Background

There are differing opinions about the need to control bovine tuberculosis (BTB), caused by Mycobacterium bovis, in cattle in many parts of the world. In the UK, for instance, the opinion has recently been expressed that the cost of attempting erad­ication is not justified given the low prevalence of the disease and the availability of pasteurized milk to all its inhabitants that protects them against the threat of contracting zoonotic TB by consuming M.

In most African countries, but for different reasons, BTB is also considered to be of minor importance, and veterinary regulatory authorities in many of the countries do not list it as a notifiable disease. The argument, based on the reasons given that may justify this attitude in the UK, does not apply to most of the African countries. The problem in Africa is that BTB occurs at a high prevalence in many of the countries although it may be in a patchy fashion, but most of the countries have insufficient data to assess the situation in cattle and in humans to allow them to make an informed decision about controlling the disease. A large proportion of Africa’s inhabitants do not have access to pasteurized milk, or prefer to drink raw or

A. B. Dibaba

Department of Pathobiology, College of Veterinary Medicine, Tuskegee University, Tuskegee, AL, USA

e-mail: adibaba@tuskegee.edu

N. P. J. Kriek (EI)

Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa

© Springer Nature Switzerland AG 2019

A.

The eradication or the ability to limit the disease to very low prevalence levels is important for those countries that manage to control the disease. They rely on the multilateral trade policy framework based on the General Agreement on Tariffs and Trade (GATT), the Agreement on the Application of Sanitary and Phytosanitary Measures (SPS), and the Agreement on Technical Barriers to Trade (TBT) of the World Trade Organization (WTO) to facilitate safe trade and to avoid unnecessary trade barriers. The WTO mandated the OIE as the international standard-setting organization to compile the international standards, guidelines, and recommenda­tions related to global animal health with the main purpose of facilitating interna­tional trade in terrestrial and aquatic animals and their products. The application of SPS measures avoids the introduction of pathogens via international trade in animals and animal products while at the same time preventing countries from setting up unjustified sanitary barriers to inhibit trade (Bruckner 2009).

Because of these reasons, the developed nations instituted campaigns and sustain them to control and eradicate M. bovis from their national cattle herd. The success of these programs has been mixed; some of the European countries managed to eradicate the disease, but even in the developed world, some experience difficulties to contain and eradicate BTB, usually because of the presence of a wildlife mainte­nance host in the same ecosystem.

Designing and applying control programs for BTB pose various challenges, many of them dependent on the diversity of people and ecological zones on the continent. Africa is often spoken of as if it were a single country. It is the second largest of the continents, and its 54 states are located in tropical and subtropical ecozones that include tropical, moist and dry forests, subtropical humid and dry forests, subtropical steppe, tropical and subtropical mountain systems, and deserts (FAO 2018). The composition of its people is as diverse, with different social norms, standards, age-old traditions, and development that vary from fairly advanced to some of the poorest countries on the globe. This influences the way in which people live and conduct their farming practices and assess the value of the livestock that they own. Cattle in certain cultures are not often slaughtered but are kept for prestige, milk, draft power, dowry, and savings to offset crop failure. The ethnic groups of Africa number in the thousands, each generally with its own language (or dialect of a language) and culture. The major ethnolinguistic groups include the Afro-Asiatic, Khoisan, Niger-Congo, and Nilo-Saharan populations. This diversity of factors makes it impossible to construct a single protocol for the control and eradication of BTB from the continent, since many of them have an impact on the epidemiology of the disease and the way in which it can be practically controlled (Zinsstag et al. 2008).

The ability to control the disease, in the final analysis, is conceivably mostly dependent on the stage of development of a particular country and the availability of competent human and sufficient financial resources that can be allocated for the control of M.

The internationally accepted method of successfully controlling and eradicating BTB is based on the test-and-slaughter approach following the detection usually of positive animals by the tuberculin skin test that is based on the assessment of the local dermal immunological response to the intradermal injection of PPD. This appears to be a simple matter, but it is an extremely tedious and expensive process. In the USA, reducing the prevalence to 0.001% in the national herd took 50 years at a cost of US$450 million (Gilsdorf et al. 2006). The successful control of the disease is also dependent on having access to adequate and sustainable funding, adequate veterinary diagnostic laboratories, and competent human resources, such as veteri­nary technicians and veterinarians, and acceptance by the policymakers, stockowners, and consumers of dairy products that the control of BTB is important and to the benefit of society as a whole.

This chapter deals with the various issues and the challenges to devise practical control programs for Africa that can be sustained with limited financial resources that would benefit the health and well-being of its inhabitants and the productivity of its livestock.

10.2