The ‘breakpoint’ in transmission for soil-transmitted helminths: dynamical behaviour near the equilibria and the impact of infected human migration

AbstractBuilding on past research, we here develop an analytic framework for describing the dynamics of the transmission of soil-transmitted helminth (STH) parasitic infections near the transmission breakpoint and equilibria of endemic infection and disease extinction, while allowing for perturbations in the infectious reservoir of the parasite within a defined location. This perturbation provides a model for the effect of infected human movement between villages with differing degrees of parasite control induced by mass drug administration (MDA). Analysing the dynamical behaviour around the unstable equilibrium, known as the transmission ‘breakpoint’, we illustrate how slowly-varying the dynamics are and develop an understanding of how discrete ‘pulses’ in the release of transmission stages (eggs or larvae, depending on the species of STH), due to infected human migration between villages, can lead to perturbations in the deterministic transmission dynamics. Such perturbations are found to have the potential to undermine targets for parasite elimination as a result of MDA and/or improvements in water and sanitation provision. We extend our analysis by developing a simple stochastic model and analytically investigate the uncertainty this induces in the dynamics. Where appropriate, all analytical results are supported by numerical analyses.

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Modeling Impact of Temperature and Human Movement on the Persistence of Dengue Disease

Computational and Mathematical Methods in Medicine ◽

10.1155/2017/1747134 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Ganga Ram Phaijoo ◽

Dil Bahadur Gurung

Keyword(s):

Basic Reproduction Number ◽

Reproduction Number ◽

Human Movement ◽

Transmission Dynamics ◽

Temperature Dependent ◽

Dengue Disease ◽

Movement Rates ◽

Vector Borne ◽

Temperature Levels ◽

The Impact

Dengue is a vector-borne infectious disease endemic in many parts of the world. The disease is spreading in new places due to human movement into the dengue disease supporting areas. Temperature is the major climatic factor which affects the biological processes of the mosquitoes and their interaction with the viruses. In the present work, we propose a multipatch model to assess the impact of temperature and human movement in the transmission dynamics of dengue disease. The work consists of system of ordinary differential equations that describe the transmission dynamics of dengue disease between humans and mosquitoes. Human population is divided into four classes: susceptible, exposed, infectious, and recovered. Mosquito population is divided into three classes: susceptible, exposed, and infectious. Basic reproduction numberR0of the model is obtained using Next-Generation Matrix method. The qualitative analysis of the model is made in terms of the basic reproduction number. Parameters used in the model are considered temperature dependent. Dynamics of vector and host populations are investigated with different human movement rates and different temperature levels. Numerical results show that proper management of human movement between patches helps reducing the burden of dengue disease. It is also seen that the temperature affects the transmission dynamics of the disease significantly.

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Analyzing the Effects of Temperature and Human Movement on Malaria Disease Transmission Dynamics

10.21203/rs.3.rs-21538/v1 ◽

2020 ◽

Author(s):

Ganga Ram Phaijoo

Keyword(s):

Disease Transmission ◽

Human Movement ◽

Transmission Dynamics ◽

Vector Borne Diseases ◽

Movement Rates ◽

Anopheles Mosquitoes ◽

Vector Borne ◽

Temperature Levels ◽

Global And Local ◽

The Impact

Abstract Background: Malaria disease is transmitted by the bite of Anopheles mosquitoes. Plasmodium parasites are responsible for the disease. Due to human movement from one place to the other, vector borne diseases like malaria are spreading rapidly throughout the world. They have become major causes of morbidity and mortality worldwide. Changing temperature levels has significant impact on the life cycle, biting behavior and death rates of the mosquitoes which can transmit the disease.Methods: A multi patch SEIRS - SEI deterministic compartmental model for malaria disease is developed to study the disease transmission dynamics. The impact of temperature and human movement in transmission dynamics is investigated. Both global and local basic reproduction numbers are computed for two patches in two patch setting.Results: Disease free equilibrium is locally stable when the basic reproduction number is less than unity and unstable when the number is greater than unity. Numerical results show that the prevalence of the disease changes with the change in human movement rates between the patches; temperature affects the transmission dynamics of malaria disease.Conclusion: The burden of malaria disease can be reduced by managing the host movement between low and high disease prevalent patches. The optimal temperature for malaria disease transmission is 25 °C.

