scholarly journals Flying ticks: anciently evolved associations that constitute a risk of infectious disease spread

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
José de la Fuente ◽  
Agustín Estrada-Peña ◽  
Alejandro Cabezas-Cruz ◽  
Ricardo Brey
2021 ◽  
Vol 3 (2) ◽  
pp. 114-126
Author(s):  
Sudi Mungkasi

We consider a SEIR model for the spread (transmission) of an infectious disease. The model has played an important role due to world pandemic disease spread cases. Our contributions in this paper are three folds. Our first contribution is to provide successive approximation and variational iteration methods to obtain analytical approximate solutions to the SEIR model. Our second contribution is to prove that for solving the SEIR model, the variational iteration and successive approximation methods are identical when we have some particular values of Lagrange multipliers in the variational iteration formulation. Third, we propose a new multistage-analytical method for solving the SEIR model. Computational experiments show that the successive approximation and variational iteration methods are accurate for small size of time domain. In contrast, our proposed multistage-analytical method is successful to solve the SEIR model very accurately for large size of time domain. Furthermore, the order of accuracy of the multistage-analytical method can be made higher simply by taking more number of successive iterations in the multistage evolution.


Author(s):  
Michael Schwartz ◽  
Paul Oppold ◽  
Boniface Noyongoyo ◽  
Peter Hancock

The current pandemic has tested systems in place as to how to fight infectious diseases in many countries. COVID-19 spreads quickly and is deadly. However, it can be controlled through different measures such as physical distancing. The current project examines through simulation model of the UCF Global building the potential spread of an infectious disease via AnyLogic Personal Learning Edition (PLE) 8.7.0 on a laptop running Windows 10. The goal is to determine the environmental and interpersonal factors that could be modified to reduce risk of illness while maintaining typical business operations. Multiple experiments were ran to see when there is a potential change in infection and spread rate. Results show that increases occur with density between 400 and 500. To curtail the spread it is therefore important to limit contact through physical distancing for it has been proven an effective measure for reducing the spread of viral infections.


2018 ◽  
Vol 285 (1893) ◽  
pp. 20182201 ◽  
Author(s):  
Nele Goeyvaerts ◽  
Eva Santermans ◽  
Gail Potter ◽  
Andrea Torneri ◽  
Kim Van Kerckhove ◽  
...  

Airborne infectious diseases such as influenza are primarily transmitted from human to human by means of social contacts, and thus easily spread within households. Epidemic models, used to gain insight into infectious disease spread and control, typically rely on the assumption of random mixing within households. Until now, there has been no direct empirical evidence to support this assumption. Here, we present the first social contact survey specifically designed to study contact networks within households. The survey was conducted in Belgium (Flanders and Brussels) from 2010 to 2011. We analysed data from 318 households totalling 1266 individuals with household sizes ranging from two to seven members. Exponential-family random graph models (ERGMs) were fitted to the within-household contact networks to reveal the processes driving contact between household members, both on weekdays and weekends. The ERGMs showed a high degree of clustering and, specifically on weekdays, decreasing connectedness with increasing household size. Furthermore, we found that the odds of a contact between older siblings and between father and child are smaller than for any other pair. The epidemic simulation results suggest that within-household contact density is the main driver of differences in epidemic spread between complete and empirical-based household contact networks. The homogeneous mixing assumption may therefore be an adequate characterization of the within-household contact structure for the purpose of epidemic simulations. However, ignoring the contact density when inferring based on an epidemic model will result in biased estimates of within-household transmission rates. Further research regarding the implementation of within-household contact networks in epidemic models is necessary.


