scholarly journals Modelling the transmission dynamics of Theileria annulata: model structure and validation for the Turkish context

Parasitology ◽  
2012 ◽  
Vol 139 (4) ◽  
pp. 441-453 ◽  
Author(s):  
A. J. SUTTON ◽  
T. KARAGENC ◽  
S. BAKIRCI ◽  
H. SARALI ◽  
G. PEKEL ◽  
...  
Keyword(s):  
Compartmental Model ◽  
Tick Infestation ◽  
Theileria Annulata ◽  
Transmission Dynamics ◽  
Tick Population ◽  
Temporal Separation ◽  
Intervention Measures ◽  
Tick Attachment ◽  
Using Data ◽  
The Impact

SUMMARYA mathematical model that describes the transmission dynamics of Theileria annulata is proposed that consists of 2 host components: the Hyalomma tick population and a compartmental model of T. annulata infection in the cattle population. The model was parameterized using data describing tick infestation and the infection status of cattle in Turkey from 2006 to 2008. The tick attachment rates are highly seasonal and because of the temporal separation of infectious and susceptible ticks virtually all ticks are infected by carrier cattle, so that annual peaks of disease in cattle do not impact on infection in the Hyalomma tick population. The impact of intervention measures that target the tick population both on the host and in the environment and their impact on the transmission of T. annulata were investigated. Interventions that have a limited ‘one-off’ impact and interventions that have a more permanent impact were both considered. The results from the model show the importance of targeting ticks during the period when they have left their first host as nymphs but have yet to feed on their second host.

Integration of fuzzy logic in the SEIRD compartmental model for the analysis of intervention and transmission heterogeneity on SARS-CoV-2 transmission dynamics

2022 ◽  
Author(s):  
Zakaria Shams Siam ◽  
Rubyat Tasnuva Hasan ◽  
Hossain Ahamed ◽  
Samiya Kabir Youme ◽  
Soumik Sarker Anik ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Compartmental Model ◽  
Fuzzy Rule ◽  
Transmission Dynamics ◽  
Intervention Measures ◽  
Proposed Model ◽  
Total Death ◽  
Linguistic Intervention ◽  
Fuzzy Linguistic ◽  
Death Cases

Different epidemiological compartmental models have been presented to predict the transmission dynamics of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, we have proposed a fuzzy rule-based Susceptible-Exposed-Infectious-Recovered-Death ([Formula: see text]) compartmental model considering a new dynamic transmission possibility variable as a function of time and three different fuzzy linguistic intervention variables to delineate the intervention and transmission heterogeneity on SARS-CoV-2 viral infection. We have analyzed the datasets of active cases and total death cases of China and Bangladesh. Using our model, we have predicted active cases and total death cases for China and Bangladesh. We further presented the correspondence of different intervention measures in relaxing the transmission possibility. The proposed model delineates the correspondence between the intervention measures as fuzzy subsets and the predicted active cases and total death cases. The prediction made by our system fitted the collected dataset very well while considering different fuzzy intervention measures. The integration of fuzzy logic in the classical compartmental model also produces more realistic results as it generates a dynamic transmission possibility variable. The proposed model could be used to control the transmission of SARS-CoV-2 as it deals with the intervention and transmission heterogeneity on SARS-CoV-2 transmission dynamics.

scholarly journals Impacts of vaccination and asymptomatic testing on SARS-CoV-2 transmission dynamics in a university setting

2021 ◽  
Author(s):  
Emily J Nixon ◽  
Amy C Thomas ◽  
Daniel A Stocks ◽  
Antoine M. G. Barreaux ◽  
Gibran Hemani ◽  
...  
Keyword(s):  
Cumulative Incidence ◽  
Compartmental Model ◽  
Student Population ◽  
University Student ◽  
Vaccine Uptake ◽  
Transmission Dynamics ◽  
Testing Uptake ◽  
University Settings ◽  
The Impact ◽  
University Setting

