ecological studies of bulinus rohlfsi, the intermediate host of schistosoma haematobium in the volta the present ecological study of cercarial transmission of schistosoma haematobium in the volta lake, ghana, habitat observations and sampling of bulinus truncatus rohlfsi were conducted within a 60-km stretch of shoreline. observations revealed that human water contact sites in each village undergo constant changes in shape and vegetation. snail sampling surveys in water contact sites were carried out monthly (for 27 months) in 8 villages using newly designed palm-leaf traps, and in 8 additio ...1977304396
trials of ecological and chemical measures for the control of schistosoma haematobium transmission in a volta lake village.urinary schistosomiasis is highly prevalent along the shores of the volta lake in ghana, where transmission occurs focally in man-water contact sites. the intermediate host, bulinus truncatus rohlfsi, prefers to harbour in ceratophyllum, a common aquatic weed in the lake. removal of this weed reduced the density of both infected and uninfected snails, but not sufficiently to interrupt transmission.niclosamide was applied at 1, 0.7, and 0.5 mg/l in combination with weed removal at five water cont ...1978307458
studies on schistosomiasis in saudi arabia.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 ...1976943963
letter: bulinus sp. (2n=36) from salisbury, rhodesia, a close relative of bulinus truncatus (audouin), being a potential intermediate host of schistosoma haematobium in south-east africa. 19761265826
[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 ...19921292427
cercarial shedding patterns of schistosoma bovis and s. haematobium from single and mixed infections of bulinus truncatus.the cercarial shedding of schistosoma bovis and s. haematobium were studied in single and mixed infections in the snail host bulinus truncatus. the two species displayed a distinctive diurnal cercarial emergence with an earlier shedding pattern for s. bovis than s. haematobium (the average emergence peaks were respectively at 0800 h and 1200 h). in mixed infections, each species kept its own cercarial shedding rhythm with no marked alterations. the cercarial emergence pattern is proposed as a ne ...19912050991
genetic variability in the compatibility between schistosoma haematobium and its potential vectors in niger. epidemiological implications.a populational study of the compatibility between schistosoma haematobium and its potential vectors has been carried out in the niger, confronting samples of s. haematobium populations from three epidemiologic foci with bulinus populations originating from the same focus (sympatric infection) and with bulinus populations from other foci (allopatric infections). the three transmission foci selected were irrigation canals in ricefields along the niger river where one finds: bulinus truncatus rohlf ...19902382092
[population dynamics of bulinus truncatus in a focus of bilharziasis in khemis-el-khechna (northern algeria)].a demographic and epidemiological study of bulinus truncatus was carried out in hamiz river, transmission site of schistosomiasis in the khemis-el-khechna focus. the results shows direct influence of hydrographic factor on the populations dynamic which is characterized by irregular variations.19873450442
transmission of schistosoma haematobium in north gezira, sudan.during this 14-month study, 128 765 bulinus truncatus snails were collected from canals located near four villages in the northern part of the gezira irrigated area, and were examined for patent trematode infections, by exposure to light. in all, 903 shedded cercariae, of which 424 were identified as s. haematobium, and one village, bashagra, was the source of 80% of these s. haematobium infections. the highest density of snails occurred from march to may and the peak of snail infections occurre ...19854032531
antagonism of echinoparyphium recurvatum against schistosoma haematobium in the snail bulinus truncatus. 19744412038
effect of sub-lethel doses of molluscicides on the susceptibility of bulinus truncatus snails to infection with schistosoma haematobium. 19744418538
the effect of schistosoma haematobium infection on the growth and fecundity of three sympatric species of bulinid snails.three species of bulinid snails were monitored to determine the effect of infection with 2 sympatric strains of schistosoma haematobium on longevity, growth, and reproductive output, from the onset of cercarial production until death. bulinus senegalensis was least affected by infection, with total fecundity reduced by less than 34%. infected bulinus truncatus showed an acceleration in growth accompanied by a 63% reduction in fecundity, although the majority of snails continued to oviposit at a ...19902380865
[mixed infestation of bulinus truncatus (audouin, 1827) by larval forms of schistosoma haematobium (bilharz, 1852) and an echinostomatidae]. 19724650809
host-parasite relationship of bulinus truncatus and schistosoma haematobium in iran. 4. effect of month of infection on cercarial-incubation periods of s. haematobium and s. bovis.studies were conducted each month for one year to determine the cercarial-incubation periods of schistosoma haematobium and schistosoma bovis in bulinus truncatus for different months of infection. the snails were kept in outdoor aquaria in order to simulate the natural temperature conditions in the endemic bilharziasis areas of iran.the results showed that the cercarial-incubation periods of these two schistosome species varied with the environmental water temperature. snails exposed in august ...19665295560
periodicity and longevity of schistosoma haematobium cercariae liberated from bulinus truncatus in central iraq. 19655889014
immunity to schistosoma haematobium in bulinus truncatus. 19665954292
monthly prevalence rates of natural infection with schistosoma haematobium cercariae in bulinus truncatus in central iraq. 19655889011
