scholarly journals Who acquires infection from whom and how? Disentangling multi-host and multi-mode transmission dynamics in the ‘elimination’ era

2017 ◽  
Vol 372 (1719) ◽  
pp. 20160091 ◽  
Author(s):  
Joanne P. Webster ◽  
Anna Borlase ◽  
James W. Rudge
Keyword(s):  
Disease Control ◽  
Infectious Agent ◽  
Transmission Dynamics ◽  
Relative Importance ◽  
Infectious Agents ◽  
Disease Dynamics ◽  
Modes Of Transmission ◽  
Selective Pressures ◽  
And Shifts ◽  
Multi Mode

Multi-host infectious agents challenge our abilities to understand, predict and manage disease dynamics. Within this, many infectious agents are also able to use, simultaneously or sequentially, multiple modes of transmission. Furthermore, the relative importance of different host species and modes can itself be dynamic, with potential for switches and shifts in host range and/or transmission mode in response to changing selective pressures, such as those imposed by disease control interventions. The epidemiology of such multi-host, multi-mode infectious agents thereby can involve a multi-faceted community of definitive and intermediate/secondary hosts or vectors, often together with infectious stages in the environment, all of which may represent potential targets, as well as specific challenges, particularly where disease elimination is proposed. Here, we explore, focusing on examples from both human and animal pathogen systems, why and how we should aim to disentangle and quantify the relative importance of multi-host multi-mode infectious agent transmission dynamics under contrasting conditions, and ultimately, how this can be used to help achieve efficient and effective disease control. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.

scholarly journals Impact of Vaccine Failure on the Transmission Dynamics of Measles in Nigeria

2021 ◽  
Author(s):  
Ann Nwankwo ◽  
Enahoro. Iboi ◽  
Daniel Okuonghae
Keyword(s):  
Disease Control ◽  
Control Strategies ◽  
Vaccination Strategy ◽  
Fold Increase ◽  
Transmission Dynamics ◽  
Disease Dynamics ◽  
Vaccine Preventable Disease ◽  
Vaccine Failure ◽  
Vaccination Rates ◽  
Public Health Challenge

AbstractMeasles is a vaccine preventable disease. However, it is still a major public health challenge in Nigeria.We therefore formulate a mathematical model for the transmission of measles with a two dose vaccination strategy and weaning of vaccine derived immunity. Using weekly measles cases for Nigeria in 2020 from the Nigeria Center for Disease Control (NCDC), the model was validated. This modelling study via numerical simulations showed that there is a possibility of disease control with a ten fold increase in the vaccination rates. Also, it was shown that primary vaccine failure has more impact on disease dynamics than secondary vaccine failure. Thus control strategies should not just focus on increase the vaccination rates but also look at measures that will help in reducing primary vaccine failure.

scholarly journals INFECTIONS AND FOLLICULAR LYMPHOMA: IS THERE A LINK?

2017 ◽  
Vol 9 (1) ◽  
pp. e2017035
Author(s):  
Francesco Zallio ◽  
Giulia Limberti ◽  
Marco Ladetto
Keyword(s):  
Follicular Lymphoma ◽  
B Cell ◽  
Bacterial Infections ◽  
Classical Model ◽  
Infectious Agent ◽  
Epidemiological Studies ◽  
Gastric Malt Lymphoma ◽  
Infectious Agents ◽  
Non Hodgkin Lymphoma ◽  
Treatment And Prevention

Several infectious agents appear to provide a proliferative signal -- “antigen-drive” – that  could be implicated in the pathogenesis of various type of Non-Hodgkin Lymphoma (NHL). A classical model of infection-driven lymphoprolipherative disorder is Helicobacter pylori-induced gastric MALT lymphoma, where antibiotic therapy allows eradication of both the infectious agent and the clonal B-cell expansion;  following the footsteps of these example, several retrospective studies have found a correlation with other pathogens and B-cell Lymphomas, adding new important informations about pathogenesis and laying the groundwork for chemotherapy-free treatments.Although no clear association with infectious agents has yet been identified for Follicular Lymphoma (FL), a growing number of biological and clinical observations suggests that interaction with physiological and pathological microbial populations might play a role also in this subtype of lymphoma: in the last years epidemiological studies investigating the association of known risk factors and FL found a potential correlation with viral or bacterial infections; moreover recent findings about the stimulation of FL clones support the importance of microbial exposure to lymphomagenesis and disease progression.In the following review we make an attempt to find tangible evidences in favor of a role of either physiological and pathological exogenous microbial species in the pathogenesis of FL, and try to integrate the findings coming from epidemiological, biological and interventional studies to define future  novel treatment and prevention strategies for FL.

scholarly journals Predation-Driven Spillover: Pathogen Bioaccumulation in Top Predators

