modifications in number of links per node for networks with average number of links per node greater than three. For six nodes, total infected people are 149.85; for five nodes, 148.97; and for four nodes, 141.57. On the other hand, for three nodes, total infected are 82.39, for two nodes, 13.95; and for one node, 2.96. This model indicates a possible pitfall if social distancing measures are not stepwise suspended and close surveillance of cases are not provided, since the relationship between average links per node and number of infected people seems to be s-shaped, and not linear.

scholarly journals An evaluation of COVID-19 transmission control in Wenzhou using a modified SEIR model

2021 ◽  
Vol 149 ◽  
Author(s):  
Wenning Li ◽  
Jianhua Gong ◽  
Jieping Zhou ◽  
Lihui Zhang ◽  
Dongchuan Wang ◽  
...  
Keyword(s):  
Emergency Preparedness ◽  
Close Contact ◽  
Control Measures ◽  
Contact Tracing ◽  
Seir Model ◽  
Social Distancing ◽  
Infected People ◽  
Travel Restrictions ◽  
Developmental Characteristics ◽  
Novel Coronavirus

Abstract In December 2019, the first confirmed case of pneumonia caused by a novel coronavirus was reported. Coronavirus disease 2019 (COVID-19) is currently spreading around the world. The relationships among the pandemic and its associated travel restrictions, social distancing measures, contact tracing, mask-wearing habits and medical consultation efficiency have not yet been extensively assessed. Based on the epidemic data reported by the Health Commission of Wenzhou, we analysed the developmental characteristics of the epidemic and modified the Susceptible-Exposed-Infectious-Removed (SEIR) model in three discrete ways. (1) According to the implemented preventive measures, the epidemic was divided into three stages: initial, outbreak and controlled. (2) We added many factors, such as health protections, travel restrictions and social distancing, close-contact tracing and the time from symptom onset to hospitalisation (TSOH), to the model. (3) Exposed and infected people were subdivided into isolated and free-moving populations. For the parameter estimation of the model, the average TSOH and daily cured cases, deaths and imported cases can be obtained through individual data from epidemiological investigations. The changes in daily contacts are simulated using the intracity travel intensity (ICTI) from the Baidu Migration Big Data platform. The optimal values of the remaining parameters are calculated by the grid search method. With this model, we calculated the sensitivity of the control measures with regard to the prevention of the spread of the epidemic by simulating the number of infected people in various hypothetical situations. Simultaneously, through a simulation of a second epidemic, the challenges from the rebound of the epidemic were analysed, and prevention and control recommendations were made. The results show that the modified SEIR model can effectively simulate the spread of COVID-19 in Wenzhou. The policy of the lockdown of Wuhan, the launch of the first-level Public Health Emergency Preparedness measures on 23 January 2020 and the implementation of resident travel control measures on 31 January 2020 were crucial to COVID-19 control.

scholarly journals VAKSINASI MASAL COVID-19 DI PELABUHAN LEMBAR LOMBOK BARAT

2021 ◽  
Vol 5 (1) ◽  
pp. 404
Author(s):  
Desi Rofita ◽  
Evi Diliana Rospia ◽  
Dwi Kartika Cahyaningtyas ◽  
Catur Esty Pamungkas ◽  
Aulia Amini ◽  
...  
Keyword(s):  
World Health Organization ◽  
Close Contact ◽  
Herd Immunity ◽  
The Elderly ◽  
Health Problems ◽  
Mass Vaccination ◽  
World Health ◽  
Contact Transmission ◽  
Health Organization ◽  
Close Contact Transmission

ABSTRAKWHO (World  Health  Organization) secara  resmi  mendeklarasikan  virus  corona (Covid-19)  sebagai  pandemi. Virus Covid-19 menyebabkan gejala seperti demam dan batuk, dan kebanyakan bisa sembuh dalam beberapa minggu. Tapi bagi sebagian orang yang berisiko tinggi (kelompok lanjut  usia  dan  orang  dengan masalah  kesehatan  menahun, seperti  penyakit  jantung,  tekanan darah  tinggi,  atau diabetes), virus corona dapat menyebabkan masalah kesehatan yang serius. Ada dua  jalur  utama  penularan COVID-19, yakni penularan droplet pernapasan dan penularan kontak dekat. Dalam rangka penanggulangan pandemi COVID-19 tidak hanya dilaksanakan dari sisi penerapan protokol kesehatan, namun juga intervensi dengan vaksinasi sebagai bagian dari upaya pencegahan dan Pengendalian COVID-19. Kegiatan vaksinasi masal ini bertujuan agar dapat terbentuk herd immunity (kekebalan kelompok) dan berkurangnya angka kematian akibat COVID-19 pada masyarakat.Jenis vaksin yang digunakan pada kegiatan vaksinasi masal ini adalah Moderna. Jumlah responden yang mengikuti kegiatan ini sebanyak 1.581 orang. Hasil pengabdian didapatkan bahwa jumlah yang melakukan vaksinasi sebanyak 1.581 orang yang terdiri remaja sebanyak 60 orang dewasa sebanyak 1497 orang dan lansia sebanyak 24 orang, diberikan vaksin sebanyak 1.536 orang, ditunda sebanyak 45 orang. Kata kunci: vaksinasi; covid-19; komunitas. ABSTRACTWHO (World Health Organization) has officially declared the coronavirus (Covid-19) as a pandemic. The Covid-19 virus causes symptoms such as fever and cough, and most recover within a few weeks. But for some people who are at high risk (the elderly and people with chronic health problems, such as heart disease, high blood pressure, or diabetes), the coronavirus can cause serious health problems. There are two main routes of transmission of COVID-19, namely respiratory droplet transmission and close contact transmission. In the context of dealing with the COVID-19 pandemic, it is not only implemented in terms of implementing health protocols but also interventions with vaccinations as part of efforts to prevent and control COVID-19. This mass vaccination activity aims to form herd immunity and reduce the mortality rate due to COVID-19 in the community. The type of vaccine used in this mass vaccination activity is Moderna. The number of respondents who participated in this activity was 1,581 people. The results of the service found that the number of people who registered for Pcare was 1,581 people, consisting of 60 teenagers, 1497 adults, and 24 elderly people, 1,536 people were given the vaccine, 45 people were delayed. Keywords: vaccination; covid-19; community. 