[epidemiologic study of s. haematobium bilharziasis in the rice fields of yagoua (north cameroon) ii. distribution and ecology of intermediate hosts].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 irrigatio ...19827201892
[study of the distribution of schistosomiasis mollusks intermediate hosts in west africa. first results (author's transl)].during 18 surveys carried out in 29 regions of 6 west african countries (benin, ivory coast, upper volta, mali, niger and togo), one species of biomphalaria (biomphalaria pfeifferi) and six species of bulinus (bulinus truncatus rohlfsi, b. globosus, b. jousseaumei, b. umbilicatus, b. senegalensis and b. forskalii) were collected. first indications of the distribution of these species demonstrated: the presence of 3 principal species (b. pfeifferi, b. globosus and b. truncatus rohlfsi); the absen ...19807366365
schistosomiasis in dogon country, mali: identification and prevalence of the species responsible for infection in the local community.the prevalence of schistosomiasis amongst the dogon people in 4 villages and one school of the bankass district of mali was determined during 2 surveys in 1992; 1398 urine and 1199 stool samples were examined. the most common schistosome was schistosoma haematobium, with an overall prevalence of 51.3%; s. mansoni had a prevalence of 12%. no s. intercalatum egg was seen in the stools. biomphalaria pfeifferi and bulinus truncatus were found in pools at the base of the dogon cliffs; bulinus forskal ...19947886759
host-parasite relationship of bulinus truncatus and schistosoma haematobium in iran. 3. effect of water temperature on the ability of miracidia to infect snails.laboratory studies were made in iran to test the effect of water temperature on the ability of the miracidia of s. haematobium to penetrate b. truncatus. snails three to four weeks old were exposed to two miracidia each for two hours at nine water temperatures ranging from 10 degrees c to 38 degrees c. after exposure, all the snails were kept in aquaria at room temperature. the cercaria-positive rates of these nine groups of snails showed that the optimum exposure temperature was in the range 20 ...19665295559
host-parasite relationship of bulinus truncatus and schistosoma haematobium in iran. 2. effect of exposure dosage of miracidia on the biology of the snail host and the development of the parasites.laboratory experiments were carried out to study the development of bulinus truncatus and the larval stages of schistosoma haematobium after the snails had been exposed to various numbers of miracidia. the results showed: (1) that in the cercarial-incubation period the growth and survival rate of snails was not influenced by the development of the larval stages of s. haematobium, but that in the cercaria-shedding period the life-span of the infected snails was shorter than that of the non-infect ...19665295558
intraspecific variation in schistosoma haematobium from algeria.a comparative analysis has been carried out between two populations of schistosoma haematobium using the same intermediate snail host, bulinus truncatus, but originating from two distinct ecological areas of algeria: khemis-el-khechna in a sub-humid mediterranean zone and djanet in a saharan bioclimatic zone. four parameters have been studied: the growth rate of adult worms, size and shape of the eggs, chronobiology of cercarial emergence and the compatibility with the intermediate host. results ...19979166441
host-parasite relationship of bulinus truncatus and schistosoma haematobium in iran. 1. effect of the age of b. truncatus on the development of s. haematobium.this paper is the first of a series of four on various aspects of the interaction between bulinus truncatus and the bilharziasis parasite schistosoma haematobium. it describes laboratory studies conducted to determine the effect of the age of b. truncatus on the development of s. haematobium. the results indicated (1) that the young snails could be infected even if they were one day old; (2) that the infection rates were higher in the snails of two to five weeks of age than in those of one week; ...19665295557
distribution and ecology of bulinus truncatus in khuzestan, iran.the results of a 5-year study on the distribution and ecology of bulinus truncatus in khuzestan, south-western iran, are described. live snails were found in 4 foci, namely, the main focus, the upper karun river, the lower karkheh river, and the bala rud watershed; in addition, dead snails were found in 3 other foci. the patchy distribution of snails was related to the presence of surface waters and to their chemical composition.monthly observations on the population dynamics of the snails and o ...19685304436
the cercarial output from three nigerian bulinids infected with two strains of schistosoma haematobium.the daily cercarial output of two nigerian strains of schistosoma haematobium in sympatric bulinus truncatus, b. globosus and b. senegalensis was measured at weekly intervals from the start of emission to the snails' death. in all cases cercariae were released throughout the life of the host, with no cases of "self cure". patterns of output through the course of infections in b. truncatus and b. senegalensis were similar to those reported for s. haematobium by other workers, with daily productio ...19883397515
the mouse as a suitable host for an isolate of schistosoma haematobium from niger.the host-parasite relationships of a schistosoma haematobium isolate, originating from niger, and the white mouse are described. swiss of1 albino mice were exposed individually to 200 cercariae and worms were recovered 9, 12, 16 and 20 weeks post infection. the mean worm returns ranged between 10.54 and 13.05% and did not alter significantly between 9 and 20 weeks post infection. the sex ratio of worms was always in favour of males; from 7.09:1 at 9 weeks after infection it decreased regularly t ...19921469258
effect of sub-lethal doses of molluscicides on the susceptibility of bulinus truncatus snails to infection with schistosoma haematobium. 19744469237
