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At least 991 records · Page 55Linked to original sources
PubMed1977

Failure of irradiated Echinostoma audyi and Hypoderaeum dingeri to sensitize Lymnaea rubiginosa snails.

Attempts to induce acquired resistance in Lymnaea rubiginosa snails against the echinostomes Echinostoma audyi and Hypoderaeum dingeri by means of irradiated miracidia were unsuccessful, although Lie and coworkers using similar methods had recently sensitized Biomphalaria glabrata against Echinostoma lindoense (1975a). In contrast to the B. glabrata-E. lindoense system, in Lymnaea rubiginosa the amebocytic response to irradiated parasites was slow: irradiated E. audyi sporocysts were encapsulated 15 to 28 days and H. dingeri sporocysts 20 to 27 days postexposure. No obvious enlargement of the amebocyte-producing organ was seen. No resistance was demonstrable to subsequent homologous challenge. Development of acquired resistance to a trematode infection in snails may be related to the speed with which the snails destroy the irradiated sporocysts.

Animals↗
PubMed1984

[Chemoprophylaxis of schistosomiasis: molluscacidal activity of natural products--assays with adult snails and oviposition].

Data concerning the molluscicidal activity of 159 extracts from 84 Brazilian plants on Biomphalaria glabrata, the most important intermediate host of Schistosoma mansoni in Brazil, are presented. Seventy eight extracts (49,0%) showed activity against snails or eggs, but only twenty nine (18.2%) were active on both, snails and eggs. Extracts of two species (Mikania hirsutissima and Qualea multiflora) have shown to be lethals to adult snails at 10 ppm concentration.

Animals↗
PubMed1980

Serial implantations of larval Schistosoma mansoni from infected to uninfected snails.

The long-term maintenance of Schistosoma mansoni in intermediate snail hosts is described. Snails were infected with one or five miracidia to obtain the initial parasitized liver tissue. The serial implantations were conducted. When the materials for serial implantation were obtained 20 to 60 days after the hosts had begun to release cercariae, the proportion of snails becoming infected was higher than when materials obtained earlier were used. It made no difference whether the initial infection was with one or five miracidia. Our findings suggest the possibility of cloning of unisexual infections in experimental infections.

Animals↗
PubMed1994

[Investigations on dynamics of somatic growth in juvenile snails Lymnaea stagnalis (Pulmonata: Basommatophora) in conditions of experimental infection with parthenites of the trematode Opisthioglyphe ranae (Digenia: Plagiorchiida)].

The effect of exposure of juvenile individuals of Lymnaea stagnalis to infectious eggs of Opisthioglyphe ranae on dynamics of their growth was investigated under controlled conditions in laboratory. In infected snails enlargement of body weight and linear parameters of shell were observed. Any differences in shell shape, analysed on the base of regression of shell width towards to its height, were not ascertained in uninfected snails and those infected with parthenites of the trematode. The findings with this host-parasite system are discussed in relation to possible mechanisms of pathogenesis of somatic gigantism in other trematode-snail interactions.

Animals↗
PubMed1994

The status of Schistosoma mansoni and snail hosts in Tigray and northern Wello regions, northern Ethiopia.

A survey of Schistosoma mansoni infection and snail hosts was carried out in 1992 in six accessible schools and 11 water bodies respectively. Five to ten per cent of the students were randomly selected for stool examination by the Ritichie's method. In Adwa town, however, stools of 100 students out of the 199 selected were re-examined by Kato's method to assess intensity of infection. Results of stools examined by Ritichie's method showed that S. mansoni positive patients were present in four out of six (66.7%) schools, the prevalence for school ranging from 1% in Maychew to 61.8% in Adwa. In all the localities, there was significant male preponderance in the prevalence of infection (p < 0.05). Among those whose stools were examined by the Kato's method in Adwa town, both prevalence and geometric mean egg count per gram of faeces (EPG) were highest in the 10 to 14 years age group reaching 68% and 597 followed by 64% and 591 respectively in the 15 to 19 years of age. Of the S. mansoni positive students in Adwa, 86% excreted 200 or more EPG, 84% of those in the 10 to 14 years of age excreted as high as 1,600 EPG. Sexwise, no significant difference was observed in EPG (p > 0.05). Biomphalaria pfeifferi, the principal snail host of S. mansoni in Ethiopia, were collected from five out of the 11 waterbodies and were found shedding human schistosome cercariae in two of them, their infection rate reaching 0.7%. The ecological characteristics observed were found suitable for snail propagation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Schistosomiasis in the southern region of Oman: vector snails and serological identification of patients in several locations.

