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the molluscicidal properties of natural products from ambrosia maritima.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 molluscicid ...199923941
effect of certain insecticides in the control of the fresh water snails, biomphalaria alexandrina and bulinus truncatus. 197567018
immunodiffusion studies on schistosoma mansoni and its host stage specific antigens. 1. immunoelectrophoresis cross-reactions between s. mansoni adults and larval stages antigens.immunoelectrophoresis was applied to evaluate the immunologic relationship between the different stages in the life cycle of schistosoma mansoni (s.m.). the preparation of antigens and antisera was described. separated female and male adult worms tested seem to be identical. eggs, miracidia and cercariae from biomphalaria glabrata and biomphalaria alexandrina showed varying degree of cross-reactions. the maximal number of pricipitin arcs was observed, when anti-miracidia-serum was checked agains ...197877218
immunodiffusion studies on schistosoma mansoni and its host stage specific antigens. 2. immunoelectrophoresis cross-reactions between hepato-pancreas of biomphalaria glabrata and biomphalaria alexandrina.immunoelectrophoresis was used for studies on immunological cross-reactions between both schistosoma mansoni (s. m.) intermediate host snails biomphalaria glabrata and biomphalaria alexandrina. the preparation of antigens and their corresponding antisera from hepato-pancreas of s. m. infected and non infected snails was described as the homologous reactions of both snails either infected or non infected were rather similar, close immunological relationship between b. glabrata and b. alexandrina ...197877219
immunodiffusion studies on schistosoma mansoni and its intermediate host stage specific antigens. 3. immunoelectrophoresis cross-reactions between s. mansoni stages and biomphalaria sp. hepato-pancreas antigens.immunoelectrophoresis was applied for cross-wise checking of the different stages in the life cycle of schistosoma mansoni with extracts of hepato-pancreas from its intermediate host snails biomphalaria glabrata and biomphalaria alexandrina. only few fractions were common to non infected snail organ and parasite development stage, while more crossreactions were detected with infected snail hepato - pancreas.197877220
the influence of temperature, darkness, and starvation on growth and survival of helisoma duryi, biomphalaria alexandrina and bulinus truncatus.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 ...1979122361
the specific methods of control and eradication of schistosomiasis in israel.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 ...1979388774
prevalence of schistosomiasis among fishermen of lake maryut.a survey was carried out to investigate the presence of bilharziasis among the fishermen of the lake maryut. schistosoma mansoni is more prevalent, than s. haematobium among fishermen of lake maryut. biomphalaria alexandrina, snails were prevalent around the lake specially in places of low salinity, where fresh water discharges exist. bulinus truncatus snails were not found during the time of the present survey and more frequent surveys are needed. there is an inverse relation between the number ...1978555758
effect of some herbicides on the toxicity of certain molluscacides against biomphalaria alexandrina snails.studies dealing with the effect of some herbicides on the molluscicidal action of certain molluscicides against b. alexandrina have been carried out. in the first part of the study the toxicity of 3 molluscicides (copper sulphate, niclosamide and frescon) and 3 herbicides (gramaxone, preforan and treflan) was tested individually. results indicated that the molluscicides were more potent than the herbicides. in the second part, snails were exposed for 24 hr to one of the tested herbicides using l ...1978555760
total proteins & free amino acids in the hemolymph of snails biomphalaria alexandrina & helisoma duryi exposed to schistosoma mansoni miracidia. 1978680845
the molluscicidal properties of some bayluscide homologues.the molluscicidal properties of 5-nitro- and 3-nitro2',4'-dichloro salicylanilides and their mixture 5.5 : 1 were investigated against the intermediate hosts of schistosomes bulinus truncatus and biomphalaria alexandrina. unlike bayluscide, the activity of the new mulluscicides is not affected by strong sun radiation or by acidic ph. their activity is resistant to storage, river-bed mud and lower temperature.1977881142
larval trematode stages in bulinus truncatus and biomphalaria alexandrina snails. 19761025238
carbohydrate metabolism in uninfected and trematode-infected snails biomphalaria alexandrina and bulinus truncatus. 19751157458
the suitability of several aquatic snails as intermediate hosts for angiostrongylus cantonensis.sixteen species of aquatic snails of four families were tested by quantitative technique under standardized conditions for their suitability as intermediate hosts for angiostrongylus cantonensis. these species were the planorbid snails biomphalaria glabrata, biomphalaria alexandrina, planorbis planorbis, planorbis intermixtus, bulinus truncatus, bulinus contortus, bulinus africanus, bulinus tropicus and helisoma sp.; the lymnaeid snails lymnaea natalensis, lymnaea tomentosa, lymnaea stagnalis, a ...19751189583
a comparative study on the effect of repeated application of bayer 73 and mollutox on biomphalaria alexandrina. 19751232085
mollutox and bayer 73 as molluscicides against bulinus truncatus and biomphalaria alexandrina. 19751235499