dynamics of the intramolluscan larval development of schistosoma haematobium: replication of daughter sporocysts and cercarial production.during the intramolluscan larval development of schistosoma haematobium (algerian strain) in bulinus truncatus, two replication processes of daughter sporocysts occur. replication by direct sporocystogenesis appears more important than sporocystogenesis post cercariogenesis. these mechanisms assure a periodic renewal of the sporocyst stock in the snail host and seem to be synchronized with the development of cercarial generations. the succession of several generations of cercariae is responsible ...19892723382
new sites of bulinus truncatus and indigenous cases of urinary schistosomiasis in jordan.thirty-two autochthonous cases of schistosoma haematobium are reported from ghore as-safi, karak lowlands, jordan. all infected persons were males (9-46 years-old). new unusual breeding sites for bulinus truncatus are discovered. the past and current distribution of the snail intermediate host is given.19989879562
endemicity, focality and seasonality of transmission of human schistosomiasis in amagunze village, eastern nigeria.the pattern of transmission of human schistosomiasis was studied in amagunze village, eastern nigeria, during 1986-1987. the prevalence of schistosoma haematobium in 119 schoolboys aged 5-12 years was 79%. the geometric mean of intensity of infection was 49 eggs/10 ml urine and the frequency of visible haematuria was 25.2%. no s. mansoni infections were demonstrated. a marked seasonality in population density of bulinus truncatus, b. forskalii and biomphalaria pfeifferi was demonstrated with red ...19892507628
[malacologic-schistosomal study of the refugee camps on the plain of ruzizi in the democratic republic of the congo].bilharziasis due to schistosoma mansoni is widespread in the eastern part of the people's republic of the congo, particularly in the ruzizi plain area. the intermediate host is the fresh-water snail biomphalaria pfeifferi whose ecology is now well documented. bilharziasis due to schistosoma haematobium and schistosoma intercalatum have not yet been observed but the potential for this development is high given the presence of the intermediate hosts, i.e. bulinus truncatus, bulinus globosus, and b ...199910472580
1983 nile delta schistosomiasis survey: 48 years after determine whether the sharply declining schistosoma haematobium infection rates in parts of the nile delta could be generalized to the entire region, and to update the status of s. mansoni infection rates, a large scale survey was undertaken in 1983 in 70 of the 71 districts of the nile delta. in a house-to-house survey, greater than 91% of the sample population of 16,675 participated by providing stool and/or urine specimens which were examined qualitatively by kato thick smear and sedimenta ...19892504069
toxic activities of the plant jatropha curcas against intermediate snail hosts and larvae of schistosomes.the aim of studies on plant molluscicides is to complement methods for controlling snails acting as intermediate hosts of schistosomes. we report on the toxic activity of extracts from jatropha curcas l. (euphorbiaceae) against snails transmitting schistosoma mansoni and s. haematobium. we studied different extracts' effects on infectious larvae, cercariae and miracidia of s. mansoni. compared to aqueous extract, methanol extract showed the highest toxicity against all tested organisms with lc10 ...200010929142
[urinary schistosomiasis in the saharan mountain plateau of air (republic of niger)].in two villages of the aïr (republic of niger) the authors have found a schistosoma haematobium overall prevalence of 24.1% at timia and 43.5% at el meki. at el meki, the distribution of prevalences by age group accords to that which is usually found. the maximum is found in the 5-14 years age group and highest in men than in women. at timia, the prevalence among young pupils is low, this seems to be due to the application of sanitary education measures. at el meki, bulinus truncatus rohlfsi, pr ...19902119898
effect of schistosome infection on protein, glycogen and glucose contents in biomphalaria arabica and bulinus truncatus.b. arabica and b. truncatus the snail intermediate hosts of intestinal and urinary schistosomiasis in yemen arab republic, were bred in the laboratory and infected with s. mansoni and s. haematobium respectively. schistosome infection caused a marked decrease in the glycogen and protein contents in the tissue of b. arabica and b. truncatus. the glucose content in the hemolymph of both infected snails was lower than that in the normal snails.19912033308
seasonal patterns in the transmission of schistosoma haematobium in attaouia, the attaouia area, the density of bulinus truncatus (audouin, 1827), was monitored monthly for a period of one year in correlation with weather variations. snails were active throughout the year and particularly abundant at the end of spring and summer. two snail generations were found to overlap. the infection rate of b. truncatus reached a maximum of 3.5% in the summer when human water contact was frequent. a selective survey conducted in the village of lamyayha showed that the prevalence o ...19921640092
implication of bulinus truncatus in the transmission of urinary schistosomiasis in senegal, west africa.studies on the compatibility between bulinus truncatus and schistosoma haematobium from various areas in the senegal river basin (srb) were carried out, to investigate the role of b. truncatus in the epidemiology of urinary schistosomiasis in senegal. the results show that b. truncatus from the lower valley is not compatible with s. haematobium from the middle valley. interestingly, the study reveals that b. truncatus from the upper valley is compatible with s. haematobium from the same area, an ...200212080978