Author(s):  
Erasmos Charamba

The year 2019 saw the emergence of COVID-19, an infectious disease spread through human-to-human transmission. This resulted in the immediate worldwide suspension of contact classes as countries tried to contain the wide spread of the pandemic. Consequently, educational institutions were thus left with only one option: e-learning. E-learning is the delivery of learning experiences through the use of electronic mail, the internet, the world wide web, and it can either be synchronous or asynchronous. Through the translanguaging lens, this chapter reports on a qualitative study that sought to explore the crucial role language plays in the e-learning of multilingual science students at a secondary school in South Africa. The e-learning lessons were in the form of videos, multilingual glossaries, and narrated slides in English and isiZulu languages. Data was collected through lesson observations and interviews held via Microsoft Teams. This chapter suggests numerous cognitive and socio-cultural benefits of multilingual e-learning pedagogy and recommends its use in education.


Parasitology ◽  
2013 ◽  
Vol 141 (5) ◽  
pp. 652-661 ◽  
Author(s):  
PETRA GANAS ◽  
BARBARA JASKULSKA ◽  
BECKI LAWSON ◽  
MARKO ZADRAVEC ◽  
MICHAEL HESS ◽  
...  

SUMMARYIn recent years,Trichomonas gallinaeemerged as the causative agent of an infectious disease of passerine birds in Europe leading to epidemic mortality of especially greenfinchesChloris chlorisand chaffinchesFringilla coelebs. After the appearance of finch trichomonosis in the UK and Fennoscandia, the disease spread to Central Europe. Finch trichomonosis first reached Austria and Slovenia in 2012. In the present study the genetic heterogeneity ofT. gallinaeisolates from incidents in Austria and Slovenia were investigated and compared with British isolates. For this purpose comparative sequence analyses of the four genomic loci ITS1-5.8S-ITS2, 18S rRNA,rpb1and Fe-hydrogenase were performed. The results corroborate that one clonalT. gallinaestrain caused the emerging infectious disease within passerine birds and that the disease is continuing to spread in Europe. The same clonal strain was also found in a columbid bird from Austria. Additionally, the present study demonstrates clearly the importance of multi-locus sequence typing for discrimination of circulatingT. gallinaestrains.


2018 ◽  
Author(s):  
David Manheim

AbstractThe potential for an infectious disease outbreak that is much worse than those which have been observed in human history, whether engineered or natural, has been the focus of significant concern in biosecurity. Fundamental dynamics of disease spread make such outbreaks much less likely than they first appear. Here we present a slightly modified formulation of the typical SEIR model that illustrates these dynamics more clearly, and shows the unlikely cases where concern may still be warranted. This is then applied to an extreme version of proposed pandemic risk, multi-disease syndemics, to show that (absent much clearer reasons for concern) the suggested dangers are overstated.The models used in this paper are available here: https://github.com/davidmanheim/Infectious-Disease-Models


2020 ◽  
Author(s):  
Melissa B. Meierhofer ◽  
Thomas M. Lilley ◽  
Lasse Ruokolainen ◽  
Joseph S. Johnson ◽  
Steven Parratt ◽  
...  

AbstractPredicting the emergence and spread of infectious diseases is critical for effective conservation of biodiversity. White-nose syndrome (WNS), an emerging infectious disease of bats, has resulted in high mortality in eastern North America. Because the fungal causative agent Pseudogymnoascus destructans is constrained by temperature and humidity, spread dynamics may vary greatly by geography. Environmental conditions in the southern part of the continent, where disease dynamics are typically studied, making it difficult to predict how the disease will manifest. Herein, we modeled the spread of WNS in Texas based on available cave densities and average dispersal distances of species occupying these sites, and projected these results out to 10 years. We parameterized a predictive model of WNS epidemiology and its effects on hibernatory bat populations with observed environmental data from bat hibernation sites in Texas. Our model suggests that bat populations in northern Texas will be more affected by WNS mortality than southern Texas. As such, we recommend prioritizing the preservation of large overwintering colonies of bats in north Texas through management actions. Our model further illustrates that infectious disease spread and infectious disease severity can become uncoupled over a gradient of environmental variation. Finally, our results highlight the importance of understanding host, pathogen and environmental conditions in various settings to elucidate what may happen across a breadth of environments.


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