Disease outbreaks: regime
shifts & contagion
Juan Carlos Rocha & Garry Peterson
Regime shifts are abrupt reorganization of a
system’s structure and function. A regime
correspond to characteristic behavior of the
system maintained by mutually reinforcing
processes or feedbacks. The shift occurs when
the strength of such feedbacks change, usually
driven by cumulative change in slow variables,
external disturbances or shocks.
Fig. 3. Catastrophe manifold illustrating that the three types of regime shifts are special cases along a continuum of internal ecosystem
structure. Adapted from Jones and Walters (1976).
J.S. Collie et al. / Progress in Oceanography 60 (2004) 281–302 287
But disease outbreaks can be
part of the process = feedbacks!
• Classic example: Poverty traps on
• Cases where the shift occurs on
the frequency of the disturbance
lead to chaotic dynamics: strange
• The frequency of disturbance
(outbreaks - ﬁre) is partially
determined by the system’s history
• Basin boundary coalitions:
pesticides that kill natural enemies
or development of drug resistance Ngonghala et al 2014
Next Steps: Embracing the
complexity of diseases outbreaks
• Vulnerability depends on temporal and spatial
• Speed, connectivity and scale is increasing: what
does it mean for resilience?
• Frontiers of research: theory development and
evidence from case studies