title: Brucellosis in adult beef cattle of Mexican origin shipped direct-to-slaughter into Texas.
abstract: OBJECTIVE
  To compare prevalence estimates of brucellosis (BR) in adult beef cattle that originated from different states and regions of Mexico and that were shipped direct-to-slaughter into Texas during 1995.
  
  
  METHODS
  Epidemiologic survey.
  
  
  METHODS
  About 65,000 adult beef cattle.
  
  
  METHODS
  Blood samples were collected during postmortem examinations and were tested for serum antibodies to Brucella abortus, using the particle concentration fluorescence immunoassay and automated complement-fixation test. Prevalence estimates and 95% confidence intervals of BR were calculated by state of origin in Mexico. The difference among prevalence estimates of BR in cattle from different states and regions was tested for significance (P < 0.05), using the proportion test.
  
  
  RESULTS
  On the basis of serologic test results, the overall prevalence estimate of BR was 0.32%. The prevalence estimate of BR in cattle from the state of Chihuahua (0.10%) was significantly different than that in cattle from the states of Nuevo Leon (0.23%), Zacatecas (0.34%), Durango (0.47%), Chiapas (1.81%), Tamaulipas (2.71%), Aguascalientes (7.89%), and Campeche (12.24%). In addition, prevalence estimates of BR in cattle were significantly different among the northern (0.22%), south-central (3.18%), and south coastal (9.42%) regions of Mexico.
  
  
  CONCLUSIONS
  Results of this study indicate that the number of cattle exposed to B abortus may be significantly different among states and regions of Mexico. Current import sanitary requirements should continue to mitigate potential risk of transmission of BR from sexually intact cattle of Mexican origin to Texas cattle.
authors.affiliation: Texas Animal Health Commission, Bi-National Liaison Office, Laredo 78041, USA.
authors.forename: W H
authors.initials: WH
authors.lastname: Brown
authors.forename: J
authors.initials: J
authors.lastname: Hernández de Anda
mesh_terms: D000003:Abattoirs; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002003:Brucella abortus / Q000276:immunology; D002007:Brucellosis, Bovine / Q000453:epidemiology*; D002417:Cattle; D016001:Confidence Intervals; D008800:Mexico / Q000453:epidemiology; D015995:Prevalence; D013781:Texas; D014186:Transportation
chemical_list: D000907:Antibodies, Bacterial