control of snail hosts of bilharziasis in egypt. 3. effect of the organophosphorous insecticide, dursban, on carbohydrate metabolism of the snails biomphalaria alexandria and bulinus truncatus.the effects of the organophosphorous insecticide, dursban, on aerobic oxidation, glycolysis, glucose utilization and gluconeogenesis in snails tissues were determined. dursban had a biphasic effect on the aerobic oxidation of succinate, glutamate + malate and tmpd + ascorbate while it had only an inhibitory action on pyruvate oxidation. the compound significantly inhibited glycolysis, glucose utilization and gluconeogenesis when used at high concentrations (ten times higher than its lc50). howev ...197552436
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
effects of schistosoma haematobium infection on reproductive success and male outcrossing ability in the simultaneous hermaphrodite, bulinus truncatus (gastropoda: planorbidae).the schistosome intermediate snail host, bulinus truncatus (mollusca: planorbidae), has two reproductive (phally) morphs. both aphallics and euphallics can self-fertilize, but aphallics cannot donate sperm because they do not develop a functional penis and prostate. this study investigated the interactions between phally and fitness consequences of schistosoma haematobium infection in b. truncatus. snails which developed patent infections produced 26% fewer eggs than controls and 35% fewer eggs ...19948152852
compatibility of schistosoma haematobium, s. intercalatum and their hybrids with bulinus truncatus and b. forskalii.schistosoma haematobium and s. intercalatum readily hybridize with each other producing generations of viable hybrid offspring. experiments were designed to investigate the infectivity and viability of the s. haematobium x s. intercalatum f1 and f2 hybrid larvae in their two intermediate snail hosts compared with the parental species. analysis of the data obtained suggested that the s. haematobium male x s. intercalatum female f1 hybrid miracidia were more infective to bulinus truncatus than to ...200312964826
experimental infection of bulinus truncatus with schistosoma haematobium. 195313045190
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
comparative studies on the effects of castration and schistosome-infection on bulinus truncatus. 19827153563
carbohydrate metabolism in uninfected and trematode-infected snails biomphalaria alexandrina and bulinus truncatus. 19751157458
letter: bulinus truncatus as a potential intermediate host for schistosoma haematobium on the kano plain, kenya. 19744419850
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
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
further study on the ecology of the intermediate host of schistosoma haematobium, bulinus truncatus baylis. 195514389815
the prepatent period and cercarial production of schistosoma haematobium in bulinus truncatus (egyptian field strains) at different constant temperatures.the developmental time of schistosoma haematobium in bulinus truncatus snails (field strains) was determined in the laboratory at different constant temperatures between 18 and 32 degrees c. the basic relationship between the length of the minimum prepatent period (y, in days) and the temperature (x, in degree c) is given by the hyperbolic formula y = 295/(x-15.3), 15.3 being the theoretical "developmental null point" and 295 the constant time-temperature product. the shortest prepatency was 17- ...19846695537
distribution and genetic diversity of schistosoma haematobium within its bulinid intermediate hosts in mali.random amplified polymorphic dna (rapd) markers were used to assess distribution and genetic diversity of schistosoma haematobium populations within their bulinid intermediate hosts in mali. naturally infected snails (bulinus truncatus and b. globosus) were collected at four sites in the bamako district. s. haematobium cercariae from single snails were used to infect mice and genotypes of the resultant adult worms were characterized using rapd markers. diversity indices were calculated at the sc ...19979177092
[schistosomiasis endemic in burkina faso].burkina faso, through the works of many teams of the occge based in bobo-dioulasso, has signi-ficant data on several tropical endemics of which schistosomiasis. with the complementary works, it appears to be possible to establish a distribution of the schistosomiasis which reveals its importance. it will be the first stage of the planned national control program. the parasitologic data-gathering which covers the period of 1951 to 2000, used all the standard techniques. it is about kato-kartz and ...200415104159
[epidemiology of schistosomiasis in a suburban school area of bamako (republic of mali)].epidemiology of schistosomiasis has been assessed in october, 1990 in three primary schools of a suburban district of bamako: magnambougou. it was a cross sectional study which was carried out on an hazardous sample of 549 pupils of 7 to 14 years old. the kato-katz and urine filtration methods were used to search schistosome eggs. the prevalence rate was 50% (256/512) in schistosoma haematobium and 5.6% (26/464) in s. mansoni. children from 11-14 years old were more infected by schistosoma haema ...19957787449
the effect of temperature on inter-relationship between schistosoma haematobium and bulinus truncatus in egypt. 19846736691
epidemiology of schistosoma mansoni infection and its relationship to snail distribution in a village at the nile bank south to cairo.the relationship between epidemiology of s. mansoni infection and snail distribution at a village, related to guiza governorate and lies south to cairo, was investigated. a systematic random sample of houses was selected. all inhabitants of the houses were invited to share in the study. the number examined was 704. urine and stools were examined using nucleopore filtration and standard kato-katz techniques, respectively. snail collection was done from 35 sites along the water bodies related to t ...200416916052
