Review on Zoonotic Importance of Bovine Tuberculosis and Its Control

Abstract

Bovine tuberculosis is a chronic infectious zoonotic disease of domestic animals and humans. It is characterized by formation of granulomas in tissue especially the lungs, lymph nodes, liver, intestines and the kidneys. Mycobacterium bovis is the main etiological agent of BTB (Bovine tuberculosis) which is an acid fast staining bacterium due to waxy substance (mycolic acid) present in its bacterial cell wall. The bacteria can be transmitted by both aerogenous and enterogenous routes. In Ethiopia bovine tuberculosis is endemic and mostly transmitted to humans through ingestion of unpasteurized contaminated milk and contact with infected animals. Disease causes development of miliary tubercular lesions, chronic cough, obstructions of air passages and alimentary tract or blood vessels and enlargement of lymph nodes. A spectrum of Cell-Mediated Immune responses (CMI) predominate infection, projecting the role of macrophages and T-cell populations. In advanced stage, there is increased humoral response. Tuberculinization test, single intradermal test and comparative intradermal test, is the valuable delayed type hyper sensitivity test used for diagnosing TB in live animal, and used in TB eradication and for international trade. Vaccination of calves with attenuated bovine-strain of tuberculosis bacterium, known as Bacillus of Calmette and Guerin (BCG) and testing and culling are important measure in BTB control and prevention endemic area like Ethiopia. It is important to pasteurize milk before human consumption to reduce public health risk.

Prevalence of bovine tuberculosis and distribution of tuberculous lesions in cattle slaughtered at Gondar, Northwest Ethiopia

“…Despite the significant economic impacts and zoonotic risks associated with BTB [ 7 , 33 ], the available data of BTB prevalence are scarce in many areas of Ethiopia. In addition, in the country, most communities of smallholders and animal keepers share the same houses and air spaces with animals, and have insufficient knowledge on risks involved through consumption of animal products, thereby risking contracting zoonotic infections [ 16 , 34 ]. In particular, studies on the prevalence of BTB in cattle slaughtered in an abattoir in the Amhara region are inadequate.…”

Knowledge and practice of bovine tuberculosis among occupational workers in abattoirs in Abuja

“…Nigeria been the most populous country in Africa with over 160 million people, with an estimated cattle population of 19.5 million and unknown wildlife ruminants' population provide an opportunity for the easy transmission and spread of bovine type of TB with the country having the thirteenth highest burden of human tuberculosis among the world's 22 countries with high Tb burden (Krauss et al, 2003;Lees et al, 2004). Due to the lack of existence of a national control strategy and high degree of zoonotic transmission of tuberculosis from animals to humans, the situation with animal tuberculosis is less clear; Preventive measures such as culling of cattle with tuberculosis should be done without the treatment of such cattle due to the fact that most species especially Mycobaterium bovis have been reported to be resistant to drugs; regular testing and removal of infected cattle at abattoirs by Veterinarians should be carried out to prevent contact and consumption of contaminated carcasses by butchers, meat sellers and the general public; specific hygiene rules can be put in place at abattoirs that discourages butchers from consuming raw meat and milk products (Jemal et al, 2016;Fekadu et al, 2018).…”

“…This disease, is wide spread in nature, infectious and a leading cause of death due to a single infectious agent (Mycobacterium) among humans in the world; Mycobacterium tuberculosis is the most common cause of human tuberculosis; however, an unknown proportion of cases are due to Mycobacterium bovis (Damene et al, 2020;Mujeeb-ur-Rahman et al, 2020). Bovine tuberculosis (bTB) is a chronic contagious zoonotic disease of both domestic and wild animals including humans, primarily caused by M. bovis (Jemal et al, 2016). The disease is caused by a slowly growing bacillus which is a member of the Mycobacterium tuberculosis complex (MTC) comprising of different species; M. tuberculosis, M. bovis, M. africanum, M. canettii, M. caprae, M. microti and M. pinnipedii (Jenkins et al, 2011).…”

Public Awareness, Prevalence and Potential Determinants of Bovine Tuberculosis in Selected Districts of Gamo Zone, Southern Ethiopia

“…6 , 7 Although, studies disclosed currently that Mycobacterium tuberculosis has been diagnosed from cattle 6 and Mycobacterium bovis from humans diseased with bovine tuberculosis (bTB). 6 , 8 Whereas M. tuberculosis is explicitly adapted to humans, M. bovis is to cattle which identified frequently from farmed cattle. 6 , 9 Despite of its difference in host specificity, the belongings of MTBC are characterized by 99.9% or higher similarity at nucleotide sequence level and are essentially identical at sequence of 16s rRNA.…”