Showing papers on "Bulinus truncatus published in 1984"

Investigations of Molluscicidal Activity of Certain Sudanese Plants Used in Folk-Medicine. Part IV*.

Abstract: 50 plants indigenous to the Sudan and of common use in Sudanese folk-medicine, were screened for their molluscicidal activity, using two local snail vectors, BULINUS TRUNCATUS and BIOMPHALARIA PFEIFFERI. At different concentrations 31 (62%) of these plant samples were found to be lethal to either one or both of the snail species. 28 (56%) proved to be lethal to BIOMPHALARIA PFEIFFERI, 22 (44%) gave 100% mortality to BULINUS TRUNCATUS; while 19 (38%) killed both snail hosts (Table I). The seven most active molluscicidal plants were phytochemically screened for their active constituents; four of them showed the presence of saponins.

The prepatent period and cercarial production of Schistosoma haematobium in Bulinus truncatus (Egyptian field strains) at different constant temperatures.

Abstract: The developmental time ofSchistosoma haematobium inBulinus truncatus snails (field strains) was determined in the laboratory at different constant temperatures between 18 and 32°C. The basic relationship between the length of the minimum prepatent period (y, in days) and the temperature (x, in °C) is given by the hyperbolic formulay=295/(x-15.3), 15.3 being the theoretical “developmental null point” and 295 the constant time-temperature product. The shortest prepatency was 17–19 days at 30, 31 and 32° C; at 18° C, cercarial development required at least 106–113 days. The maturation time frequently exceeded the possible minimum by several weeks. No schistosome matured in our experiments at 17° or 33° C. The cercarial release per snail at weekly exposures showed a maximum at 25°C with a geometric mean of 109 cercariae (95% confidence limits 79–149), decreasing to 8 (2–30) at 18° C and 62 (38–100) at 32° C. The absolute maximum of cercariae shed by one snail during 5 h “stimulation” was 2,150 in a 25° C batch, 48 at 18° C and 529 at 32° C. The epidemiological application, the prognosis of the transmission period and the estimation of the transmission potential in relation to climatic conditions are discussed.

The invasion of Biomphalaria pfeifferi by Schistosoma mansoni miracidia and the development of daughter sporocysts

Abstract: Laboratory experiments have been carried out to determine the susceptibility of Gezira Biomphalaria pfeifferi snails to S. mansoni miracidia and the relationship between miracidia and daughter sporocyst production at the 10–17 day development stage. The relationship between snail numbers, miracidia numbers and water volume has also been studied. Two non susceptible snails, Bulinus truncatus and Cleopatra bulimoides, both of which occur naturally in Gezira canals, were tested to see if they act as decoys for S. mansoni miracidia.