Differential susceptibility and infectivity epidemic models

We formulate differential susceptibility and differential infectivitymodels for disease transmission in this paper. The susceptibles are divided inton groups based on their susceptibilities, and the infectives are divided into mgroups according to their infectivities. Both the standard incidence and...

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Main Authors: James M. Hyman, Jia Li
Format: Article
Language:English
Published: AIMS Press 2005-10-01
Series:Mathematical Biosciences and Engineering
Subjects:
Online Access:https://www.aimspress.com/article/doi/10.3934/mbe.2006.3.89
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author James M. Hyman
Jia Li
author_facet James M. Hyman
Jia Li
author_sort James M. Hyman
collection DOAJ
description We formulate differential susceptibility and differential infectivitymodels for disease transmission in this paper. The susceptibles are divided inton groups based on their susceptibilities, and the infectives are divided into mgroups according to their infectivities. Both the standard incidence and thebilinear incidence are considered for different diseases. We obtain explicitformulas for the reproductive number. We define the reproductive numberfor each subgroup. Then the reproductive number for the entire populationis a weighted average of those reproductive numbers for the subgroups. Theformulas for the reproductive number are derived from the local stability ofthe infection-free equilibrium. We show that the infection-free equilibrium isglobally stable as the reproductive number is less than one for the models withthe bilinear incidence or with the standard incidence but no disease-induceddeath. We then show that if the reproductive number is greater than one,there exists a unique endemic equilibrium for these models. For the generalcases of the models with the standard incidence and death, conditions arederived to ensure the uniqueness of the endemic equilibrium. We also providenumerical examples to demonstrate that the unique endemic equilibrium isasymptotically stable if it exists.
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spelling doaj-art-c4f35328bda140d59aa16e747091e83c2025-01-24T01:51:11ZengAIMS PressMathematical Biosciences and Engineering1551-00182005-10-01318910010.3934/mbe.2006.3.89Differential susceptibility and infectivity epidemic modelsJames M. Hyman0Jia Li1Center for Nonlinear Studies (MS B284), Los Alamos National Laboratory, Los Alamos, NM 87545Department of Mathematical Sciences, University of Alabama in Huntsville, Huntsville, AL 35899We formulate differential susceptibility and differential infectivitymodels for disease transmission in this paper. The susceptibles are divided inton groups based on their susceptibilities, and the infectives are divided into mgroups according to their infectivities. Both the standard incidence and thebilinear incidence are considered for different diseases. We obtain explicitformulas for the reproductive number. We define the reproductive numberfor each subgroup. Then the reproductive number for the entire populationis a weighted average of those reproductive numbers for the subgroups. Theformulas for the reproductive number are derived from the local stability ofthe infection-free equilibrium. We show that the infection-free equilibrium isglobally stable as the reproductive number is less than one for the models withthe bilinear incidence or with the standard incidence but no disease-induceddeath. We then show that if the reproductive number is greater than one,there exists a unique endemic equilibrium for these models. For the generalcases of the models with the standard incidence and death, conditions arederived to ensure the uniqueness of the endemic equilibrium. We also providenumerical examples to demonstrate that the unique endemic equilibrium isasymptotically stable if it exists.https://www.aimspress.com/article/doi/10.3934/mbe.2006.3.89endemic equilibriumdifferential susceptibilityreproductive numberglobal stability.differential infectivity
spellingShingle James M. Hyman
Jia Li
Differential susceptibility and infectivity epidemic models
Mathematical Biosciences and Engineering
endemic equilibrium
differential susceptibility
reproductive number
global stability.
differential infectivity
title Differential susceptibility and infectivity epidemic models
title_full Differential susceptibility and infectivity epidemic models
title_fullStr Differential susceptibility and infectivity epidemic models
title_full_unstemmed Differential susceptibility and infectivity epidemic models
title_short Differential susceptibility and infectivity epidemic models
title_sort differential susceptibility and infectivity epidemic models
topic endemic equilibrium
differential susceptibility
reproductive number
global stability.
differential infectivity
url https://www.aimspress.com/article/doi/10.3934/mbe.2006.3.89
work_keys_str_mv AT jamesmhyman differentialsusceptibilityandinfectivityepidemicmodels
AT jiali differentialsusceptibilityandinfectivityepidemicmodels