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ecological studies of bulinus rohlfsi, the intermediate host of schistosoma haematobium in the volta lake.in 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
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
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
seasonal patterns in the transmission of schistosoma haematobium in attaouia, morocco.in 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
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
carbohydrate metabolism in uninfected and trematode-infected snails biomphalaria alexandrina and bulinus truncatus. 19751157458
techniques for estimating densities of bulinus truncatus rohlfsi and its horizontal distribution in volta lake, ghana.bulinus truncatus rohlfsi is the intermediate host of urinary schistosomiasis, which is highly endemic in the man-made volta lake. in 1971, a who/undp schistosomiasis project was established in the pawmpawm branch and part of the afram branch of volta lake. malacological findings of the preliminary phase indicated that the snails were distributed in the littoral zone of the lake, and that this distribution was correlated with the presence of vegetation, especially ceratophyllum. transmission nea ...19761088354
larval trematode stages in bulinus truncatus and biomphalaria alexandrina snails. 19761025238
on the larval trematodes recovered from bulinus truncatus in assiut governorate. part ii. leptocercous and amphistome cercariae. 19761025234
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
experimental studies on the suitability of aquatic snails as intermediate hosts for paramphistomum cervi in iraq.three of the most common species of aquatic snails in iraq were examined for their susceptibility to infection with paramphistomum cervi. bulinus truncatus was the only susceptible species. no development occurred in physa acuta or lymnaea lagotis euphratica. these findings and a previous field observation that infection of b. truncatus with amphistome larvae is not uncommon indicate that b. truncatus is an intermediate host of p. cervi in iraq. young snails of b. truncatus were more susceptible ...1978666386
studies of the relationships between schistosoma and their intermediate hosts. iv. the genus bulinus and schistosoma bovis from morocco.schistosoma bovis from morocco was used in infection experiments with several populations of bulinus truncatus. the snails from libya, malawi, morocco and senegal were very compatible with the schistosome since the infection rates were approximately 90%, the mortality was low, and a very high production of cercariae, approximately 1.2 million per 100 exposed snails, was observed. only a very few b. truncatus (2n = 36) from rhodesia became infected. b. permembranaceus and b. forskalii were refrac ...1979541499
investigation of molluscicidal activity of certain sudanese plants used in folk-medicine. i. a preliminary biological screening for molluscicidal activity of certain sudanese plants used in folk-medicine.a preliminary biological screening for molluscicidal activity of certain sudanese plants used in folk-medicine was carried out. 78 samples belonging to 51 species, 45 genera and 28 families were screened. the aqueous extracts of 18 samples belonging to 8 species, 6 genera and 5 families were found to be active against bulinus truncatus and 7 of these were also found to be active against biomphalaria pfeifferi. successive extraction of the 18 active samples with petroleum ether, ethanol and water ...1979529347
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
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
schistosomiasis control in saudi arabia with special reference to the period 1983-1988.schistosomiasis control operations carried out between 1983 and 1988 are described, together with information of the impact of schistosomiasis. the prevalence of schistosomiasis has declined from 9.5% in 1983 to 1.8% in 1988 (p less than 0.05). bulinus truncatus, b. beccarii, and b. reticulatus wrighti are the intermediate hosts of s. haematobium in saudi arabia and are distributed unevenly in the different regions. biomphalaria arabica is the intermediate host of s. mansoni and is found whereve ...19902382008
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
interference of echinoparyphium elegans with the host-parasite system bulinus truncatus-schistosoma bovis in natural conditions.histological observations of bulinus truncatus naturally infected by both schistosoma bovis and echinoparyphium elegans in sardinia (italy) have shown that e. elegans is pathogenic to the mollusc and dominant to the schistosome. the larval stages, rediae and metacercariae, acted as compressors. rediae, mainly the young and very motile ones, also behaved as predators. the organs of the mollusc were variably affected; the ovotestis totally disappeared. the larval development of the schistosome was ...19902260898
[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
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
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
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
the occurrence of schistosomin, an antagonist of female gonadotropic hormones, is a general phenomenon in haemolymph of schistosome-infected freshwater snails.in haemolymph of lymnaea stagnalis, parasitized with the digenetic trematode parasite trichobilharzia ocellata, a neuropeptide (schistosomin) occurs which antagonizes female gonadotropic hormones, e.g. calfluxin (cafl). by means of an ultracytochemical hormone-assay, the cafl assay, it was demonstrated that the occurrence of schistosomin is a general phenomenon in schistosome-infected freshwater snails. haemolymph of the schistosomiasis-transmitting snail species biomphalaria glabrata and b. pfe ...19911780174
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
letter: bulinus truncatus as a potential intermediate host for schistosoma haematobium on the kano plain, kenya. 19744419850