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“I think Canadians look like all sorts of people”: ethnicity, political leadership, and the case of Jagmeet Singh

The Journal of Race Ethnicity and Politics ◽

10.1017/rep.2020.51 ◽

2021 ◽

pp. 1-32

Author(s):

Joanie Bouchard

Keyword(s):

Political Behavior ◽

Political Leadership ◽

Past Research ◽

Vote Choice ◽

Party Leader ◽

Political Leaders ◽

Party Leaders ◽

Sociodemographic Profile ◽

The Impact ◽

Voting Intentions

Abstract Research into the impact of a politician's sociodemographic profile on vote choice in Westminster-style systems has been hindered by the relative sociodemographic homogeneity of party leaders. Past research has focused mainly on the evaluation of local candidates in the American context, but given that elections in plurality systems are far less candidate-oriented , the evaluation of local candidates tells us little about the prevalence of affinity or discrimination in other contexts. This article investigates the effect of political leaders' ethnicity on political behavior by looking at the case of Jagmeet Singh in Canada, the first federal party leader of color in the country's history. While the literature has shown that the gender of leaders in Canada can matter, little is known about the attitudes of Canadians toward party leaders of color specifically. We are interested in the evaluations of Singh and his party, as well as the shifts in voting intentions between elections in 2015 and 2019. We uncover affinity-based behaviors from individuals who identify as Sikh, as well as a negative reception of Singh's candidacy in Quebec.

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Variation in human mobility and its impact on the risk of future COVID-19 outbreaks in Taiwan

BMC Public Health ◽

10.1186/s12889-021-10260-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Meng-Chun Chang ◽

Rebecca Kahn ◽

Yu-An Li ◽

Cheng-Sheng Lee ◽

Caroline O. Buckee ◽

...

Keyword(s):

Disease Surveillance ◽

Initial Conditions ◽

Human Mobility ◽

Human Movement ◽

Disease Spread ◽

Spatial Spread ◽

Movement Data ◽

Intercity Travel ◽

Travel Restrictions ◽

The Impact

Abstract Background As COVID-19 continues to spread around the world, understanding how patterns of human mobility and connectivity affect outbreak dynamics, especially before outbreaks establish locally, is critical for informing response efforts. In Taiwan, most cases to date were imported or linked to imported cases. Methods In collaboration with Facebook Data for Good, we characterized changes in movement patterns in Taiwan since February 2020, and built metapopulation models that incorporate human movement data to identify the high risk areas of disease spread and assess the potential effects of local travel restrictions in Taiwan. Results We found that mobility changed with the number of local cases in Taiwan in the past few months. For each city, we identified the most highly connected areas that may serve as sources of importation during an outbreak. We showed that the risk of an outbreak in Taiwan is enhanced if initial infections occur around holidays. Intracity travel reductions have a higher impact on the risk of an outbreak than intercity travel reductions, while intercity travel reductions can narrow the scope of the outbreak and help target resources. The timing, duration, and level of travel reduction together determine the impact of travel reductions on the number of infections, and multiple combinations of these can result in similar impact. Conclusions To prepare for the potential spread within Taiwan, we utilized Facebook’s aggregated and anonymized movement and colocation data to identify cities with higher risk of infection and regional importation. We developed an interactive application that allows users to vary inputs and assumptions and shows the spatial spread of the disease and the impact of intercity and intracity travel reduction under different initial conditions. Our results can be used readily if local transmission occurs in Taiwan after relaxation of border control, providing important insights into future disease surveillance and policies for travel restrictions.

