scholarly journals Mathematical models of SIR disease spread with combined non-sexual and sexual transmission routes

2016 ◽  
Author(s):  
Joel C Miller
Keyword(s):  
Direct Contact ◽  
Sexual Transmission ◽  
Large Population ◽  
Sexual Contact ◽  
Transmission Mechanism ◽  
Disease Spread ◽  
Contact Network ◽  
Low Dimensional ◽  
Large Population Limit

AbstractThe emergence of diseases such as Zika and Ebola has highlighted the need to understand the role of sexual transmission in the spread of diseases with a primarily non-sexual transmission route. In this paper we develop a number of low-dimensional models which are appropriate for a range of assumptions for how a disease will spread if it has sexual transmission through a sexual contact network combined with some other transmission mechanism, such as direct contact or vectors. The equations derived provide exact predictions for the dynamics of the corresponding simulations in the large population limit.

scholarly journals Modeling disease spread in populations with birth, death, and concurrency

2016 ◽  
Author(s):  
Joel C. Miller ◽  
Anja C. Slim
Keyword(s):  
Stochastic Model ◽  
Large Population ◽  
Dynamic Network ◽  
Disease Spread ◽  
Initial Growth ◽  
Concurrent Partnerships ◽  
Equilibrium Size ◽  
The Impact ◽  
Concurrent Relationships

AbstractThe existence of sexual partnerships that overlap in time (concurrent relationships) is believed by some to be a significant contributing factor to the spread of HIV, although this is controversial. We derive an analytic model which allows us to investigate and compare disease spread in populations with and without concurrency. We can identify regions of parameter space in which its impact is negligible, and other regions in which it plays a major role. We also see that the impact of concurrency on the initial growth phase can be much larger than its impact on the equilibrium size. We see that the effect of concurrency saturates, which leads to the perhaps surprising conclusion that interventions targeting concurrency may be most effective in populations with low to moderate levels of concurrency.Author SummaryWe consider the spread of an infectious disease through a population modeled by a dynamic network with demographic turnover. We develop a stochastic model of the disease and derive governing equations that exactly predict the large population (deterministic) limit of the stochastic model. We use this to investigate the role of concurrency and find that interventions targeting concurrency may be most effective in populations with lower levels of concurrency.Our model is not intended to be an accurate representation of any single population. Rather it is intended to give general insights for intervention design and to provide a framework which can be further specialized to particular populations.This model is the first model to allow for analytic investigation of the impact of concurrent partnerships in a population exhibiting demographic turnover. Thus it will be useful for investigating the “concurrency hypothesis.”

scholarly journals Understanding the survival of Zika virus in a vector interconnected sexual contact network

2019 ◽  
Author(s):  
Tanvir Ferdousi ◽  
Lee W. Cohnstaedt ◽  
D. S. McVey ◽  
Caterina M. Scoglio
Keyword(s):  
Zika Virus ◽  
Sexual Transmission ◽  
Sexual Contact ◽  
Contact Network ◽  
Mosquito Vector ◽  
Mosquito Abundance ◽  
Sexually Transmitted ◽  
Modes Of Transmission ◽  
Epidemic Size ◽  
Outbreak Size

ABSTRACTThe recent outbreaks of the insect-vectored Zika virus have demonstrated its potential to be sexually transmitted, which complicates modeling and our understanding of disease dynamics. Autochthonous outbreaks in the US mainland may be a consequence of both modes of transmission, which affect the outbreak size, duration, and virus persistence. We propose a novel individual-based interconnected network model that incorporates both insect-vectored and sexual transmission of this pathogen. This model interconnects a homogeneous mosquito vector population with a heterogeneous human host contact network. The model incorporates the seasonal variation of mosquito abundance and characterizes host dynamics based on age group and gender in order to produce realistic projections. We use a sexual contact network which is generated on the basis of real world sexual behavior data. Our findings suggest that for a high relative transmissibility of asymptomatic hosts, Zika virus shows a high probability of sustaining in the human population for up to 3 months without the presence of mosquito vectors. Zika outbreaks are strongly affected by the large proportion of asymptomatic individuals and their relative transmissibility. The outbreak size is also affected by the time of the year when the pathogen is introduced. Although sexual transmission has a relatively low contribution in determining the epidemic size, it plays a role in sustaining the epidemic and creating potential endemic scenarios.

