Survey of bovine tuberculosis in Nigerian beef cattle

Bovine tuberculosis (bTB) is a zoonotic disease caused by Mycobacterium tuberculosis complex (MTBC) that primarily affects cattle, but also other domestic and wild mammals. In Nigeria, abattoir monitoring of gross bTB lesions is the only control method being applied in all animals. This study aims to investigate tubercle bacilli infection in slaughtered cattle found with visible tuberculosis-like lesions. Lesions suggesting bTB were detected in 226 cattle during abattoir monitoring in Zamfara State, Nigeria. Tissue samples collected from the affected carcasses were subjected to Ziehl-Neelsen stain (ZN). Of the 226 carcasses with lesions, 37 (16.4%) were positive by the Ziehl-Neelsen stain (ZN), and MTBC was detected from 34 (91.9%) of the 37 ZN-positive samples. Molecular typing by region of difference (RD) deletion analysis revealed the genotype of Mycobacterium bovis, Mycobacterium caprae and Mycobacterium tuberculosis. Infection was most significantly associated with age of the animals (OR = 3.49; CI: 1.29-9.47 [p = 0.002]). The findings indicate a serious threat for health as well as for TB control in Nigeria.