Should we expect population thresholds for wildlife disease?
Host population thresholds for the invasion or persistence of infectious disease are core concepts of disease ecology and underlie disease control policies based on culling and vaccination. However, empirical evidence for these thresholds in wildlife populations has been sparse, although recent studies have begun to address this gap. Here, we review the theoretical bases and empirical evidence for disease thresholds in wildlife. We see that, by their nature, these thresholds are rarely abrupt and always difficult to measure, and important facets of wildlife ecology are neglected by current theories. Empirical studies seeking to identify disease thresholds in wildlife encounter recurring obstacles of small sample sizes and confounding factors. Disease control policies based solely on threshold targets are rarely warranted, but management to reduce abundance of susceptible hosts can be effective.
Lloyd-Smith
James O
JO
Department of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley, CA 94720-3114, USA. jls@nature.berkeley.edu
Cross
Paul C
PC
Briggs
Cheryl J
CJ
Daugherty
Matt
M
Getz
Wayne M
WM
Latto
John
J
Sanchez
Maria S
MS
Smith
Adam B
AB
Swei
Andrea
A