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BACKGROUND: Ethiopia ranks seventh in the list of 22 high tuberculosis (TB) burden countries, with an incidence rate of 379 cases per 100 000 population for TB all forms. However, information on the genomic diversity of Mycobacterium tuberculosis in Ethiopia is limited. OBJECTIVE: To investigate the molecular characteristics of M. tuberculosis strains implicated in pulmonary TB in the study area. METHODS AND RESULTS: A cross-sectional study was conducted using socio-demographic, clinical and culture data combined with molecular typing analysis. The proportion of TB and M. tuberculosis isolates was not associated with risk factors (P > 0.05). Of 99 sputum samples, 80.8% were culture-positive. Speciation of isolates showed that 88.8% were M. tuberculosis. Further characterisation led to the identification of 27 different spoligotype patterns of M. tuberculosis; the most dominant shared types were SIT149, SIT53 and SIT54. Of the 27 strains, three strains were new and were reported to the SITVIT database. More than two thirds of the strains belonged to the Euro-American lineage. CONCLUSION: This study shows the presence of several clusters and new strains of M. tuberculosis circulating in pulmonary TB patients in the study area, suggesting recent transmission. Nationwide studies are recommended to map the population structure of M. tuberculosis and set control measures.

Despite huge global efforts in tuberculosis (TB) control, pastoral areas remain under-investigated. During two years sputum and fine needle aspirate (FNA) specimens were collected from 260 Ethiopian pastoralists of Oromia and Somali Regional States with suspected pulmonary TB and from 32 cases with suspected TB lymphadenitis. In parallel, 207 suspected tuberculous lesions were collected from cattle, camels and goats at abattoirs. All specimens were processed and cultured for mycobacteria; samples with acid-fast stained bacilli (AFB) were further characterized by molecular methods including genus and deletion typing as well as spoligotyping. Non-tuberculous mycobacteria (NTM) were sequenced at the 16S rDNA locus. Culturing of AFB from human sputum and FNA samples gave a yield of 174 (67%) and 9 (28%) isolates, respectively. Molecular typing was performed on 173 of these isolates and 160 were confirmed as Mycobacterium tuberculosis, three as M. bovis, and the remaining 10 were typed as NTMs. Similarly, 48 AFB isolates (23%) yielded from tuberculous lesions of livestock, of which 39 were molecular typed, including 24 M. bovis and 4 NTMs from cattle, 1 M. tuberculosis and 1 NTM from camels and 9 NTMs from goats. Isolation of M. bovis from humans and M. tuberculosis from livestock suggests transmission between livestock and humans in the pastoral areas of South-East Ethiopia.

Mycobacterium bovis strains isolated from tuberculosis (TB) lesions from 1138 cattle slaughtered at Kombolcha abattoir in north eastern Ethiopia were characterised. Detailed postmortem examination, bacteriological culturing, regions of difference PCR and spoligotyping were used. At least one TB lesion was observed in 57 (5 per cent) of the cattle, of which 27 (47 per cent) yielded mycobacteria isolates. Of the 27 isolates, 25 were identified as M bovis and two as Mycobacterium tuberculosis. The M bovis isolates were grouped into six clusters of strains, and the M tuberculosis isolates were typified to one strain only with the reference SIT262. Three clusters of previously unreported M bovis strains were identified and reported to the Mycobacterium bovis spoligotype database. They were designated the reference numbers SB1490, SB1491 and SB1492.

A preliminary study to characterise mycobacteria infecting tuberculous cattle from two different management systems in central Ethiopia was carried out. Approximately 27% of isolates from grazing cattle were Mycobacterium tuberculosis, while cattle in a more intensive-production system were exclusively infected with M. bovis. The practice of local farmers discharging chewed tobacco directly into the mouths of pastured cattle was identified as a potential route of human-to-cattle transmission of M. tuberculosis.

Background Ethiopia, a high tuberculosis (TB) burden country, reports one of the highest incidence rates of extra-pulmonary TB dominated by cervical lymphadenitis (TBLN). Infection with Mycobacterium bovis has previously been excluded as the main reason for the high rate of extrapulmonary TB in Ethiopia. Methods Here we examined demographic and clinical characteristics of 953 pulmonary (PTB) and 1198 TBLN patients visiting 11 health facilities in distinct geographic areas of Ethiopia. Clinical characteristics were also correlated with genotypes of the causative agent, Mycobacterium tuberculosis. Results No major patient or bacterial strain factor could be identified as being responsible for the high rate of TBLN, and there was no association with HIV infection. However, analysis of the demographic data of involved patients showed that having regular and direct contact with live animals was more associated with TBLN than with PTB, although no M. bovis was isolated from patients with TBLN. Among PTB patients, those infected with Lineage 4 reported “contact with other TB patient” more often than patients infected with Lineage 3 did (OR = 1.6, CI 95% 1.0-2.7; p = 0.064). High fever, in contrast to low and moderate fever, was significantly associated with Lineage 4 (OR = 2.3; p = 0.024). On the other hand, TBLN cases infected with Lineage 4 tended to get milder symptoms overall for the constitutional symptoms than those infected with Lineage 3. Conclusions The study suggests a complex role for multiple interacting factors in the epidemiology of extrapulmonary TB in Ethiopia, including factors that can only be derived from population-based studies, which may prove to be significant for TB control in Ethiopia. Electronic supplementary material The online version of this article (doi:10.1186/s12879-015-0846-7) contains supplementary material, which is available to authorized users.

