Abstract #256

# 256
Johne’s disease and bovine tuberculosis: Updates on control and prevention.
Scott J. Wells*1, Kimberley L. VanderWaal1, Catalina Picasso1, Eva A. Enns1, Meggan Craft1, Federico Fernandez2, Andres Gil3, Julio Alvarez1, Lucas Dominguez1, Andres Perez1, 1University of Minnesota, St Paul, MN, 2Ministerio de Ganadería, Agricultura y Pesca, Montevideo, Uruguay, 3Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay.

While improved understanding of within-herd transmission of Mycobacterium avium ssp. paratuberculosis through conduct of longitudinal herd control studies has led to identification of effective long-term herd control measures, between-herd transmission continues unabated in many cattle herds through movements. Cattle movements serve as one important contributor to transmission of Mycobacterium bovis between herds, pointing to the need to better understand the role of cattle movements in disease transmission. Although complete cattle movement and traceability information is not available in the United States, the origin and destination farms for cattle movements in some countries, such as Uruguay and Spain, are captured in official cattle traceability systems. This information can be critical to understanding the risk of disease spread in the endemic cattle populations, which could be adapted to improve understanding of transmission in US cattle. In Uruguay, while the prevalence of M. bovis in cattle has been low since implementation of an active surveillance program, multiple outbreaks were reported during 2011–2013. In our study, Uruguayan cattle movements were evaluated using network analysis to understand cattle flows and identify high-risk farms for surveillance and control. Farms represented nodes in the network, which were linked based on the frequency and number of cattle moved. The distribution of in-movements and out-movements from farms was severely right-skewed, and the 10% most highly connected farms accounted for 72–83% of cattle moved each year. In comparison, during the time when bovine tuberculosis was identified in Minnesota (2008 to 2011), 20% of farms performed 90% of the movements. This heterogeneity in movement patterns indicates that some farms are likely critical for disease spread. In Uruguay, farms that experienced outbreaks of M. bovis during this period engaged in substantially more movements than the population average. Results from these studies highlight the importance of collecting livestock movement data, and of integrating and coordinating actions for infectious diseases to understand the vulnerability of livestock trade networks to infectious diseases.

Key Words: bovine tuberculosis, cattle, movement

Speaker Bio
Dr. Scott Wells is a veterinary epidemiologist and professor of Veterinary Population Medicine at the University of Minnesota.  He has experience working in private veterinary practice as well as public practice with the Centers for Epidemiology and Animal Health, USDA-APHIS-Veterinary Services.  Dr. Wells’s research interests relate to surveillance, prevention, and control of pathogens of cattle.  He is currently the Director of Academic Programs of the Center for Animal Health and Food Safety, which uses a service delivery model to improve global animal health, food safety, and public health.