The snail Biomphalaria arabica is apparently ubiquitous in the south of Oman (Dhofar province). Snails bred in the laboratory were susceptible to infection with miracidia of Schistosoma mansoni (Puerto Rican strain). The snail Bulinus wrighti, a potential intermediate host of S. haematobium, was found for the first time in Dhofar. Human sera from five localities had antibodies against adult worm antigens and in particular against Sm31/32. The prevalence of seropositive patients was 28% of 47 farm workers, 12% of 99 out-patients from a clinic and 1% of 389 children from four localities. Autochthonous transmission of schistosomiasis in Dhofar is discussed.

Adolescent↗
PubMed1993

Alteration in protein carbohydrate complexes in plasma of freshwater gastropod snail, Lymnaea luteola, challenged with foreign tissue implant.

Levels of protein bound hexose, hexosamine and proteins in ethanol precipitate of the body fluid and protein bound hexose and proteins in the perchloric acid filtrate of the body fluid of the snail L. luteola which received a xenoplastic implant in its cephalopedal sinus, are determined. The significant increase in protein bound hexose in the ethanol precipitate of bodyfluid in recipient snail as compared to sham operated and control snails is interesting. The results are discussed in the light of what is known about glycoproteins and their role in invertebrate immunity.

Animals↗
PubMed1993

Studies on Lymnaea snails and their trematode parasites in Abis II village, Alexandria.

Lymnaea snails in Abis II village were studied as regard their species, monthly distribution, density and infection rates in different water bodies. The trematode parasites in L. cailliaudi, the only species of Lymnaea in Abis II village were xiphidio in 40% of snails and Fasciola in 10%. Echinostome cercariae were detected from few snails outside Abis II village. The morphological characters of the different larval stages of the detected parasites were described.

Animals↗
PubMed1976

Ultrastructural study of the shell-repair membrane in the snail, Helix pomatia L..

The shell-repair membrane of the snail, Helix pomatia, has been studied with the transmission electron microscope (TEM). The ultrastructure of the repair membrane, in the initial stages of calcification, revealed the presence of a fibrillar protein, proteoglycan granules, osmiophilic vesicles, and cytoplasmic dense bodies of different size and structure. The involvement of the cell constituents in the formation of calcifying centra and initial crystal formation is discussed. The amoebocytes present within the repair membrane appeared to be involved in three different functions: (1) phagocytosis, (2) release of granules, vesicles and dense bodies, and (3) secretin of a fibrillar protein. The possible lytic function of the amoebocytes is mentioned. The common features in the minearlizing process of the shell-repair membrane of the snail and the epiphyseal cartilage of the mammals were noted.

Animals↗
PubMed1975

The amino-acid sequence of isoinhibitor K form snails (Helix pomatia). A sequence determination by automated Edman degradation and mass-spectral identification of the phenylthiohydantoins.

Performic-acid-oxidized isoinhibitor K of snails (Helix pomatia) was subjected to arginine-directed tryptic proteolysis. Six peptide fragments including one overlap peptide from limited cleavage of the Arg-3-Pro-4 bond were purified to homogeneity. Four arginine peptides and the C-terminal peptide were sequenced by automatic Edman degradation using a special peptide program. The phenylthiohydantoins were all identified by chemical ionization mass spectrometry, except four cysteic acid residues that were identified on an amino acid analyzer after acid hydrolysis. Quantitative evaluation of the phenylthiohydantoins by chemical ionization mass spectrometry using total molecular-ion beam integration greatly facilitated sequencing. The mass spectrum of the dipeptide less than Glu-Gly revealed that the N-terminus was blocked by pyroglutamic acid. The complete amino acid sequence of isoinhibitor K was determined. An almost 50% homology between the sequences of the snail inhibitor and the bovine trypsin-kallikrein inhibitor (Kunitz) became obvious. A comparison of all homologous sequences of this particular class of proteins known to date is presented.

Amino Acid Sequence↗
PubMed1964

SCHISTOSOMIASIS: AGE OF SNAILS AND SUSCEPTIBILITY TO X-IRRADIATION.

Studies on sensitivity of Australorbis glabratus to x-rays have defined the chronological and physiological age at which the snail is most sensitive to radiation damage. Results showed that the dose producing 50percent mortality at 30 days after irradiation increased with age but that at 90 days it was practically constant from 2 to 210 days of age. In view of the available data on recovery from radiation damage caused by doses from 6000 to 9000 roentgens it is suggested that doses above those causing 50 percent lethality at 60 days but below those causing 50 percent lethality for 30 days should be considered in setting up "radiation barriers" to control snails in water-distribution systems.