studies on carbohydrates extracted from native and chemically treated biomphalaria alexandrina snails.1. carbohydrates were extracted from total tissue extracts of biomphalaria alexandrina snails and were analyzed to their monosaccharides using glc. 2. the snails were chemically treated with thioxanthone derivatives (compounds i, ii, iii) and the change in the monosaccharide constituents of their carbohydrates was investigated. 3. the isolated monosaccharides from native and chemically pretreated snails were injected into mice and their protective effects were examined after infection of mice wi ...19921360350
effect of the organophosphorous insecticide, chlorpyrifos (dursban), on growth, fecundity and mortality of biomphalaria alexandrina and on the production of schistosoma mansoni cercariae in the snail.exposure of biomphalaria alexandrina to sublethal concentrations (0.125, 0.25 and 0.05 ppm) of the organophosphorous insecticide, chlorpyrifos (dursban), induced a reduction in egg production and egg hatchability. exposure of schistosoma mansoni miracidia to the insecticide (60 min, 0.50 ppm) prior to infection of b. alexandrina did not affect the subsequent production of cercariae. however, exposure of s. mansoni-infected snails to the insecticide until day 55, from day 20 to day 62 and from da ...19921379273
ultrastructural aspects of intramolluscan developing cercariae of echinostoma liei.the ultrastructure of the daughter redia of echinostoma liei inside their host biomphalaria alexandrina is described. the tegument consists of one layer, bearing numerous microvilli on its outer surface. besides, the description of the ultrastructure of the developing cercariae within the daughter rediae is also included in the present study. the young cercariae are covered with a thin nucleated primitive temporary epithelium, which is lost when the true tegument is formed beneath it. the mechan ...19921500788
succinate-dcpip and nadh-fumarate oxidoreductases in fresh water snails susceptible and non susceptible to schistosoma infection.the activities of succinate-dcpip oxidoreductase (so) and nadh-fumarate oxidoreductase (fr) were determined in tissue homogenate of biomphalaria alexandrina and bulinus truncatus, the snail vectors of schistosomiasia. a parallel study was done on lymnea truncatula snails which are not susceptible to schistosoma infection. the michaelis constant (km) and maximum velocities (vmax) for fumarate reduction and succinate oxidation by the tissue homogenates from the three species were determined. the r ...19921571942
activity of some hydrolytic enzymes in tissue homogenates and haemolymph of fresh water snails, intermediate hosts in schistosomiasis.the activities of 5-nucleotidase (ec.3.1.3.5), alkaline phosphatase (ec.3.1.3.1), glucose-6-phosphatase (ec.3.1.3.9), and ribonuclease (ec.3.1.13) had been measured in tissue homogenate and in haemolymph of biomphalaria alexandrina, the specific intermediate host for the parasitic disease schistosomiasis, induced by the parasite schistosoma mansoni.19911657390
selection of susceptible lines of biomphalaria alexandrina and bulinus truncatus snails to s.mansoni and s.haematobium infection.selection of progenies from infected b.alexandrina and b.truncatus snails resulted in higher infection rates. this observation was consistent when the source of micardia were from either infected human or hamsters. infection rate of b.alexandrina increased up to 88.2% while b.truncatus did not. compatibility between the parasites and their intermediate hosts were also studied.19911791409
inhibition of lactate dehydrogenase isoenzyme associated with anaerobic respiration in schistosomiasis intermediate host snails.lactate dehydrogenase isoenzyme (ld5) which is associated with anaerobic respiration was inhibited to a certain degree in biomphalaria alexandrina snails, the intermediate host for schistosoma mansoni. urea and thiourea were used as inhibitors. the effect of ld5 inhibition on the mortality rate of infected biomphalaria alexandrina snails and on the susceptibility of the snails to the trematode infection was also studied.19911905584
experimental observations on the specificity of strigea falconispalumbi (trematoda: strigeidae) toward planorbid first intermediate hosts.planorbis planorbis, planorbarius corneus and biomphalaria alexandrina (egyptian strain) were ascertained as new experimental first intermediate hosts, thus bringing the total number of planorbid experimental first intermediate hosts to eight. the highest degree of compatibility was exhibited with p. planorbis (infection prevalence 80%) followed by p. corneus (46.6%), whereas b. alexandrina (as snail species not occurring in the geographical range of s. falconispalumbi) showed the lowest degree ...19911928800
variation of transaminases and lactate dehydrogenase in irradiated biomphalaria alexandrina snails.effect of ultraviolet and gamma radiations on the activities of aspartate aminotransferase (ast), alanine aminotransferase (alt) and lactate dehydrogenase (ld) in biomphalaria alexandrina snails, the specific intermediate host of schistosomiasis, was investigated. changes in the electrophoretic pattern of ld in the species under study were also taken as a measured parameter and the effect of gamma-irradiation on the glutathione content in the haemolymph of the snails have been included.19911934013
measurement of some selected enzymatic activities in infected biomphalaria alexandrina snails.the activities of aspartate (ast) and alanine (alt) aminotransferases and that of lactate dehydrogenase (ld) were measured in the homogenate of infected biomphalaria alexandrina snails, the specific intermediate hosts for the parasite schistosoma mansoni which is the cause of the disease schistosomiasis. the isoenzymatic pattern of ld was also studied in the infected snails tissue.19902083418