2020 ◽  
Author(s):  
Jennifer Malmberg ◽  
Lauren White ◽  
Sue Vandewoude
Keyword(s):  
Empirical Research ◽  
Threatened Species ◽  
Disease Risk ◽  
High Morbidity ◽  
Infectious Agents ◽  
Disease Dynamics ◽  
Sensitive Species ◽  
Predator Prey ◽  
Conservation Implications ◽  
Top Predators

Predator-prey interactions present heightened opportunities for pathogen spillover, as predators are exposed to novel parasites through consumption of prey harboring potentially infectious agents. Epizootics with high morbidity and mortality have been recorded following prey-to-predator spillover events with significant conservation implications, particularly for sensitive species. However, relatively few virulent infections following prey consumption are reported, given the very large number of exposures that presumably occur. Further, many transmitted agents are infectious but clinically silent and thus go unrecognized. Mechanisms that determine outcome of predator exposure to prey-based pathogens therefore represent an important, understudied component of disease dynamics that should be considered in modeling approaches and empirical research to better understand disease risk and emergence, particularly in vulnerable or threatened species.

scholarly journals The Causal Relationship between Eating Animals and Viral Epidemics

2020 ◽  
Vol 30 (1-6) ◽  
pp. 2-8
Author(s):  
Bhaskara L. Reddy ◽  
Milton H., Jr. Saier
Keyword(s):  
Endangered Species ◽  
Causal Relationship ◽  
Plant Virus ◽  
Prion Diseases ◽  
Infectious Agent ◽  
Vegetarian Diet ◽  
Infectious Agents ◽  
Host Organism ◽  
Animal Host ◽  
Relative Ease

For decades it has been known that infectious agents including pathogenic protozoans, bacteria, and viruses, adapted to a particular animal host, can mutate to gain the ability to infect another host, and the mechanisms involved have been studied in great detail. Although an infectious agent in one animal can alter its host range with relative ease, no example of a plant virus changing its host organism to an animal has been documented. One prevalent pathway for the transmission of infectious agents between hosts involves ingestion of the flesh of one organism by another. In this article we document numerous examples of viral and prion diseases transmitted by eating animals. We suggest that the occurrence of cross-species viral epidemics can be substantially reduced by shifting to a more vegetarian diet and enforcing stricter laws that ban the slaughter and trade of wild and endangered species.

scholarly journals Optimal control approaches for combining medicines and mosquito control in tackling dengue

2020 ◽  
Vol 7 (4) ◽  
pp. 181843 ◽  
Author(s):  
Thomas Rawson ◽  
Kym E. Wilkins ◽  
Michael B. Bonsall
Keyword(s):  
Optimal Control ◽  
Disease Control ◽  
Mosquito Control ◽  
Large Population ◽  
Human Movement ◽  
Mitigation Strategies ◽  
Disease Dynamics ◽  
Vector Ecology ◽  
Dengue Disease ◽  
The Impact

Dengue is a debilitating and devastating viral infection spread by mosquito vectors, and over half the world’s population currently live at risk of dengue (and other flavivirus) infections. Here, we use an integrated epidemiological and vector ecology framework to predict optimal approaches for tackling dengue. Our aim is to investigate how vector control and/or vaccination strategies can be best combined and implemented for dengue disease control on small networks, and whether these optimal strategies differ under different circumstances. We show that a combination of vaccination programmes and the release of genetically modified self-limiting mosquitoes (comparable to sterile insect approaches) is always considered the most beneficial strategy for reducing the number of infected individuals, owing to both methods having differing impacts on the underlying disease dynamics. Additionally, depending on the impact of human movement on the disease dynamics, the optimal way to combat the spread of dengue is to focus prevention efforts on large population centres. Using mathematical frameworks, such as optimal control, are essential in developing predictive management and mitigation strategies for dengue disease control.

Infectious animal disease and its control

1985 ◽  
Vol 310 (1144) ◽  
pp. 259-274 ◽  
Keyword(s):  
Infectious Disease ◽  
Infectious Agent ◽  
Animal Husbandry ◽  
Diagnostic Tools ◽  
Genetic Constitution ◽  
Infectious Agents ◽  
Local Farm ◽  
Technological Opportunities ◽  
Density Population ◽  
Methods Of Control

The control of infectious diseases in the main food-producing animals is considered and the main factors involved in the epizootiology of disease are presented. The properties of infectious agents and their natural history together with factors that influence the spread and development of disease are summarized. The factors in intensive animal husbandry that affect the occurrence of infectious disease and its control are considered. These include population density, population movement, management, hygiene and genetic constitution of the host. They encourage the appearance of new diseases, changes in the character of established diseases and the development of pathogenicity in infectious agents that were previously of no importance. Intensive animal husbandry has also increased the importance of multifactorial disease, which includes diseases that require more than one infectious agent or one or more infectious agents plus other factors for their cause. The methods of control of infectious disease currently available are described and the success and difficulties of their control on a global, national and local (farm or enterprise) basis are considered. Examples of diseases of global importance where national and world programmes of control and eradication have been of varying success are described. Examples of diseases that are enzootic throughout the world and the procedures used for their control are also described. The technological opportunities for the improvement of the control of infectious disease in the future are discussed. It is considered that developments in molecular biology and immunology will provide improvements in diagnostic tools and will revolutionize the development of animal resistance to disease and the production and use of vaccines.

