Dr. Holló Ferenc szerk.: Parasitologia Hungarica 3. (Budapest, 1970)

very low percent of soluble oxygen content, at a time when the bacterial flora and the fauna of unicellular animals are already rich in the water of the pools (MIHÁLYI et al

.,1954-1963). Some words should yet be said on the problem of the final liquidation of mosquito breeding sites in the inundation area. There is no doubt that a final solution can be expected only from the technical regulation (draining, pumping, filling, etc.) of the given area (ZOITAI, 1957). However, a most important aspect of the case should never be forgotten! And this is the fish replacement problem of the rivers. Owing to the regulation of rivers, most of the natural fish spawning sites had disappeared beginning with the fifties of the last century. I,t is only in the inundation a,rea of the rivers that fish today find occasional sites for spawning. The undiscriminating eradication of these sites for the sake of eliminating mosquito breeding at all costs is worth reconsideration. Mosquitos can and should be controlled, but only with measure and after the reconciliation of all demands. Even the chemical treatment of the breeding sites should be launched only after fish had returned to the live waters of the river and no fresh, prolongedly high water can be expected.Chemical control of mosquitos abiding on coastal vegetation must also be executed so that no insecticide substance comes into the water. Einall y

, we should like to emphasize that making an area free of mosquitos, be it by any one of the applicable methods, is a rather expensive and painstaking process. In principle, one should therefore undertake an institutional control in two cases only: a. at the danger of an epidemy (e.g. malaria); b. in places habitually visited by masses of people, and then, too, only in strictly circumscribed areas (e.g. in the parks of summer resorts, camping sites, etc.), and only if a significant density of mosquitos has been found. Eor individual protection, we suggest the application of mosquito repellents („Mosquito" cream) or aerosol flasks (e.g. „Chemotox") for indoors control.