Showing papers on "Bulinus truncatus published in 1982"

The effect of temperature, darkness, starvation and various food types on growth, survival and reproduction of Helisoma duryi, Biomphalaria alexandrina and Bulinus truncatus (Gastropoda: Planorbidae)

Abstract: Helisoma duryi has been proposed as a biological control agent in schistosomiasis due to its superiority in laboratory competition experiments with various species of the intermediate host snails. Therefore it was considered important to evaluate the response of this snail species and the intermediate host species, Biomphalaria alexandrina and Bulinus truncatus, to various physical, chemical and biological factors under laboratory conditions in order to obtain information on the similarities in the ecological niches of these species. The factors considered in the present paper are: temperature, darkness, starvation and food. All three species had optimal growth and egg laying at 26–28 °C. Only H. duryi survived for a longer period at 33°C and it was capable of starting egg laying at this temperature although the onset was delayed. However, low temperature (18°C) caused a relatively larger decrease in egg laying of H. duryi than in the other two species. Growth and egg laying was reduced for H. duryi and B. truncatus kept under darkness and B. alexandrina could not tolerate maintenance under darkness. A few days of starvation of juvenile snails had no effect on later growth and egg laying capacity of the survivors, although mortality in B. truncatus was increased. B. alexandrina had a lower tolerance to starvation than the other two species. Egg laying of snails fed only one of the three laboratory food types decreased for all three species in the order: Vov-vov (dog food in dry pellets), Tetramin (fish food) and lettuce. Combinations of lettuce and one or more proteinaceous food types gave optimal growth and egg laying for all three species.

Molluscicidal properties of Acacia nilotica.

Abstract: The acetone, alcohol and aqueous extracts of fruits of ACACIA NILOTICA (L) W ILLD. ex D EL. (Mimosaceae) showed molluscicidal activity against BULINUS TRUNCATUS and BIOMPHALARIA PFEIFFERI, the two snail species which transmit schistosomiasis in the Sudan (S. haematobium and S. mansonii). TAN, a new vegetable molluscicide prepared from the aqueous extract of the fruits of A. NILOTICA was produced on a pilot scale by using the spray drying procedure. Due to the high content of tannins in the powder (more than 56%), the molluscicidal properties of this plant may well be due to these compounds.

Comparative effects of schistosome infection and starvation on the respiratory transport chain of the snails Biomphalaria alexandrina and Bulinus truncatus

Abstract: 1. 1. The activity of succinate oxidase, NADH oxidase, Succinate—methylene blue reductases and Cytochrome oxidasa was determined. 2. 2. The rate of oxidation of these enzymes was higher in B. truncatus then B. alexandrina . However, the mitochondrial system of B. truncatus is more sensitive to starvation and Schistosome infection conditions. 3. 3. Both starvation and schistosome infection inhibit the oxidation of these enzymes which was more pronounced in case of starvation. 4. 4. Addition of Amytal, glutamate α-keto-glutarate, ATP and ADP to mitochondrial preparation reversed the inhibition effects caused by schistosome infection and did not reduce the inhibitory effects of starvation. 5. 5. It is suggested that the reduction in oxygen consumption by mitochondria prepared from infected snails is attributed to accumulation of oxaloacetate, and that from starved snails attributed to other mechanisms in which accumulation of oxaloacetate is not involved.

Epidemiologic study of S. haematobium bilharziasis in the rice fields of Yagoua (North Cameroon) II. Distribution and ecology of intermediate hosts

Abstract: While inventoring the local malacological fauna and evaluating the density of species acting as intermediate hosts of human schistosomes it has been shown that Bulinus truncatus is predominant in the study area. Bulinus globosus is scarcely encountered. Biomphalaria pfeifferi is only found in the Mayo Guerleo, in irrigation canals and draining ditches. But B. globosus and B. pfeifferi have not yet invaded the recent aquatic network and are not found in the lake nor in the newly created irrigation systems. Snails shedding cercariae of S. haematobium and S. mansoni have been collected in the area. Bulinus forskalii is found in all types of permanent of temporary waterbodies but S. intercalatum has not yet been reported from North-Cameroon. Lymnaea natalensis, the intermediate host of Fasciola gigantica, is found in the lake and in the canals, in the Mayo Guerleo and in the Toupasko pool. The rice field does not form by itself a favorable environment for snails to develop in it. Spots where transmission occurare more often in the area the secondary of tertiary irrigation canals and the brains. The ditches obstructed by plants are the places where the snails are developing best. Bulinus spp. are found in large numbers in the lowest parts of the aquatic network and they accumulate there to survive drought conditions in the mud. The recently built irrigation systems are not massively invaded by the snails yet and the prevalence of bilharziasis in the area correspond to the distribution of the intermediate hosts of schistosomes and to the density of the snails populations.

The molluscicidal properties of the crude saponins in Agave angustifolia «Marginata» Agave celsii and Yucca filamentosa «Variegata»

Abstract: L'etude comparative de la sensibilite de Biomphalaria alexandrina et Bulinus truncatus a l'action de saponines dans des extraits aqueux de Agave angustifolia, A. celsii et Yucca filamentosa est determinee. L'action de quelques facteurs de l'environnement sur l'activite molluscicide de ces saponines est recherchee