human helminthosis in a rural community of plateau state, nigeria.urine and faecal samples were obtained from 1,517 people in fier, a typical rural village in plateau state, nigeria, for a parasitological survey among the population. 643 (42.39%) persons were found to be infected with altogether 9 helminths, namely: ascaris lumbricoides, hookworm, taenia sp., trichuris trichiura, enterobius vermicularis, schistosoma mansoni, s. haematobium, hymenolepis nana and strongyloides stercoralis. age and religion as opposed to sex, type of sewage system, and type of ho ...19921456465
[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
[remarks on the ecological adaptation of the snail aquatic fauna in saline medium of the dallol ponds. (republique du niger) (author's transl)].human vesical and intestinal bilharziasis, bovine fasciolosis and paramphistomosis, equine gastrodiscosis and ovine carmyeriosis, are frequent in the dallols'region, (12 degrees - 13 degrees 30 n. lat. ; 3 degrees e. long.), republique du niger, africa. dallols are fossil valleys pouring water from late saharian lakes. they are also tributaries of the niger river. during the dry season, they become dry and many residual ponds of varied dimensions; from tens feet to one or two miles long, are lyi ...19751221913
[mixed infestation of bulinus truncatus (audouin, 1827) by larval forms of schistosoma haematobium (bilharz, 1852) and an echinostomatidae]. 19724650809
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
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
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
1983 nile delta schistosomiasis survey: 48 years after scott.to 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
the life cycle of echinoparyphium ralphaudyi sp. n. (trematoda: echinostomatidae).the life cycel and morphology of echinoparyphium ralphaudyi sp. n. is described. natural infections were found in bulinus truncatus from egypt, ethiopia, and the yemen arab republic, and later in b. forskalii and b. sericinus from ethiopia. sporocysts develop near the places of miracidial entry into the snail (the head-foot region, mantle edge, pseudobranch, and antennae). rediae occur mainly in the ovotestis and in tissues anterior to the liver. the first cercariae are released 24 days postexpo ...19751117371
a large-scale snail control trial with trifenmorph in the gezira irrigation scheme, sudan.a large-scale field trial was carried out during december 1973 to assess the effect of trifenmorph on bulinus truncatus and biomphalaria pfeifferi in 379 000 feddans ( approximately 159 000 ha) of the gezira irrigation system in the sudan. the commercial formulation used (frescon) is an emulsifiable concentrate containing 16.5% trifenmorph. five dispensers were used to add the commercial product to the water continuously for 7.5 days; 18 121 litres were used to treat 28.4 million m(3) of water. ...19761088406
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
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
observations on the infection of bulinid snails with schistosoma mattheei. i. the susceptibility of bulinus africanus and bulinus truncatus. 19685714964
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
periodicity and longevity of schistosoma haematobium cercariae liberated from bulinus truncatus in central iraq. 19655889014
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
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
immunity to schistosoma haematobium in bulinus truncatus. 19665954292
schistosoma bovis: variability of cercarial production as related to the snail hosts: bulinus truncatus, b. wright and planorbarius metidjensis. 19873440697
the ability of bulinus truncatus, biomphalaria alexandrina and lymnaea gedrosiana to survive out of water in the laboratory. 19676051532
the location of bulinus truncatus in dry habitats in iran. 19676063490
the survival time and fecundity of bulinus truncatus after desiccation in mud. 19676063491
the survival of bulinus truncatus buried in mud under experimental outdoor conditions. 19676069306
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
snails and aquatic vegetation in gezira irrigation canals.all 38 minor canals in a limited area of the gezira irrigated area were surveyed four times over a 2-year period to determine the aquatic and semi-aquatic vegetation types found and their distribution. a more detailed 2-year study of the correlation between snail density and aquatic vegetation was carried out in 18 of these canals. a total of 22 different species of weed were recorded, with floating and submerged weeds being more widespread and dense in the clear, slow-moving water at the end of ...19854032532
molluscicidal properties of acacia nilotica subspecies tomentosa and astringens i.the acetone, alcohol and aqueous extracts of the fruits and stem bark of acacia nilotica subspp. tomentosa, astringens and nilotica showed molluscicidal activity against the two snail species which transmit schistosomiasis in the sudan. being effective against bulinus truncatus and biomphalaria pfeifferi, extracts of the acacia nilotica subspecies may be promising vegetable molluscicides.19854068076
molluscicidal properties of acacia nilotica subspecies tomentosa and astringens ii.a screening programme of plants rich in plant phenolic tannins for molluscicidal activity against the snail species bulinus truncatus and biomphalaria pfeifferi is now under way. the spray-dried powders of the pods and stem bark of acacia nilotica subspp. nilotica, tomentosa and astringens prove to be promising vegetable molluscicides.19854068077
antagonism of echinoparyphium recurvatum against schistosoma haematobium in the snail bulinus truncatus. 19744412038
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
effect of sub-lethel doses of molluscicides on the susceptibility of bulinus truncatus snails to infection with schistosoma haematobium. 19744418538
effect of sub-lethal doses of molluscicides on the susceptibility of bulinus truncatus snails to infection with schistosoma haematobium. 19744469237
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
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
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
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
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
effect of molluscicide application against bulinus truncatus in iraq on the structure of eggs produced by treated snails. 19695388192