kinetic properties of two transaminases and lactate dehydrogenase of biomphalaria alexandrina snails, intermediate hosts of schistosoma mansoni.aspartate (ast) and alanine (alt) aminotransferase together with lactate dehydrogenase (ld) from the tissue homogenate of the biomphalaria alexandrina snails, were partially characterized by measuring the michaelis constant (km) and the maximum velocity (vmax). the isoenzymatic pattern of lactate dehydrogenase was investigated through polyacrylamide gel electrophoresis.19902279260
pseudechinoparyphium echinatum (digenea: echinostomatidae): experimental observations on cercarial specificity toward second intermediate hosts.infectivity of pseudechinoparyphium echinatum cercariae to 11 species of gastropod was examined experimentally. broad specificity and differential host-parasite compatibility were exhibited. nine gastropod species functioned as second intermediate hosts. planorbarius corneus, physa fontinalis, lymnaea peregra and biomphalaria alexandrina showed high levels of compatibility with the parasite. in single-species exposures over 90% of cercariae encysted in each of these hosts. low compatibility with ...19902362767
selected enzymatic activities in fresh water snails, specific intermediate host for human schistosomiasis.the activities of aspartate aminotransferase (ast) (ec.2.6.1.1.) i, alanine aminotransferase (alt) (ec.2.6.1.2) ii and lactate dehydrogenase (ld) (ec.1.1.1.27) iii have been measured in tissue homogenate and in haemolymph of biomphalaria alexandrina snails, the specific intermediate host for the human parasitic disease schistosomiasis due to schistosoma mansoni.19892499422
the molluscicidal properties of ambrosia maritima l. (compositae). 4. temporal and spatial distribution of biomphalaria alexandrina in egyptian village irrigation systems with reference to schistosomiasis transmission control.data on the temporal and spatial distribution of biomphalaria alexandrina were collected throughout one year in two village irrigation systems near alexandria, egypt. snails bearing schistosoma mansoni cercariae were found from may to december but about 80% of annual transmission potential was confined from june to august. although snail infection rates were generally 0-2%, higher rates were recorded and tended to be associated with smaller number snail collections. infected snails were found in ...19892505371
studies on fresh water snails, specific intermediate hosts for schistosomiasis 1--isolation of total lipids from native and irradiated snails.total lipids were isolated from native and irradiated biomphalaria alexandrina snails, specific intermediate hosts for schistosoma mansoni.19892514998
effect of schistosoma mansoni infection, starvation and molluscicides on acid phosphate, transaminases and total protein in tissues and hemolymph of biomphalaria alexandrina.the activities of got and gpt in the hemolymph of b. alexandrina were significantly decreased by s. mansoni infection. however, the total protein concentration and acp activity were increased. although the snail starvation decreased acp activity in the ovotestis, it increased got activity in the other organs of the snails. on the other hand, the snail feeding after starvation increased significantly acp activity in ovotestis. natural and synthetic molluscicides inhibited the activities of got an ...19892708850
intermediate host (biomphalaria alexandrina) antigens partly protect against subcutaneous infections with cercariae of schistosoma mansoni but are ineffective in infections by percutaneous invasion.mice were immunized against hepatopancreas homogenate of biomphalaria alexandrina, using al(oh)3 as adjuvant, and challenged by subcutaneous (s.c.) injection of schistosoma mansoni cercariae, percutaneous invasion of cercariae and intravenous (i.v.) injection of mechanically prepared schistosomula of different ages. significantly reduced (about 50%) numbers of adult s. mansoni were found 42 days after challenge in immunized animals infected by s.c. injection of cercariae. protective effects were ...19873122204
intramolluscan development of echinostoma liei (trematoda:echinostomatidae) in its snail host biomphalaria alexandrina. 20133722883
effect of some factors upon the susceptibility of biomphalaria alexandrina to infection with schistosoma mansoni. 19853932525
the effect of helisoma duryi on the cercarial production of schistosoma mansoni-infected biomphalaria alexandrina: evaluation of chemical interferences and direct competition.the effect of helisoma duryi or uninfected biomphalaria alexandrina conditioning of water, as well as the effect of direct competition with these, on the total cercarial production, growth and survival of schistosoma mansoni-infected b. alexandrina was investigated. the total cercarial production varied considerably between experimental groups. no differences were found between groups maintained in water-conditioned by h. duryi or by uninfected b. alexandrina with regard to the total cercarial p ...19853984453
phosphoglucoseisomerases in the sporocyst of the trematode schistosoma mansoni and its intermediate host biomphalaria alexandrina (pulmonata). 19744133208
antagonism of echinostoma revolutum against schistosoma mansoni in the snail biomphalaria alexandrina. 19744412039
laboratory studies on the direct effect of temperature on bulinus truncatus and biomphalaria alexandrina, the snail intermediate hosts of schistosomes in egypt. 19744414053
some helminths of bulinus truncatus and biomphalaria alexandrina from the irrigation system near cairo. 19744415826
