A perspective for parasite management

Abstract

This paper refers to the limitations of the traditional linear approaches to parasite control in livestock systems as exemplified by their reliance on the use of limited specific control methods. It is claimed that these approaches show little appreciation of the complex dynamic nature of host/parasite associations and give little indication of concern for economic, ecological or social consequences. The emerging re-orientation of agricultural research associated with the development and application of systems ecology to production problems, and the appeals for higher order interdisciplinary investigations implicit in protection ecology, provide the impetus to develop a perspective for parasite management. The latter refers to the sum of informed manipulations of host/parasite systems to assure favourable economic, ecological and sociological consequences. As such it provides an approach subordinate to but directly relevant to, the wider spectrum of total pest management. The areas of information considered crucial to permit optimal informed manupulations and which can identify research priorities for parasite management are displayed schematically and discussed. Finally a paradigm is presented which attempts to illustrate the critical steps in a formal decision analysis of a parasite management programme. The probable outcome of interactions between relevant environmental predictors and livestock production depression events can be assessed in relation to the manipulations possible to the system. The optimizing actions indicated by the expected monetary returns from these interactions are themselves qualified by utility functions as well as by environmental, sociological and macro-economic impacts of the various manipulations and their combinations as management programmes. It is concluded that greater awareness of the form, function and dynamics of agroecosystems is needed if management manipulations are to be compatible with long term stability and high productivity.