The Chemical Ecology of Biomphalaria glabrata (Say), The Snail Host of Schistosoma mansoni Sambon: The Search for Factors in Media Conditioned by Snails which Inhibit their Growth and Reproduction

1975 ◽  
Vol 12 (2) ◽  
pp. 421 ◽  
Author(s):  
J. D. Thomas ◽  
A. S. Lough ◽  
R. W. Lodge
Keyword(s):  
Schistosoma Mansoni ◽  
Chemical Ecology ◽  
Biomphalaria Glabrata ◽  
Snail Host ◽  
Growth And Reproduction

Energy constraint exerted by the parasite Schistosoma mansoni on the locomotion of its snail host, Biomphalaria glabrata

1996 ◽  
Vol 74 (4) ◽  
pp. 594-598 ◽  
Author(s):  
Claudia Gérard
Keyword(s):  
Resource Allocation ◽  
Schistosoma Mansoni ◽  
Biomphalaria Glabrata ◽  
Snail Host ◽  
Locomotory Activity ◽  
Patent Period ◽  
Energy Constraint

The consequences of the constraint caused by the parasite Schistosoma mansoni on the locomotory activity of its snail host, Biomphalaria glabrata, were studied during the patent period. Rates of locomotion were determined 6 times per 24-h period for juvenile and adult snails with single-miracidium infections, then compared with those of healthy snails of the same age. The locomotory activity of infected snails was the same during the day and at night, whereas control snails moved less at night than during the day. The locomotion of snails infected when immature was similar to that of the controls during the day and superior at night. The locomotion of snails infected when mature decreased regularly during patency and clearly decreased in comparison with that of healthy snails. The results are interpreted in terms of energy constraint on the mode of resource allocation of the host due to the parasite.

scholarly journals Molluscicidal and parasiticidal activities of Eryngium triquetrum essential oil on Schistosoma mansoni and its intermediate snail host Biomphalaria glabrata, a double impact

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ronaldo de Carvalho Augusto ◽  
Nadjiya Merad ◽  
Anne Rognon ◽  
Benjamin Gourbal ◽  
Cédric Bertrand ◽  
...  
Keyword(s):  
Essential Oil ◽  
Schistosoma Mansoni ◽  
Vector Control ◽  
Biological Effects ◽  
Biomphalaria Glabrata ◽  
Snail Host ◽  
Intermediate Hosts ◽  
Egg Hatching ◽  
Toxic Activity ◽  
Oil Extract

Abstract Background Freshwater snails are the intermediate hosts of a large variety of trematode flukes such as Schistosoma mansoni responsible for one of the most important parasitic diseases caused by helminths, affecting 67 million people worldwide. Recently, the WHO Global Vector Control Response 2017–2030 (GVCR) programme reinforced its message for safer molluscicides as part of required strategies to strengthen vector control worldwide. Here, we present the essential oil from Eryngium triquetrum as a powerful product with molluscicide and parasiticide effect against S. mansoni and the snail intermediate host Biomphalaria glabrata. Methods In the present study, we describe using several experimental approaches, the chemical composition of E. triquetrum essential oil extract and its biological effects against the snail B. glabrata and its parasite S. mansoni. Vector and the free-swimming larval stages of the parasite were exposed to different oil concentrations to determine the lethal concentration required to produce a mortality of 50% (LC50) and 90% (LC90). In addition, toxic activity of this essential oil was analyzed against embryos of B. glabrata snails by monitoring egg hatching and snail development. Also, short-time exposure to sublethal molluscicide concentrations on S. mansoni miracidia was performed to test a potential effect on parasite infectivity on snails. Mortality of miracidia and cercariae of S. mansoni is complete for 5, 1 and 0.5 ppm of oil extract after 1 and 4 h exposure. Results The major chemical component found in E. triquetrum oil determined by GC-FID and GC/MS analyses is an aliphatic polyacetylene molecule, the falcarinol with 86.9–93.1% of the total composition. The LC50 and LC90 values for uninfected snails were 0.61 and 1.02 ppm respectively for 24 h exposure. At 0.5 ppm, the essential oil was two times more toxic to parasitized snails with a mortality rate of 88.8 ± 4.8%. Moderate embryonic lethal effects were observed at the concentration of 1 ppm. Severe surface damage in miracidia was observed with a general loss of cilia that probably cause their immobility. Miracidia exposed 30 min to low concentration of plant extract (0.1 ppm) were less infective with 3.3% of prevalence compare to untreated with a prevalence of 44%. Conclusions Essential oil extracted from E. triquetrum and falcarinol must be considered as a promising product for the development of new interventions for schistosomiasis control and could proceed to be tested on Phase II according to the WHO requirements.