monthly prevalence rates of natural infection with schistosoma haematobium cercariae in bulinus truncatus in central iraq. 19655889011
factors inherent in the egg-masses of bulinus truncatus (snail intermediate host of urinary bilharziasis in iraq) affecting the efficacy of molluscicides. 19645890098
effect of low concentrations of sodium pentachlorophenate on the fecundity and egg viability of bulinus truncatus from central iraq. 19655896523
studies on the biology and ecology of bulinus truncatus (intermediate host of urinary bilharziasis in central iraq with suggestions for control). 19665985995
effect of rice cultivation on the prevalence and infection rates of schistosoma intermediate host.in this study, it was aimed to explore the effect of rice cultivation on the prevalence, density and infection rates on the snail intermediate hosts of human schistosomiasis. a village was chosen and examine for the main water canal supplying the rice field by making three successive scoops at 10.20, 30, 40 and 50 meters up stream the site of the pump supplying the rice field. the same was done in the large irrigation canal supplying 50 feddans of rice up to 100 meters (i.e. 10 sampling sites). ...19938308352
[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
[comparative analysis of the rhythm of cercariae emergence in three strains of schistosoma bovis (trematoda: schistosomatidae)].a comparative experimental study of the rhythmic shedding of three geographic strains of schistosoma bovis cercariae (sardinian, sudanese and spanish) by bulinus truncatus showed a significant difference in the emergence patterns. the results support the existence of a genetic variability of the emergence rhythms. the origin of the variability is discussed and could be found in the pastoral practice and the ecological characteristics of the different transmission foci.19873508513
genetic variability of schistosoma bovis cercarial production according to miracidial dose.cercarial production related to miracidial dose variation with schistosoma bovis strains from sudan and spain in bulinus truncatus from tunisia was studied. results showed that an increase in the miracidial dose proposed to the host-mollusc (1 and 5 miracidia) gave rise to a decrease in cercarial productivity of sudanese s. bovis and to an increase for spanish s. bovis. it is concluded that this response difference to the miracidial dose variation depends on genetic characters peculiar to the pa ...19873571926
schistosoma bovis: patterns of cercarial emergence from snails of the genera bulinus and planorbarius.a comparative experimental study of the rhythmic shedding of two geographic strains of schistosoma bovis cercariae by bulinus truncatus and planorbarius metidjensis did not show any differences in emergence patterns. in our opinion, the results support the hypothesis that cercarial emission rhythms are determined primarily by the parasite in these snail/parasite associations.19863780932
studies on the effects of population density on the growth and survivorship of bulinus truncatus from assiut. 19836631096
the effects of population density on the reproductive capacity of bulinus truncatus from assiut, egypt. 19836663097
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
the effect of temperature on inter-relationship between schistosoma haematobium and bulinus truncatus in egypt. 19846736691
ecological studies on bulinus truncatus and biomphalaria alexandrina in zagazig, egypt. 19846736706
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
comparative studies on the effects of castration and schistosome-infection on bulinus truncatus. 19827153563
[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
[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
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
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 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
[distribution of intermediate mollusc hosts in human schistosomiasis in the office of niger (mali).ii. role of different habitats in the transmission].to determine the role of habitats in the schistosomiasis transmission all the year, a study on snail hosts distribution was carried out within various parts in the irrigated system of the "office du niger". bulinus truncatus and biomphalaria pfeifferi were the only snail hosts recorded. densities were low and 85% (46/54) of breeding sites contained less than 50 snails collected per man/hour. primary and secondary canals play the most important role in disease transmission because of the stabilit ...19947827516
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
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
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
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
[development of the sporocysts of schistosoma bovis after microsurgical transplantation in bulinus truncatus].microsurgical transplantations of schistosoma bovis daughter sporocysts to uninfected bulinus truncatus leads to a dedifferenciation of transplanted sporocysts producing an additional generation of daughter sporocysts. these ones settle into the whole digestive gland and produce infective cercariae. for all the parasitosis, a part of the daughter sporocysts born from the transplanted ones, remains in the head-foot region and are in their turn responsible for an active sporocystogeny. data demons ...19846508141
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
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
[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
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
antibacterial and molluscicidal activities of the essential oil of chrysanthemum viscidehirtum.the volatile fraction of chrysanthemum viscidehirtum aerial parts, consisting mainly of limonene, beta-farnesene and many oxygenated sesquiterpenes, was screened for activity against 21 microbial strains. this essential oil exhibited activity against all germs tested, in particular salmonella typhi and proteus mirabilis. it also showed molluscicidal activity against bulinus truncatus.200011449503
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
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