Assessing the impact of mitigation measures on cattle movement patterns in Austria: bluetongue virus outbreaks as a case study

Outbreaks of infectious animal diseases pose significant challenges, including economic losses, animal welfare concerns, and disruptions to livestock production systems. Livestock movement is a critical transmission route during such outbreaks, and movement restrictions are commonly employed as spread mitigation measures. Understanding how such regulatory interventions affect livestock movement networks is essential for planning and implementing contingency measures and designing effective surveillance strategies. However, few studies have analyzed the interactions between network properties and regulatory perturbations during animal disease outbreaks. In this study, we assess the effects of two bluetongue outbreaks and their associated mitigation measures on the Austrian cattle movement network between 2003 and 2022. Using social network analysis and time series methods, we compare network properties using monthly cattle movement networks before, during, and after the outbreaks to identify any unexpected changes and assess network stability and variability over time. We found that the introduction of restriction zones led to temporary disruptions in network connectivity and reduced movement volumes, particularly when highly interconnected regions were separated by restriction zone boundaries. Many observed network metrics fell outside their predicted intervals shortly after the introduction of restriction zones. Subsequent measures that facilitated cattle movements, such as the establishment of a single nationwide restriction zone, vaccination of animals and vector-free periods, returned network indicators to expected levels, highlighting a notable degree of system resilience. Our findings demonstrate how network and time series analysis can be used to retrospectively evaluate the impact of regulatory interventions on livestock movement systems. The methodology presented here can assist veterinary authorities in evaluating disease outbreaks, understanding the impact of intervention measures on livestock trade, and planning future mitigation strategies. Ultimately, this approach supports veterinary authorities in effectively managing disease containment and minimizing disruption to livestock trade.