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At least 1,423 records · Page 79Linked to original sources
PubMed1999

Molluscicidal activity of the diterpenoids jatrophone and jatropholones A and B isolated from Jatropha elliptica (Pohl) Muell. Arg.

In the search for new molluscicidal natural products, the activity of the crude ethanol extract of the rhizome of Jatropha elliptica (Pohl.) Muell. Arg. was tested. The LC(50) was 13.07 ppm. The fractionation and purification of the extract furnished jatrophone and a mixture of jatropholones A and B, as the main compounds. They were tested against the snail Biomphalaria glabrata. Jatrophone showed an LC(50) of 1.16 ppm as a molluscicide and an LC(50) of 1.14 ppm for the assay of egg mass, while the mixture of jatropholones A and B presented an LC(50) of 58.04 ppm as a molluscicide and was not active against the second assay at a concentration up to 100 ppm.

Animals↗
PubMed2000

Molluscicidal saponins from Anagallis arvensis against schistosome intermediate hosts.

The molluscicidal activity of saponins isolated from the plant Anagallis arvensis (Primulaceae) was studied against schistosome intermediate hosts, Biomphalaria glabrata and Oncomelania quadrasi. @Strong molluscicidal activity was found in two compounds called desglucoanagalloside B and anagalloside B. Their structures were identified on the basis of chemical and spectroscopic analyses and their activities are comparable to that of the synthetic molluscicide, niclosamide.

Animals↗
PubMed2000

Synthetic approaches towards benzo[h]quinoline-3-carbonitriles.

2-Alkoxybenzo[h]quinoline-3-carbonitriles 2 were readily synthesized via Dimroth rearrangement of 2-amino-4-aryl-5,6-dihydro-4H-naphtho[1,2-b]pyran-3-carbonitriles 5 induced by ethanolic and methanolic KOH. Compounds 2 were also obtained by the reaction of 2-arylmethylidene-3,4-dihydro-1(2H)-naphthalenones 1 with malononitrile or of ylidenemalononitriles 4 with 1,2,3,4-tetrahydro-1-naphthalenone in ethanolic and methanolic KOH. The molluscicidal activity of the products towards Biomphalaria alexandrina snails was screened.

Animals↗
PubMed1976

Snail control in urban sites in Brazil with slow-release hexabutyldistannoxane and pentachlorophenol.

Slow release formulations of hexabutyldistannoxane (TBTO) and pentachlorophenol (PCP) were tested for the control of Biomphalaria tenagophila in 52 urban sites in Rio de Janeiro. TBTO acted faster and lasted longer than PCP and at 15 g/m(2) it eliminated snails from 76% of the treated sites for 1 year. Water pollution and rate of flow had no significant influence on the molluscicidal properties of either compound, but alkalinity lowered the activity of TBTO. Failure to control snail populations was due mainly to human interference and to the non-treatment of adjacent breeding sites that were temporarily dry and therefore overlooked.

Animals↗
PubMed1976

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. In addition, each minor canal was hand-sprayed from the tail to 300 m upstream of the last open field outlet pipe; 360 litres of the commercial formulation were used for this operation.A minimum concentration of 0.035 mg trifenmorph per litre of water was produced at the head of each minor canal. The use of caged snails showed that a concentration as low as 0.015 mg/litre was sufficient to produce 100% mortality in B. truncatus in 7.5 days; this is equivalent to a concentration x time product of 0.12 mg/litre days.

Animals↗
PubMed2000

[Parasitologic survey of schistosomiasis due to Schistosoma mansoni in Katana, Democratic Republic of Congo].

It is now widely recognized that development of irrigation projects in endemic areas for schistosomiasis invariably leads to a recrudescence of the disease by increasing the habitat of the intermediate snail host of Schistosoma mansoni. This fatality was again demonstrated by experience in the Katana region of the Democratic Republic of Congo where development of 43 fresh water reservoirs for raising Tilapia nilotica led to multiplication of Biomphalaria pfeifferi. A parasitological study was conducted in three new villages around these basins and in neighboring villages. Stool examinations were performed in a total of 787 people. Infestation rates were 8.1 p. 100 and 4 p. 100 respectively. Infestation exceeded 25 p. 100 in children between the ages of 10 and 14 years. These findings underline the need for preventive measures.

