Seasonal factors influencing the location of Bulinus (Physopsis) globosus by miracidia of Schistosoma haematobium in nature.

摘要: Host location of Schistosoma haematobium has been investigated by using sentinel snails in a natural pond, summer and winter. During summer, miracidia/snail contacts were most frequent on the bottom or at surface shade; did not occur open water. In winter there was decline occurring along while an increase among confined surface-both shade light. Miracidia are sensitive to temperature light, their normal negative response light warm temperatures is reversed when drops 18 13 C. absence stimuli, miracidia seem scan nearest which they hatch, but under conditions orient prevailing stimuli warmth so that tend congregate specific regions habitat. Aspects host schistosome have recent years, evidence discreet behavioral mechanisms operate oriented physicochemical factors such as gravity, water depth, temperature, turbidity, salinity, chemical substances emitted themselves (Chemin Dunavan, 1962; Chernin Perlstein, 1969; Shiff, 1968, Upatham, 1972a, b; others). These interact any one time, Sturrock Upatham (1973) measured mutual effect pH, salinity infectivity mansoni miracidia. However, nature diversity interrelation increases, change may influence behavior both The pelagic, dwell surfaces. They undergo trophic activities bottom, vegetation either submerged upper surface, occasionally will crawl air-water meniscus. likely locality for snail-miracidium interaction these It logical expect orientate them use monitor dispersal established technique, here it used waterbody with caged anchored fixed localities associated some feature Received publication 4 October 1973. habitat shade, etc. Eggs S. introduced into left disperse naturally. Subsequently examined pattern infections found indicated extent dispersion. experiments repeated various times year apparently anomalous results further