Molecular Microbiology Research 2016, Vol.6, No.1, 1-15 http://mmr.biopublisher.ca 1 Research Article Open Access Molecular Epidemiology of Bovine Tuberculosis in Cattle and its Public Health Implications in Gambella Region, Ethiopia Alemu J. 1, Mamo G. 2 , Ameni G. 3 , Pal M. 2, 1 Faculty of Agriculture and Natural Resource Management, Gambella University, Gambella, Ethiopia 2 College of Veterinary Medicine and Agriculture, Addis Ababa University, Debre Zeit, Ethiopia 3. Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia Corresponding author email: Email: palmahendra2@gmail.com Molecular Microbiology Research, 2016, Vol.6, No.1 doi: 10.5376/mmr.2016.06.0001 Received: 15 Dec., 2015 Accepted: 28 Dec., 2015 Published: 21 Apr., 2016 Copyright © 2016 Alemu et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Alemu et al., 2016, Molecular Epidemiology of Bovine Tuberculosis in Cattle and its Public Health Implications in Gambella Region, Ethiopia, Molecular Microbiology Research, Vol.6, No.1 1-15 (doi: 10.5376/mmr.2016.01.0001) Abstract A cross sectional study was conducted from December 2014 to May 2015 in Gambella town municipal abattoir and health centers to investigate the prevalence of bovine tuberculosis, isolation and molecular characterization of its causative agents, and to assess its public health implications in Gambella, Ethiopia. Postmortem examination, bacteriological culturing, RD deletion typing, and spoligotyping were used for investigation. The overall prevalence of bovine tuberculosis in cattle was 13.2% (66/500) on the basis of detailed postmortem examination. Statistical significant difference was observed in the prevalence of bovine tuberculosis among different body conditioned animals (χ2 = 39.105, P=0.000 and breeds (χ2 = 24.996, P=0.000). Molecular characterization of 11 mycobacter ial isolates from human patients using RD9 deletion typing showed that all were M. tuberculosis, and further spoligotyping of the isolates revealed that SIT289, SIT134, SIT1634, SIT142 and one new strain (not found in the spoligotype databases). Of these M. tuberculosis strains identified, SIT 289 and SIT134 were found in cluster with 45.5% (5/11) cluster rate. Lineage of the human isolates indicated that 27.3% (3/11) were in Euro-American, and 9.1% (1/11) Indo-oceanic family in TB-insight database. Interestingly, one isolate from animal taken from mediastinal lymph node was confirmed to be M. tuberculosis using RD4 deletion typing and spoligotyping, in which the isolate was identified as SIT523 with Indo-oceanic lineage family. Awareness of cattle owners for bovine tuberculosis was found insufficient (22%), and the results also revealed the presence of potential risk factor for zoonotic transmission. In conclusion, isolation of M. tuberculosis in cattle, and occurrence of various strains of M. tuberculosis in the communities warrants further systematic investigation on the transmission of the disease in Gambella region of Ethiopia. Keywords Bovine tuberculosis; Molecular epidemiology; RD typing; Spoligotyping; Public health; Zoonosis Introduction Tuberculosis, a highly communicable mycobacterial disease of humans and animals, is caused by members of Mycobacterium tuberculosis complex (MTBC) (Malama et al., 2013; Pal et al., 2014). Although, recent studies indicated that M. tuberculosis has been isolated from cattle (Ameni et al., 2011) and M .bovis from humans infected with bovine tuberculosis (Zeweld, 2014), M. tuberculosis is specifically adapted to humans while M. bovis is most frequently isolated from domesticated cattle (Girmay et al., 2012; Pal et al., 2014). In spite of variation in host specificity, the members of MTBC are characterized by 99.9% or greater similarity at nucleotide level, and are virtually identical at 16s rRNA sequence (Brosch et al., 2002). Bovine tuberculosis is a contagious disease, which can affect most warm blooded animals, including human beings (Pal, 2007; Radostits et al., 2007; Pal et al., 2014). Organisms are excreted in the exhaled air, in sputum, feces (from both intestinal lesions and swallowed sputum from pulmonary lesions), milk, urine, vaginal and uterine discharges, and discharges from open peripheral lymph nodes of infected animals (Radostits et al., 2007). In cattle, exposure to this organism can result in a chronic disease that jeopardizes animal welfare and productivity, and in some countries