WILDLIFE PARASITES - LESSONS FOR PARASITE CONTROL IN LIVESTOCK

For sustainable livestock production it is suggested that the parasito logist take a leaf out of Nature's book in the search for solutions to the mounting problems concerning parasite control. While the farmer h as come to regard all parasites affecting livestock as entirely withou t benefit, indigenous parasites and diseases are normal and play an es sential role as interacting components of a natural environment in an ecosystem such as the 19000 km(2)-sized Kruger National Park, Republic of South Africa. The parasites help to select their hosts for fitness and are assisted by predators and intra-species territorial aggressio n which continually eliminate the weak individuals from the system. It is essential to guard against the introduction of foreign parasites o r infectious agents which have no real ecological niche or role in an established ecosystem, however, as they cause untoward interactions, s ometimes of a violent nature. The policy must be to block off or, fail ing that, to control or eliminate these foreign parasites and diseases as far as possible. Often, when Man intervenes in an ecosystem, it le ads to stress, overcrowding and stagnation and predisposes to disease and death. Intensification of the system, as in farming units, denies Nature the chance to manage on its own, because of clashing interests with Man. Frank parasitism and disease should almost invariably be see n as indicators of an imbalance in the ecosystem and should be rectifi ed. Chemicals and vaccines should be used to produce sufficient food f or all, but without exploiting Nature, or else Nature will be unable t o continue catering for Man's needs. (C) 1997 Elsevier Science B.V.