Antagonism of Echinostoma liei (Trematoda: Echinostomatidae) against the trematodes Paryphostomum segregatum and Schistosoma mansoni

Parasitology ◽  
1972 ◽  
Vol 65 (2) ◽  
pp. 223-233 ◽  
Author(s):  
D. Heyneman ◽  
H.-K. Lim ◽  
U. Jeyarasasingam
Keyword(s):  
Schistosoma Mansoni ◽  
Lethal Effect ◽  
Biomphalaria Glabrata ◽  
Snail Host ◽  
Schistosome Infection ◽  
Host Snail ◽  
Human Schistosomiasis ◽  
Different Ages

Echinostoma liei, a newly described 37-spined eehinostome from Egypt, was tested against two trematodes in paired infections in the snail host, Biomphalaria glabrata (NIH strain). E. liei, when matched with the highly predacious Brazilian echinostome Paryphostomum segregatum, was dominated by the latter's predatory rediae. Pre-existing E. liei infections were destroyed, although the P. segregatum infection was itself delayed in development by an unidentified ‘indirect antagonism’ elicited by the E. liei larvae. In concurrent exposures with the two species, or with E. liei challenge of an established P. segregatum infection, the E. liei miracidia penetrated the snail, but the infection did not become established. When E. liei and S. mansoni were paired, the former species dominated. Exposure of snails already infected with E. liei to miracidia of S. mansoni slowed growth of the latter and the schistosome sporocysts eventually disintegrated without producing cercariae. When E. liei miracidia were exposed to snails with S. mansoni infections of different ages, the echinostome became established but developed slowly. Subsequently, however, it destroyed the schistosome infection. Although E. liei is itself quickly eliminated by P. segregatum, the two species appear almost equal in anti-schistosome capacity. This can be credited in part to a deleterious or lethal effect of the E. liei-schistosome combination on the host snail, as well as to a direct anti-schistosomal effect. Greater knowledge of this host-inter-trematode balance may permit the use of trematodes to attack infected snails and their parasites in regions hyperendemic with human schistosomiasis.

Intergeneric reproductive stimulation and parthenogenesis inSchistosoma mansoni

Parasitology ◽  
1984 ◽  
Vol 89 (2) ◽  
pp. 369-376 ◽  
Author(s):  
P. F. Basch ◽  
Natalicia Basch
Keyword(s):  
Schistosoma Mansoni ◽  
Biomphalaria Glabrata ◽  
Snail Host ◽  
Diploid Male ◽  
Normal Appearance ◽  
Female Partners ◽  
Lymnaeid Snail

SummaryWhen mice were infected with female cercariae ofSchistosoma mansoniand male cercariae ofSchistosomatium douthitti, many mixed pairs formed. The paired females were approximately the same size as those in unisexual infections, far smaller than females paired withS. mansonimales. Although theSch. douthittimales possessed well-developed testes, sperm were not found in their female partners, which developed scanty vitelline glands and produced laterally spined eggs typical ofS. mansoni. Such eggs yielded swimming miracidia infective to the snail host ofS. mansoni, Biomphalaria glabrata, but not to the lymnaeid snail host ofSch. douthitti. Sporocysts arising from these miracidia were haploid and produced cercariae infective to mice. Parthenogenetically derived female cercariae in mice co-infected with either parthenogenetically derived male or normal diploid maleS. mansonideveloped to large adults of normal appearance, whose eggs yielded diploid miracidia and subsequent generations of normal diploid schistosomes. Parthenogenetically derived females co-infected withSch. douthittimales also paired and produced some eggs containing viable miracidia, which gave rise once again to haploid sporocysts. These observations confirm previous suggestions that the stimulus for maturation in femaleS. mansoniis distinct from that for growth, and is independent of insemination and fertilization. It is concluded that both diploid and haploidS. mansonifemales are capable either of parthenogenesis or of bisexual reproduction when appropriately stimulated.

Parasite (Schistosoma mansoni) and host (Biomphalaria glabrata) genetic diversity: population structure in a fragmented landscape

Parasitology ◽  
2001 ◽  
Vol 122 (5) ◽  
pp. 545-554 ◽  
Author(s):  
C. SIRE ◽  
J. LANGAND ◽  
V. BARRAL ◽  
A. THÉRON
Keyword(s):  
Genetic Diversity ◽  
Schistosoma Mansoni ◽  
Gene Diversity ◽  
Random Amplified Polymorphic Dna ◽  
Rattus Rattus ◽  
Biomphalaria Glabrata ◽  
Genetic Distances ◽  
Snail Host ◽  
Fragmented Landscape ◽  
Geographical Distances

Random amplified polymorphic DNA (RAPD) markers were used to quantify genetic diversity within and between 5 populations ofSchistosoma mansoniwithin its definitive host (Rattus rattus) and the 5 corresponding populations of the snail intermediate host (Biomphalaria glabrata) from a limited endemic area of murine schistosomiasis on the island of Guadeloupe. Analysis of molecular variance (AMOVA) and canonical correspondence analysis (CCA) were used to test the significance of genetic differentiation between populations. Both methods gave similar results. Of total gene diversity, 15.1% (AMOVA) and 18.8% (CCA) was partitioned between localities forS. mansoniwith an absence of association between genetic and geographical distances. Geographical localities accounted for 20.5% (CCA) of the total diversity forB. glabratapopulations. The genetic distances between pairs of parasite populations were not correlated with the genetic distances between the corresponding pairs of snail host populations. Such strong patterns of local differentiation of both parasite and snail populations are consistent with predictions based on metapopulation dynamics and may have implications on host–parasite susceptibility relationship through local adaptation processes.

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