THE ROLE OF PREDATION IN DISEASE CONTROL: A COMPARISON OF SELECTIVE AND NONSELECTIVE REMOVAL ON PRION DISEASE DYNAMICS IN DEER

2011 ◽  
Vol 47 (1) ◽  
pp. 78-93 ◽  
Author(s):  
Margaret A. Wild ◽  
N. Thompson Hobbs ◽  
Mark S. Graham ◽  
Michael W. Miller
Keyword(s):  
Disease Control ◽  
Prion Disease ◽  
Disease Dynamics

COVID-19 and Circuits of Capital

2020 ◽  
pp. 1-15 ◽  
Author(s):  
Rob Wallace ◽  
Alex Liebman ◽  
Luis Fernando Chaves ◽  
Rodrick Wallace
Keyword(s):  
Land Use ◽  
Search Engines ◽  
Clinical Course ◽  
Infectious Agent ◽  
Modes Of Transmission ◽  
Different Parts

The cause of COVID-19 and other such pathogens is not found just in the object of any one infectious agent or its clinical course, but also in the field of ecosystemic relations that capital and other structural causes have pinned back to their own advantage. The wide variety of pathogens, representing different taxa, source hosts, modes of transmission, clinical courses, and epidemiological outcomes, all the earmarks that send us running wild-eyed to our search engines upon each outbreak, mark different parts and pathways along the same kinds of circuits of land use and value accumulation.

MODELING CHOLERA TRANSMISSION UNDER DISEASE CONTROL MEASURES

2020 ◽  
pp. 1-26
Author(s):  
MARGARET BROWN ◽  
MIKO JIANG ◽  
CHAYU YANG ◽  
JIN WANG
Keyword(s):  
Disease Control ◽  
Disease Transmission ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Threshold Dynamics ◽  
Education Programs ◽  
Multiple Control ◽  
Indirect Transmission ◽  
Transmission Pathways ◽  
The Impact

We present a new mathematical model to investigate the transmission dynamics of cholera under disease control measures that include education programs and water sanitation. The model incorporates the impact of education programs into the disease transmission rates and that of water sanitation into the environmental pathogen dynamics. We conduct a detailed analysis to the autonomous system of the model and establish the local and global stabilities of its equilibria that characterize the threshold dynamics of cholera. We then perform an optimal control study on the general model with time-dependent controls and explore effective approaches to implement the education programs and water sanitation while balancing their costs. Our analysis and simulation highlight the complex interaction among the direct and indirect transmission pathways of the disease, the intrinsic growth of the environmental pathogen and the impact of multiple control measures, and their roles in collectively shaping the transmission dynamics of cholera.

Analysis of a mathematical model for the transmission dynamics of human melioidosis

2020 ◽  
Vol 13 (07) ◽  
pp. 2050062
Author(s):  
Yibeltal Adane Terefe ◽  
Semu Mitiku Kassa
Keyword(s):  
Human Population ◽  
Deterministic Model ◽  
Reproduction Number ◽  
Backward Bifurcation ◽  
Endemic Equilibrium ◽  
Transmission Dynamics ◽  
Asymptotically Stable ◽  
Disease Dynamics ◽  
Number Formula ◽  
Disease Free

A deterministic model for the transmission dynamics of melioidosis disease in human population is designed and analyzed. The model is shown to exhibit the phenomenon of backward bifurcation, where a stable disease-free equilibrium co-exists with a stable endemic equilibrium when the basic reproduction number [Formula: see text] is less than one. It is further shown that the backward bifurcation dynamics is caused by the reinfection of individuals who recovered from the disease and relapse. The existence of backward bifurcation implies that bringing down [Formula: see text] to less than unity is not enough for disease eradication. In the absence of backward bifurcation, the global asymptotic stability of the disease-free equilibrium is shown whenever [Formula: see text]. For [Formula: see text], the existence of at least one locally asymptotically stable endemic equilibrium is shown. Sensitivity analysis of the model, using the parameters relevant to the transmission dynamics of the melioidosis disease, is discussed. Numerical experiments are presented to support the theoretical analysis of the model. In the numerical experimentations, it has been observed that screening and treating individuals in the exposed class has a significant impact on the disease dynamics.

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