Tuberculosis, caused by Mycobacterium bovis, was first diagnosed in African buffalo in South Africa's Kruger National Park in 1990. Over the past 15 years the disease has spread northwards leaving only the most northern buffalo herds unaffected. Evidence suggests that 10 other small and large mammalian species, including large predators, are spillover hosts. Wildlife tuberculosis has also been diagnosed in several adjacent private game reserves and in the Hluhluwe-iMfolozi Park, the third largest game reserve in South Africa.The tuberculosis epidemic has a number of implications, for which the full effect of some might only be seen in the longterm. Potential negative long-term effects on the population dynamics of certain social animal species and the direct threat for the survival of endangered species pose particular problems for wildlife conservationists. On the other hand, the risk of spillover infection to neighboring communal cattle raises concerns about human health at the wildlife-livestock-human interface, not only along the western boundary of Kruger National Park, but also with regards to the joint development of the Greater Limpopo Transfrontier Conservation Area with Zimbabwe and Mozambique. From an economic point of view, wildlife tuberculosis has resulted in national and international trade restrictions for affected species. The lack of diagnostic tools for most species and the absence of an effective vaccine make it currently impossible to contain and control this disease within an infected free-ranging ecosystem. Veterinary researchers and policy-makers have recognized the need to intensify research on this disease and the need to develop tools for control, initially targeting buffalo and lion. #

VP1 gene sequences of SAT-2 type foot-and-mouth disease (FMD) viruses recovered from impala and African buffalo in the Kruger National Park (KNP) were used to determine intra- and interspecies relationships of viruses circulating in these wildlife populations. On this basis five distinct lineages of SAT-2 virus were identified in routine sampling of oesophageopharyngeal epithelium from buffalo between 1988 and 1996. Different lineages were associated with discrete geographic sampling localities. Over the period 1985-95, four unrelated epizootics occurred in impala in defined localities within the KNP. Evidence for natural transmission of FMD between buffalo and impala is presented for the most recent 1995 outbreak, with data linking the 1985 and 1988/9 impala epizootics to viruses associated with specific buffalo herds.

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Transmission of a plaque-purified SAT-2 foot-andmouth disease virus (FMDV) occurred erratically from artificially infected African buffaloes in captivity to susceptible buffaloes and cattle in the same enclosure; in some instances transmission occurred only after contact between persistently infected carriers and susceptible animals lasting a number of months. Because the rate at which FMDV mutations accumulated in persistently infected buffaloes was approximately linear (1.64% nucleotide substitutions per year over the region of the 1D gene sequenced), both buffaloes and cattle that became infected some months after the start of the experiment were infected with viruses that differed from the original clone. The nucleotide differences were reflected in significant antigenic change. A SAT-1 FMDV from a separate experiment inadvertently infected some of the buffalo in the SAT-2 experiment. The SAT-1 FMDV also accumulated mutations at a constant rate in individual buffaloes (1.54% nucleotide changes per year) but the resultant antigenic variation was less than for SAT-2. It is concluded that persistently infected buffaloes in the wild constantly generate variants of SAT-1 and SAT-2 which explains the wide range of genomic and antigenic variants which occur in SAT-1 and SAT-2 viruses in southern Africa.

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