Zoonotic Transmission of Tuberculosis Between Pastoralists and Their Livestock in South-East Ethiopia

Abstract

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

Molecular Epidemiology of Bovine Tuberculosis in Cattle and its Public Health Implications in Gambella Region, Ethiopia

“…Humans suffering from active TB are the most probable source of M. tuberculosis in animals, with infection spread via sputum, and rarely urine or feces (Thoen and Steele, 1995) or respiratory route as in rural area of Ethiopia, grazing cattle are commonly brought into the farmer's households at night where they may become infected via aerosol transmission from humans . Previous studies in Ethiopia had confirmed transmission of M. tuberculosis from farmers to their cattle, goat, and camel ( Ameni et al, 2011;Gumi et al, 2012;Mamo et al, 2012) supporting the result of our study. Even though human to cattle transmission of M. tuberculosis has been reported, it is generally held that disease in cattle due to M. tuberculosis is less severe than that caused by M. bovis ,and the identification of M. tuberculosis in cattle by itself is intriguing (Tsegaye et al, 2010).…”

First approach to molecular epidemiology of bovine tuberculosis in Colombia

“…In this regard, there exist studies that demonstrate that the M. tuberculosis find in the ranching it's a reflection of the situation of tuberculosis in human beings in such regions (30)(31)(32). This finding puts…”

Prevalence of bovine tuberculosis in dromedary camels and awareness of pastoralists about its zoonotic importance in Eastern Ethiopia

“…M. bovis strains were also isolated by Donchenko et al (1975) in Russia from bulked samples of raw dromedary milk. Recent studies in Ethiopian abattoirs also reported isolation of M. bovis (Mamo et al, 2011) and M. tuberculosis from tissue lesions (Gumi et al, 2012;Zerom et al, 2012). Five to twelve percent abattoir-based prevalence of tuberculosis compatible lesions (TCL) in dromedary camels slaughtered at Dire Dawa abattoir in Eastern Ethiopia and in Addis Ababa abattoir were recorded (Mamo et al, 2009;Mamoet al, 2011;Zerom et al, 2012).…”