We investigate the impact of vaccination and asymptomatic testing uptake on SARS-CoV-2 transmission in a university student population using a stochastic compartmental model. We find that the magnitude and timing of outbreaks is highly variable under different vaccine uptake levels. With low level interventions (no asymptomatic testing, 30% vaccinated), 53-71% of students become infected during the first term; with high interventions (90% using asymptomatic testing, 90% vaccinated) cumulative incidence is 7-9%, with around 80% of these cases estimated to be asymptomatic. Asymptomatic testing is most useful when vaccine uptake is low: when 30% of students are vaccinated, 90% uptake of asymptomatic testing leads to almost half the case numbers. Under high levels of vaccine uptake (70-90%), case numbers in the student population are largely driven by community importation. Our findings suggest that vaccination is critical for controlling SARS-CoV-2 transmission in university settings with asymptomatic testing being a useful supporting measure.

scholarly journals A New Extension of State-Space SIR Model to Account for Underreporting- An Application to the COVID-19 transmission in California and Florida

2020 ◽  
Author(s):  
Vishal Deo ◽  
Gurprit Grover
Keyword(s):  
State Space ◽  
Gibbs Sampling ◽  
Compartmental Model ◽  
State Space Model ◽  
Case Fatality ◽  
Sampling Procedure ◽  
Transmission Dynamics ◽  
List Type ◽  
Space Formulation ◽  
The Impact

AbstractIn the absence of sufficient testing capacity for COVID-19, a substantial number of infecteds are expected to remain undetected. Since the undetected cases are not quarantined, they are expected to transmit the infection at a much higher rate than their quarantined counterparts. That is, under the lack of extensive random testing, the actual prevalence and incidence of the SARS-CoV-2 infection may be entirely different from that being reported. Thus, it is imperative that the information on the percentage of undetected (or unreported) cases be considered while estimating the parameters and forecasting the transmission dynamics of the epidemic.In this paper, we have developed a new version of the basic susceptible-infected-removed (SIR) compartmental model, called the susceptible-infected (quarantined/ free) -recovered-deceased [SI(Q/F)RD] model, to incorporate the impact of undetected cases on the transmission dynamics of the epidemic. Further, we have presented a Dirichlet-Beta state-space formulation of the SI(Q/F)RD model for the estimation of its parameters using posterior realizations from Gibbs sampling procedure. As a demonstration, the proposed methodology is implemented to forecast the COVID-19 transmission in California and Florida.HighlightsData calibrated for underreporting using excess deaths and case fatality rate.A new extension of SIR compartmental model, called SI(Q/F)RD, is introduced.A Dirichlet-Beta state-space formulation of the SI(Q/F)RD model is developed.Gibbs sampling used to estimate the Bayesian hierarchical state-space model.Proposed methodology is applied on the COVID-19 data of California and Florida.

scholarly journals Importation of SARS-CoV-2 following the "semaine de relâche" and Québec's (Canada) COVID-19 burden - a mathematical modeling study

2020 ◽  
Author(s):  
Arnaud Godin ◽  
Yiqing Xia ◽  
David L Buckeridge ◽  
Sharmistha Mishra ◽  
Dirk Douwes-Schultz ◽  
...  
Keyword(s):  
Public Health ◽  
Mathematical Modeling ◽  
Compartmental Model ◽  
Credible Interval ◽  
Transmission Dynamics ◽  
Cumulative Number ◽  
Imported Cases ◽  
The Impact ◽  
Very High

Background: The Canadian epidemics of COVID-19 exhibit distinct early trajectories, with Québec bearing a very high initial burden. The semaine de relâche, or March break, took place two weeks earlier in Québec as compared to the rest of Canada. This event may have played a role in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to examine the role of case importation in the early transmission dynamics of SARS-CoV-2 in Québec. Methods: Using detailed surveillance data, we developed and calibrated a deterministic SEIR-type compartmental model of SARS-CoV-2 transmission. We explored the impact of altering the number of imported cases on hospitalizations. Specifically, we investigated scenarios without case importation after March break, and as scenarios where cases were imported with the same frequency/timing as neighboring Ontario. Results: A total of 1,544 and 1,150 returning travelers were laboratory-confirmed in Québec and Ontario, respectively (with symptoms onset before 2020-03-25). The cumulative number of hospitalizations could have been reduced by 55% (95% credible interval [95%CrI]: 51-59%) had no cases been imported after Québec's March break. However, had Québec experienced Ontario's number of imported cases, cumulative hospitalizations would have only been reduced by 12% (95%CrI: 8-16%). Interpretation: Our results suggest that case importation played an important role in the early spread of COVID-19 in Québec. Yet, heavy importation of SARS-CoV-2 in early March could be insufficient to resolve interprovincial heterogeneities in cumulative hospitalizations. The importance of other factors -public health preparedness, responses, and capacity- should be investigated.