control of snail hosts of bilharziasis in egypt. i. effect of triphenyltin hydroxide (du-ter) on aerobic oxidation of the snails biomphalaria alexandrina and bulinus truncatus. 19744471061
helobdella punctato-lineata as a potential predator of biomphalaria alexandrina snail populations under laboratory conditions. 19724643873
studies on the mode of action of some molluscicides on the snail, biomphalaria alexandrina. ii. inhibition of succinate oxidation by bayluscide, sodium pentachlorophenate, and copper sulphate. 19724666049
susceptibility of biomphalaria alexandrina to infection with schistosoma mansoni in egypt. 19734692876
the ecology of bulinus truncatus and biomphalaria alexandrina and its implications for the control of bilharziasis in the egypt-49 project area.the respective vectors of the two forms of bilharziasis in egypt do not have the same ecological distribution. bulinus truncatus is most abundant in large canals, and decreases in density as the water approaches and flows into drains. biomphalaria alexandrina is most abundant in drains, and decreases in density upstream from these habitats. both species are most abundant in the presence of aquatic vegetation, but they differ in their respective associations with the water hyacinth, eichhornia cr ...19665297630
field tests on two new molluscicides (molucid and wl 8008) in the egypt-49 project area.in a continuing search for more effective molluscicides, tests were carried out in the egypt-49 area on molucid and wl 8008. molucid, a 35% w/v solution of isobutyltriphenyl-methylamine (ici 24223), was applied at 2 ppm for 6 hours; after the treatment, no live bulinus truncatus, biomphalaria alexandrina or lymnaea caillaudi were observed for at least three months and snail densities remained low for at least seven months. egg-masses were not affected by the treatment, however. wl 8008, n-trityl ...19665298040
results of exposure of batches from highly susceptible and less-susceptible strains of biomphalaria alexandrina alexandrina from egypt to strains of schistosoma mansoni from cairo and alexandria. 19685306108
cercarial production from biomphalaria alexandrina infected with schistosoma mansoni.the present paper deals with longitudinal and cross-sectional methods of counting cercariae shed from biomphalaria alexandrina in egypt, both experimentally and naturally infected with schistosomes. by the longitudinal method, the daily output of cercariae was counted from the first shedding from experimentally infected snails and from the day of collection from naturally infected ones. the results show that the size of the snails at the time of shedding exerts a very large effect on the output ...19705310951
cercarial transmission seasons of schistosoma mansoni in the nile delta area.the cercarial transmission seasons of schistosoma mansoni in the nile delta area were determined by 3 methods: (1) monthly cercarial infection rates in biomphalaria alexandrina, (2) monthly numbers of infected snails collected by means of a uniform sampling method, and (3) monthly cercarial output and monthly numbers of infected snails collected by means of a uniform sampling method. it was found that the third method is more logical and defines more precisely the transmission seasons of s. mans ...19705310952
susceptibility of the small biomphalaria alexandrina alexandrina from the uar and the sudan to infection with a strain of schistosoma mansoni from tanzania.a series of laboratory experiments was carried out to determine the susceptibility of biomphalaria alexandrina alexandrina, the snail vector of schistosomiasis in the united arab republic and the sudan, to a strain of schistosoma mansoni from mwanza, tanzania. the objective of the investigation was to determine whether or not b. alexandrina is refractory or partially refractory to infection with strains of s. mansoni other than the egyptian strain.in one series of 5 exposures, snails from a colo ...19705314014
studies on the mode of action of some molluscicides on the snail, biomphalaria alexandrina. i. effect of bayluscide, sodium pentachlorophenate, and copper sulphate on succinate, glutamate, and reduced tmpd oxidation. 19705527555
the ability of bulinus truncatus, biomphalaria alexandrina and lymnaea gedrosiana to survive out of water in the laboratory. 19676051532
the molluscicidal properties of ambrosia maritima l. (compositae). 2. results from a field trial using dry plant material.a field trial in egypt of the plant molluscicide, ambrosia maritima is described. applications of 140, 70 and 35 mg/l-1 dry, whole plant were made to irrigation canals and drains in june. the treatment effect took between 1 and 5 weeks to become fully established. the reduction in the numbers of alive biomphalaria alexandrina snails was generally more than 90% and was virtually the same at all treatment levels and in both types of watercourse. the snail population remained at a low level for at ...19846464183
the egg mass and growth rate of biomphalaria alexandrina under laboratory conditions. 19846512287
semi-field studies on the bionomics of biomphalaria alexandrina in egypt. 19846512295
distinguishing helisoma (seminolina) duryi from biomphalaria alexandrina in egypt. 19836663109
genetic studies on fresh water snails, specific intermediate hosts for schistosomiasis--vi. effect of chemical mutation on histones of biomphalaria alexandrina snails. 19846697344
genetic studies on fresh water snails, specific intermediate hosts for schistosomiasis--vii. effect of gamma radiation as a physical mutagen on histones in biomphalaria alexandrina snails. 19846697345
