Abstract

A cross-sectional study was conducted from September, 2010 to July, 2011 on 1,066 cattle (484 dairy and 582 beef) in two districts of Western Tigray Zone, Northern Ethiopia, to investigate the epidemiology of mycobacterial infections in cattle and characterize its causative agents. Comparative intradermal tuberculin (CIDT) test, pathological and bacteriological examination, and molecular typing were employed to undertake this study. The study found the animal tuberculosis (TB) reactor prevalence in dairy cattle to be 6.6% (95% CI, 4.4 to 8.8) and 8.7% (95% CI, 6.2 to 11.2) at ≥4 and ≥2 mm cut-offs, respectively, while the herd prevalence were 61.3% (95% CI, 43.1 to 79.5) at cut-off ≥4 mm and 77.4% (95% CI, 61.8 to 93.0) at cut-off ≥2 mm. On the basis of abattoir survey, the prevalence of tuberculoid lesions was 5.8% in beef cattle with the largest proportion (61.8%) of lesions recorded from the respiratory tract. Bacteria were successfully cultured from 35.3% (12/34) tissue samples; however, only four of these isolates showed signal to the genus Mycobacterium using multiplex polymerase chain reaction (PCR). These four were members of the non-mycobacterium tuberculosis complex (NMTC). In conclusion, the result of this study suggested the importance of NMTC in cattle of the study area.

Key words: Bovine tuberculosis, tuberculin test, risk factors, meat inspection, Western Tigray, Ethiopia.

Abbreviation

CIDT, Comparative intradermal tuberculin; AFB, acid-fast bacilli; PCR,polymerase chain reaction; NTMB, non-tuberculous mycobacterium; BTB, bovine tuberculosis.