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PubMed1964

[Field survey on the freshwater snails in Cheju Province(Quelpart lsland), Korea: Especially on presence or not of Parafossarulus manchouricus]

The question of infectivity and prevalence of Clonorchis sinensis in Cheju province (Quelpart Island) was arisen to authors since the several surveys on the endemic diseases were performed in this island. Therefore, authors decided to solute this question. Then the survey on the possible second intermediate host of Clonorchis sinensis was performed and reported already with negative finding. At present time, authors carried out the collection of all kinds of fresh-water snails through all areas of this island, to confirm the presence or not of Parafossarulus manchouricus, the only first intermediate host of Clonorchis sinensis in Korea. And the following results were obtained. 1)The fresh-water snails collected in the survey were Semisulcospira libertina Gould and Lymnaea ollula Gould. 2)Parafossarulus manchouricus Bourguigant was not collected in this island. 3)It is confirmed that the Clonorchis sinensis can not be prevalent in this island.

Journal Article↗
PubMed2003

Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa.

This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares) on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0%) recovered from swamps. Most samples (45.8%) were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5% of the samples. Most samples (86.3%) were collected in habitats with a mean annual air temperature of 10-20 degrees C, and more than 69% came from localities with a mean annual rainfall of 600-900 mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

Animals↗
PubMed2005

Distribution, habitats and role as intermediate host of the freshwater snail, Bulinus forskalii, in South Africa.

This paper focuses on the geographical distribution and habitats of Bulinus forskalii, the snail intermediate host of the conical fluke of equids, Gastrodiscus aegyptiacus as reflected by the 1209 samples in the database of the National Freshwater Snail Collection of South Africa. The 362 different loci on record represent an extensive distribution in KwaZulu-Natal Province, the Limpopo Province, the coastal areas of the Eastern Cape Province and the south-eastern part of the North West Province. Although it was recorded from all types of water-body represented in the database, the highest percentages of samples were recovered from dams (30.4%) and brooks (28.2%). The majority of samples came from perennial habitats (59.1%), 60.7% from habitats with standing water, 54.0% from habitats with clear water and 71.8% from habitats of which the water was described as fresh. The majority of samples (39.5%) were collected in habitats of which the substratum was recorded as muddy. The highest percentage of samples, by far (81.5%), was collected in habitats that fell within the mean yearly temperature interval ranging from 15-20 degrees C. An integrated decision tree constructed from the data in the database indicated that temperature and type of water-body played a decisive role in determining the presence of B. forskalii in a given area. The results of experimental exposure to miracidia of a local strain of both Schistosoma haematobium and Schistosoma mattheei in the laboratory indicated that a local strain of B. forskalii was incompatible with both these strains of parasite. Research to clarify the role of B. forskalii in the transmission of both Calicophoron microbothrium and G. aegyptiacus in South Africa, is recommended.

Animals↗
PubMed1977

Rearing of the snail Biomphalaria glabrata under axenic conditions in isolators.

Germfree Biomphalaria glabrata were successfully reared through their life cycle in isolators. The snails were fed a diet sterilized either by heat or by irradiation. Snails fed an irradiated diet had a better growth and higher reproduction rate than the ones fed an autoclaved diet. There was no difference in survival between the two groups.

Animals↗
PubMed1990

Human schistosomiasis in Cameroon. II. Distribution of the snail hosts.

A nationwide survey for snail hosts of human schistosomes was carried out in Cameroon between 1985 and 1988. In total, 668 sites at 432 locations were sampled. In the arid, northern half of the country (tropical climatic zone), where both intestinal and urinary schistosomiasis are hyperendemic, Biomphalaria pfeifferi was the only Schistosoma mansoni host and Bulinus globusus and B. senegalensis the most common S. haematobium hosts. In that region, these snails occurred almost exclusively in temporary bodies of water. Taking into account results from a companion study on the distribution of schistosomiasis in humans, our results clearly show that temporary water bodies in the tropical zone are the principal foci of transmission. These findings disagree with commonly held views about schistosome transmission in Cameroon. B. truncatus, a S. haematobium host, was also present in the tropical zone but was found principally in perennial habitats. Although some perennial habitats were important transmission sites, they represent only a small portion of the overall problem. B. truncatus is the principal S. haematobium host in the wetter southern half of the country where schistosomiasis haematobium is highly focal. Biom. camerunensis was far more common than Biom. pfeifferi in the South but did not occur where S. mansoni prevalence rates were high; thus it appears to be a poor host. B. forskalii, the sole host of S. intercalatum in Cameroon, occurs widely throughout the country; however, the schistosome is restricted to a small region in the South.

