Showing papers on "Biomphalaria alexandrina published in 1979"
TL;DR: The data showed that despite continuous presence of food in the aquaria food competition was involved in the direct interference between the two species, while the role of chemical interactions could not be evaluated conclusively from the present experiments.
Abstract: Biological control of schistosomiasis by means of introduction of a competitor, Helisoma duryi, of the intermediate host snails has been proposed. In the present laboratory studies the competitive relationships between H. duryi and two Biomphalaria species were investigated both when direct interference between the two competing species was possible and when not. A reduction of growth and reproduction of Biomphalaria was found when direct interference was involved but the effect of competition was lessened when the two species were separated by a mesh. The data showed that despite continuous presence of food in the aquaria food competition was involved in the direct interference between the two species, while the role of chemical interactions could not be evaluated conclusively from the present experiments. The role of food is discussed.
10 citations
Journal Article•
TL;DR: Biomphalaria alexandrina, the snail vector of S. mansomi, was eradicated through ecological factors (salinity and pollution by sewage) and human activities and the elimination of snail vectors by applications of chemicals succeeded when the entire infested foci were isolated.
Abstract: A review of the epidemiological status of urinary schistosomiasis and intestinal schistosomiasis in Israel is made. The ecology, bionomy and geographical distribution of the snail vectors were studied and research on their vectorial capacity to the imported Schistosoma strains was undertaken. Biomphalaria alexandrina, the snail vector of S. mansomi, was eradicated through ecological factors (salinity and pollution by sewage) and human activities. The elimination of snail vectors by applications of chemicals succeeded when the entire infested foci were isolated. The factors responsible for the reappearance of snail vectors after those chemical applications are described. Examples are given of successfully combined measures used for the control of snail vectors; increase of water currents to over 20 cm/sec, rapid emptying and drying up of water reservoirs, weekly deflection of infested water courses in different directions, etc. In 1951, 19 schoolchildren became infected with S. mansoni and in 1955, 97 schoolchildren became infected with S. haematobium. Since 1955 no more new infections with Schistosomiasis have been reported in Israel.
5 citations
Journal Article•
TL;DR: Under the chosen experimental conditions H. duryi revealed higher tolerance limits and survival rates than B. alexandrina and B. truncatus, and as biological control agent of Schistosome vector snails is discussed.
Abstract: The influence of 10 degrees, 18 degrees, 26 degrees, 28 degrees and 33 degrees C, different periods of complete darkness and starvation on growth and survival of H. duryi, B. alexandrina and B. truncatus were studied. The optimum temperature for the growth and survival was about 26 degrees C. Survivorship and growth rates decreased proportionately according to starvation period. However, darkness had no significant effect on the growth of B. truncatus and H. duryi. Under the chosen experimental conditions H. duryi revealed higher tolerance limits and survival rates than B. alexandrina and B. truncatus. The potential of H. duryi as biological control agent of Schistosome vector snails is discussed.
2 citations