biological studies on the snail intermediate hosts of schistosomiasis with a special emphasis on using larval echinostomes as biocontrol agent against larval schistosomes and snails.the present investigation deals with the infectivity of the two snail intermediate hosts of schistosomiasis, biomphalaria alexandrina and bulinus truncatus collected from nine drains in sharkia governorate, egypt. the rate of infection among the snails was general low being 0% in many drains. regarding b. alexandrina, the rate of infection ranged from 4-16%, and in b. truncatus ranged from 4-8%. infection with larval echinostomes was dominant over larval schistosomes in the two snail vectors. th ...200212512810
observations on compatibility between bulinus truncatus and schistosoma haematobium in the senegal river experiments to determine the compatibility between isolates of schistosoma haematobium and bulinus truncatus from mali and senegal, the parasite isolates were shown to differ in their intermediate host specificity. bulinus truncatus from the lower and middle valleys (senegal) and the upper valley (mali) of the senegal river basin (srb) were all susceptible to s. haematobium isolated from the urines of children living in tenegue, office du niger, mali. however, none of the b. truncatus tested ...19979290844
environmental control of schistosomiasis through community participation in a moroccan oasis.summary akka oasis, in the province of tata, southern morocco, is one of the oldest foci of urinary schistosomiasis in morocco where transmission is still taking place. we report the results of two studies: a cross-sectional snail survey investigated the distribution of bulinus truncatus in relation to habitat factors in the akka traditional irrigation system. the presence of aquatic vegetation, especially potamogeton sp. was identified as a key factor determining snail occurrence and abundance ...200415361113
schistosomiasis in newly reclaimed areas in egypt. 2--patterns of transmission.the distribution, abundance and seasonality of infected biomphalaria alexandrina and bulinus truncatus were studied for 2 years (1992-1994) in two newly reclaimed areas, namely el manayef and el-morra areas located on both sides of suez canal near ismailia city. the results confirm the occurrence of transmission of both schistosoma mansoni and s. haematobium since infected snails of both species were recovered in these areas. this consequently proves that reclamation of parts of the desert utili ...199910605512
evaluation of three methods to control bulinus truncatus, the intermediate host of schistosoma haematobium in an irrigation scheme, tessaout-amont, morocco, the implementation of new irrigation schemes resulted in the introduction of schistosomiasis haematobium to new areas. canal structures (especially syphon boxes) were found to be favourable habitats for bulinus truncatus and they constitute important transmission sites. three methods for snail control in these syphon boxes were assessed in the tessaout-amont irrigation scheme. molluscicide (niclosamide) application resulted in a pronounced reduction in the snail population density, b ...19989588241
evaluation of environmental methods to control snails in an irrigation system in central morocco.the moroccan ministry of public health has launched a programme to eliminate schistosomiasis. one of the components in this process is the control of bulinus truncatus, the intermediate host snail of schistosoma haematobium. we evaluated three environmentally safe measures to control b. truncatus in siphon boxes, the main breeding sites for these snails in the tessaout amont irrigation system. the first method involved covering the siphon boxes to exclude light and reduce algal growth, the secon ...200010995096
[focusing of schistosoma haematobium transmission in irrigated perimeters of the niger valley (niger): importance of malacological factors].currently, the control of urinary schistosomiasis is mostly based on mass treatment. characterization of schistosoma haematobium transmission could lead to adding new methods to the control strategy.200818314284
egg-laying capacity of the small bulinus truncatus in relation to infection with schistosoma haematobium. 196113727550
[transmission of schistosoma haematobium in the town of niamey, niger].located in an area where schistosoma haematobium is hyperendemic, the town of niamey is a focus of hypoendemicity. the aim of the malacological follow-up studies undertaken over a one year period was the determination of the mollusc species present in the water bodies, the appreciation of their space-time distribution of the snail and to find out the potential seasons of transmission. the investigation applied to 22 sites of transmission in the urban community. four molluscs species (bulinus tru ...200314582291
molecular approaches to the identification of bulinus species in south-west nigeria and observations on natural snail infections with schistosomes.the current study considers the distribution of a small sample of 138 bulinus snails, across 28 localities within eight nigerian states. snails were identified using a combination of molecular methods involving both dna sequencing of a partial cytochrome oxidase subunit 1 (cox1) fragment and restriction profiles obtained from ribosomal internal transcribed spacer (its) amplicons. the results showed that the majority of bulinus samples tested belonged to the species bulinus truncatus while only t ...201020854706
strong genetic structure in cameroonian populations of bulinus truncatus (gastropoda: planorbidae), intermediate host of schistosoma order to evaluate the snail host contribution on the variability of mollusk/schistosome compatibility, the genetic structure of seven cameroonian populations of the schistosome vector, bulinus truncatus, was studied using four variable microsatellite loci. a substantial polymorphism mainly distributed among populations was observed. no heterozygous genotype was scored, confirming the high level of selfing rate occurring in b. truncatus populations. contemporaneous samples were highly and sign ...201021075219
