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At least 19 recordsLinked to original sources
PubMed1984

[Experimental taxonomy of Bulinus (Gastropoda:Planorbidae). VI. The possibility of using enzyme characteristics for the distinction between the species Bulinus liratus and Bulinus obtusispira in Madagascar].

Based on a study of one laboratory culture of each of the three species Bulinus forskalii, B. obtusispira and B. liratus it is shown that the two last mentioned species differ in enzyme mobility in seven out of eight enzymes investigated. It is pointed out, that, prior to using enzyme characters for identification purposes, a study of the intra- and interpopulation variation should be carried out. It is mentioned, that the difference in absolute mobility, the quality of the bands and the price for the enzyme stainings should be taken into consideration, when enzymes are used for identification of Bulinus species. For the specific problem of separating B. liratus and B. obtusispira it is suggested to study the intra- and interpopulation variation in the enzymes alpha-glycerophosphate dehydrogenase, phosphoglucose isomerase, hydroxybutyrate dehydrogenase and esterase-d with the aim of finding one or more enzymes usable for distinguishing these two, morphologically similar, species.

Animals↗
PubMed1993

Purification of an agglutinin from the haemolymph of the snail Bulinus nasutus and demonstration of related proteins in other Bulinus spp.

The snail Bulinus nasutus 1214 possesses a potent haemagglutinin (end-point titre with human erythrocytes, 2(-18)) in its cell-free haemolymph which also binds to the miracidia (but not other larvae) of the incompatible parasite Schistosoma margrebowiei. We have purified a protein possessing this haemagglutinating property from the plasma of this snail. The native Mr of this protein was estimated by SDS polyacrylamide gel electrophoresis to be 210 kDa; under denaturing conditions in a 7.5% PAGE gel it ran as a major band of 135 kDa. Proteins of similar Mr were also found in the haemolymph of 16 other Bulinus spp. (the major intermediate hosts of human and veterinary schistosomiasis in Africa) although the plasma of none of these agglutinated human erythrocytes. Nonetheless, Cleveland mapping of the Mr 135 kDa bands from these different Bulinus spp. revealed 4 identical major peptide fragments (30, 28, 19 and 16 kDa) in each, thus demonstrating a similarity in the primary structure of these plasma proteins. Antisera from Balb/C mice immunized with the 135 kDa polypeptide from Bulinus truncatus 1521 cross-reacted in Western blots with the 135 kDa band of other members of the same truncatus/tropicus species complex but not with species from the africanus or forskalii species groups.

Animals↗
PubMed1993

The sugar chemoreception niches of Bulinus (physopsis) globosus (Morelet) and Bulinus rohlfsi (Clessin), the two most important snail hosts of Schistosoma haematobium (Bilharz) in west Africa.

1. The behavioural responses of two species of freshwater pulmonate snails [Bulinus (P.) globosus and Bulinus rohlfsi] to sugar gradients were investigated by means of diffusion olfactometers. 2. Both snail species proved to be very discriminating in their responses. Of the 17 sugars tested, 35.3%, namely D(-)glucuronic, maltotriose, maltose, cellobiose, D(-)arabinose, D(+)mannose proved to be statistically significant attractants or arrestants to B. rohlfsi. Only 23.5% of these sugars (maltotriose, maltose), D(+) mannose and D(+) xylose were significant attractants or arrestants to B. (P.) globosus. 3. Glucuronic acid was a significant repellent to B. rohlfsi but none of the sugars was a repellent to B. (P.) globosus. 4. The results are compared with those obtained for other snail species and their relevance to the ecology and control of the snails are discussed.

Animals↗
PubMed1992

[Population dynamics and infestation of Bulinus truncatus and Bulinus forskalii by schistosomal larvae in the Sudan-Sahelian zone of Cameroon].

The evolution of the population densities of Bulinus truncatus and Bulinus forskalii has been studied during 18 months in a number of sites of the Sudan-Sahelian zone of Cameroon, in relation to certain environmental factors. Only the altitude of the water in the sites has an influence on the density of the snails. The populations of B. truncatus present a greater proportion of young molluscs during the entire year, with the exception of the last months of the dry season. The population dynamics of B. forskalii varies depending on whether the environment is temporarily stagnant, temporarily running or stable. The proportions of B. truncatus and B. forskalii that emit cercariae of schistosomes are 1.2% and 0.8% respectively. Study of the adult worms obtained after infestation of the laboratory mammals show that B. truncatus emits cercariae of Schistosoma haematobium at the end of the dry season and at the beginning of the rainy season. We have not been able to identify precisely the cercariae emitted by B. forskalii, which raises the necessity of further systematic studies being carried out on the schistosomes of Cameroon.

