The Status of Bovine Tuberculosis in Sudan

Little information about the occurrence and prevalence of BTB in Sudan is available. While most of the states in Sudan do not have the means to do research, Khartoum State is unique in having access to facilities allowing them to do research in animal diseases, and most of the diagnostic work that has been done thus focused on the central regions of the country where these research facilities are located.

Various publications reported a limited number of fragmented studies that were undertaken to determine the presence of BTB in some of the provinces of Sudan. Given the size of the national herd and the small number of animals tested, the data obtained are inadequate to provide a reliable estimate of the prevalence of the disease in any one of the regions. The limited available information suggests though that the distribution and prevalence of the disease are not uniform, in that the northern regions harbor cattle with a low prevalence of BTB, while higher infection rates are present in the central and southern regions.

BTB was first reported in Sudan in 1915 (Anon 1915). Subsequently, screening for the presence of BTB using the single or comparative intradermal tuberculin skin tests, microscopy, and culture for diagnostic purposes also indicated that the disease was more prevalent in Southern Sudan (16%; n = 631) than in Northern Sudan where the prevalence was much lower (2.4%; n = 1143) (Awad et al. 1959; Awad 1962). Several successive studies during the 1960s and early 1970s confirmed the persistence of the disease (Karib 1962; El Nasri 1966; Mustafa 1970; Tageldin 1971; El-Kareem and Moustafa 1974).

Limited information about its occurrence and rough estimates of the prevalence are available for some of the regions.

In Southern Sudan, an investigation of the presence of BTB demonstrated the presence of acid-fast rods in 3.3% of smears prepared from lymph node aspirates, while PCR detected M. bovis in 26 (65%) of milk and in 12 (40%) of lymph node samples (Zackaria et al. 2008). Given the limited number of specimens examined, it was not possible to determine the prevalence of the infection in this region.

A cross-sectional, abattoir-based study of BTB and other tuberculous diseases (bovine farcy) in South Darfur State (Western Sudan) (Fig. 20.1) during 2007-2009 revealed that 0.2% (12 of 6680) of the slaughtered animals contained lesions consistent with those of BTB and that 3% of the specimens collected from the caseous exudates from these lesions and subjected to m-PCR diagnostics contained mycobacteria. Filamentous, acid-fast mycobacteria consistent with those that cause bovine farcy were present in 0.9% (59 of 6680) of the animals slaughtered (Salih et al. 2010). During 2006 to 2008 at the Nyala abattoirs, in the same region (Fig. 20.1), 1.4% of the 2794 carcasses examined contained tuberculous lesions (Aljameel et al. 2014). Following culture of specimens from these lesions, 17 (10.3%) of the isolates were identified as M. bovis (6.7%) and six (3.6%) as M. farcinogenes.

Limited data too are available for Eastern Sudan. In a number of small surveys, 64 of 120 (53.3%) caseous lesions, similar to those caused by mycobacterial infec­tions, contained acid-fast bacilli, while 56 (46.7% of 569 cattle) were due to other causes (Sulieman and Hamid 2002). Recently, a BTB prevalence of 1.9%, using the comparative intradermal test (CCT), was detected in an area that shares its border with Eritrea (Fig. 20.1), suggesting that the infection could be the consequence of in-bound cattle movement from the neighboring country (Ayman et al. 2014).

Although BTB has not been detected in them, the presence of various species of wildlife susceptible to BTB in Sudan could play a role in sustaining the infection and in the transmission of BTB to cattle. Wildlife as a potential source of infection should thus be taken into consideration when developing BTB prevention and control measures for this region.

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