the susceptibility and resistance of bulinus (physopsis) globosus and bulinus (bulinus) truncatus rohlfsi to two strains of schistosoma haematobium in ghana.the author presents the results of some laboratory experiments carried out to determine the susceptibility of the snail vectors of bilharziasis in ghana to local strains of schistosoma haematobium, isolated from children living in two districts near accra: the ke district, where bulinus (bulinus) truncatus rohlfsi is the important snail vector, and the pokoasi district, where bulinus (physopsis) globosus is the exclusive intermediate host.each strain was found to be virtually specific in its abi ...195913638791
ecology and distribution of bulinus truncatus in the middle east; with comments on the effect of some human activities in their relationship to the snail host on the incidence of bilharziasis haematobia in the middle east and africa.the author gives a comprehensive account of the present status of knowledge regarding the ecology and distribution of bulinus truncatus, the intermediate host of schistosoma haematobium in the middle east and north africa. he discusses in detail the types of habitat favoured by this snail, its life-cycle and seasonal variations in its populations, the effect of ecological factors on its distribution and occurrence, and the relationship between its control and its bionomics, stressing the many as ...195813573115
[recent evolution of schistosomiasis in the water project of sourou in burkina faso].in order to help the hydro-agricultural projects in the management of water resources together with a schistosomiasis control programme, it is important to evaluate the extent of the problem. this is the reason why parasitological and clinical surveys were conducted in schools associated with malacological surveys in transmission sites of several water projects including the one from sourou. the data-collecting for the research on molluscs was carried out in surface water and as for parasitologi ...200415104151
[heterogeneity of schistosoma haematobium transmission in irrigated fields].heterogeneity of schistosoma haematobium transmission in irrigated fields. although irrigated areas exist since a long time in the niger valley the distribution of the urinary schistosomiasis does not appear homogeneous, testifying to the existence of limiting or favourable factors. the identification of these factors could lead to a better definition of the distribution of the schistosomiasis risks and to optimise control programmes. the population of five villages about 1,900 inhabitants livin ...200415104152
intraspecific diversity of schistosoma haematobium in west africa: chronobiology of cercarial emergence.cercarial emergence patterns were used to analyse the intraspecific variability within and between nine populations of schistosoma haematobium collected along a transect line from the north to the south of the ivory coast (africa) and using bulinus truncatus or bulinus globosus as intermediate snail hosts. statistical comparison demonstrated the existence of a chronobiological polymorphism and the existence of three homogeneous groups of s. haematobium isolates with mean shedding times of the ce ...19979177094
molluscicidal and schistosomicidal activities of a steroidal saponin containing fraction from dracaena fragrans (l.).the steroidal saponin-containing fraction from methanolic extract of dracaena fragrans (family: agavaceae) was tested for molluscicidal and ovicidal activities against biomphalaria alexandrina and bulinus truncatus, the snail vectors of schistosoma mansoni and s. haematobium in egypt, respectively. it was also tested for schistosemicidal activity in vitro on adult s. mansoni and against the free-living miracidia and cercariae of the parasite. the homogenated soft body of b. alexandrina was used ...200818853630
identification of the boudicca and sinbad retrotransposons in the genome of the human blood fluke schistosoma haematobium.schistosomes have a comparatively large genome, estimated for schistosoma mansoni to be about 270 megabase pairs (haploid genome). recent findings have shown that mobile genetic elements constitute significant proportions of the genomes of s. mansoni and s. japonicum. much less information is available on the genome of the third major human schistosome, s. haematobium. in order to investigate the possible evolutionary origins of the s. mansoni long terminal repeat retrotransposons boudicca and s ...200617072464
histological and histochemical studies on the digestive gland of bulinus truncatus infected with schistosoma haematobium.the structure of the uninfected and infected digestive gland of the fresh-water snail, bulinus truncatus, was studied histologically and histochemically. the digestive gland consists of two types of cells: digestive and secretory cells clearly differentiated from each other. the pathological effects of infection of the snail with cercariae of schistosoma haematobium have resulted in considerable structural and histochemical alterations in the digestive gland. generally, the main effects were ref ...19892768865
[bulinus truncatus, intermediate host of schistosoma haematobium in the senegal river basin (srb)].to assess the role of bulinus truncatus in the transmission of urinary schistosomiasis in the senegal river basin (srb), the relations between b. truncatus and schistosoma haematobium were studied. the compatibility study shows that b. truncatus is susceptible to infection with s. haematobium in the upper valley of the srb. the malacological follow up reveals the presence of b. truncatus naturally infected with schistosomes cercariae in the middle valley. the identification of these schistosomes ...200415104154
