title: High prevalence of bovine tuberculosis in dairy cattle in central ethiopia: implications for the dairy industry and public health.
abstract: BACKGROUND
  Ethiopia has the largest cattle population in Africa. The vast majority of the national herd is of indigenous zebu cattle maintained in rural areas under extensive husbandry systems. However, in response to the increasing demand for milk products and the Ethiopian government's efforts to improve productivity in the livestock sector, recent years have seen increased intensive husbandry settings holding exotic and cross breeds. This drive for increased productivity is however threatened by animal diseases that thrive under intensive settings, such as bovine tuberculosis (BTB), a disease that is already endemic in Ethiopia.
  
  
  RESULTS
  An extensive study was conducted to: estimate the prevalence of BTB in intensive dairy farms in central Ethiopia; identify associated risk factors; and characterize circulating strains of the causative agent, Mycobacterium bovis. The comparative intradermal tuberculin test (CIDT), questionnaire survey, post-mortem examination, bacteriology, and molecular typing were used to get a better understanding of the BTB prevalence among dairy farms in the study area. Based on the CIDT, our findings showed that around 30% of 2956 tested dairy cattle from 88 herds were positive for BTB while the herd prevalence was over 50%. Post-mortem examination revealed gross tuberculous lesions in 34/36 CIDT positive cattle and acid-fast bacilli were recovered from 31 animals. Molecular typing identified all isolates as M. bovis and further characterization by spoligotyping and MIRU-VNTR typing indicated low strain diversity within the study area.
  
  
  CONCLUSIONS
  This study showed an overall BTB herd prevalence of 50% in intensive dairy farms in Addis Ababa and surroundings, signalling an urgent need for intervention to control the disease and prevent zoonotic transmission of M. bovis to human populations consuming dairy products coming from these farms. It is suggested that government and policy makers should work together with stakeholders to design methods for the control of BTB in intensive farms in Ethiopia.
authors.affiliation: Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
authors.forename: Rebuma
authors.initials: R
authors.lastname: Firdessa
authors.forename: Rea
authors.initials: R
authors.lastname: Tschopp
authors.forename: Alehegne
authors.initials: A
authors.lastname: Wubete
authors.forename: Melaku
authors.initials: M
authors.lastname: Sombo
authors.forename: Elena
authors.initials: E
authors.lastname: Hailu
authors.forename: Girume
authors.initials: G
authors.lastname: Erenso
authors.forename: Teklu
authors.initials: T
authors.lastname: Kiros
authors.forename: Lawrence
authors.initials: L
authors.lastname: Yamuah
authors.forename: Martin
authors.initials: M
authors.lastname: Vordermeier
authors.forename: R Glyn
authors.initials: RG
authors.lastname: Hewinson
authors.forename: Douglas
authors.initials: D
authors.lastname: Young
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Gordon
authors.forename: Mesfin
authors.initials: M
authors.lastname: Sahile
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
authors.forename: Stefan
authors.initials: S
authors.lastname: Berg
mesh_terms: D000818:Animals; D002417:Cattle; D003612:Dairying; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008892:Milk; D058889:Molecular Typing; D009163:Mycobacterium bovis / Q000235:genetics / Q000302:isolation & purification; D015995:Prevalence; D011634:Public Health; D012307:Risk Factors; D014380:Tuberculosis, Bovine / Q000175:diagnosis / Q000453:epidemiology*