Date of this Version
In: Zoonotic Tuberculosis: Mycobacterium bovis and Other Pathogenic Mycobacteria, Third Edition. Edited by Charles O. Thoen, James H. Steele, and John B. Kaneene. Published 2014 by John Wiley & Sons, Inc.
The U.S. National Tuberculosis Eradication Program began in 1917 and has made great strides in reducing the prevalence of M. bovis in U.S. cattle. Sporadic cases, however, continue to be identified in beef and dairy herds and, more recently, captive cervid herds. The ultimate goal of eradication requires that disease management strategies adapt to changing risks associated with the transmission of M. bovis. This chapter describes the low level of BTB occurrence in cattle in the United States. Finding the source of infection is challenging due to the chronic nature and latent behavior of BTB in cattle and cervids, the performance of live-animal BTB tests in cattle, and the challenges associated with epidemiologic investigations. From 2001 to 2011, 92 U.S. cattle herds were affected with M. bovis. Investigation of these herds revealed several emerging challenges to the goal of BTB eradication in the United States, including changes in management practices, disease emergence in freeranging white-tailed deer and other cervids, commingling domestic cattle with infected imported animals, and limitations in the ability of tracing animals. Data in this chapter were collected by state or federal investigators and reported to the U.S. Department of Agriculture (USDA), unless otherwise noted. Most of the data refer to the period January 2001 through December 2011. Some data, however, refer to a respective federal fiscal year—October through September—or to cases that occurred before 2001.