Animals↗
PubMed1975

The moroccan food snail, Helix aspersa, as a source of Salmonella.

A total of 270 samples, nine lots of 30 samples each, of imported Moroccan food snails was examined for the presence of Salmonella. Eighty-four samples (an overall incidence of 31.11%) and all nine lots contained Salmonella. No significant difference (P greater than 0.25) in the number of positive samples was observed by using either selenite cystine both or tetrathionate broth when the samples had been pre-enriched in lactose broth. When used as direct selective enrichments with samples not pre-enriched in lactose broth, tetrathionate broth was significantly (P less than 0.05) more productive than selenite cystine broth. The overall detection of Salmonella-positive samples by direct enrichment was significantly greater (P less than 0.001) than by pre-enrichment. A variety of uncommon serotypes occurrence and incidence, and the concomitant human health potential, of Salmonella in one species of live, imported food snails.

Culture Media↗
PubMed1958

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 aspects of these subjects that require further investigation and suggesting lines for future research.In addition, the author outlines briefly the effect of some human activities (for example, extension of irrigation and agriculture), in their relationship to the snail host, on the incidence of bilharziasis haematobia in the Middle East and Africa. He concludes the paper with a summary of the three basic needs in respect of bilharziasis control: ecological research; prevention of pollution of waters with human excrement; and avoidance of human contact with infective water.

Africa↗
PubMed1964

OBSERVATIONS ON BILHARZIASIS AND THE POTENTIAL SNAIL HOSTS IN THE REPUBLIC OF THE CONGO (BRAZZAVILLE).

In 1962, the author conducted a preliminary investigation of bilharziasis in the Republic of the Congo (Brazzaville), at the request of the Government, in order to review existing information and work done on bilharziasis, to assess the prevalence and distribution of the disease, to make observations on the potential snail hosts, and to propose further suitable studies and control measures.Although little time was available for this study, it appears reasonable to conclude that Schistosoma haematobium is confined to a few foci in the west of the country, the main snail host being a new subspecies of Bulinus (B.) truncatus. Intestinal bilharziasis is apparently very rare, but systematic stool surveys have not been done; S. mansoni may be, or become, endemic at Dolisie, where Biomphalaria camerunensis is abundant. The main factors governing the restricted distribution of bilharziasis are discussed.Bilharziasis control appears to merit relatively low priority compared with that due to several other diseases, and the author concludes that bilharziasis is unlikely to become widespread in future years unless there is major environmental change, although the intensity of transmission may increase in some present endemic foci.

Animals↗
PubMed2003

[Helix and drugs: snails for health care from Antiquity to these days].

Land helix, so called snails, have been used in medicine since Antiquity. We find them until today in pharmaceutical specialties and it is the subject of several studies. Why this gastropod has much interested and what products were used, based on this unique active ingredient? Some famous pharmacists like Mure, Figuier and Barin-Barthélémy, made specialties that were well known along the 19th century as proven by the Dorvault reference book in 1877. But the history of snails in medicine continued during the 20th century with hélicidine, commercialized in France in 1957, and with HPA (HElix Pomatia Lectin) that is fixed by metastatic tissues.

Animals↗
PubMed1997

Morphology of interneurons in the procerebrum of the snail Helix aspersa.

Terrestrial snails have a highly developed sense of olfaction. Because the procerebrum has a large number of cells and is located at the entry site of the olfactory nerve into the brain, the structure is thought to have a significant role in the processing of olfactory stimuli. The morphology of the procerebral neurons in the snail Helix aspersa was investigated through intracellular injections of biocytin. No formal categorization of neuronal types was possible, but some cells were seen to have neurites entirely intrinsic to the procerebrum, whereas others had both intrinsic and extrinsic arborizations, and still others had only extrinsic arborizations. These interneurons were previously thought to have arborizations restricted to the procerebral lobe. We demonstrated the extent of the neurite projections outside of the procerebral lobe by making focal injections of biocytin or Neurobiotin into various regions of the cerebral ganglion. This technique revealed subsets of cells that send neurites not only in the ipsilateral ganglion but also through the cerebral commissure into the contralateral cerebral ganglion. Our results demonstrate not only that the procerebral cell population is heterogeneous but also that the procerebrum interacts more directly with the rest of the central nervous system than was formerly believed.

Animals↗