The Burden of Mycobacterial Disease in Ethiopian Cattle: Implications for Public Health

Abstract

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.

African 2, a Clonal Complex of Mycobacterium bovis Epidemiologically Important in East Africa

“…An extensive slaughterhouse study in Ethiopia of 58 M. bovis strains isolated from six abattoirs dispersed throughout the country showed that many isolates lacked spacers 3 to 7 in their spoligotype pattern, in addition to the absence of spacers 9, 16, and 39 to 43 (8). We supplemented this sample with an additional 62 isolates from the same abattoirs and found that over 75% (n ϭ 91; total ϭ 120) of these Ethiopian isolates had spoligotype patterns that were missing spacers 3 to 7 (Table 1).…”

“…The majority of all M. bovis strains analyzed in this study were isolated from cattle and are described in more detail in the supplemental material. One hundred twenty strains were collected from six abattoirs in Ethiopia during 2006 to 2008 (8); nine strains were collected at an abattoir in Kampala from cattle originating from seven districts in Uganda (5); ten strains were collected from three sites in or close to the capital Bujumbura in Burundi (48); and fourteen strains were collected from cattle at a Morogoro slaughterhouse in Tanzania (41). Additional population samples of M. bovis isolated from cattle from South Africa (n ϭ 22) (40]), Chad (n ϭ 5) (35]), Mali (n ϭ 20) (42), Cameroon (n ϭ 3), Nigeria (n ϭ 5), Mozambique (n ϭ 14), Algeria (n ϭ 17) (51), Italy (n ϭ 93) (10), and Spain (n ϭ 20) (49]) were analyzed (see the supplemental material).…”

“…On the African continent, information on the prevalence of bovine TB is scarce and control programs are in place in only a few countries (6,16). However, a number of reports suggest that the disease is widely spread over the African continent and highly prevalent in several countries (8,21,38,42,51), with infection present mainly in cattle but also in wildlife (39).…”

Pre-Multidrug-Resistant Mycobacterium tuberculosis Beijing Strain Associated with Disseminated Tuberculosis in a Pet Dog

“…The notion that M. tuberculosis lineages are almost exclusively associated with human TB has been progressively challenged with expanding descriptions in the literature of M. tuberculosis infections in domestic animals (8,9) and wild animals (10)(11)(12). However, data gathered so far suggest that most M. tuberculosis-infected animals probably represent accidental hosts.…”

Intrafamilial Cluster of Pulmonary Tuberculosis Due to Mycobacterium bovis of the African 1 Clonal Complex

“…Furthermore, Berg et al have recently described a new clonal complex in Africa, the Af2 clonal complex, which is dominant in countries of East Africa (Uganda, Burundi, Tanzania, and Ethiopia) (4; N. H. Smith et al, unpublished data). The Eu1, Af1, and Af2 clonal complexes display specific genetic signatures that permit differentiation from one another (4,12,15).…”