Failure to identify non-bovine reservoirs of Mycobacterium bovis in a region with a history of infected dairy-cattle herds Suresh D. Pillai a,* , Kenneth W. Widmer a , Louis J. Ivey b , Kevin C. Coker c , Everett Newman c , Sonia Lingsweiler d , Daniel Baca e , Michael Kelley f , Donald S. Davis g,h , Nova J. Silvy h , L. Garry Adams g a Environmental Science Program, Texas A&M University Research Center, 1380 A&M Circle, El Paso, TX-79927, USA b Texas Animal Damage Control Service, USDA Ð APHIS Ð Wildlife Services, P.O. Box 100410, San Antonio, TX 78201-1710, USA c Texas Department of Health, 6070 Gateway East, Suite 401, El Paso, TX 79984-0428, USA d Texas Veterinary Medical Diagnostic Laboratory, College Station, TX, USA e Texas Animal Health Commission, 1716 South San Marcos Street Room #15, San Antonio, TX 78207, USA f Texas Department of Health, 1100 West 49th Street, Austin, TX 78756, USA g Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843-4467, USA h Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA Accepted 24 June 1999 Abstract The State of Texas had the most (cumulative) tuberculous cattle herds of any state in the United States during the decade ending in 1997. Of the cumulative 18 infected herds in Texas, 12 herds were concentrated in El Paso County (designated the `El Paso milkshed'). To identify whether non- bovine reservoirs were a source of Mycobacterium bovis infection of cattle in this region, an investigation was conducted on the premises of 14 dairy herds (12 tuberculous and 2 non-affected herds) between May 1995 and June 1997. None of the 670 mammalian, avian and environmental (soil, water and air) samples collected and cultured from the premises of these herds was positive for the presence of M. bovis. None of the 119 human urine samples obtained from employees of these dairies was culture positive for M. bovis. Of 124 dairy-farm workers with tuberculin skin-test results, 48 showed positive test results. There was, however, no difference in percentages of positive skin-test results between farms without, and farms having, bovine tuberculosis within the last two Preventive Veterinary Medicine 43 (2000) 53±62 * Corresponding author. Tel.: 1-915-859-9111, ext. 231; fax: 1-915-859-1078. E-mail address: s-pillai@tamu.edu (S.D. Pillai) 0167-5877/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII:S0167-5877(99)00070-7