Bovine Tuberculosis In Ethiopia Research Articles

Bovine Tuberculosis: Ethiopian Perspective

Bovine tuberculosis is a significant zoonotic disease affecting livestock and humans worldwide, causing substantial economic losses and posing serious public health risks. This review aims to provide an overview of bovine tuberculosis in Ethiopia, highlighting its prevalence, risk factors, transmission routes, clinical manifestations, and diagnostic methods. Mycobacterium bovis primarily causes bovine tuberculosis, which is characterized by granulomatous lesions in various organs. Transmission occurs through inhalation, ingestion of contaminated materials, and direct contact with infected animals. The age, breed, herd size, and management practices are some of the risk factors for bovine tuberculosis. In Ethiopia, the disease is prevalent but poorly controlled, lacking a national control program. Effective diagnosis relies on methods such as the tuberculin skin test, culture, and PCR. Control measures include test-and-slaughter programs, movement restrictions, biosecurity protocols, and public health education. This review underscores the urgent need for a comprehensive national control strategy, enhanced surveillance, public awareness campaigns, and investment in research to mitigate the impact of bovine tuberculosis in Ethiopia, thereby safeguarding both animal and human health.

Review on current epidemiological status and public health importance of bovine tuberculosis in Ethiopia

Review on current epidemiological status and public health importance of bovine tuberculosis in Ethiopia

Evaluation of the Control Options of Bovine Tuberculosis in Ethiopia Using a Multi-Criteria Decision Analysis.

Bovine tuberculosis (BTB) is a zoonotic bacterial infection caused by Mycobacterium bovis and is characterized by the development of granulomatous lesions in the lymph nodes, lungs and other tissues. It poses serious public health impacts and food security challenges to the agricultural sector in terms of dairy and meat productions. In Ethiopia, BTB has been considered as a priority disease because of its high prevalence in urban and peri-urban dairy farms. However, there has not been any national control program in the country. Thus, in order to initiate BTB control program in the country, information on control options is needed to tailor the best option for the Ethiopian situation. The objective of this study was to identify, evaluate and rank various BTB control options in Ethiopia using a multi-criteria decision analysis based on preference ranking organization method for enrichment evaluations (PROMETHEE) approach while accounting for the stakeholders' preferences. Control options were evaluated under two scenarios: with (scenario 1) and without (scenario 2) bacillus Calmette–Guérin (BCG) vaccination. Nine potential control options were identified that include combinations of three control options (1) test and slaughter with or without government support, (2) test and segregation, and (3) BCG vaccination. Under scenario 1, BCG vaccination, BCG vaccination and test and slaughter with partial compensation by government, and BCG vaccination and test and slaughter with full compensation by government were the top three ranked control options. Under scenario 2, test and slaughter with full compensation by government was the preferred control option, followed by test and segregation supported by test and slaughter with full government compensation, and test and slaughter with half compensation by government. Irrespective of the variability in the weighting by the stakeholders, the sensitivity analysis showed the robustness of the ranking method. In conclusion, the study demonstrated that BCG vaccination, and test and slaughter with full compensation by government were the two most preferred control options under scenarios 1 and 2, respectively. National level discussions were strongly recommended for further concretization and implementation of these control measures.

Multi-locus variable-number tandem repeat analysis (MLVA) reveals heterogeneity of Mycobacterium bovis strains and multiple genotype infections of cattle in Ethiopia