scholarly journals Molecular Analysis of Prothrombotic Gene Variants in Patients with Acute Ischemic Stroke and with Transient Ischemic Attack

Medicina ◽  
2021 ◽  
Vol 57 (7) ◽  
pp. 723
Author(s):  
Gustavo Cernera ◽  
Marika Comegna ◽  
Monica Gelzo ◽  
Marcella Savoia ◽  
Dario Bruzzese ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Causes Of Death ◽  
Southern Italy ◽  
Large Population ◽  
Mthfr C677t ◽  
Geographic Area ◽  
Gene Variants ◽  
Interesting Possibility ◽  
Ischemic Attack

Background and objectives: ischemic stroke (IS) is among the most frequent causes of death worldwide; thus, it is of paramount relevance to know predisposing factors that may help to identify and treat the high-risk subjects. Materials and Methods:we tested nine variants in genes involved in thrombotic pathway in 282 patients that experienced IS and 87 that had transient ischemic attacks (TIA) in comparison to 430 subjects from the general population (GP) of the same geographic area (southern Italy). We included cases of young and child IS to evaluate the eventual differences in the role of the analyzed variants. Results: we did not observe significant differences between TIA and the GP for any of the variants, while the allele frequencies of methylene-tetrahydrofolate reductase (MTHFR) C677T, beta-fibrinogen -455G>A and factor (FXIII) V34L were significantly higher in patients with IS than in the subjects from the GP. No significant interaction was observed with sex. Conclusions: the present data argue that some gene variants have a role in IS and this appears to be an interesting possibility to be pursued in large population studies to help design specific strategies for IS prevention.

scholarly journals The Role of Risk Preferences in Responses to Messaging About COVID-19 Vaccine Take-Up

2021 ◽  
pp. 194855062199962
Author(s):  
Jennifer S. Trueblood ◽  
Abigail B. Sussman ◽  
Daniel O’Leary
Keyword(s):  
Large Scale ◽  
Risk Preferences ◽  
Herd Immunity ◽  
Disease Spread ◽  
Short Term ◽  
Policy Makers ◽  
Health Crisis ◽  
Flu Vaccine ◽  
Nationally Representative

Development of an effective COVID-19 vaccine is widely considered as one of the best paths to ending the current health crisis. While the ability to distribute a vaccine in the short-term remains uncertain, the availability of a vaccine alone will not be sufficient to stop disease spread. Instead, policy makers will need to overcome the additional hurdle of rapid widespread adoption. In a large-scale nationally representative survey ( N = 34,200), the current work identifies monetary risk preferences as a correlate of take-up of an anticipated COVID-19 vaccine. A complementary experiment ( N = 1,003) leverages this insight to create effective messaging encouraging vaccine take-up. Individual differences in risk preferences moderate responses to messaging that provides benchmarks for vaccine efficacy (by comparing it to the flu vaccine), while messaging that describes pro-social benefits of vaccination (specifically herd immunity) speeds vaccine take-up irrespective of risk preferences. Findings suggest that policy makers should consider risk preferences when targeting vaccine-related communications.

scholarly journals Modifying the network-based stochastic SEIR model to account for quarantine: an application to COVID-19

2021 ◽  
Vol 10 (s1) ◽  
Author(s):  
Chris Groendyke ◽  
Adam Combs
Keyword(s):  
Network Model ◽  
Transmission Rate ◽  
Disease Spread ◽  
Contact Network ◽  
Model Parameters ◽  
Seir Model ◽  
Disease States ◽  
Potential Contact ◽  
The Mean ◽  
Infectious State