Animals↗
PubMed2000

Distribution and developmental changes in GABA-like immunoreactive neurons in the central nervous system of pond snail, Lymnaea stagnalis.

We examined three-dimensionally the arrangement of gamma-aminobutyric acid (GABA)-like immunoreactive neurons in the central nervous system (CNS) of the pond snail, Lymnaea stagnalis, by a combination of immunohistochemistry and confocal laser scanning microscopy on whole-mount preparations. GABA-like immunoreactivity was detected in all ganglia of the adult CNS. The following distribution of immunoreactive cell bodies was noted in the adult snail. Buccal ganglia: one cell body and five pairs of cell bodies, cerebral ganglia: one pair of cell bodies, pedal ganglia: two single cell bodies, two pairs of cell bodies, and three pairs of cell clusters, and pleural ganglia: one pair of cell bodies. In the asymmetrical parietal ganglia, three cell bodies were located in the left parietal ganglion; three cell bodies and three cell clusters were located in the right parietal ganglion. In the single visceral ganglion, a few scattered individual cell bodies and a cell cluster were GABA-like immunoreactive. Our results showed that the occurrence of GABA is widely spread in the CNS of adult L. stagnalis. GABA-like immunoreactivity in the CNS was not detected in the embryo but was observed after hatching, although the number of stained cells was less than in the adult, with the exception of those in the cerebral ganglia where their number decreased with maturation. Our results provide detailed maps of the central GABA-like immunoreactive neurons in juveniles, immatures, and adults of L. stagnalis.

Aging↗
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↗
PubMed1975

Fascioliasis of livestock and snail host for Fasciola in the Altiplano Region of Bolivia.

Fascioliasis caused by Fasciola hepatica was a serious problem for sheep and alpacas in the Altiplano Region of Bolivia. In some provinces close to Lake Titicaca, the raising of sheep was forced to discontinue, because infection with the fluke made it unprofitable and almost impossible. It was proved that in the Altiplano Region, two species of freshwater snails, Lymnaea viatrix and L. cubensis var., served as intermediate hosts for F. hepatica. In some subtropical areas of Bolivia, these snails could not be found, although other Lymnaea sp. was widely distributed there. As it is possible for Lymnaea sp. to be intermediate host for the fluke, further studies are required on the identification. Acute fascioliasis of sheep occurred in the Altiplano Region principally during a period from May to July, or the dry season. In some areas, the mortality rate of infected sheep was roughly estimated as 15 to 25% annually. Contamination with Fasciola metacercariae of herbage and semi-aquatic plants grown in a swamp in one of these areas was biologically assessed, using guinea pigs. Plants of Compositae and Eleocharis sp. were contaminated most intensely and those of Senicio sp. and Vallisneria sp. carried a fairly large number of cysts, while plants of Scirpus sp. and Ranunclaceae carried only a few cysts. No signs of Fasciola infection were observed in any animal given the plants of Liliaceae.

Animals↗
PubMedDate not supplied

[Cell culture of snails. Their use in the study of immunologic host-parasite relationships in schistosomiasis].

The host-parasite relationship between Schistosoma mansoni and the snail Biomphalaria glabrata is so complex that its experimental study needs some particularly working methods: for instance molluscan organs and tissue's cultures. In the experiment described we report that digestive gland's cells cultures were grown on synthetic cultural medium. This one contained a physiological salt solution and a basal nutrient medium consisting of foetal calf serum, chicken embryo extract and amino-acids. In this case we observed good growth and multiplication of the digestive gland cells. This preliminary experiment has to be used in immunological studies regarding the origin and the mode of acquisition of the snail antigen by the cercariae membrane.