scholarly journals EPIFIL: The development of an age-structured model for describing the transmission dynamics and control of lymphatic filariasis

2000 ◽  
Vol 124 (3) ◽  
pp. 529-541 ◽  
Author(s):  
R. A. NORMAN ◽  
M. S. CHAN ◽  
A. SRIVIDYA ◽  
S. P. PANI ◽  
K. D. RAMAIAH ◽  
...  
Keyword(s):  
Vector Control ◽  
Lymphatic Filariasis ◽  
Wuchereria Bancrofti ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Infection Model ◽  
Force Of Infection ◽  
Dynamics And Control ◽  
Using Data ◽  
The Impact

Mathematical models of transmission dynamics of infectious diseases provide a useful tool for investigating the impact of community based control measures. Previously, we used a dynamic (constant force-of-infection) model for lymphatic filariasis to describe observed patterns of infection and disease in endemic communities. In this paper, we expand the model to examine the effects of control options against filariasis by incorporating the impact of age structure of the human community and by addressing explicitly the dynamics of parasite transmission from and to the vector population. This model is tested using data for Wuchereria bancrofti transmitted by Culex quinquefasciatus in Pondicherry, South India. The results show that chemotherapy has a larger short-term impact than vector control but that the effects of vector control can last beyond the treatment period. In addition we compare rates of recrudescence for drugs with different macrofilaricidal effects.

scholarly journals INFEKTA—An agent-based model for transmission of infectious diseases: The COVID-19 case in Bogotá, Colombia

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245787
Author(s):  
Jonatan Gomez ◽  
Jeisson Prieto ◽  
Elizabeth Leon ◽  
Arles Rodríguez
Keyword(s):  
Infectious Diseases ◽  
Disease Transmission ◽  
Computational Models ◽  
Compartmental Model ◽  
Transmission Dynamics ◽  
Agent Based Model ◽  
Agent Based ◽  
Social Distancing ◽  
The Impact ◽  
The Town

The transmission dynamics of the coronavirus—COVID-19—have challenged humankind at almost every level. Currently, research groups around the globe are trying to figure out such transmission dynamics under special conditions such as separation policies enforced by governments. Mathematical and computational models, like the compartmental model or the agent-based model, are being used for this purpose. This paper proposes an agent-based model, called INFEKTA, for simulating the transmission of infectious diseases, not only the COVID-19, under social distancing policies. INFEKTA combines the transmission dynamic of a specific disease, (according to parameters found in the literature) with demographic information (population density, age, and genre of individuals) of geopolitical regions of the real town or city under study. Agents (virtual persons) can move, according to its mobility routines and the enforced social distancing policy, on a complex network of accessible places defined over an Euclidean space representing the town or city. The transmission dynamics of the COVID-19 under different social distancing policies in Bogotá city, the capital of Colombia, is simulated using INFEKTA with one million virtual persons. A sensitivity analysis of the impact of social distancing policies indicates that it is possible to establish a ‘medium’ (i.e., close 40% of the places) social distancing policy to achieve a significant reduction in the disease transmission.

scholarly journals Estimating effects of intervention measures on COVID-19 outbreak in Wuhan taking account of improving diagnostic capabilities using a modelling approach

2020 ◽  
Author(s):  
Jingbo Liang ◽  
Hsiang-Yu Yuan ◽  
Lindsey Wu ◽  
Dirk U. Pfeiffer
Keyword(s):  
Disease Transmission ◽  
Case Definition ◽  
Transmission Dynamics ◽  
Intervention Measures ◽  
Diagnostic Capability ◽  
Peak Transmission ◽  
Diagnostic Capabilities ◽  
The Impact ◽  
Diagnostic Criterion ◽  
Epidemiological Parameters