Abstract Objectives: Diseases such as SARS-CoV-2 have novel features that require modifications to the standard network-based stochastic SEIR model. In particular, we introduce modifications to this model to account for the potential changes in behavior patterns of individuals upon becoming symptomatic, as well as the tendency of a substantial proportion of those infected to remain asymptomatic. Methods: Using a generic network model where every potential contact exists with the same common probability, we conduct a simulation study in which we vary four key model parameters (transmission rate, probability of remaining asymptomatic, and the mean lengths of time spent in the exposed and infectious disease states) and examine the resulting impacts on various metrics of epidemic severity, including the effective reproduction number. We then consider the effects of a more complex network model. Results: We find that the mean length of time spent in the infectious state and the transmission rate are the most important model parameters, while the mean length of time spent in the exposed state and the probability of remaining asymptomatic are less important. We also find that the network structure has a significant impact on the dynamics of the disease spread. Conclusions: In this article, we present a modification to the network-based stochastic SEIR epidemic model which allows for modifications to the underlying contact network to account for the effects of quarantine. We also discuss the changes needed to the model to incorporate situations where some proportion of the individuals who are infected remain asymptomatic throughout the course of the disease.

scholarly journals Women’s Vulnerability to the Economic Crisis through the Lens of Part-time Work in Spain

2021 ◽  
pp. 095001702110012
Author(s):  
Valeria Insarauto
Keyword(s):  
Economic Crisis ◽  
Labour Supply ◽  
Labour Force ◽  
Gender Norms ◽  
Transmission Mechanism ◽  
Female Employment ◽  
Time Work ◽  
Part Time ◽  
Part Time Work

This article studies women’s vulnerability to the economic crisis of 2008 through the lens of part-time work in Spain. It posits that part-time work made the female employment position more fragile by acting as a transmission mechanism of traditional gender norms that establish women as secondary workers. This argument is tested through an analysis of Labour Force Survey data from 2007 to 2014 that examines the influence of the employment situation of the household on women’s part-time employment patterns. The results expose the limited take-up of part-time work but also persistent patterns of involuntariness and underemployment corresponding to negative household employment situations, highlighting the constraining role of gender norms borne by the relative position of part-time work in the configuration of employment structures. The article concludes that, during the crisis, part-time work participated in the re-establishment of women as a family dependent and flexible labour supply, increasing their vulnerability.

scholarly journals Detection and Sequence Analysis of Human Polyomaviruses DNA from Autoptic Samples of HIV-1 Positive and Negative Subjects

2003 ◽  
Vol 16 (3) ◽  
pp. 269-276 ◽  
Author(s):  
V. Pietropaolo ◽  
D. Fioriti ◽  
P. Simeone ◽  
M. Videtta ◽  
C. Di Taranto ◽  
...  
Keyword(s):  
Uterine Cervix ◽  
Sexual Transmission ◽  
Prostatic Urethra ◽  
Hiv Positive ◽  
Nested Polymerase Chain Reaction ◽  
Immunodeficiency Virus ◽  
Positive Subject ◽  
Coding Control ◽  
Human Polyomaviruses

The distribution of DNA of BK and JC human polyomaviruses (BKV and JCV) was investigated in samples from autopsies of different organs in 2 groups of patients: Human Immunodeficiency Virus −1 (HIV) positive and negative. Samples from various organs were analysed by a nested polymerase chain reaction (PCR) for the non-coding control and for the VP1 regions of both viruses. The results obtained showed that BKV DNA was present in both males and females with a higher prevalence in HIV-positive subject samples (spleen: 33%; kidney: 44%; brain: 22%, uterine cervix:100%; prostatic urethra: 50%). In prostatic urethra samples of HIV-positive subjects, the JCV DNA was revealed in a low percentage (33%), while it was not found at all in uterine cervix samples of both groups. The varying presence of BK and JC viral DNA in the different organs seems to reflect the different pathogenetic attitude of these viruses. JCV was mainly present in the brain (55%), confirming its typical neurotropism and its etiological role in neurological disorders found in immunodeficient patients. BKV, on the other hand, was mainly present in the kidney (44%) and in genital organs (uterine cervix: 100%; prostatic urethra: 50%) with the latter finding favouring the hypothesis of a possible sexual transmission of BKV. Furthermore, our results confirm the crucial role of the immune system in the persistence of human polyomaviruses in the host.