Animals↗
PubMed2002

[Somatic polyploidy in neurons of the gastropod mollusca. III. Mitosis and endomitosis in the postnatal development of neurons in the Succinea snail central nervous system].

General morphology of chromatin, the number of chromosomes and chromocenters in normal condition and at the increase of bivalent cation (Ca2+, Mg2+) concentration were studied with the purpose to reveal mechanisms of polyploidization of neuron nuclei in the snail Succinea lauta (Gastropoda, Pulmonata). The morphology of nuclei was studied on squashed preparations. Normal diploid mitoses are described in the cerebral ganglia. A possibility is supposed that part of neurons or neuroblasts in the central nervous system (CNS) of succineid snail may divide mitotically. It has been shown that the basic mechanism of neuron postnatal growth is endomitotic polyploidization of nuclei. The transition from ordinary mitosis to polyploid cycles occurs via restitutional (polyploidizing) mitosis (4c2n-->4c4n). The next endocycles are carried out by means of classic endomitosis up to reaching the highest ploidy levels--4096n--16,384n. The study of general morphology of chromatin and chromocenters at normal condition and at artificial compactization enabled us to exclude any probability of polyteny in the CNS of lauta.

Animals↗
PubMed1999

Studies on the molluscicidal actvity of Calendula micrantha officinalis (Compositae) on fascioliasis transmitting snails.

The molluscicidal activity of ethanolic extracts of Calendula m. officinalis (flowers and leaves) was used as plant molluscicides against Lymnaea cailliaudi. The results indicated that flowers extract possess a molluscicidal activity more than leaves extract and the LC50 was 35 and 52.17 ppm respectively. The mortality rate of exposed snails was increased by prolongation of the exposure time. The molluscicidal effect resulted in enhancing energy utilization and nutrient consumption since glucose, lipids, proteins and triglycerids were greatly reduced. The stomach and digestive gland of the treated L. cailliaudi snails were greatly altered.

Animals↗
PubMed2003

Copper bioaccumulation by the freshwater snail Lymnaea peregra: a toxicological marker of environmental and human health?

Snails (Lymnaea peregra) were exposed to both low and high concentrations of copper(as copper nitrate) undercontrolled conditions and then were sacrificed and dissected; various tissues/organs were removed and subsequently analyzed by atomic absorption spectrophotometry to determine both the copper concentration and the nature of localization. At low concentrations, bioaccumulation was evident in various tissues/organs; a dose response occurred in tissues derived from both the head and foot. At high concentrations, the copper concentrations of the liver-like body and kidney became massively enhanced. There was some variability in the ranking of tissues/organs with regard to copper bioaccumulation--this was predominantly linked to the copper concentration to which the snails were exposed. Mechanisms of copper bioaccumulation are reviewed and comparisons with other organisms made.

Animals↗
PubMed2003

[Case report-fatal snail bait (metaldehyde) overdose presenting aspiration pneumonia].

A-55-year-old man ingested unknown amount of snail poison bait containing metaldehyde. He was mentally retarded and presented pica. On admission, his vital sign was stable, and the extremeties were spastic. Then, gastric lavage was unsuccessful because of massive unbited food. Activated charcoal and cathartic were administrated. On the next day, general convulsion occurred and respiratory distress advanced, so he was intubated. On the 3rd day, infiltration shadow appeared on chest roentogenogram and, his respiration was assisted mechanically. Thereby, acute lung injury advanced regardless of tracheostomy, kinetic therapy, antibiotics and steroid pulse therapy. He died of respiratory failure on the 33rd day. Serum test showed HBs and HBe antigen, CT scan revealed ascites and splenomegaly; the clinical course might be worsened by liver cirrhosis. HPLC revealed metaldehyde in the serum (total 80.6 microg/ml). He ingested 2.7 g of metaldehyde maximally estimated. Although Japan Poison Information Center reported that snail poison bait poisoning is often in dogs in Japan, human poisoning is rare.

Acetaldehyde↗
PubMed2004

Ingestion of Fasciola gigantica metacercariae by the intermediate host snail, Lymnaea ollula, and infectivity of discharged metacercariae.