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Modelling the impact of detection on COVID-19 transmission dynamics in Ghana

RMS: Research in Mathematics & Statistics ◽

10.1080/27658449.2021.1953722 ◽

2021 ◽

Vol 8 (1) ◽

pp. 1953722

Author(s):

Josiah Mushanyu ◽

Zviiteyi Chazuka ◽

Frenick Mudzingwa ◽

Chisara Ogbogbo

Keyword(s):

Transmission Dynamics ◽

The Impact

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Meaning Matters: Self-Perceived Meaning in Life, Its Predictors and Psychological Stressors Associated with the COVID-19 Pandemic

Behavioral Sciences ◽

10.3390/bs11040050 ◽

2021 ◽

Vol 11 (4) ◽

pp. 50

Author(s):

Ashley Humphrey ◽

Olivia Vari

Keyword(s):

Life Events ◽

Meaning In Life ◽

Protective Factor ◽

Negative Life Events ◽

Past Research ◽

Coping Resources ◽

Life Meaning ◽

Life Orientation ◽

Psychological Stressors ◽

The Impact

Past research has found that a perceived meaning in life can act as a protective factor against adverse mental health symptomology, while also providing coping resources to buffer against the impact of negative life events. The current research investigated how the impact of self-perceived meaning in life as well as its predictors interact with stressors and worry related to the COVID-19 pandemic. We collected survey based data (n = 260) from Australian participants during the pandemic, measuring their meaning in life, orientation to differing life goals and COVID-19 related stressors via the impact of events scale. We found that meaning in life predicted less stress and worry associated with COVID-19. We also found that intrinsic based aspirations related positively to meaning in life within this context whereas extrinsic based goals related negatively to it, although these aspirations were not significant in reducing the stressors associated with COVID-19. These results reinforce past findings that meaning in life can effectively buffer against the impact of negative life events such as the COVID-19 pandemic. They also suggest that intrinsic based aspirations centred on relationships and self-acceptance may be an important mechanism in how people choose to pursue life meaning during uncertain life events.

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The impact of late-career job loss and genetic risk on body mass index: Evidence from variance polygenic scores

Scientific Reports ◽

10.1038/s41598-021-86716-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Lauren L. Schmitz ◽

Julia Goodwin ◽

Jiacheng Miao ◽

Qiongshi Lu ◽

Dalton Conley

Keyword(s):

Body Mass Index ◽

Body Mass ◽

Complex Traits ◽

Job Loss ◽

Past Research ◽

Long Term Effects ◽

Polygenic Scores ◽

Show Evidence ◽

Using Data ◽

The Impact

AbstractUnemployment shocks from the COVID-19 pandemic have reignited concerns over the long-term effects of job loss on population health. Past research has highlighted the corrosive effects of unemployment on health and health behaviors. This study examines whether the effects of job loss on changes in body mass index (BMI) are moderated by genetic predisposition using data from the U.S. Health and Retirement Study (HRS). To improve detection of gene-by-environment (G × E) interplay, we interacted layoffs from business closures—a plausibly exogenous environmental exposure—with whole-genome polygenic scores (PGSs) that capture genetic contributions to both the population mean (mPGS) and variance (vPGS) of BMI. Results show evidence of genetic moderation using a vPGS (as opposed to an mPGS) and indicate genome-wide summary measures of phenotypic plasticity may further our understanding of how environmental stimuli modify the distribution of complex traits in a population.

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Elucidating the Local Transmission Dynamics of Highly Pathogenic Avian Influenza H5N6 in the Republic of Korea by Integrating Phylogenetic Information

Pathogens ◽

10.3390/pathogens10060691 ◽

2021 ◽

Vol 10 (6) ◽

pp. 691

Author(s):

Dae-Sung Yoo ◽

Byungchul Chun ◽

Kyung-Duk Min ◽

Jun-Sik Lim ◽

Oun-Kyoung Moon ◽

...