Animals↗
PubMed1981

Mixed populations of Bulinus senegalensis (Muller) and Bulinus forskali (Ehrenburg) (Mollusca: Planorbidae) in The Gambia.

A brief survey of alluvial pools and irrigated ricefields in The Gambia shows that the distribution of Bulinus senegalensis is not confined to laterite pools and is similar to that in neighbouring Senegal. B. senegalensis was found in every site at least once, alone or with B. forskali. The proportion of the two species varies during the season and from year to year. It is no longer necessary to consider B. forskali as a natural host of S. haematobium.

Animals↗
PubMed1989

[Resistance to drought of mollusks of the genus Bulinus, vectors of human and animal trematode infections in Senegal. II. Study under natural conditions in the North-Sudan area. Ecology and resistance to drought of Bulinus umbilicatus and B. senegalensis].

The authors report on the results of a 2-year study on the ecology and resistance to drought of B. umbilicatus and B. senegalensis on 3 temporary ponds in the North-Sudan area (region of Tambacounda, Senegal). The variations in some abiotic factors like the temperature and the pH of water do not seem to have a strong influence on the ecology while rainfall has a great importance on the distribution and the density of molluscs. As a fact, the quantity of water and the drying out period of these ponds depend upon rain factors which rule the existence and the survival of the malacological fauna. In the second part of the rainy season, the population reaches its maximum, i.e., during the reproduction period. Monthly observations show that the relative abundance of B. umbilicatus is higher than that of B. senegalensis. These ponds are dry during 6 to 8 months per year. However the populations of molluscs regenerate regularly, a fact which presupposes a certain ability to resist drought. Some come through this period successfully, but the middle-sized ones (7 to 9.9 mm) resist better than others (70 to 80 per cent of the population). Immediately after the first rains they resume their activity and lay intensively in order to reconstitute the population. B. umbilicatus and B. senegalensis are potential intermediate hosts for human and animal trematode infections, but in the studied region only B. umbilicatus intervenes in the transmission of S. haematobium and S. curassoni which occurs between September and November. Under natural Sahel conditions the epidemiological cycle is short and everything happens within 4 to 6 months with the regeneration and the growth of the population of molluscs, its infestation and the transmission of trematode infections. The ecological behaviour of these molluscs in the North-Sudan region is very important in the epidemiology of human and animal trematode infections and requires a new controlling strategy. The destruction of molluscs is more effective and more economic at the end of the rain season, which is the beginning of the drying of ponds, a period in which they concentrate in the residual water pools.

Animals↗
PubMed1985

Studies on the ecology of Bulinus globosus, the intermediate host of Schistosoma haematobium in the Ifakara area, Tanzania.

During a period of 2 years, the ecology of Bulinus globosus was studied in 8 habitats in two streams near Ifakara, SE-Tanzania. The relative Bulinus densities were followed monthly. Two different methods for estimating snail densities (man/time vs. palmleaf traps) gave comparable results. Bulinus densities were constantly low throughout the year in the stream, but they showed distinct seasonal fluctuations in adjacent pools, with a density-peak at the end of the small rainy season. B. globosus, identified by starch gel electrophoresis, was found to be the only intermediate host for urinary schistosomiasis in the investigated streams. A correlation of the Bulinus densities with several abiotic and biotic factors revealed that pH, temperature and conductivity had little effect on the Bulinus population, as they oscillated within the tolerated limits. No correlation of the distribution of B. globosus and other snail species was found. Rainfall patterns have a distinct influence on snail densities. They determine the duration of desiccation and affect the snails by fluctuations of the water level and by the fast increase of water velocity after heavy rains. B. globosus shows a clear predilection for the sedge Cyperus exaltatus as support for oviposition. It is also preferred as food and/or food-support. During the dry season, oviposition of B. globosus is concentrated in clearly defined sites ("breeding pockets"), which, due to the lowering of the water level, become isolated from the stream or retain only a small connection to it. These sites form important reservoirs of B. globosus, from where the snails are spread when the sites are flooded during the subsequent rainy season. The significance of these observations for control measures is discussed.

Animals↗
PubMed1997

Cockroach allatostatin-like immunoreactivity in the central nervous system of the freshwater snails Bulinus globosus (Planorbidae) and Stagnicola elodes (Lymnaeidae).