Bovine tuberculosis (BTB) remains a major threat to animal and human health, and obstructs international and inter-regional livestock trade in Ethiopia. Many aspects of epidemiology of BTB and its causative agent, Mycobacterium bovis (M. bovis) are not well known. Aims of the study were to elucidate molecular characteristics of M. bovis strains using MLVA typing method. Further aim was to determine infection pressure associated with occurrence of multiple genotypes in individual infected cattle. Data and samples were collected in the period July 2006–January 2007 in cattle slaughtered at five representative abattoirs across the country. Molecular investigation of the isolates was carried out using multilocus variable-number tandem-repeat analysis (MLVA) of 28 variable numbers of tandem repeat (VNTR) loci, and the results were compared to spoligotyping. This study is believed to contribute to the knowledge of molecular genetics and epidemiology of M. bovis in Ethiopia and elsewhere with similar BTB epidemic situation and livestock production settings. Four-hundred and six tissue samples from 337 carcasses revealing gross pathologic lesions compatible with BTB were collected from five abattoirs. Fifty-eight isolates obtained from cultured samples were subjected to region of difference (RD) analysis and MLVA typing. RD confirmed all isolates as being M. bovis. MLVA revealed a high heterogeneity of M. bovis (19 genotypes) and the discriminatory power of MLVA was higher than for spoligotyping (Hunter–Gaston Diversity Index (HGDI) 0.92 vs. 0.82). Adoption of the nine VNTR loci with ⩾3 alleles provided good differentiation between the isolates. However, differentiation was optimized when MLVA was combined with spoligotyping (HGDI=0.99). MLVA confirmed infections with multiple genotypes in 38.5% (10/26) of individual animals. In conclusion, the usefulness of MLVA for genotyping M. bovis in high prevalence settings was demonstrated. BTB in Ethiopia is caused by heterogeneous populations of M. bovis and individual carcasses were often infected with different genotypes, indicating a high infection pressure perhaps related to the absence of protective immunity conferred by infection.

The influence of cattle breed on susceptibility to bovine tuberculosis in Ethiopia

Bovine tuberculosis in domestic livestock such as cattle is an economically important disease with zoonotic potential, particularly in countries with emerging economies. We discuss the findings of recent epidemiological and immunological studies conducted in Ethiopia on host susceptibility differences between native zebu and the exotic Holstein–Friesian cattle that are increasingly part of the Ethiopian National herd, due to the drive to increase milk yields. These findings support the hypothesis that native Zebu cattle are more resistant to bovine tuberculosis. We also summarise the results of experimental infections that support the epidemiological data, and of laboratory experiments that suggest a role for the innate immune response, and in particular interleukin-6, in the outcome of bovine tuberculosis infection.

Immune Response in Holstein-Zebu Cross and Zebu Calves Vaccinated with Bacillus Calmette-Guérin (BCG) at Bako Agricultural Research Centre, Western Ethiopia

Background: Mycobacterium bovis (M. bovis) bacillus Calmette-Gue´rin (BCG) currently remains the only licensed vaccine for the prevention of tuberculosis. The purpose of this study was to evaluate immune responses in calves vaccinated with BCG in western Ethiopia. Methods: Twelve Holstein-zebus cross breed calves (six vaccinated with 0.5ml of 1 x 106 CFU of BCG and six controls) and nine pure zebu calves (five vaccinated with 0.5ml of 1 x 106 CFU of BCG and four controls) were used in this study. Immune responses were monitored for 23 weeks post vaccination using gamma interferon (IFN-γ) assay and comparative intra-dermal tuberculin test to assess cellular response, and enzyme-linked immunosorbant assay (ELISA) to measure antibody response. Results and interpretation: IFN-γ response was observed starting from week 2, attaining its peak at week 4 post vaccination after which a fall in the response of IFN-γ was observed attaining a constant concentration from week 8 onwards. The mean IFN-γ response (OD450nm: Mean ± SEM, 0.205 ± 0.018) in vaccinated calves was significantly (tcal=2.85, P<0.05) higher than the non-vaccinated calves (Mean ± SEM, 0.168±0.008) at 4th week post vaccination. Within the vaccinated group, the mean IFN-γ response was significantly (tcal=3.01, P<0.05) greater in cross breed (Mean ± SEM, 0.217 ± 0.021) than in zebu breeds (Mean ± SEM, 0.194 ± 0.015) at 4th week post vaccination. On the other hand, no detectable antibody response was observed in vaccinated and non-vaccinated calves while the mean of skin thickness following skin test was significantly (P<0.05) higher in vaccinated calves than in non-vaccinated calves 23 weeks post vaccination. Conclusion: BCG induced IFN-γ responses in both Holstein-zebu cross and zebu calves although stronger IFN-γ response was observed in Holstein-zebu cross breed as compared to the response in zebu, which could suggest the possibility of using BCG for the control of bovine tuberculosis in Ethiopia.

