Dr. Murai Éva szerk.: Parasitologia Hungarica 22. (Budapest, 1989)

An objective insight into the nature of biocenotic relationships and interactions of compounds of a parasitic system at a given level can be obtained only by a thorough Investigation of their biocenotic relationships within the system of a higher level. A systemic approach makes it possible to elaborate precise ideas of the dialectical unity of interrelated systems of different levels and interactions of their compounds both vertical and horizontal. The most complete and adequate view on parasitism can be obtained by considering it at the level of symbiocenotic ecosystem comprising, in addition to parasites, all other symbionts of a given biocenosis as well as hostal environment. A symbiocenotic ecosystem is represented by (1) symbiocenosis divided Into monoxenous symbiocenoses developing in populations of one host species and microsymbiocenoses (parasitocenoses, according to Ye. N. Pavlovsky) as well as by (2) a symbiocenogenic hemisystem that unites all populations of free-living stages of symbionts (including parasites). This hemisystem should also be divided into monoxenous symbiocenogenic hemisystems which consist of microsymbiocenogenlc hemisystems that contribute to the formation of monoxenous symbiocenoses and many microsymbiocenoses . The study of a very complicated symbiocenotic ecosystem and most multiform relationships between its components is the problem of symbiocenology - the science of the remote future. It should have as the object the whole immense world of symbionts (including all parasites) that by far surpasses, with regard to its species composition, the world of free-living organisms. When creating integrative parasitology there will undoubtedly arise possibilities of studying at least few-component symbiocenotic ecosystems. This research will not only stimulate the evolution of symbiocenology but will enable us to more adequately perceive the essence of parasitism. In order to develop a systemic approach and to study existing processes and phenomena, a general method of cognition - namely modelling - has proved to be an effective tool. In parasitology as well as in medicine and veterinary science methods of mathematics, physics and statistics are widely used. They are able to benefit the study of the nature and development of epidemic, epizootic and epiphytotlc processes, the elucidation of their dependence upon principal écologie factors and stability of a parasitic ecosystem. These methods enable us to quantitatively estimate regularities on which the phenomena of parasitism are based, to establish numerical interdependencies between parasites and hosts, to prognosticate the dynamics of their number, to solve the problems of landscape parasitology. They broaden the limits of scientific knowledge, solve complicated theoretical, methodical and applied tasks. However, one cannot forget that a purely mathematical Interpretation of parasitism and events they engender in a host raises great difficulties of methodological nature. First of all, it is very difficult to isolate and express quantitatively all factors that play a part in the phenomena of parasitism. In addition, it is impossible to take into account all innumerable variables that characterize not only a certain parasitic ecosystem, but also Its principal compounds as well as all kinds of anthropogenic factors this system Is affected by. A successful application of mathematical analysis requires correct understanding of its essence and potential a precise consideration of characteristics of objects and phenomena studied, their dependence upon factors of environment and those related to the economic activity of man. Due to ungrounded abstractions the connection with reality can be lost and a researcher can be misled into false theoretic constructions. Despite the fact that mathematical methods are far from providing an adequate reflection of reality, one cannot forget that these methods, when used by high-skilled experts, provide them with keener knowledge of factors defining parasitic events, with rationalization of collecting and processing parasitological data.