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Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem

January 1, 2007

Every winter, government agencies feed ∼6000 metric tons (6 × 106 kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed these possibilities using snowpack and feeding data from 1952 to 2006 and disease testing data from 1993 to 2006. Brucellosis seroprevalence was strongly correlated with the timing of the feeding season. Longer feeding seasons were associated with higher seroprevalence, but elk population size and density had only minor effects. In other words, the duration of host aggregation and whether it coincided with peak transmission periods was more important than just the host population size. Accurate modeling of disease transmission depends upon incorporating information on how host contact rates fluctuate over time relative to peak transmission periods. We also found that supplemental feeding seasons lasted longer during years with deeper snowpack. Therefore, milder winters and/or management strategies that reduce the length of the feeding season may reduce the seroprevalence of brucellosis in the elk populations of the southern GYE.

Publication Year 2007
Title Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem
DOI 10.1890/06-1603
Authors P.C. Cross, W.H. Edwards, B.M. Scurlock, E.J. Maichak, J.D. Rogerson
Publication Type Article
Publication Subtype Journal Article
Series Title Ecological Applications
Index ID 70030097
Record Source USGS Publications Warehouse
USGS Organization Northern Rocky Mountain Science Center