Disease control strategies can have both intended and unintended effects on the dynamics of infectious diseases. Routine testing for the harmful pathogen Bovine Tuberculosis (bTB) was suspended briefly during the foot and mouth disease epidemic of 2001 in Great Britain. Here we utilize bTB incidence data and mathematical models to demonstrate how a lapse in management can alter epidemiological parameters, including the rate of new infections and duration of infection cycles. Testing interruption shifted the dynamics from annual to 4-year cycles, and created long-lasting shifts in the spatial synchrony of new infections among regions of Great Britain. After annual testing was introduced in some GB regions, new infections have become more de-synchronised, a result also confirmed by a stochastic model. These results demonstrate that abrupt events can synchronise disease dynamics and that changes in the epidemiological parameters can lead to chaotic patterns, which are hard to be quantified, predicted, and controlled.

Faculty of Environmental Sciences Czech University of Life Sciences Prague Kamýcká 129 Praha Suchdol 165 00 Czech Republic

Institute for Applied Data Analytics Universiti Brunei Darussalam Jalan Tungku Link Gadong BE 1410 Brunei Darussalam

School of Biological Sciences Kadoorie Biological Sciences Building The University of Hong Kong Pok Fu Lam Road Hong Kong SAR China

School on Environmental Engineering Technical University of Crete Polytechnioupolis Chania 73100 Greece Department of Agriculture Technological Educational Institute of Crete Estavromenos Heraklion 71004 Greece

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