Adolescent↗
PubMed1975

Introduced schistosomiasis. Evaluation as a public health hazard.

Schistosomiasis was found in many agricultural workers from Yemen who are residing in the San Joaquin Valley, and a study was done to evaluate the public health hazard of this imported disease. If the necessary intermediate hosts are present, a local focus of infection could be established. Numerous Biomphalaria obstructa snails collected in the vicinity of the Avenue 82 irrigation canal near Oasis, Riverside County, showed no evidence of natural schistosome infection. Laboratory-reared offspring of these snails were exposed to miracidia of Schistosoma mansoni originating from Yemen immigrants and to miracidia from a standard laboratory strain of Puerto Rican origin obtained from the National Institutes of Health. All exposures of California B. obstructa were made with a laboratory stock of highly susceptible B. glabrata snails also obtained from NIH as controls. Although miracidia penetrated California snails no evidence of infection was detected whereas the B. glabrata controls showed normal, mature infections with numerous cercariae.There appears little likelihood that B. obstructa can serve as intermediate host for schistosomiasis.

Biomphalaria↗
PubMed1975

Schistosoma mansoni miracidial behavior: an assay system for chemostimulation.

A new system for evaluating the responses of miracidia to chemostimulants is described. The apparatus consists of a translucent plastic block with a center well and a hole in the edge leading to the well. One end of a glass tube, covered with a dialysis membrane, was inserted into the hole. Experimental solutions to be tested were put into the tube and Schistosoma mansoni miracidial behavior was observed in the well on the other side of the permeable membrane. Miracidia were released near the membrane; those which contacted the membrane were scored as to whether they returned (contact with return) or did not return (contact without return) before leaving the field of view. Materials eliciting significantly more contact with return responses than did controls were considered to be stimulatory. In this assay system, snail (Biomphalaria glabrata) conditioned water elicited 75% contact with return as compared to 8% for well water control (P less than 0.05). Tracings from motion pictures showed swimming behavior of miracidia toward snail-conditioned water to be different from behavior toward well water controls. This system permits generation of dilution response curves for chemicals and provides generally quantitative results.

Animals↗
PubMed1975

Genetic studies on variation in infectivity of Schistosoma mansoni.

Biomphalaria glabrata snails of known genetic susceptibility types were exposed to miracidia from 2 strains of Schistosoma mansoni differing in infectivity.. Individual snails were exposed to single miracidia and penetration observed. Snails of a genetic type susceptible to both parasite strains served as controls, while snails of a genetic type susceptible to one parasite strain but relatively refractory to the other served as test snails to demonstrate the difference in parasite infectivity. Cercariae from snails with single sex infection of each of the 2 parasite strains were injected into mice to provide crosses. Results of test snail exposures to F1 miracidia from reciprocal crosses suggested that the parasite strain difference in infectivity was genetic and involved sex linkage. Results also suggested that the female S. mansoni was heterogametic (XY), the male XX.

Animals↗
PubMed1992

The C.E.B.A.S.-Aquarack project: the laboratory prototype and first results of the scientific frame program.

The paper explains the basic conception of a "Closed Equilibrated Biological Aquatic System" (C.E.B.A.S.) incorporated in a Aquarack as a research tool for zoological, botanical and interdisciplinary research in space biology and describes the construction principle of laboratory prototype consisting of a modular habitat for aquatic animals a semi-biological/physical water recycling system and a computerized control unit. Further on the running scientific frame program in which as well five german and two U.S.-universities as the DLR Institute of Aerospace Medicine are involved is presented which includes the subtopics reproductive biology, genetics, embryology/teratology, neurobiology, vestibularis research, stress research general endocrinology, ethology, gerontology and skeleton research. Within this the choice of the experimental animals, the teleost Xiphophorus helleri (vertebrate model) and the pulmonate snail Biomphalaria glabrata (invertebrate model) is explained. Examples of results of the scientific program mainly derive from the hardware-related research and from the reproductive biology subproject with X. helleri.