The rate of ingestion of Fasciola normal metacercariae (NMc) encysted on plants by Lymnaea ollula was examined, and the infectivity of the ingested metacercariae (IMc) in the feces of the host snail to mice was studied. As a result of ingestion by snails, the metacercarial outer cyst disappeared in about 50% of IMc in feces. There was no significant difference in the liver juvenile recovery at autopsy between mice inoculated with NMc and IMc kinds of metacercariae. Compared with NMc, the number of IMc could more easily be counted, because the separation of IMc from fecal contents under a microscope was not laborious.

Animals↗
PubMed2005

Biological and biochemical studies on Biomphalaria alexandrina snails, treated with low concentrations of certain molluscicides (synthetic and of plant origin).

The effect of low concentrations of different synthetic and natural mollusciciding agents may introduce to fresh water environment on reproduction and biochemical aspects of Biomphalaria alexandrina was studied. Different mollusciciding agents (copper sulphate, Bayluscide, Uccmaluscide, Agave filifera & A. attenuate) inhibited egg production, induced marked increased the percent of abnormal laid eggs and induced marked reduction in their hatchability. The maximal reductions in egg hatchability resulted with Bayluscide (0.0%) and Uccmaluscide (18%), A. filifera (21%) and A. attenuata (15%). All the antimolluscal materials caused a successful killing effect against miracidia and cercariae of Schistosoma mansoni. CuSo4, Bayluscide and Uccmaluscide killed 40% of the exposed miracidia and 50% of cercariae after an hour exposure. The plants sublethal concentration killed 100% of cercariae and miracidia after 6 hours exposure. Water leaving behaviour among the exposed snails was noticed especially during the first three weeks, showing maximal percentage (60%) after one week of exposure to Bayluscide. A general decrease in the activity of alkaline phosphatase (ALP) especially with Bayluscide (48.4%) and in acetylcholine esterase activity in the haemolymph especially on applying plant molluscicide A. filifera (50.8%) was noticed. Transaminases showed marked elevations in activities during the 1st three weeks, then began to drop (ASAT: 61.5%, with Bayluscide & ALAT: 50.8% with Uccmaluscide). The results reflect the effect of the metabolic disorders on life, egg laying, egg hatchability, hepatic cells damages, lack of smooth transmission at nerve junction, loss of muscular coordination and convulsions, then snails' death.

Animals↗
PubMed2006

Microgeographic evolution of snail shell shape and predator behavior.

Genetic divergence in geographically isolated populations is a prerequisite for allopatric speciation, one of the most common modes of speciation. In ecologically equivalent populations existing within a small, environmentally homogeneous area, an important role for environmentally neutral divergence is often found or inferred. We studied a species complex of conspicuously shaped Opisthostoma land snails on scattered limestone outcrops within a small area of lowland rainforest in Borneo. We used shell morphometrics, mitochondrial and nuclear DNA sequences, and marks of predation to study the factors involved in allopatric divergence. We found that a striking geographic divergence exists in shell morphology, which is partly associated with neutral genetic divergence. We also found geographic differentiation in the behavior of the snails' invertebrate predator and evidence of an evolutionary interaction between aspects of shell shape and predator behavior. Our study shows that adaptation to biotic aspects of the environment may play a more important role in allopatric speciation than previously suspected, even on a geographically very small scale.

Adaptation, Physiological↗
PubMed1991

Variation of transaminases and lactate dehydrogenase in irradiated Biomphalaria alexandrina snails.

Effect of ultraviolet and gamma radiations on the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LD) in Biomphalaria alexandrina snails, the specific intermediate host of schistosomiasis, was investigated. Changes in the electrophoretic pattern of LD in the species under study were also taken as a measured parameter and the effect of gamma-irradiation on the glutathione content in the haemolymph of the snails have been included.

Alanine Transaminase↗
PubMed1990

Measurement of some selected enzymatic activities in infected Biomphalaria alexandrina snails.

The activities of aspartate (AST) and alanine (ALT) aminotransferases and that of lactate dehydrogenase (LD) were measured in the homogenate of infected Biomphalaria alexandrina snails, the specific intermediate hosts for the parasite Schistosoma mansoni which is the cause of the disease schistosomiasis. The isoenzymatic pattern of LD was also studied in the infected snails tissue.

Alanine Transaminase↗