Isolation and Molecular Identification of Mycobacterium bovis from Slaughtered Cattle in Nekemte Municipality Abattoir, Ethiopia

Abstract

Tuberculosis (TB) is a zoonotic disease that can spread from animals to humans as well as from human to human. Little research has been conducted on bovine tuberculosis prevalence and molecular characterization in the western part of Ethiopia. To investigate this, a cross-sectional study was conducted on slaughtered cattle at the Nekemte municipal abattoir between January 2020 and June 2021. A detailed postmortem examination, culture, acid-fast staining technique, molecular characterization using RD4 deletion, and spoligotyping were all carried out. Based on a detailed postmortem examination, the overall prevalence of bovine tuberculosis was 7.8% (80 of 1020). Mycobacterium isolation confirmed only 12.5% (10/80) of the suspected tuberculosis tissue lesions. With acid-fast bacilli staining, all Mycobacterium spp. isolates (n = 10) were positive. However, only 9/10 isolates were confirmed to be M. bovis with RD4 molecular deletion typing. Spoligotyping revealed that 55.6% (5/9) of the isolate patterns had previously been reported, but 44.4% (4/9) of the isolates were new. In the current investigation, it was discovered that 80% (4/5) of the M. bovis strains circulating in the cattle population of study regions were SB2233 (2/5) and SB0134 (2/5), whereas 20% (1/5) of the strains corresponded to SB1176, which is compatible with previously documented M. bovis spoligotypes. These findings suggested that M. bovis was the main cause of bovine tuberculosis in the study area and posed a risk of disease transmission from cattle to humans due to low levels of public health awareness. As such, improved awareness among citizens and the development of control policies are warranted.