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.

A cross-sectional study was conducted on 500 cattle slaughtered at Addis Ababa abattoir to determine the prevalence of bovine tuberculosis (BTB) and characterize its causative agents. Postmortem examination, mycobacteriological culturing, region of difference-4 (RD4)-based PCR and spoligotyping were applied. The prevalence of BTB was 5 % on the basis of postmortem inspection alone but 1.2 % based on molecular confirmation. Factors including age, sex, and breed showed statistically significant association with BTB (p

A cross-sectional study of bovine tuberculosis (BTB) detected by the comparative intradermal tuberculin test (CIDT) was conducted in livestock of the Somali region in southeast Ethiopia—in four pastoral associations from January to August 2009. In 94 herds, each of 15 cattle, camels, and goats was tested per herd leading to a total of 1,418 CIDT tested animals, with 421 cattle, 479 camels, and 518 goats. A herd was considered positive if it had at least one reactor. Prevalence per animal species was calculated using a xtgee model for each species. The individual animal prevalence was 2.0% [95% confidence interval (CI), 0.5–8.4], 0.4% (95% CI, 0.1–3%), and 0.2% (95% CI, 0.03–1.3) in cattle, camels, and goats, respectively. Prevalence of avian mycobacterium purified protein derivative (PPD) reactors in cattle, camels, and goats was 0.7% (95% CI, 0.2–2.0%), 10.0% (95% CI, 7.0–14.0%), and 1.9 (95% CI, 0.9–4.0%), respectively, whereby camels had an odds ratio of 16.5 (95% CI, 5.0–55.0) when compared to cattle. There was no significant difference between livestock species in BTB positivity. In the present study, the prevalence of bovine tuberculosis was low in Somali pastoral livestock in general and in camels and goats in particular. The high proportion of camel reactors to avian PPD needs further investigation of its impact on camel production.

BACKGROUND: Ethiopia 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 FINDINGS: AN 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/SIGNIFICANCE: This 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

A cross-sectional study of bovine tuberculosis (BTB) was conducted in pastoral cattle herds in southern Ethiopia, from February to August 2008 using the comparative intradermal tuberculin test. The prevalence of BTB and the risk factors for having positive reactor herds were assessed in four pastoral associations in two districts of southern Ethiopia, namely Goro-Dola with 242 cattle in 16 herds and Liben with 231 cattle in 15 herds. A herd was considered positive if there was at least one reactor animal in a herd. The test results were interpreted based on the Office Internationale des Epizooties recommended 4-mm and a recently suggested 2-mm cut-off. The apparent individual animal prevalence of tuberculin reactors was 5.5% (95% confidence interval (CI), 4.0–8.0%) and 7.0% (95% CI, 5.0–10.0%), whereas the true prevalence estimate was 4.4% (95% CI, 0.8–8.0%) and 6.1% (95% CI, 2.6–9.5%), when using the 4-mm and the 2-mm cut-offs, respectively. The overall herd apparent prevalence of tuberculin reactor animals was 41.9% (95% CI, 24.9–60.9%) and 48.4% (95% CI, 30.2–66.9%) with the 4-mm and 2-mm cut-offs, respectively. A positive tuberculin test was associated with the age of animals and the main drinking water sources during dry seasons. In order to investigate the public health risks and the epidemiological importance of BTB in the area, we recommend to include other livestock species (camels and goats) as well as humans in future studies.

Background Bovine 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 Findings Here 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/Significance Our analysis has revealed that bTB is widely spread throughout Ethiopia, albeit at a low prevalence, and provides underpinning evidence for public health policy formulation.

Background Bovine tuberculosis (BTB) is endemic in Ethiopian cattle. The aim of this study was to assess BTB prevalence at an intensive contact interface in Meskan Woreda (district) in cattle, small ruminants and suspected TB-lymphadenitis (TBLN) human patients. Methods The comparative intradermal test (CIDT) was carried out for all animals involved in the cross-sectional study and results interpreted using a > 4 mm and a > 2 mm cut-off. One PPD positive goat was slaughtered and lymph nodes subjected to culture and molecular typing. In the same villages, people with lymphadenitis were subjected to clinical examination. Fine needle aspirates (FNA) were taken from suspected TBLN and analyzed by smear microscopy and molecular typing. Results A total of 1214 cattle and 406 small ruminants were tested for BTB. In cattle, overall individual prevalence (> 2 mm cut-off) was 6.8% (CI: 5.4-8.5%) with 100% herd prevalence. Only three small ruminants (2 sheep and 1 goat) were reactors. The overall individual prevalence in small ruminants (> 2 mm cut-off) was 0.4% (CI: 0.03-5.1%) with 25% herd prevalence. Cattle from owners with PPD positive small ruminants were all PPD negative. 83% of the owners kept their sheep and goats inside their house at night and 5% drank regularly goat milk. FNAs were taken from 33 TBLN suspected cases out of a total of 127 screened individuals with lymph node swellings. Based on cytology results, 12 were confirmed TBLN cases. Nine out of 33 cultures were AFB positive. Culture positive samples were subjected to molecular typing and they all yielded M. tuberculosis. M. tuberculosis was also isolated from the goat that was slaughtered. Conclusions This study highlighted a low BTB prevalence in sheep and goats despite intensive contact with cattle reactors. TBLN in humans was caused entirely by M. tuberculosis, the human pathogen. M. tuberculosis seems to circulate also in livestock but their role at the interface is unknown.