Showing papers on "Bulinus truncatus published in 1976"

Studies on schistosomiasis in Saudi Arabia.

Abstract: During studies on schistosomiasis in Saudi Arabia, urine and stool samples from inhabitants of various areas (mostly rural) were examined, and 97 aquatic habitats in 46 localities were searched for snails. The results indicate the occurrence of both urinary and intestinal schistosomiasis in most parts of the country, with a patchy distribution and varying infection rates. The snail intermediate host of Schistosoma mansoni was found to be Biomphalaria arabica. For S. haematobium three species of snails, namely, Bulinus truncatus and B. beccarii in the west and B. reticulatus wrighti in the northeast, may transmit the infection; the susceptibility of the two former species has been confirmed in the laboratory. The limitation in the size of snail habitats--which consist of wells, small canals, cisterns, small swamps, interrupted streams, and ponds--creates a special type of transmission which can be defined as "oasis transmission," making control of the disease both simple and practical.

Techniques for estimating densities of Bulinus truncatus rohlfsi and its horizontal distribution in Volta Lake, Ghana.

Abstract: Bulinus truncatus rohlfsi is the intermediate host of urinary schistosomiasis, which is highly endemic in the man-made Volta Lake. In 1971, a WHO/UNDP schistosomiasis project was established in the Pawmpawm branch and part of the Afram branch of Volta Lake. Malacological findings of the preliminary phase indicated that the snails were distributed in the littoral zone of the lake, and that this distribution was correlated with the presence of vegetation, especially Ceratophyllum. Transmission nearly always occurred in "water contact sites", i.e., places where people come into contact with water.A snail-sampling technique with palm-leaf mats was developed and standardized after it had been shown in sensitivity trials to compare favourably with a modified version of the "man-time" sampling method, in which the number of snails collected per man-hour is recorded. It is recommended that both these methods should be used to conduct ecological studies of B. rohlfsi in water contact sites.

The molluscicidal properties of natural products from Ambrosia maritima.

Abstract: The molluscicidal properties of Damsin "I", Ambrosin "II", and tribromodamsin "III" were investigated against the intermediate hosts of schistosomiasis Biomphalaria alexandrina and Bulinus truncatus. Although Damsin was to some extent more toxic against B. alexandrina than the other two compounds, it was less toxic than them against B. truncatus after 24 hr exposure periods. There is a flex relationship between concentration of Damsin and exposure period to prodce 100% mortality. The molluscicidal potency of Damsin remained stable over a wide range of pH values, but was affected by storage, sunlight and river bed-mud. Structure-activity relationship is included.

A tetraploid freshwater snail (Planorbidae: Bulinus) in the highlands of Kenya

Abstract: Summary Several levels of polyploidy are known in freshwater snails belonging to the Bulinus truncatus/tropicus complex. All are present in the highlands of Ethiopia, but only the tetraploid B. truncatus has been recorded from Kenya, living in the western lowlands. Observations are reported here on the chromosome number, shell, internal organs and egg-proteins of snails from 26 localities in the highlands of central Kenya; data are also given for B. truncatus from five localities in western Kenya. Diploid (2n = 36) and tetraploid (2n = 72) snails were obtained in central Kenya, the tetraploid being found only on the Kinangop Plateau (Aberdare Range) and Mau Escarpment at altitudes above 2400 m (7900 ft). There appeared to be no significant differences between diploid and tetraploid snails from the highlands in respect of morphological features or egg-proteins. However, the highland tetraploid differs from B. truncatus in characters of the shell, internal organs and egg-proteins and appears to have origina...

Studies on the biology of bulinus truncatus under laboratory conditions

Abstract: A two-year laboratory study on the biology (including self-fertilization) of Bulinus truncatus, the intermediate host of Schistosoma haematobium, S. bovis and Paramphistomum microbotrium in Iran, has revealed information on the longevity, reproduction, hatchability rate, hatching time during various months of the year, and growth and mortality rates of this snail. It was found that the reproduction, hatchability and growth rate of Bulinus truncatus increase under condition of self-fertilization.