title: A curve of thresholds governs plague epizootics in Central Asia.
abstract: A core concept of infectious disease epidemiology is the abundance threshold, below which an infection is unable to invade or persist. There have been contrasting theoretical predictions regarding the nature of this threshold for vector-borne diseases, but for infections with an invertebrate vector, it is common to assume a threshold defined by the ratio of vector and host abundances. Here, we show in contrast, both from field data and model simulations, that for plague (Yersinia pestis) in Kazakhstan, the invasion threshold quantity is based on the product of its host (Rhombomys opimus) and vector (mainly Xenopsylla spp.) abundances, resulting in a combined threshold curve with hyperbolic shape. This shape implies compensation between host and vector abundances in permitting infection, which has important implications for disease control. Realistic joint thresholds, supported by data, should promote improved understanding, prediction and management of disease occurrence in this and other vector-borne disease systems.
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, Antwerp, Belgium.
authors.forename: Jonas
authors.initials: J
authors.lastname: Reijniers
authors.forename: Stephen
authors.initials: S
authors.lastname: Davis
authors.forename: Mike
authors.initials: M
authors.lastname: Begon
authors.forename: Johan A P
authors.initials: JA
authors.lastname: Heesterbeek
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Ageyev
authors.forename: Herwig
authors.initials: H
authors.lastname: Leirs
mesh_terms: D000818:Animals; D003198:Computer Simulation; D007303:Insect Vectors; D007623:Kazakhstan / Q000453:epidemiology; D008954:Models, Biological; D009115:Muridae / Q000469:parasitology*; D010930:Plague / Q000453:epidemiology / Q000635:transmission*; D005423:Siphonaptera / Q000382:microbiology*; D015010:Yersinia pestis