title: Preliminary investigation of the transmission of tuberculosis between farmers and their cattle in smallholder farms in northwestern Ethiopia: a cross-sectional study.
abstract: BACKGROUND
  The feeding habits and close physical contact between Ethiopian farmers and their cattle promote the transmission of tuberculosis (TB) between the farmers and their cattle. This study aimed to investigate the transmission of TB between farmers and their cattle in smallholder farms in northwestern Ethiopia.
  
  
  RESULTS
  A total of 70 human TB lymphadenitis (TBLN) cases visiting the Felegehiwot Comprehensive Specialized Hospital in Bahir Dar City and 660 cattle were investigated. Half of the cattle were owned by households with TB cases, and the remaining half by TB free households. Among the 70 human TBLN patients interviewed, 65.7% (46 out of 70) of the respondents were not aware of zoonotic TB, and 67.1% (47/70) of them consumed raw milk. Positive cultures of TB were obtained in 40 of the 70 cases where TBLN tests were positive with fine needle aspiration cytology. Spoligotyping resulted in 31 different patterns, of which 25 isolates were Mycobacterium (M.) tuberculosis, and the remaining were M. africanum (4 isolates) and M. bovis (2 isolates). None of the animals showed positive test results for bovine TB by comparative intradermal tuberculin test.
  
  
  CONCLUSIONS
  Based on the identification of M. bovis from two patients diagnosed with TBLN, we obtained preliminary evidence of zoonotic transmission of TB in northwestern Ethiopia. We did not identify a direct route of transmission between cattle and its owners. This is the objective of further investigations.
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. hamduanwar@yahoo.com.|College of Veterinary Medicine and Animal Sciences, University of Gondar, P.O. Box 346, Gondar, Ethiopia. hamduanwar@yahoo.com.
authors.forename: Anwar
authors.initials: A
authors.lastname: Nuru
authors.affiliation: College of Veterinary Medicine and Agriculture, Addis Ababa University, P.O. Box 34, Debre Zeit, Ethiopia.
authors.forename: Gezahegne
authors.initials: G
authors.lastname: Mamo
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Aboma
authors.initials: A
authors.lastname: Zewude
authors.affiliation: Felegehiwot Comprehensive Specialized Hospital, P. O. Box: 47, Bahir Dar, Ethiopia.
authors.forename: Yitayal
authors.initials: Y
authors.lastname: Mulat
authors.affiliation: Bahir Dar Regional Health Research Laboratory Centre, P.O. Box 641, Bahir Dar, Ethiopia.
authors.forename: Gashaw
authors.initials: G
authors.lastname: Yitayew
authors.affiliation: Bahir Dar Regional Health Research Laboratory Centre, P.O. Box 641, Bahir Dar, Ethiopia.
authors.forename: Aschalew
authors.initials: A
authors.lastname: Admasu
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Girmay
authors.initials: G
authors.lastname: Medhin
authors.affiliation: J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA.
authors.forename: Rembert
authors.initials: R
authors.lastname: Pieper
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Gobena
authors.initials: G
authors.lastname: Ameni
mesh_terms: D000818:Animals; D044963:Biopsy, Fine-Needle; D002417:Cattle; D003430:Cross-Sectional Studies; D005002:Ethiopia; D000067565:Farmers; D005506:Food Contamination; D005516:Food Microbiology; D006801:Humans; D009163:Mycobacterium bovis; D016273:Occupational Exposure; D014373:Tuberculin / Q000737:chemistry; D014376:Tuberculosis / Q000635:transmission*; D014380:Tuberculosis, Bovine / Q000175:diagnosis / Q000382:microbiology / Q000635:transmission*; D014388:Tuberculosis, Lymph Node / Q000175:diagnosis / Q000382:microbiology / Q000635:transmission*; D015047:Zoonoses / Q000175:diagnosis / Q000382:microbiology / Q000635:transmission*
chemical_list: D014373:Tuberculin
keywords: Cattle; Farmer; Mycobacterium bovis; Transmission; Tuberculous lymphadenitis