Animals↗
PubMed1975

Seasonal population densities of snails transmitting urinary and intestinal schistosomiasis in Lusaka, Zambia.

The two molluscan intermediate hosts of S. haematobium schistosomiasis: Bulinus africanus and Bulinus globosus, were found most commonly in habitats that retained water for a substantial part of the year rather than in temporary rain-filled pools. Biomphalaria pfeifferi which transmits S. mansoni were found principally in streams and impoundments like dams but scarce in rivers. In a permanent habitat, the peak density of snails was between the warm, dry months of August and September while in a temporary habitat B. (Physopsis) sp. were most abundant towards the end of the rainy season in March and April. The influence of rainfall and the prevailing the temperature on the fluctuations in the density of snails populations is considered. Further, the low infection rate in snails found in the field is discussed in relation to the critical effect of temperature on this feature. The problem of increasing migration of rural inhabitants to the peri-urban areas and the possible escalation of prevalence rates is considered in relation to the control measures that may be instituted in view of the substantial body of base-line data now available to effect focal control.

Animals↗
PubMed2001

Studies on the molluscicidal and larvicidal properties of Solanum nigrum L. leaves ethanol extract.

Toxicological studies on three ethanol extract preparations of Solanum nigrum L. leaves were made on Biomphalaria alexandrina. Extract (A), made by soaking leaves powder over night in cold 70% ethanol, has the highest activity, (LC50 3.37 mg/L within 24 hr). This extract also showed larvicidal activity against larvae of two mosquito species, Aedes caspius and Culex pipiens, (LC50 51.29 and 125.89 mg/L within 24 hr, and 21.38 and 38.11 mg/L within 48 hr, respectively). Sunlight, pH, and turbidity did not affect the activity of this extract, but the molluscicidal activity seems to be correlated with the increase of temperature. The concentrated extract (1000 mg/L) can be stored at room temperature for six months without any change in its activity, but diluted solutions of this extract lost their activity after four weeks.

Aedes↗
PubMed1979

Bge snail cell-line antigens: ineffectiveness as antischistosomal vaccine in mice.

Mice and rabbits were immunized with antigens derived from Bge cells, Biomphalaria glabrata hemolymph, or Schistosoma mansoni. Antisera from mice given molluscan antigens did not form immunoprecipitates with soluble antigen from adult worms, but their binding to surfaces of sporocysts, cercariae, and schistosomules suggests the presence of cross-reacting determinants. In vitro, cell-mediated immune responses to Bge antigens were not demonstrable in infected nor in immunized mice. Mice immunized with Bge cell-line antigens and challenged with S. mansoni cercariae showed no reduction in worm burden when compared with control mice.

Animals↗
PubMed2002

Resistance to cadmium and parasite infection are inversely related in two strains of a freshwater gastropod.

Phenotypes that are either resistant or susceptible to infection by the trematode parasite Schistosoma mansoni exist in the tropical freshwater snail Biomphalaria glabrata. We tested the hypothesis that a cost of parasite resistance in B. glabrata is greater sensitivity to cadmium toxicity, using parasite-resistant and parasite-susceptible strains exposed to cadmium in the laboratory. Survival analysis showed that time to death for cadmium was significantly shorter in eggs, juveniles, and adults of the parasite-resistant BS90 strain in comparison with the parasite-susceptible NMRI strain. Cadmium exposure increased time to hatch in both strains, but the effect was greater in BS90. Percentage hatch decreased with increased cadmium; BS90 was again more sensitive than NMRI. Comparison of the median effective concentration (EC50) for hatching and median lethal concentrations (LC50s) for survival of juveniles and adults showed that the order for cadmium resistance was adults > juveniles > eggs in NMRI and adults > eggs > juveniles in BS90. Cadmium resistance of F1 and F2 progeny of BS90/NMRI crosses was intermediate to that of parental strains. Numerical estimates indicated that a single genetic factor was responsible for the difference in cadmium resistance in the two strains. These findings were consistent with the hypothesis that greater sensitivity to cadmium is a cost of resisting parasitic infection.