Intergenerational Transmission of Violence Among Substance-Abusing Chinese Parents: Roles of Detachment and Social Support

2021 ◽  
pp. 088626052110374
Author(s):  
Ruixin Cao ◽  
Hechun Li ◽  
Huiping Zhang
Keyword(s):  
Social Support ◽  
Child Abuse ◽  
Childhood Abuse ◽  
Intergenerational Transmission ◽  
Parenting Practices ◽  
Large Population ◽  
Substance Abusing ◽  
Abuse History ◽  
Intergenerational Transmission Of Violence

Despite a large population of registered people with drug addiction, child protection in substance-abusing families is a neglected issue in China. The present study aims to investigate the association between parents’ childhood abuse history and the risk of abusing their own children in substance-abusing Chinese families and also to examine the mediating role of detachment and moderating role of social support during the intergenerational transmission of abuse. A total of 173 men and 116 women were selected using cluster sampling from two compulsory drug rehabilitation centers in Jiangsu Province. Results indicated that one’s childhood abuse history was positively associated with the current perpetration of child abuse for both fathers and mothers. Detachment mediated the linkage between a history of childhood maltreatment and perpetration of child abuse in all types of abuse for both men and women except for women’s sexual abuse. Social support from family members buffered the intergenerational transmission of child abuse for fathers but not for mothers. Child maltreatment in substance-abusing families is an urgent issue that needs measures to prevent the intergenerational transmission of violence in China. Intervention programs could involve helping parents cope with their childhood abuse history through rebuilding secure attachment and facilitating social support for their parenting practices, especially for fathers.

Sukuk and monetary policy transmission in Indonesia: the role of asset price and exchange rate channels

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Suriani Suriani ◽  
M. Shabri Abd. Majid ◽  
Raja Masbar ◽  
Nazaruddin A. Wahid ◽  
Abdul Ghafar Ismail
Keyword(s):  
Monetary Policy ◽  
Exchange Rate ◽  
Interest Rates ◽  
Asset Price ◽  
Transmission Mechanism ◽  
Monetary Policy Transmission ◽  
Content Type ◽  
Policy Transmission ◽  
Monetary Policy Transmission Mechanism

Purpose The purpose of this study is to empirically analyze the role of sukuk in the monetary policy transmission mechanism through the asset price and exchange rate channels in the Indonesian economy. Design/methodology/approach Using the monthly data from January 2003 to November 2017, this study uses a multivariate vector error correction model causality framework. To examine the role of sukuk in the monetary policy transmission mechanism through the asset price channel, this study uses the variables of consumption, inflation, interest rates, economic growth and the composite stock price index. Meanwhile, to examine the role of sukuk in the monetary policy transmission mechanism through the exchange rate channel, this study used variables of inflation, interest rates, economic growth, foreign investment and exchange rate. Findings This study documented that sukuk has no causal relationship with inflation through asset price and exchange rate channels. Nevertheless, sukuk has a bidirectional causal relationship with economic growth through asset price and exchange rate channels. Sukuk is also documented to have a causal relationship with monetary policy variables of interest rate and stock prices through asset price and exchange rate channels. Finally, a unidirectional causality is recorded running from the exchange rate to sukuk in the exchange rate channel. Research limitations/implications The finding of independence of the sukuk market from interest rates provides evidence that the trading of the sukuk in Indonesia has been in harmony with the Islamic tenets. Practical implications The relevant Indonesian authorities need to enhance both domestic and global sukuk markets as part of efforts to promote the sustainability of Islamic capital market development in Indonesia. Originality/value To the best of the authors’ knowledge, this study is among the first attempts to empirically investigate the role of sukuk in monetary policy transmission through asset price and exchange rate channels in the context of the Indonesian economy.

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