No abstract

Molecular typing of 964 specimens from patients in Ethiopia with lymph node or pulmonary tuberculosis showed a similar distribution of Mycobacterium tuberculosis strains between the 2 disease manifestations and a minimal role for M. bovis. We report a novel phylogenetic lineage of M. tuberculosis strongly associated with the Horn of Africa.

BackgroundBovine tuberculosis (bTB), caused by Mycobacterium bovis, is a debilitating disease of cattle. Ethiopia has one of the largest cattle populations in the world, with an economy highly dependent on its livestock. Furthermore, Ethiopia has one of the highest incidence rates of human extrapulmonary TB in the world, a clinical presentation that is often associated with transmission of M. bovis from cattle to humans.Methodology/Principal FindingsHere we present a comprehensive investigation of the prevalence of bTB in Ethiopia based on cases identified at slaughterhouses. Out of approximately 32,800 inspected cattle, ∼4.7% showed suspect tuberculous lesions. Culture of suspect lesions yielded acid-fast bacilli in ∼11% of cases, with M. bovis accounting for 58 of 171 acid-fast cultures, while 53 isolates were non-tuberculous mycobacteria. Strikingly, M. tuberculosis was isolated from eight cattle, an unusual finding that suggests human to animal transmission.Conclusions/SignificanceOur analysis has revealed that bTB is widely spread throughout Ethiopia, albeit at a low prevalence, and provides underpinning evidence for public health policy formulation.

BackgroundEthiopia has the largest cattle population in Africa. The vast majority of the national herd is of indigenous zebu cattle maintained in rural areas under extensive husbandry systems. However, in response to the increasing demand for milk products and the Ethiopian government's efforts to improve productivity in the livestock sector, recent years have seen increased intensive husbandry settings holding exotic and cross breeds. This drive for increased productivity is however threatened by animal diseases that thrive under intensive settings, such as bovine tuberculosis (BTB), a disease that is already endemic in Ethiopia.Methodology/Principal FindingsAn extensive study was conducted to: estimate the prevalence of BTB in intensive dairy farms in central Ethiopia; identify associated risk factors; and characterize circulating strains of the causative agent, Mycobacterium bovis. The comparative intradermal tuberculin test (CIDT), questionnaire survey, post-mortem examination, bacteriology, and molecular typing were used to get a better understanding of the BTB prevalence among dairy farms in the study area. Based on the CIDT, our findings showed that around 30% of 2956 tested dairy cattle from 88 herds were positive for BTB while the herd prevalence was over 50%. Post-mortem examination revealed gross tuberculous lesions in 34/36 CIDT positive cattle and acid-fast bacilli were recovered from 31 animals. Molecular typing identified all isolates as M. bovis and further characterization by spoligotyping and MIRU-VNTR typing indicated low strain diversity within the study area.Conclusions/SignificanceThis study showed an overall BTB herd prevalence of 50% in intensive dairy farms in Addis Ababa and surroundings, signalling an urgent need for intervention to control the disease and prevent zoonotic transmission of M. bovis to human populations consuming dairy products coming from these farms. It is suggested that government and policy makers should work together with stakeholders to design methods for the control of BTB in intensive farms in Ethiopia.

An outbreak of skin lesions was reported in June 2005 in the district of Silti woreda, 150 km south of Addis Ababa, by the Christian Children's Fund (CCF) and confirmed to be cutaneous leishmaniasis (CL) by our group from the Armauer Hansen Research Institute in July 2005. A house-to-house survey of 1907 residents in three kebeles of Silti woreda conducted in April 2006 showed a prevalence of 4.8%. RFLP analysis of the internal transcribed spacer RNA (ITS1) showed that Leishmania aethiopica was the causative agent. In the survey, it was found that the age group 11-20 years was the most affected. Environmental factors such as proximity of the house to the gorge where hyraxes reside, presence of the plants Adhatoda schimperiana and Acacia spp. in the compound and sharing the same room with domestic animals were significantly associated with developing CL. The prevalence of active disease was higher in Kibet town (10.4%) compared to the rural kebeles. The identified risk factors of CL in the area need further study. The appearance of leishmaniasis in Silti, which was not known to be endemic for the disease, underlines the need to initiate a leishmaniasis control program in Ethiopia to limit its expansion.