Wildlife tuberculosis in South African conservation areas: implications and challenges.

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 long-term. 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.

Prevalence of bovine tuberculosis in African buffalo at Kruger National Park.

Bovine tuberculosis (BTB) was first detected in Kruger National Park (KNP) in a single African buffalo (Syncerus caffer) in 1990. In 1991/1992, 2,071 African buffalo were examined for BTB as part of a culling program that removed animals from all known herds in KNP. The prevalence of BTB in 1991/1992 was estimated to be 0%, 4.4% (+/-0.6%), and 27.1% (+/-1.4%), in the north, central, and south zones of KNP, respectively. In 1998, a stratified, two-stage cluster sampling method was used to estimate that the prevalence of BTB was 1.5% (+/-2.5%), 16% (+/-5.3%), and 38.2% (+/-6.3%), in the north, central, and south zones, respectively. This represented a significant increase in prevalence (P < or = 0.05) in the south and central zones, but not in the north zone. Continued monitoring of BTB in KNP is important for understanding disease transmission risks, potential population effects, and the efficacy of disease management strategies. The methodology and sample sizes used in 1998 are appropriate for future BTB monitoring in KNP.

Trichinosis (Trichinella spiralis infestations) in wild animals of the Kruger National Park.

In Africa trichinosis is essentially a disease of wild carnivores. Once established in a suilline cycle it becomes a more important threat to man. The results of tests on 8,000 specimens of 20 wildlife species in the Kruger National Park are discussed and the epizootiology of trichinosis in South Africa is briefly reviewed. The first case of trichinosis in an African civet, Viverra civetta Schreber, 1776, is reported. The confirmed absence of trichinosis in true herbivores is of practical significance in view of the increasing utilization of game meat as food.