[experimental study of the compatibility between schistosoma haematobium and two species of bulinus in cameroon].a study on the compatibility between schistosoma haematobium from three remote localities (mourtourwa, gounougou and kékem) and four populations of bulinus truncatus (gounougou, ngaoundéré, bertoua and kékem) and four populations of b. globosus (mourtourwa, ouroudoukoudje, bafia and yaoundé) was undertaken in order to estimate the risk of extension of urinary schistosomiasis in cameroon. first generation of offspring from wild bulinus was exposed to miracidia liberated by schistosome eggs extrac ...200415104158
[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 < o ...19968767791
kinetic potentials of certain scavenger enzymes in fresh water snails susceptible and non-susceptible to schistosoma infection.the activities of catalase (h2o2-oxidoreductase ec and glutathione reductase (ec 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
habitats of bulinus truncatus and planorbarius metidjensis, the intermediate hosts of urinary schistosomosis, under a semiarid or an arid climate.since bulinus truncatus and planorbarius metidjensis are the intermediate hosts of schistosoma haematobium in southwestern morocco, five rivers were investigated to identify sites colonized by either of both species and determine the characteristics of their habitats via the study of 12 physicochemical parameters in running water. p. metidjensis was observed in the upper valleys of three rivers, whereas b. truncatus was found in sites of lower altitude. a component analysis demonstrated that alt ...200717340142
a comparative study of the shedding of cercariae of schistosoma haematobium in newborn bulinus truncatus.a comparative study of the shedding of cercariae of schistosoma haematobium was performed in bulinus truncatus and planorbarius metidjensis individually exposed to 5 miracidia in their first 72 h of life. no significant difference was noted between the mean values of the two snail groups concerning the prepatent period duration (53-57 days at 24 degrees-26 degrees c), the patent period duration (41 days for b. truncatus, 70 days for p. metidjensis), or the total number of cercariae (1,499 per b. ...19957567915
effects of schistosoma mansoni and schistosoma haematobium infections on calcium content in their intermediate hosts.flame atomic absorption spectrometry was performed to determine the alteration of calcium concentration in the soft parts and shells of biomphalaria alexandrina and bulinus truncatus due to the infection with schistosoma mansoni and s. haematobium, respectively. the results showed significant lowering in the calcium content of the shells of cercariae shedding b. alexandrina and b. truncatus relative to the calcium content in the shells of uninfected ones. in contrast, the calcium content in the ...200717497170
effect of water plants and non-target snails on the infectivity of bulinus truncatus with schistosoma haematobium.the application of the water plant (ceratophyllum demersum, eichhornia crassipes and lemna gibba) and/or non-target snails (planorbis planorbis, physa acuta and melanoides tuberculata) gave a significant degree of reduction in the infection rate of b. truncatus subjected to s. haematobium miracidia. the data also indicated a reduction in mean total number of cercarial production/snail. however, no significant difference was detected in the prepatent period and duration of cercarial shedding of t ...200516333895
emergence of schistosoma mansoni infection in upper egypt: the giza governorate.we found an unexpectedly high prevalence of schistosoma mansoni in a village in the upper egyptian governorate of giza. historically, s. mansoni is endemic in the northern egyptian nile delta rather than in the southern upper egypt. this observation was made during an evaluation of a rural health care schistosomiasis surveillance program using a cross sectional survey for s. haematobium and s. mansoni in the village of el-gezira el-shakra el-saf district in the upper egypt giza governorate. a 10 ...199910344658
[comparative study of 3 schistosoma haematobium foci in burkina faso].the comparative study of the three most common schistosomiasis foci in burkinabé villages shows a great disparity both in parasitological and malacological results. parasitological investigations by reagent strips and urine filtration conducted on school children indicated respective prevalence rates of 85% at thion, 37.5% at donsin and 10.5% at djerma. malacological prospections found two species (bulinus senegalensis and bulinus truncatus) of intermediate hosts of schistosomiasis in the water ...200111346977
seasonal abundance of trematode cercariae in bulinus truncatus in a small focus of schistosomiasis in the nile delta.bulinus truncatus was most numerous from june to august, and echinostome cercariae, present in 19.3% of snails, were the most prevalent of the 4 types of trematode cercariae found. the echinostomes occurred throughout the year, other cercariae only in certain months. double infections were uncommon. the findings suggest that echinostome cercariae exercise some biological control of schistosoma haematobium in the area studied.19724539823
potential of origanum compactum as a cercaricide in 1 mg/litre, an ethyl-acetate extract of the molluscicidal plant origanum compactum benth. (lamiaceae) immobilized all of the furcocercariae of schistosoma haematobium exposed to it, within 15 min. this apparently cercaricidal activity was attributed to the presence of terpenoids and flavonoids in the extract. encouragingly, several non-target aquatic organisms (larvae of culex pipiens and artemia salina and adult gambusia affinis) and drosophila melanogaster appeared largely unaffected by exp ...200212396321
