An age-structured extension to the vectorial capacity model.
Abstract
BACKGROUND: Vectorial capacity and the basic reproductive number (R(0)) have been
instrumental in structuring thinking about vector-borne pathogen transmission and
how best to prevent the diseases they cause. One of the more important simplifying
assumptions of these models is age-independent vector mortality. A growing body of
evidence indicates that insect vectors exhibit age-dependent mortality, which can
have strong and varied affects on pathogen transmission dynamics and strategies for
disease prevention. METHODOLOGY/PRINCIPAL FINDINGS: Based on survival analysis we
derived new equations for vectorial capacity and R(0) that are valid for any pattern
of age-dependent (or age-independent) vector mortality and explore the behavior of
the models across various mortality patterns. The framework we present (1) lays the
groundwork for an extension and refinement of the vectorial capacity paradigm by introducing
an age-structured extension to the model, (2) encourages further research on the actuarial
dynamics of vectors in particular and the relationship of vector mortality to pathogen
transmission in general, and (3) provides a detailed quantitative basis for understanding
the relative impact of reductions in vector longevity compared to other vector-borne
disease prevention strategies. CONCLUSIONS/SIGNIFICANCE: Accounting for age-dependent
vector mortality in estimates of vectorial capacity and R(0) was most important when
(1) vector densities are relatively low and the pattern of mortality can determine
whether pathogen transmission will persist; i.e., determines whether R(0) is above
or below 1, (2) vector population growth rate is relatively low and there are complex
interactions between birth and death that differ fundamentally from birth-death relationships
with age-independent mortality, and (3) the vector exhibits complex patterns of age-dependent
mortality and R(0) ∼ 1. A limiting factor in the construction and evaluation of new
age-dependent mortality models is the paucity of data characterizing vector mortality
patterns, particularly for free ranging vectors in the field.
Type
Journal articleSubject
Age FactorsAlgorithms
Animals
Basic Reproduction Number
Communicable Diseases
Disease Vectors
Humans
Longevity
Models, Statistical
Population Dynamics
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https://hdl.handle.net/10161/14911Published Version (Please cite this version)
10.1371/journal.pone.0039479Publication Info
Novoseltsev, Vasiliy N; Michalski, Anatoli I; Novoseltseva, Janna A; Yashin, Anatoliy
I; Carey, James R; & Ellis, Alicia M (2012). An age-structured extension to the vectorial capacity model. PLoS One, 7(6). pp. e39479. 10.1371/journal.pone.0039479. Retrieved from https://hdl.handle.net/10161/14911.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Anatoli I. Yashin
Research Professor in the Social Science Research Institute

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