ecological studies on bulinus truncatus and biomphalaria alexandrina in zagazig, egypt. 19846736706
preliminary study on biomphalaria alexandrina chromosomes. 19827153569
genetic studies on fresh water snails, specific intermediate hosts for schistosomiasis--iv. gamma radiation as a physical mutagen on deoxyribonucleic acid 'dna' in biomphalaria alexandrina snails. 19817296604
effect of prolonged exposure of biomphalaria alexandrina to low concentrations of some molluscicides. i. effects on longevity, growth rate, fecundity and susceptibility to schistosome infection. 19817299171
effect of prolonged exposure of biomphalaria alexandrina snails to low concentrations of some molluscicides. ii. on total tissue proteins, carbohydrates and lipids. 19817299180
biomphalaria alexandrina naturally infected with fasciola gigantica in egypt. 19957747303
characterization of biomphalaria alexandrina-derived lectins recognizing a fucosyllactose-related determinant on schistosomes.two novel lectins that bind selectively to a schistosome-associated fucosyllactose-related determinant have been characterized and purified from the hemolymph of biomphalaria alexandrina, the snail vector of schistosoma mansoni. both lectins were purified by affinity chromatography on a column of equimolar mixture of d- and l-glucose coupled to epoxy-activated sepharose 6b and sequential elution by d-glucose (designated basi) and l-fucose (designated basii). assessment of the structural characte ...19957770082
worm development in hamsters infected with unisex and cross-mated schistosoma mansoni and schistosoma haematobium.schistosoma mansoni and schistosoma haematobium coexist in egypt and in other areas in africa, and people frequently are infected with parasites of both species. the effects of the interactions between worms of both sexes of the 2 species on development and egg laying were evaluated in vivo by infecting hamsters with cercariae from biomphalaria alexandrina and bulinus truncatus snails infected with single miracidia. in hamsters with unisex infections, male worms of both species were small. schis ...19957876983
laboratory study on the molluscicidal effect of earth tec: an environmentally responsible copper sulfate product.studies were carried out, under laboratory conditions to evaluate the molluscicidal activity of earth tec on biomphalaria alexandrina snails, the intermediate host of schistosoma mansoni. earth tec is an environmentally responsible copper sulfate product manufactured and marketed as an algicide/bactericide with an active ingredient form of copper ion (cu++). a single application, of 1 ppm of copper equivalent, for 24 hours caused 100% mortality rate of the snails. exposure for 48 hours to 1 ppm ...19948077750
foci of schistosoma mansoni in assiut province in middle egypt.following detection of schistosoma mansoni in a 12 years old boy who had both schistosomal polyposis and periportal fibrosis with hepatosplenomegaly, epidemiological studies to confirm local transmission were performed in his and 30 other villages in assiut governorate, egypt. the index case's brother and 6 of 380 inhabitants of his village who provided stool specimens were infected with s. mansoni and a farmer with dysentery and hepatosplenomegaly had a positive rectal snip biopsy. all had hepa ...19938249064
is schistosoma mansoni replacing schistosoma haematobium in the fayoum?schistosoma mansoni is progressively replacing s. haematobium along the nile river in egypt. this change has occurred in the past 15-20 years following construction of the aswan high dam in the 1960s. the cause is a shift in relative abundance of the snail vectors biomphalaria alexandrina and bulinus truncatus. biomphalaria is increasing while the latter has disappeared from a village in the fayoum where formerly only schistosomiasis haematobia was endemic. a cross-sectional household survey in ...19938279637
population dynamics and schistosomal infection of biomphalaria alexandrina in four irrigation canals in egypt.the natural growth, reproductivity, mortality and schistosomal infection of biomphalaria alexandrina, the snail vector of schistosoma mansoni in egypt, were studied for one year in four irrigation canals, namely el-khassa and radwan (giza governorate) and sendebis and sanafeer (qalyoubiya governorate). radwan canal contains a considerably dense biomphalaria population and three generations of snails (parents generation and autumn and spring generations) were recognized. two phases of growth were ...19938308336
kinetic potentials of certain scavenger enzymes in fresh water snails susceptible and non-susceptible to schistosoma infection.the activities of catalase (h2o2-oxidoreductase ec 1.11.1.6)- and glutathione reductase (ec 1.6.4.2) as two important scavenger enzymes, were measured in tissue homogenates of biomphalaria alexandrina and bulinus truncatus, the snail vectors of schistosomiasis. a parallel study was done on lymnea truncatula snails which are not susceptible to schistosoma infection. the apparent michaelis constant (km) for both anzymes were determined in tissue homogenates of the three studied species. the result ...19938329984
schistosoma cercariae in biomphalaria alexandrina in atania, al minia governorate. 19938376879
helisoma duryi: its present range of distribution and implications with schistosomiasis snails in egypt.the range of distribution of helisoma duryi, a potential competitor to schistosomiasis snail vectors in egypt, was determined in the south of nile delta. results show that h. duryi was found in the river nile, geziret el kerateyeen banks, damietta and rosetta branches, tawfiky and menoufy canals and their branches and bassoussiya, bahadiya and sheshaa canals and their branches. helisoma was found in all categories of canals and drains co-existing in various degrees with other snail species inclu ...19938482866