Animals↗
PubMed2002

Incidence of Parastrongylus cantonensis larvae in different fresh water snails in Dakahlia Governorate.

Samples of snails were collected from different water bodies in Dakahlia governorate to assess a survey on the naturally infected snails and their infection rate with the Parastrongylus cantonensis larvae. The nematode P. cantonensis is associated in the etiology of eosinophilic meningeoencephalitis of man. Lanistes carinatus showed the highest rate of infection with 19-400 larvae per snail. Biomphalaria alexandrina, B. glabrata, Bulinus truncatus, Lymnaea cailliaudi (natalensis), L. alexandrina, and Cleopatra cyclostomoides were found naturally infected with the larvae of P. cantonensis for the first time in Egypt. The number of larvae per infected snail varied depending on the snail type. The highest rate (39.2%) of infected snails was collected from the end canals at Tanneekh and the lowest in the river Nile (12.5%).

Angiostrongylus cantonensis↗
PubMedDate not supplied

[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 lying along the valley bottom. The water is sometimes fresh but more frequently salt, (sodium, calcium and potassium, chlorides, sulfates, carbonates and bicarbonate), are in solution of variable proportions. From november to april, the total salt concentration is increasing by high evaporation and the medium becomes non likely to live for aquatic vector snails, Bulinus truncatus, Biomphalaria pfeifferi, Bulinus forskalii, Lymnaea natalensis and Afrogyrus coretus.

Adaptation, Physiological↗
PubMed2002

Epidemiological studies on intestinal schistosomiasis in Wondo Genet, southern Ethiopia.

A cross-sectional epidemiological survey was made on intestinal schistosomiasis due to Schistosoma mansoni in Wondo Genet, southern Ethiopia, in 1999 to generate preintervention parasitological and malacological baseline data to be used as a reference in evaluation of community-based pilot control trial to be launched using wild-growing Endod. A total of 3000 stool specimens were collected from schoolchildren enrolled in 14 schools and microscopically examined using Kato method. The overall prevalence and intensity of schistosomiasis mansoni was 34.6% and 184 eggs per gram of stool (EPG), respectively. Children excreting Schistosoma mansoni eggs were found in all of the 14 schools surveyed with a prevalence of infection ranging from 1.9% in Abaye School to 80.6% in Shesha Kekele School. The overall prevalence of S. mansoni infection among males and females was 38.4% and 27.3%, respectively (P = 0.0001, 95% C.I = 7.5%-14.7%) where as the intensity of infection was 186 EPG and 181 EPG, respectively (P = 0.8045, 95% C.I = 1.17%-1.23%). Malacological surveys of 27 water contact sites revealed the occurrence of Biomphalaria pfeifferi in 8 sites out of which 3 harbored infected snails shedding schistosome cercariae. The necessity for initiating community-based sustainable control programme is discussed.

Animals↗
PubMedDate not supplied

[Parasitological survey, with special reference to schistosomiasis mansoni, conducted in the region of Jacupiranga (Ribeira valley, State of São Paulo). Survey of the location and distribution of planorbidian snails in the State of São Paulo. VII].

The results of a parasitological survey, emphasizing particularly schistosomiasis mansoni, are presented. The area under study was the district of Cajati, situated in the "município" of Jacupiranga (State of São Paulo, Brazil) near schistosomiasis-endemic areas in Vale do Ribeira. Though the presence of parasitized people by Schistosoma mansoni has been reported and focuses of Biomphalaria tenagophila, the species responsible for the spreading of the parasites through great areas of the state, has been localized, it has not been reported any autochthonous case nor the presence of schistosoma-infected planorbidian snails. As a contribution to the planorbidical chart of the State, it is reported as original the discovery of the species Drepanotrema cimex and D. depressissimum in that area. The detection of antitoxoplasmic antibodies in a sample of the studied population showed a significant prevalence rate corresponding to 76,4%.

Animals↗