AbstractBackgroundAlthough by late February 2020 the COVID-19 epidemic was effectively controlled in Wuhan, China, the virus has since spread around the world and been declared a pandemic on March 11. Estimating the effects of interventions, such as transportation restrictions and quarantine measures, on the early COVID-19 transmission dynamics in Wuhan is critical for guiding future virus containment strategies. Since the exact number of COVID-19 infected cases is unknown, the number of documented cases was used by many disease transmission models to infer epidemiological parameters. However, this means that it would not be possible to adequately estimate epidemiological parameters and the effects of intervention measures, because the percentage of all infected cases that were documented changed during the first 2 months of the epidemic as a consequence of a gradually increasing diagnostic capability.MethodsTo overcome the limitations, we constructed a stochastic susceptible-exposed-infected-quarantined-recovered (SEIQR) model, accounting for intervention measures and temporal changes in the proportion of new documented infections out of total new infections, to characterize the transmission dynamics of COVID-19 in Wuhan across different stages of the outbreak. Pre-symptomatic transmission was taken into account in our model, and all epidemiological parameters were estimated using Particle Markov-chain Monte Carlo (PMCMC) method.ResultsOur model captured the local Wuhan epidemic pattern as a two-peak transmission dynamics, with one peak on February 4 and the other on February 12, 2020. The impact of intervention measures determined the timing of the first peak, leading to an 86% drop in the Re from 3.23 (95% CI, 2.22 to 4.20) to 0.45 (95% CI, 0.20 to 0.69). An improved diagnostic capability led to the second peak and a higher proportion of documented infections. Our estimated proportion of new documented infections out of the total new infections increased from 11% (95% CI 1% - 43%) to 28% (95% CI 4% - 62%) after January 26 when more detection kits were released. After the introduction of a new diagnostic criterion (case definition) on February 12, a higher proportion of daily infected cases were documented (49% (95% CI 7% - 79%)).

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Interculturalism and the Acceptance of Minority Groups

2020 ◽  
Vol 51 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Maykel Verkuyten ◽  
Kumar Yogeeswaran
Keyword(s):  
Minority Groups ◽  
Psychological Research ◽  
Survey Experiment ◽  
Social Psychological ◽  
Negative Attitudes ◽  
Positive Attitudes ◽  
Social Psychological Research ◽  
Using Data ◽  
The Impact ◽  
Situational Effect

Abstract. Multiculturalism has been criticized and rejected by an increasing number of politicians, and social psychological research has shown that it can lead to outgroup stereotyping, essentialist thinking, and negative attitudes. Interculturalism has been proposed as an alternative diversity ideology, but there is almost no systematic empirical evidence about the impact of interculturalism on the acceptance of migrants and minority groups. Using data from a survey experiment conducted in the Netherlands, we examined the situational effect of promoting interculturalism on acceptance. The results show that for liberals, but not for conservatives, interculturalism leads to more positive attitudes toward immigrant-origin groups and increased willingness to engage in contact, relative to multiculturalism.

International Remittances and Private Healthcare in Kerala, India

2020 ◽  
Vol 17 (3) ◽  
pp. 445-460
Author(s):  
Mohd Imran Khan ◽  
Valatheeswaran C.
Keyword(s):  
Instrumental Variable ◽  
Capital Investment ◽  
Healthcare Expenditure ◽  
Healthcare Services ◽  
Private Healthcare ◽  
International Remittances ◽  
Variable Approach ◽  
Using Data ◽  
The Impact ◽  
Instrumental Variable Approach

The inflow of international remittances to Kerala has been increasing over the last three decades. It has increased the income of recipient households and enabled them to spend more on human capital investment. Using data from the Kerala Migration Survey-2010, this study analyses the impact of remittance receipts on the households’ healthcare expenditure and access to private healthcare in Kerala. This study employs an instrumental variable approach to account for the endogeneity of remittances receipts. The empirical results show that remittance income has a positive and significant impact on households’ healthcare expenditure and access to private healthcare services. After disaggregating the sample into different heterogeneous groups, this study found that remittances have a greater effect on lower-income households and Other Backward Class (OBC) households but not Scheduled Caste (SC) and Scheduled Tribe (ST) households, which remain excluded from reaping the benefit of international migration and remittances.

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