Pathology of Camel Tuberculosis and Molecular Characterization of Its Causative Agents in Pastoral Regions of Ethiopia

Abstract

A cross sectional study was conducted on 906 apparently healthy camels slaughtered at Akaki and Metehara abattoirs to investigate the pathology of camel tuberculosis (TB) and characterize its causative agents using postmortem examination, mycobacteriological culturing, and multiplex polymerase chain reaction (PCR), region of difference-4 (RD4)-based PCR and spoligotyping. The prevalence of camel TB was 10.04% (91/906) on the basis of pathology and it was significantly higher in females (χ2 = 4.789; P = 0.029). The tropism of TB lesions was significantly different among the lymph nodes (χ2 = 22.697; P = 0.002) and lung lobes (χ2 = 17.901; P = 0.006). Mycobacterial growth was observed in 34% (31/91) of camels with grossly suspicious TB lesions. Upon further molecular characterization using multiplex PCR, 68% (21/31) of the colonies showed a positive signal for the genus Mycobacterium, of which two were confirmed Mycobacterium bovis (M. bovis) by RD4 deletion typing. Further characterization of the two M. bovis at strains level revealed that one of the strains was SB0133 while the other strain was new and had not been reported to the M. bovis database prior to this study. Hence, it has now been reported to the database, and designated as SB1953. In conclusion, the results of the present study have shown that the majority of camel TB lesions are caused by mycobacteria other than Mycobacterium tuberculosis complex. And hence further identification and characterization of these species would be useful towards the efforts made to control TB in camels.

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

“…The Ethiopian Somalia camel rearing community in Shinile such as Issa is almost pure camel herders and keep their camels in open land just making a fence with thorny plants around it during night time, but in case of Oromia camel rearing areas where most of the camels are kept in close confinement with cattle, especially during night camels and cattle are kept together. Close confinement of camels and cattle together might be the source of cross infection (Mamo et al, 2011).…”

“…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).…”

Prevalence of camel tuberculosis and associated risk factors in camels slaughtered at Akaki Abattoir, Ethiopia

“…Studies conducted in Egypt, Sudan, India, Somalia, Kazakhstan and Ethiopia has shown that tuberculosis is occurring in camels (Fassi Fehri, 1987). Camel TB has been described in Egypt (Mustafa, 2013), the United Arab Emirates (Kinne et al, 2006;Wernery et al, 2007;, Pakistan, Kazakhstan (Elmossalami et al, 1971), Somalia, Nigeria (Abubaker et al, 2014, and Ethiopia (Mamo et al, 2009;Zerom et al, 2013 (Kinne et al, 2006;Elmossalami et al, 1971;Mamo et al, 2011;Zerom et al, 2013, Rhodes et al, 2015.…”

Molecular Characterization of Mycobacterium bovis and its Significance: Role for Control of Zoonotic Tuberculosis in Africa

“…The same study by Berg et al [7,[67][68][69] identified a clonal complex of Mycobacterium bovis isolated at high frequency from cattle in Uganda, Burundi, Tanzania, and Ethiopia. Other studies showed M. bovis isolates in Ethiopia were also reported [70][71][72][73][74]. M. bovis and M. tuberculosis molecularly characterized and summarized by Brudey et al [74,75].…”