Age-prevalence and household clustering ofStrongyloides stercoralisinfection in Jamaica

Parasitology ◽  
1995 ◽  
Vol 110 (1) ◽  
pp. 97-102 ◽  
Author(s):  
J. F. Lindo ◽  
R. D. Robinson ◽  
S. I. Terry ◽  
P. Vogel ◽  
A. A. Gam ◽  
...  
Keyword(s):  
Close Contact ◽  
Spatial Separation ◽  
Strongyloides Stercoralis ◽  
Stool Examination ◽  
Place Of Residence ◽  
General Study ◽  
Reference Case ◽  
Contact Transmission ◽  
Study Population ◽  
Close Contact Transmission

The epidemiology ofStrongyloides stercoraliswas studied in families of clinical (reference) cases and their neighbours at endemic foci in Jamaica. Thirteen foci were studied based on the place of residence of a reference case. For each household of a reference case, the 4 most proximal neighbourhood households (spatial controls) were included in the study. Out of 312 persons contacted 244 were followed up using questionnaires, stool examination and serology. Prevalence of infection based on stool examination was 3·5% and on ELISA 24·2%. Prevalence increased with age but was not related to gender. Reference cases were significantly older than the general study population. The prevalence of infection based on both serology and stool examination was significantly higher in reference than in neighbouring households (the reference cases, themselves, were not included in the analysis). Furthermore, prevalence of infection was highest among persons who shared a bedroom with a reference case and decreased significantly with increasing spatial separation. This is indicative of close contact transmission which has not been previously shown for a geohelminth, but which is common among microparasites.

scholarly journals Factors Affecting COVID-19 Transmission and Modelling of Close Contact Tracing Strategies

2021 ◽  
Author(s):  
Shahram Yazdani ◽  
Majid Heydari ◽  
Zeynab Foroughi ◽  
Hadi Jabali
Keyword(s):  
Risk Score ◽  
Close Contact ◽  
Transmission Risk ◽  
Contact Tracing ◽  
Rapid Review ◽  
Risk Scores ◽  
Virus Shedding ◽  
Factors Affecting ◽  
Contact Transmission ◽  
Close Contact Transmission

Background: Close contact tracing is an essential measure that countries are applying to combat the epidemic of COVID-19. The purpose of contact tracing is to rapidly identify potentially infected individuals and prevent further spread of the disease. In this study, based on the factors affecting the COVID-19 transmission, a scoring protocol is provided for close contact tracing. Methods: First, the factors affecting the COVID-19 transmission in close contacts were identified by a rapid review of the literature. Data were gathered by searching the Embase, PubMed, Google Scholar, and Scopus databases. Then, by formulating and scoring the identified factors with two sessions of the expert panel, close contact transmission risk score determined, and a protocol for contacts tracing was designed. Results: Close contact transmission risk depends on the contact environment characteristics, the infectivity (virus shedding) of the sentinel case, and contact characteristics. Based on these factors, the close contact transmission risk score and contact tracing protocol were prepared.   Conclusion: The close contact transmission risk scores will provide the ability to contact classifications and developing specific tracing strategies for them. Given that there are not any specific treatments for COVID-19 and lack of universal vaccination, applying nonpharmaceutical measures such as contact tracing along with physical distancing is very crucial. Therefore, we recommended this model to the evaluation of exposure risk and contact tracing.

scholarly journals Dynamics of infectious disease transmission by inhalable respiratory droplets

2010 ◽  
Vol 7 (50) ◽  
pp. 1355-1366 ◽  
Author(s):  
Nikolaos I. Stilianakis ◽  
Yannis Drossinos
Keyword(s):  
Disease Transmission ◽  
Close Contact ◽  
Droplet Diameter ◽  
Droplet Dynamics ◽  
Contact Rates ◽  
Transmission Modes ◽  
Contact Transmission ◽  
Close Contact Transmission ◽  
Respiratory Droplets

