A case-control study was carried out for determining epidemiological patterns at the beginning of the Mexican campaign against bovine tuberculosis (BTB) in the State of Tamaulipas, Mexico, bordering the United States of America. From January 1995 to March 1998, 599 direct tissue smears of cattle from routine slaughterhouse inspection were analyzed for the presence of Mycobacterium bovis acid-fastness with Ziehl-Neelsen stain. BTB status was associated with year of diagnosis, age, breed, geographical origin of cattle, and type of slaughterhouse using the odds ratio (OR) (95% confidence level). The prevalence at slaughterhouse surveillance was 15.36%, which was considerably higher in 1995 (41.38%, OR=5.78, P<0.0001), in comparison with 8.09%, 14.42%, and 10.14% for the years 1996, 1997, and 1998, respectively. BTB was associated with cattle from the State of Tamaulipas (19.73%, OR= 4.438, P=0.01), adult cattle (19.13%, OR=2.19, P<0.0001), Bos taurus (22.54%, OR=2.135, P<0.0001) and B. taurus x B. indicus cross bred animals (29.31%, 2.769, P<0.0001), and cattle slaughtered at federal inspected abattoir (17.58%, OR=1.23, P<0.0001).