Keyword(s):

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Transmission Dynamics ◽

Republic Of Korea ◽

Transmission Risk ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

The Republic ◽

The Impact ◽

Local Transmission

Highly pathogenic avian influenza (HPAI) virus is one of the most virulent and infectious pathogens of poultry. As a response to HPAI epidemics, veterinary authorities implement preemptive depopulation as a controlling strategy. However, mass culling within a uniform radius of the infection site can result in unnecessary depopulation. Therefore, it is useful to quantify the transmission distance from infected premises (IPs) before determining the optimal area for preemptive depopulation. Accordingly, we analyzed the transmission risk within spatiotemporal clusters of IPs using transmission kernel estimates derived from phylogenetic clustering information on 311 HPAI H5N6 IPs identified during the 2016–2017 epidemic, Republic of Korea. Subsequently, we explored the impact of varying the culling radius on the local transmission of HPAI given the transmission risk estimates. The domestic duck farm density was positively associated with higher transmissibility. Ring culling over a radius of 3 km may be effective for areas with high dense duck holdings, but this approach does not appear to significantly reduce the risk for local transmission in areas with chicken farms. This study provides the first estimation of the local transmission dynamics of HPAI in the Republic of Korea as well as insight into determining an effective ring culling radius.

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The Effect of Vocal Alarms on Operator Mistrust

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193120004402252 ◽

2000 ◽

Vol 44 (22) ◽

pp. 694-697

Author(s):

James P. Bliss ◽

Freida Kilpatrick

Keyword(s):

Past Research ◽

Primary Task ◽

Duty To Warn ◽

Complex Information ◽

The Impact ◽

Operator Workload

The use of alarms has increased in many operational areas because of increased reliance on automation and the duty to warn about system anomalies. Past research has supported the use of verbal alarms for relaying complex information. However, researchers have not considered the impact of vocal alarms on operator trust. In this research, 56 participants reacted to auditory alarms while performing a complex primary task. Half of the participants experienced vocal alarms, and the others experienced nonvocal alarms. Contrary to expectations, we noted that participants reacted to nonverbal alarms more quickly than verbal alarms. Furthermore, participants responded to verbal alarms more often than verbal alarms. We also noted that verbal alarms interfered with the primary task more than nonverbal alarms. We suggest that alarm designers alter verbal alarm onset algorithms during high operator workload.

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MODELING THE IMPACT OF VOLUNTARY TESTING AND TREATMENT ON TUBERCULOSIS TRANSMISSION DYNAMICS

International Journal of Biomathematics ◽

10.1142/s1793524511001726 ◽

2012 ◽

Vol 05 (04) ◽

pp. 1250029 ◽

Cited By ~ 3

Author(s):

S. MUSHAYABASA ◽

C. P. BHUNU

Keyword(s):

Deterministic Model ◽

Reproduction Number ◽

Positive Impact ◽

Transmission Dynamics ◽

Effective Control ◽

Reproductive Number ◽

Voluntary Testing ◽

Manifold Theory ◽

The Impact ◽

Disease Free

A deterministic model for evaluating the impact of voluntary testing and treatment on the transmission dynamics of tuberculosis is formulated and analyzed. The epidemiological threshold, known as the reproduction number is derived and qualitatively used to investigate the existence and stability of the associated equilibrium of the model system. The disease-free equilibrium is shown to be locally-asymptotically stable when the reproductive number is less than unity, and unstable if this threshold parameter exceeds unity. It is shown, using the Centre Manifold theory, that the model undergoes the phenomenon of backward bifurcation where the stable disease-free equilibrium co-exists with a stable endemic equilibrium when the associated reproduction number is less than unity. The analysis of the reproduction number suggests that voluntary tuberculosis testing and treatment may lead to effective control of tuberculosis. Furthermore, numerical simulations support the fact that an increase voluntary tuberculosis testing and treatment have a positive impact in controlling the spread of tuberculosis in the community.

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