Transmission of respiratory infectious diseases in humans, for instance influenza, occurs by several modes. Respiratory droplets provide a vector of transmission of an infectious pathogen that may contribute to different transmission modes. An epidemiological model incorporating the dynamics of inhalable respiratory droplets is developed to assess their relevance in the infectious process. Inhalable respiratory droplets are divided into respirable droplets, with droplet diameter less than 10 µm, and inspirable droplets, with diameter in the range 10–100 µm: both droplet classes may be inhaled or settle. Droplet dynamics is determined by their physical properties (size), whereas population dynamics is determined by, among other parameters, the pathogen infectivity and the host contact rates. Three model influenza epidemic scenarios, mediated by different airborne or settled droplet classes, are analysed. The scenarios are distinguished by the characteristic times associated with breathing at contact and with hand-to-face contact. The scenarios suggest that airborne transmission, mediated by respirable droplets, provides the dominant transmission mode in middle and long-term epidemics, whereas inspirable droplets, be they airborne or settled, characterize short-term epidemics with high attack rates. The model neglects close-contact transmission by droplet sprays (direct projection onto facial mucous membranes), retaining close-contact transmission by inspirable droplets.

scholarly journals Anti coronavirus optimization algorithm: A socio-inspired meta-heuristic for numerical and engineering optimization problems

2021 ◽  
Author(s):  
Hojjat Emami
Keyword(s):  
Optimization Problems ◽  
Physical Distance ◽  
Test Problems ◽  
Engineering Optimization ◽  
Social Distancing ◽  
Infected People ◽  
The Social ◽  
Multi Agent ◽  
Single Objective ◽  
Close Contacts

Abstract This paper introduces a new swarm intelligence strategy, anti coronavirus optimization ( ACVO ) algorithm. This algorithm is a multi -agent strategy, in which each agent is a person that tries to stay healthy and slow down the spread of COVID -19 by observing the containment protocols. The algorithm composed of three main steps: social distancing, quarantine, and isolation. In the social distancing phase, the algorithm attempts to maintain a safe physical distance between people and limit close contacts. In the quarantine phase, the algorithm quarantines the suspected people to prevent the spread of disease. Some people who have not followed the health protocols and infected by the virus should be taken care of to get a full recovery. In the isolation phase, the algorithm cared for the infected people to recover their health. The algorithm iteratively applies these operators on the population to find the fittest and healthiest person. The proposed algorithm is evaluated on standard multi -variable single-objective optimization problems and compared with several counterpart algorithms. The results show the superiority of ACVO on most test problems compared with its counterparts.

scholarly journals The composition and dynamics of cell-substratum adhesions in locomoting fish keratocytes

1997 ◽  
Vol 110 (22) ◽  
pp. 2833-2844 ◽  
Author(s):  
J. Lee ◽  
K. Jacobson
Keyword(s):  
Close Contact ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Stress Fibers ◽  
Contact Pattern ◽  
Contact Formation ◽  
Predominant Type ◽  
Total Internal Reflection Microscopy ◽  
The Relationship ◽  
Close Contacts

Close contacts are the predominant type of cell-substratum adhesion in rapidly moving cells yet little is known about their composition and dynamics. To address these issues we have attempted to identify the molecular components of close contacts formed in rapidly moving fish epithelial keratocytes. In addition we have utilized the simple shape of keratocytes to explore the relationship between close contact formation and rapid locomotion. Beta1 integrin and talin molecules were found to be localized within a narrow rim of very close contact along the leading edge. These molecules together with vinculin were also found within small foci distributed evenly throughout the lamella, corresponding to regions of variable close contact. Alpha-actinin was found in foci within older, more posteriorly located regions of the lamella and along stress fibers. In addition to close contacts, small focal adhesion-like structures which stained positively for all antibodies tested were found at the tips of stress fibers within retracting cell margins. Interference reflection and total internal reflection microscopy of moving keratocytes showed cell-substratum contacts to be organized into distinct patterns that appear to move forwards, in concert with the leading edge. A feature common to all cells is a rim of very close contact at the leading edge. This region is specialized for the formation of new cell-substratum adhesions and is the site where patterns of close contact are generated. We have found that cell locomotion is most rapid when a uniform contact pattern is present but cell speed is progressively reduced as the contact pattern becomes more irregular. Furthermore, the local rate of lamellar extension is most rapid when underlain by regions of intermediate closeness to the substratum, but is reduced or ceases if the underlying contact is either very close or more distant, respectively. Our results suggest that close contacts and focal adhesions are related structures formed from a common hierarchy of molecular interactions. In addition the relationship between close contact formation and lamellar extension indicates a direct coupling between these two processes at the leading edge. Furthermore, we can explain the dynamic behaviour of close contacts in terms of the relative rates of trapping and release of component molecules that is initiated at the leading edge. We suggest that regulation of the molecular dynamics involved in leading edge specialization determines both the pattern of cell-substratum contacts and the net rate of actin filament assembly.

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