Title: Emergence and growth of plague foci in africa
Authors: Leirs, Herwig
Neerinckx, Simon
Laudisoit, Anne
Makundi, Rhodes H #
Issue Date: Feb-2010
Publisher: Mary ann liebert inc
Host Document: Vector-borne and zoonotic diseases vol:10 issue:1 pages:97-97
Conference: Symposium on the Ecology of Plague and Its Effects on Wildlife location:Fort Collins date:4-6 November 2009
Abstract: Plague is globally distributed but in most cases occurs locally in relatively small areas.
These areas are linked to enzootic foci that seem to be stable and from where plague
rarely moves away. This is remarkable for a disease which through history has become
iconic for a rapidly spreading infection travelling over large distances. It is usually
assumed that ecological conditions determine local persistence and that human movements
are responsible for long-range spreading. Well established plague foci exist in
eastern Africa. Their borders are fairly well documented but the underlying ecology for
their persistence remains unsure. Ecological Niche Modelling (ENM) suggests that
plague foci are found in highly diverse ecological conditions, and hence predict enormous
areas where plague could occur, but nevertheless also equally large areas where
plague is unlikely to persist. At a regional scale, predictions show more patchy patterns
that are confirmed by recently emerged epidemic areas and observations of plague
infected rodents in the absence of human plague. The ecological mechanisms that are
responsible for these patterns remain elusive, however, and the niche dimensions selected
in the ENMare not easy to interpret.At the local scale, assemblages of rodents and
fleas may differ in a complex way between sites with high and low plague incidence but
patterns seem to differ between separate foci. As a result, it is extremely hard to convincingly
explain the patchy distribution of plague, or to predict how focimay change or
where they could emerge. Anthropogenic spreading of the infection may play a role but
is certainly not sufficient for the establishment of foci, as illustrated by the numerous
outbreaks along Africa’s coast that did not result in the persistent infection of local
rodent populations. Climatic factors have been shown in several studies to have an effect
on the temporal variation in plague transmission in an area, and therefore it has been
suggested that climate change would also affect the spatial characteristics of the foci.
Data to support this are mostly lacking, but we make attempts to see whether climate
variation can be linked to the growing foci in northeastern R.D.Congo, or the emergent
foci of Mbulu and Karatu in Tanzania. Based on the available information, we make a
hesitant prediction of areas and situations where plague foci could emerge or grow, with
the explicit warning that for now, such predictions must still be used as the testing of
hypotheses rather than practical instruments for public health.
ISSN: 1530-3667
Publication status: published
KU Leuven publication type: IMa
Appears in Collections:Division Soil and Water Management
# (joint) last author

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