ecology of biomphalaria alexandrina the snail vector of schistosoma mansoni in egypt.the patterns of spreading and seasonal variation of population density of biomphalaria alexandrina, the snail vector of schistosoma mansoni in egypt, in correlation with some environmental parameters were studied for 1988-1990 in four irrigation canals in giza and qalyoubiya governorates. results shown that the spreading patterns of snails along canals are changeable because of water current and irrigation activities. the snail population density showed two peaks, different in height, in april-m ...19938482878
evidence for a family of schistosome glycan-binding lectins in biomphalaria alexandrina.a novel family of isolectins that selectively recognize a schistosome-associated fucosyllactose determinant was identified in the hemolymph of biomphalaria alexandrina, a snail vector of schistosoma mansoni. three lectins of this family were purified by serial affinity chromatography on a column of l-fucose and elution with a gradient of 0.1-1 m l-fucose (designated basii and basiii), followed by a column of d-glucose and elution with 0.3 m d-glucose (designated basi). assessment of the structur ...19958654664
purification and characterization of sm 37: a fucosyllactose determinant-bearing glycoprotein probed by a biomphalaria alexandrina lectin on adult male schistosomes.utilizing a biomphalaria alexandrina-derived lectin (basii) of proven specificity to a schistosoma mansoni-associated fucosyllactose [(fuc alpha 1-2)gal beta 1-4 glc] determinant, a 37-kda determinant-bearing glycoprotein (sm 37) was identified selectively on adult male schistosomes. sm 37 was purified to homogeneity from extracts of adult male worms metabolically radiolabeled with [35s] methionine by basii affinity chromatography followed by separation on an hplc column. treatments with endogly ...19968691365
antifungal and molluscicidal saponins from serjania salzmanniana.an investigation of serjania salzmanniana for biologically active substances has led to the isolation of two novel saponins, salzmannianoside a (3-o-[[beta-d- glucopyranosyl-(1-->4)]-[alpha-l-rhamnopyranosyl-(1-->2)]-alpha-l- arabinopyranosyl] gypsogenin) [3] and salzmannianoside b (3-o-[[beta-d-glucopyranosyl-(1-->4)]-[alpha-l- arabinopyranosyl-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)] -alpha-l-arabinopyranosyl] hederagenin) (4). two known saponins, pulsatilla saponin d (3-o-[[beta-d- glucopyran ...19968699187
prevalence of schistosomiasis and dynamics of its distribution in some villages in qalyoubia governorate.a total of 1535 persons of different age, sex and occupation from 5 villages (tanan, el-sad, sandiun, kalama and taha-nob) in qalyoubia governorate in nile delta were subjected to clinical, stool, urine and intradermal tests accompanied by a questionnaire for 500 of them. snail vectors of schistosome parasites were collected from 2 villages (el-sad and taha-nob) and snail densities in the waterways as well as the prevalence rate of infection with schistosomal cercariae were recorded. the results ...19968721234
biomphalaria glabrata: a new threat for schistosomiasis transmission in egypt.this is the first report on the infestation of irrigation and drainage systems at giza, qalyoubiya and kafr el shiekh governorates, with biomphalaria glabrata (the snail host of schistosoma mansoni in the new world). identification of this snail species was based on morphometry of the shell, shape of the radular lateral teeth and presence of the characteristic renal ridge. b. glabrata snails collected from natural water courses in egypt proved to be susceptible to a local strain of s. mansoni. t ...19968721240
differences in susceptibility of biomphalaria alexandrina to schistosoma mansoni from gize and dakahlia governorates, egypt.biomphalaria alexandrina snails were collected from irrigation canals at gize and dakahlia governorates. they were exposed to strains of schistosoma mansoni from these localities. the snails showed different rates of susceptibility to the parasite. there was a high range of snail sensitivity to s. mansoni infection (53.9%-60.7%) when snail populations and parasite strains were from the same governorate. supporting this was the high cercarial production from infected snails of these cases (288.2 ...19968754642
cercariometry in the study of schistosoma mansoni transmission in egypt.the recovery of schistosoma mansoni cercariae was studied in experimental ditches and natural irrigation canals using a continuous operating centrifuge and a water suction sampling technique. recovery of cercariae from static water in the ditches where caged infected biomphalaria alexandrina snails were placed showed that cercariae recovered were more with increase of infected snails and decrease of water volume and were most abundant in the proximity of the snails which produced them. shade or ...19968754644
effect of x-ray on the snails of schistosomiasis in egypt.biomphalaria alexandrina and bulinus truncatus snails were exposed to sublethal doses 0.2, 3, 5, 10 and 20 rad of x-ray. the survival and reproductive rates of these snails were highly affected by these doses. the maximum survival periods of laboratory populations of biomphalaria snails were less than those of field ones which means a high sensitivity of laboratory snails to x-ray. the reproductive capacity of irradiated biomphalaria and bulinus snails was highly suppressed and this will interru ...19968754647
