Pathologie und Abwehrreaktionen bei Insekten als Wirte von Parasiten des Menschen1

Abstract

AbstractPathology and defence reactions of insects as vectors of human parasitesIt is shown by means of numerous examples how the vector can be damaged: some organs of the vector might become unfunctional, the reproduction rate might decrease and the rate of mortality might increase. Due to these pathological effects there is a negative selection pressure upon the susceptible part of a vector population. On the other hand the resistant individuals are favoured. The special conditions for the parasites in genetically resistant vectors are not known exactly. But there ist known a lot of defence reactions in insects against parasites. The midgut barrier and cellular or humoral defence reactions of the haemolymph can inhibit the development of parasites. ‐ Pathological effects as well as defence reactions are factors bringing into existence a host‐parasite‐system with a vector tolerant against some kind of damage and an inoffensive parasite. But there is the need too for the parasite for adaptation on newly emerging defence mechanisms of the vector. These things are discussed on the system Plasmodium‐mosquito. Here it is important to differentiate between the reaction of the vector against damage through the parasite (sensible or tolerant individuals) and the effect of the vector on the development of the parasite (susceptible or resistant individuals).