Allatostatin-like immunoreactivity was demonstrated in the central nervous system (CNS) neurons of the freshwater pulmonate snails Bulinus globosus (Planorbidae) and Stagnicola elodes (Lymnaeidae). Immunopositive neurons were localized using a monoclonal antibody highly specific to allatostatin I (APSGAQRLYGFGL-amide) from the cockroach Diploptera punctata. All CNS ganglia in both snail species contained immunopositive neurons. The pedal ganglia showed large numbers (80-100) of neurons in Bulinus and Stagnicola. Large numbers of immunopositive cells were also found in the cerebral (60) and buccal ganglia (20) of Bulinus. Other ganglia contained fewer immunopositive cells, but these cells were most concentrated in the cerebral (Stagnicola) and left parietal (Bulinus) ganglia and the visceral ganglia of both species. The high concentration of immunopositive cells in the pedal ganglia and axons demonstrable in the pedal nerves suggests that one possible function for a molluscan allatostatin-like peptide would be to modulate muscular function. Extract of Stagnicola CNS effected 50% inhibition of juvenile hormone synthesis by corpora allata of D. punctata at between 15 and 30 CNS equivalents, providing further evidence that the molluscan immunoreactive material is a peptide, or peptides, with sequence similarity to the active part of the D. punctata allatostatins.

Animals↗
PubMed1977

On Schistosoma margrebowiei Le Roux, 1933: the morphology of the egg, miracidium and cercaria, the compatibility with species of Bulinus, and development in Mesocricetus auratus.

The morphology of the egg, miracidium, and cercaria of Schistosoma margrebowiei are described. The compatibility of S. margrebowiei with species of Bulinus has been examined. The parasite develops well in the diploid, tetraploid and octoploid snails of the truncatus/tropicus complex with overall infection rates of 38.1%, 30.1% and 29.1% respectively, and in reticulatus group snails (Bulinus wrighti) with an infection rate of 45.8% of those snails surviving the prepatent period. Only two species of the forskali complex (Bulinus bavayi, Aldabra; Bulinus beccarii, South Arabia) are slightly compatible, and snails of the africanus group are incompatible. The overall worm return from 24 hamsters exposed individually to 100 cercariae was 39.8%; 82.1% of the worms were paired, the remainder unpaired. The growth of the paired worms was recorded from 28-60 days. The prepatent period in hamsters in 33 days, in sheep 38 days. The mean egg production was 837 eggs/day in infections ranging from 33 to 60 days. Most eggs (80.9%) were deposited in the intestine, and only 18.2% were deposited in the liver. The parasite is pathogenic in hamsters, and peak death rate occurred in the 50-60 day group infections which coincided with the period of peak egg production.

Animals↗
PubMed1994

[Experimental study of a Malagasy strain of Schistosoma haematobium: compatibility with different Bulinus snails, potential intermediate hosts].

Experimental investigation on a malagasy strain of S. haematobium: compatibility with different Bulinus snails, potential intermediate hosts. A comparative experimental study of the infectivity of different Bulinus snails by a reference S. haematobium strain was made under laboratory conditions. The results support the role of Bulinus obtusispira as an intermediate host in Madagascar but some other Bulinus species could exist and play a role in the fields far away from the experimental criteria here described.

Adolescent↗
PubMed1996

[Survival of Bulinus truncatus and Biomphalaria pfeifferi in sewer water purified in stabilization ponds in a sudanese-saharan zone].

In subsaharan Africa wastewater purification to protect the health of the population could create stagnate water reservoirs for parasitic vectors such as snails which are intermediate hosts of bilharzia. Laboratory studies of the survival of Bulinus truncatus, an intermediate host of Schistosoma haematobium, and Biomphalaria pfeifferi, an intermediate host of Schistosoma mansoni, in waste water purified in stabilization ponds showed that Biomphalaria pfeifferi thrives to dirty water (60 mg/l < or = COD < or = 1060 mg/l) while Bulinus truncatus survived only in slightly cleaner water (60 mg/l < or = COD < or = 200 mg/l). Field studies showed that Biomphalaria pfeifferi disappeared after 48 hours as compared to 25 days in the laboratory. In both laboratory and field studies Bulinus truncatus survived only 24 hours in raw waste water. The duration of survival grew longer as quality of the water improved. Temperature variations, high amounts of organic material in water, high oxygen content in water, and absence of plant-life are factors which could limit the development of the intermediate snail hosts (i.e. Bulinus truncatus and Biomphalaria pfeifferi) in the waste stabilization ponds of the Interstate School of Rural Equipment Engineers in Ouagadougou, Burkina Faso.

Animals↗