Approach to assess the economic impact of bovine tuberculosis in Ethiopia

No Abstract. Ethiopian Journal of Health Development Vol. 22 (special issue) 2008: pp. 135-138

Bovine tuberculosis infection in animal and human populations in Ethiopia: a review

Ethiopia is one among the nations that possesses the largest number of livestock population in the African continent estimated to be 33 million cattle, 24 million sheep and 18 million goats. In contrast to the huge livestock resource, the livestock productivity is however, found to be very low. The major biological and socio-economical factors attributing to the low productivity includes: the low genetic potential and performance, poor nutrition (in quality and quantity terms), the prevailing of different diseases, traditional way of husbandry systems and inadequate skilled manpower, among others. Ethiopia is one of the African countries where tuberculosis is wide spread in both humans and cattle and the endemic nature of tuberculosis in humans and cattle has long been documented. The disease is considered as one of the major livestock diseases that results in high morbidity and mortality, although the current status on the actual prevalence rate of bovine tuberculosis (BTB) at a national level is yet unknown. Detection of BTB in Ethiopia is carried out most commonly on the basis of tuberculin skin testing, abattoir meat inspection and very rarely on bacteriological techniques. Recently undertaken studies indicated the prevalence rate of BTB with a range of 3.4% (in small holder production system) to 50% (in intensive dairy productions) and a range of 3.5% to 5.2% in slaughterhouses in various places of the country. BTB in cattle remains to be a great concern due to the susceptibility of humans to the disease. The infections mainly take place by drinking raw milk and occur in the extra-pulmonary form, in the cervical lymphadenitis form in particular. The aim of this paper is to review the status of BTB in Ethiopia in relation with the existing animal husbandry systems and abattoir meat inspection surveillances. Control measures, economic impacts and the zoonotic aspect of the disease are also briefly addressed.

Bovine tuberculosis—incorporating a review of John Francis' book

Bovine tuberculosis (bTB) is a known endemic disease of cattle in Ethiopia; however, there is lack of a comprehensive information on the status and distribution of the disease in the country. The objectives of this systematic review and meta-analysis were to provide a pooled prevalence estimate of bTB at a national level, assess the level of in-between variance among study reports and illustrate the spatial distribution pattern in the country. Articles published on bTB from January 2000 to December, 2016 in English language were included in the review. Pubmed, CAB direct, AJOL and Web of Science were the databases used in electronic search. A total of 127 articles were retrieved from online sources, of which 56 articles were selected for data extraction based on the specified inclusion criteria. From these selected published articles, 114 animal level data were extracted for quantitative analysis. A pooled prevalence estimate of bovine tuberculosis in Ethiopia was found to be 5.8% (95% CI: 4.5, 7.5). In a multivariable meta-regression analysis, breed and production system explained 40.9% of the explainable proportion of the in-between study variance computed. The prevalence of bovine tuberculosis in Holstein-Friesians, 21.6% (95% CI: 14.7–30.7), was higher than the prevalence in local zebus 4.1 (95% CI: 3.4–4.9). Cattle kept under intensive and semi-intensive production systems had higher prevalence, 16.6% (95% CI: 12.4–21.6), of bTB than those kept in extensive livestock production system, 4.6 (95% CI: 3.4–6.2). Bovine tuberculosis is widely distributed across major livestock producing regions of Ethiopia. However, no valid data could be retrieved from Benishanul-Gumuz, Harari and Dire Dawa. Data obtained on bTB from Somali and Gambella regional states are also few and further studies are suggested in these regions. In conclusion, this review showed that bTB in cattle in Ethiopia is widespread with high prevalence in intensive and semi-intensive management systsems that keep exotic breeds and their crosses in urban and peri-urban areas. Thus, it is suggested that the design and implementation of bTB control strategies in Ethiopia should prioritize these hotspots in order to reduce the impact of the disease on the growing dairy sector.