Short communication Prevalence of serum antibodies to Mycobacterium avium subsp. paratuberculosis in cattle in Galicia (northwest Spain) Francisco J. Die ´guez a, * , Ignacio Arnaiz b , Marı ´a L. Sanjua ´n a , Marı ´a J. Vilar a , Manuel Lo ´pez b , Eduardo Yus a a Epidemiology and Animal Health Unit, Institute of Food Analysis and Research, Santiago de Compostela University, Campus Universitario s/n, 27002 Lugo, Spain b Animal Health and Production Laboratory of Galicia, Av. Madrid 77, 27002 Lugo, Spain Received 9 January 2007; received in revised form 13 July 2007; accepted 26 August 2007 Abstract Prior to establishing a control and prevention program for Johne’s disease in cattle in Galicia (northwest Spain), a survey was conducted to estimate the prevalence of the disease. For this survey, 61,069 animals of at least 1-year of age from 2735 randomly selected herds were bled and samples analyzed with a commercial ELISA. The estimated true individual-level prevalences – assuming the manufacturer’s reported test sensitivity of 48.5% and specificity of 98.9% – were 3.02% in dairy cattle, 1.03% in beef cattle and 2.83% in animals from farms with both dairy and beef cattle. True herd prevalences (with herds declared positive if one or more animals tested positive) were 10.69% for dairy herds, 0% for beef herds and 2.71% for mixed herds. When herds were declared positive if at least two animals tested positive, true herd prevalences were 14.75% for dairy herds, 1.47% for beef herds and 12.01% for mixed herds. Assuming a higher specificity of 99.4%, true individual-level prevalences increased to 4.03% in dairy herds, 2.07% in beef herds and 3.84% in mixed herds. Herd prevalences were 27.77%/18.79%, 2.78%/2.40% and 5.70%/ 12.24% (using the one/two-animal cut-offs) in dairy, beef and mixed herds, respectively. In conclusion, these results seem to indicate that a small percentage of cows and a rather high percentage of dairy herds in this region are MAP-seropositive. # 2007 Elsevier B.V. All rights reserved. Keywords: Cattle; Johne’s disease; Prevalence www.elsevier.com/locate/prevetmed Preventive Veterinary Medicine 82 (2007) 321–326 * Corresponding author. Tel.: +34 982285858; fax: +34 982252195. E-mail address: jdieguez@lugo.usc.es (F.J. Die ´guez). 0167-5877/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.prevetmed.2007.08.006