characterization of fucosyllactose determinant-bearing glycoproteins probed by a biomphalaria alexandrina lectin in schistosoma mansoni cercariae.utilizing a biomphalaria alexandrina-derived lectin (basii) of proven specificity to a schistosoma mansoni-associated fucosyllactose [(fuc alpha 1-2) gal beta 1-4 glc] determinant, two determinant-bearing glycoproteins of 40 and 37 kda were found to be synthesized by the cercarial stage of the parasite. the two glycoproteins were isolated by basii affinity column chromatography from extracts of cercariae metabolically radiolabelled with 35s-methionine. treatments with endoglycosidases, alkaline ...19968799614
schistosoma mansoni miracidial host-finding: species specificity of an egyptian strain.the effect of snail-conditioned water (scw) from biomphalaria alexandrina, a pigmented and an albino strain of b. glabrata, and lymnaea stagnalis on the host-finding behavior of miracidia of two brazilian and one egyptian strain of schistosoma mansoni was studied. miracidia of the egyptian strain significantly preferred their suitable host b. alexandrina versus the other snail species with their behavior patterns of host location and their responses after contact with the host. however, miracidi ...19968825437
the interactive effect of some molluscicides on the inermediate host of human bilharziasis and their associated zoosporic fungi in the river nile, egypt.biomphalaria alexandrina and bulinus truncatus are the main vectors of human bilharziasis in egypt. the mycotic inhabitants of both control and treated snails were surveyed at 7 and 15 days intervals. the two molluscicides affected more on the mortality of biomphalaria alexandrina than bulinus truncatus. the highest population of zoosporic fungi was collected from biomphalaria alexandrina, the lowest from bulinus truncatus. copper sulphate was more effective than bayluscide on the fungal species ...19968955964
new possible molluscicides from calendula micrantha officinalis and ammi majus. ii. molluscicidal, physiological, and egg-laying effects against biomphalaria alexandrina and bulinus truncatus.in the present study, the effects of cuso4 and crude extracts of the different parts of calendula micrantha officinalis and ammi majus, i. e., leaves, stems, roots, and flowers, on adult biomphalaria alexandrina and bulinus truncatus were investigated. generally, leaves and flowers of both plants exhibited marked potency in killing the snail vectors of schistosomiasis. the recorded lc50 and lc90 values showed that c. officinalis was more toxic to both snails than a. majus, and b. truncatus are m ...19969007003
effect of uv-irradiation, gamma irradiation and praziquantel on infected biomphalaria alexandrina snails.schistosomiasis control represent the main target of many research programme allover the world. effect of physical (uv- and gamma-irradiation) treatment as well as chemical (pzq) treatment on infected laboratory bred biomphalria alexandrina snails have been studied. gamma irradiation and pzq-treatment induced high rate of mortality than uv-irradiated and non-treated control snails. the cercarial production was severely reduced as a result of uv-, gamma-irradiation and pzq-treatment. pre-patent p ...19979097525
detection of schistosoma mansoni in biomphalaria using nested pcr.a nested polymerase chain reaction (pcr) protocol was developed for detecting the presence of schistosoma mansoni sporocysts in intermediate host snails of the genus biomphalaria. to accomplish this, rdna genes encoding the 18s rrna of s. mansoni and biomphalaria alexandrina from egypt were sequenced, as were 18s-encoding genes of the 13-16-r1 and salvador strains of biomphalaria glabrata. based on a comparison of host and parasite sequences, a nested set of pcr primers was designed to allow spe ...19979194817
susceptibility of three successive snail generations from positive and negative laboratory bred biomphalaria alexandrina from different localities in egypt to infection with schistosoma mansoni from giza.susceptibility of snail vectors to schistosome infection varies between geographical areas, populations in the same area and among individuals in the same population. it is also affected by biological factors of which are snail size (age), number and age of miracidia exposed to water, temperature, illumination and darkness. our preview studies indicated that snails 4-6 mm in diameter exposed to 5 freshly hatched miracidia under light and in water at 25 degrees c are optimum conditions for infect ...19979257970
development of bait formulations for control of intermediate hosts of african schistosome species.exploration of methods of snail control indicated a need for a new method because many failures in control programmes are due to lack of contact between molluscicides and the target snail population. the incorporation of molluscicides inside food pellets that are attractive to and ingestible by the target snails is suggested. different concentrations of alcoholic extracts of ambrosia maritima, cucumis prophetarum and rhynchosia minima-molluscicides of plant origin-were compared with niclosamide ...20139418947
effect of aprotinin on schistosoma mansoni miracidial penetration into biomphalaria alexandrina.the effect of aprotinin on schistosoma mansoni miracidial penetration process, by its direct topical application on biomphalaria alexandrina snails, was studied the snails were exposed to s. mansoni miracidial suspension which was mixed with aprotinin at concentrations ranging from 0.02 to 20 kallikrein inactivator units (kiu)/ml of applied solution. results showed that aprotinin had marked inhibitory effect on miracidial penetration of the snails. the concentration that resulted in 50% inhibiti ...19979425816
