Brucella abortus is a bacterial infection of cattle, bison and elk in the Greater Yellowstone Ecosystem. In multi-host systems there is often significant uncertainty about how management actions on one host species may affect others and historically there was a large focus on bison as they were the dominant reservoir of the disease. However, the disease has been increasing in prevalence in some elk herds with coincident increases in cattle outbreaks that result in trade restrictions, additional testing, and complete or partial depopulation. We review how disease research has interacted with management actions over the last 40 years.
Results/Conclusions:
Initial vaccine trials suggested that elk vaccination may be effective on the supplemental feeding grounds. The elk vaccination program was then discontinued over 30 years later due to a combination of logistical constraints and scientific evidence. Extensive research on how disease transmission among elk is related to host aggregations patterns has resulted in ongoing adaptive management trials of shorter and more dispersed feeding regimes on the feeding grounds. However, these results have not been strong enough to support broader management actions to reduce elk population size. Finally, recent whole genome sequencing of brucellosis isolates showed that isolates within Yellowstone National Park are unrelated to those elsewhere in the system suggesting that management actions targeted at bison are unlikely to translate into seroprevalence reductions in elk in other locations. We conclude with a general discussion of how, in practice, adaptive management is implemented given logistical and political constraints as well as scientific uncertainty. We hypothesize that political sensitivity is inversely correlated with the ability to conduct active adaptive management, such that the learning process may be slowest in the most publically scrutinized systems.