population genetics and dynamics at short spatial scale in bulinus truncatus, the intermediate host of schistosoma haematobium, in morocco.the population biology of the schistosome-vector snail bulinus truncatus was studied in an irrigation system near marrakech, morocco using both genetic and demographic approaches. the population genetic survey was conducted in 4 sites, 2 sites being sampled on 2 separate occasions. individuals were genotyped at 6 microsatellite loci. no variability was found at 4 loci, and the 2 other loci had less than 4 alleles. the differentiation, both spatial and temporal, among populations was extremely we ...200212403323
further observations on bulinus (bulinus) truncatus rohlfsi (clessin) in ghana: seasonal population fluctuations and biology.bulinus (b.) truncatus rohlfsi is an important snail host of schistosoma haematobium in ghana and probably elsewhere in west africa. study of this snail in natural habitats in northern ghana has shown that the pronounced population fluctuations can be broadly related to the alternating wet and dry seasons and to any marked changes in the aquatic vegetation. an increase in snail density and reproductive activity begins during the rainy season, reaching a peak in the dry season. the onset of the c ...196220604118
immunolocalization of schistosoma mansoni and schistosoma haematobium antigens reacting with their egyptian snail vectors.the reaction of the haemolymph and the tissue of infected intermediate hosts, biomphalaria alexandrina and bulinus truncatus to schistosoma mansoni and s. haematobium antigens were investigated using the indirect immunoperoxidase technique. a new technique, agarose cell block was used in collection of haemolymph which helped in collecting plenty of well formed cells in comparison to the ordinary one using the cytospin. collected haemolymph and prepared tissues of uninfected and infected b. alexa ...200718383803
studies on the biology of schistosomiasis with emphasis on the senegal river basin.the construction of the diama dam on the senegal river, the manantali dam on the bafing river, mali and the ensuing ecological changes have led to a massive outbreak of schistosoma mansoni in northern senegal, associated with high intensity of infections, due to intense transmission, and the creation of new foci of s. haematobium. data on the vectorial capacity of biomphalaria pfeifferi from ndombo, near richard toll, senegal are presented with sympatric and allopatric (cameroon) s. mansoni. com ...200111586429
urinary schistosomiasis contracted from an irrigation pool in ramah, the southern jordan valley, jordan.autochthonous cases of urinary schistosomiasis are reported for the second time in jordan. eight jordanian juveniles (seven males and one female) ranging in age from 10 to 15 years were diagnosed in 1995 as having the disease. urine examination using the membrane filtration technique showed varying intensities of infection. the patients were treated with praziquantel and a follow-up showed the passage of dead eggs in the urine of five patients one month after treatment. all had egg-negative urin ...19979288808
[bulinus truncatus, planorbarius metidjensis and endemic bilharziosis in the southwestern morocco].since planorbarius metidjensis was recently found to be an experimental intermediate host of schistosoma haematobium in the south-west of morocco, a study on planorbid and b. truncatus was carried out from 1997 to 2005. eleven planorbid populations were identified in 1997 in the agadir province, all living at high altitude (from 340 to 1380 m). in contrast, most of the seven bulinid populations inhabited low-lying zones. three annual generations of p. metidjensis (april-july june-september, and ...200717824308
susceptibility of saudi bulinus truncatus to infection with egyptian schistosoma haematobium with observations on protein electrophoretic pattern of the snails.a laboratory-based susceptibility study was carried out on snails bulinus truncatus collected from highland abha, asser, saudi arabia to egyptian schistosoma haematobium to investigate the potential role of saudi b. truncatus in the transmission of egyptian s. haematobium and to know the possibility that the parasite might be able to spread into saudi arabia. the results revealed that, compared to egyptian snails, survival of snails at day 25 post-exposure was significantly higher in saudi b. tr ...200919329256
age-acquired resistance and predisposition to reinfection with schistosoma haematobium after treatment with praziquantel in mali.the effect of age, previous intensity of infection, and exposure on reinfection with schistosoma haematobium after treatment was studied in a cohort of 468 subjects six years of age and over living in an irrigation scheme area in mali. prevalence and intensity of s. haematobium infection were measured each year between 1989 and 1991, but the reinfection study period was restricted to the last year of the follow-up. observations were made at the principal water contact sites where the number of b ...19957611564
epidemiology of human schistosoma haematobium infection around volta lake, ghana, 1973-75.there was a dramatic rise in the prevalence of urinary schistosomiasis around volta lake within a year of its full impoundment in 1968. research was undertaken to investigate the epidemiology of the disease in preparation for a control programme. the interplay of three factors-age, sex, and ethnic affiliation-largely defined the demographic patterns of the prevalence and the intensity of infection. both of these increased in young children up to a peak at age 10-14 years, and then declined, the ...19826979420
[schistosomiasis in tunisia. results after 10 years of the endemics control].despite the progress already made in the field of epidemiology and the control of schistosomiasis, the practical application of an efficient and economically acceptable methodology still remains a difficult problem to solve. in the saharian and pre-saharian regions of tunisia, bulinus truncatus was successfully controlled while at the same time most of the infected people were treated, so that the transmission did not show up through the appearance of new cases at the outset of the 2nd semester ...19827165899
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