infection of laboratory bred biomphalaria alexandrina from giza and alexandria governorates with schistosoma mansoni from giza in relation to snail size and number of penetrated miracidia.snail size and the number of schistosoma mansoni miracidia penetrated are two important factors among others that might influence biomphalaria alexandrina infection with s. mansoni. groups of 16 snails of fixed age but of different size class (2-4 mm), (4-6 mm), (6-8 mm), (8-10 mm) and (10-12 mm) from three successive generations of positive and negative laboratory bred b. alexandrina from giza and alexandria governorates were each exposed to five s. mansoni miracidia (tbri from giza) under ligh ...19979425819
effect of the plant azolla pinnata on survival, growth rate, fecundity and hatchability of egg-masses of biomphalaria alexandrina snails.data indicated that azolla pinnata plants variously reduce the growth rate of biomphalaria alexandrina snails expressed as net increase in shell diameter (direct or indirect exposure). the plant density played an important role in this respect. the higher the plant density was the lower the growth rate and vice versa. too, indirect exposure of newly hatched b. alexandrina resulted from exposed treated eggs reduced the growth rate of these snails. data revealed that direct and/or indirect exposur ...19979425826
laboratory assessment of the molluscicidal and cercaricidal activities of the egyptian weed, solanum nigrum l.the molluscicidal properties of solanum nigrum l. were tested against three egyptian snail species (biomphalaria alexandrina, bulinus truncatus and lymnaea natalensis), each an intermediate host of parasites causing human schistosomiasis or fascioliasis. the plant was collected in two regions within egypt: fayium and giza. snails were exposed for 24 and 48 h, to the dry powdered fruits and leaves or to crude water extracts of the powders, and mortality was recorded. the water extract of the leav ...19979579213
susceptibility of biomphalaria alexandrina to the plant azolla pinnata and some herbicides in relation to infection with schistosoma mansoni miracidia.molluscicidal activity of the herebicides 2,4-d and graminol, as well as both extracts and dry powder of the plant azolla pinnata were evaluated against b. alexandrina snails. it was observed that 2,4-d proved to be the most toxic compound among he tested ones, showing lc90 of 52 ppm after 24 h of exposure. ethanol extract of azolla showed the highest molluscicidal activity against the tested snails compared with the other extracts and dry powder (lc90 = 3300 ppm). ethanol extract at 6600 ppm af ...19989617046
studies on the molluscicidal action of some isatin derivatives against biomphalaria alexandrina in egypt.some compounds selected from the isatin derivatives and their metalleted products were used to study their molluscicidal effect on biomphalaria alexandrina. the results indicated that some of these compounds showed good results and seem to be promising molluscicides.19989707676
effect of six non-target snails on schistosoma mansoni miracidial host finding and infection of biomphalaria alexandrina under laboratory conditions.six snail species naturally associated with biomphalaria alexandrina, the snail host of schistosoma mansoni in egypt, were tested under standard laboratory conditions, for impact on miracidial host findings and infection of the snail host. these snails are the prosobranchs melanoides tuberculata, cleopatra bulimoides, bellamys unicolor and lanistes carinatus, the pulmonates planorbis planorbis and physa acuta. the tested snail ssp. reduced considerably the infection rate of biomphalaria with s. ...19989707684
invasion of the nile valley in egypt by a hybrid of biomphalaria glabrata and biomphalaria alexandrina, snail vectors of schistosoma mansoni.two years (1996-1997) of systematic survey showed that a hybrid of biomphalaria glabrata and biomphalaria alexandrina has invaded the irrigation and drainage systems in the nile delta and the valley nor the of el-menya. however, the infestation of water courses by and the population density of this snail were variable in various localities. the infestation rate ranged between 7.1% in el-fayoum governorate and 52.6% in el-dakahliya governorate and the snail density from 2 snails/site to 69.7 snai ...19989707685
seasonal variation in molluscicidal activity of solanum nigrum l.solanum nigrum l. leaves and fruits were shown to have molluscicidal activities against snails transmitting schistosomiasis and fascioliasis. in the present study, their molluscicidal activity against adult biomphalaria alexandrina snails was assessed to determine whether plants collected at various seasons would have different degrees of toxicity. leaves and fruits of three s. nigrum varieties were collected from faiyoum and/or giza during the four seasons. leaves collected in autumn had the hi ...19989914685
compatibility of biomphalaria alexandrina, biomphalaria glabrata and a hybrid of both to seven strains of schistosoma mansoni from egypt.the susceptibility of biomphalaria alexandrina, biomphalaria glabrata and a hybrid snail of both, all obtained from natural habitats in egypt, to infection with six human local strains of schistosoma mansoni and a laboratory strain of human origin was determined. the infection rate, prepatent period, periodic cercarial production and duration of cercarial shedding were compared in all cases. the results showed that each of the three studied biomphalaria snails had different rates of infection an ...19989914708
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