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Scientific Reports Oct 2022Biomphalaria snails, namely B. pfeifferi and B. sudanica, are the principal intermediate hosts for Schistosoma mansoni infection in Ethiopia. Epidemiological studies of...
Biomphalaria snails, namely B. pfeifferi and B. sudanica, are the principal intermediate hosts for Schistosoma mansoni infection in Ethiopia. Epidemiological studies of Biomphalaria snails and their infection status with S. mansoni is vital for public health planning. This study aimed to assess the spatial and seasonal abundance of Biomphalaria snails as well as their infection status with S. mansoni around Lake Tana, northwest Ethiopia. Malacological survey was conducted from January 2021 to December 2021 in ten different collection sites in and around Lake Tana. Snail collection was performed for 20 min from each collection site seasonally (four times in a year) using a standard scoop and handpicking from aquatic vegetation. All collected snails were carefully examined based on their morphological features and all live Biomphalaria snails were subjected to cercariae shedding experiment. Descriptive statistics were used to determine the prevalence of S. mansoni infection and its relationship with snail collection sites and seasons. A total of 3886 freshwater snails were collected from ten collection sites around Lake Tana. Out of the total snails collected, 1606 (41.3%; 95% CI 39.77-42.89%) were Biomphalaria spp. The highest (374) and the lowest numbers (98) of Biomphalaria snails were collected from Shinne River and Qunzela Lakeshore, respectively. Out of the 1375 live Biomphalaria snails, 14.4% (95% CI 12.59-16.37%) snails shed cercariae, but only 4.87% (95% CI 3.79-6.15%) were cercariae of S. mansoni. The infection prevalence of S. mansoni ranged from 10.59% at the Cherechera site to 1.49% at Gumara River. Biomphalaria snail infections with S. mansoni cercariae were observed throughout the season, the highest and the lowest infection rates being in the spring and summer seasons. Significant differences in the prevalence of S. mansoni infection in Biomphalaria snails were observed across study sites and seasons (p < 0.05). Biomphalaria snails were the most abundant freshwater snails found in nearly all of snail collection sites throughout the year. It was revealed that nearly five percent of Biomphalaria snails were infected with S. mansoni cercariae. This study highlights the importance of appropriate snail control strategies to support the ongoing prevention and control of schistosomiasis around Lake Tana.
Topics: Animals; Biomphalaria; Cercaria; Ethiopia; Lakes; Schistosoma mansoni; Schistosomiasis mansoni; Seasons
PubMed: 36224227
DOI: 10.1038/s41598-022-21306-0 -
GigaScience Feb 2022Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Infection by Schistosoma mansoni in humans results when...
BACKGROUND
Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Infection by Schistosoma mansoni in humans results when cercariae emerge into water from freshwater snails in the genus Biomphalaria and seek out and penetrate human skin. The snail Biomphalaria straminea is native to South America and is now also present in Central America and China, and represents a potential vector host for spreading schistosomiasis. To date, genomic information for the genus is restricted to the neotropical species Biomphalaria glabrata. This limits understanding of the biology and management of other schistosomiasis vectors, such as B. straminea.
FINDINGS
Using a combination of Illumina short-read, 10X Genomics linked-read, and Hi-C sequencing data, our 1.005 Gb B. straminea genome assembly is of high contiguity, with a scaffold N50 of 25.3 Mb. Transcriptomes from adults were also obtained. Developmental homeobox genes, hormonal genes, and stress-response genes were identified, and repeat content was annotated (40.68% of genomic content). Comparisons with other mollusc genomes (including Gastropoda, Bivalvia, and Cephalopoda) revealed syntenic conservation, patterns of homeobox gene linkage indicative of evolutionary changes to gene clusters, expansion of heat shock protein genes, and the presence of sesquiterpenoid and cholesterol metabolic pathway genes in Gastropoda. In addition, hormone treatment together with RT-qPCR assay reveal a sesquiterpenoid hormone responsive system in B. straminea, illustrating that this renowned insect hormonal system is also present in the lophotrochozoan lineage.
CONCLUSION
This study provides the first genome assembly for the snail B. straminea and offers an unprecedented opportunity to address a variety of phenomena related to snail vectors of schistosomiasis, as well as evolutionary and genomics questions related to molluscs more widely.
Topics: Animals; Biomphalaria; Disease Vectors; Humans; Schistosoma mansoni; Schistosomiasis; Schistosomiasis mansoni
PubMed: 35166339
DOI: 10.1093/gigascience/giac012 -
The Journal of Comparative Neurology Jun 2021Freshwater snails of the genus Biomphalaria serve as obligatory hosts for the digenetic trematode Schistosoma mansoni, the causative agent for the most widespread form...
Freshwater snails of the genus Biomphalaria serve as obligatory hosts for the digenetic trematode Schistosoma mansoni, the causative agent for the most widespread form of intestinal schistosomiasis. Within Biomphalaria, S. mansoni larvae multiply and transform into the cercariae form that can infect humans. Trematode development and proliferation is thought to be facilitated by modifications of host behavior and physiological processes, including a reduction of reproduction known as "parasitic castration." As neuropeptides participate in the control of reproduction across phylogeny, a neural transcriptomics approach was undertaken to identify peptides that could regulate Biomphalaria reproductive physiology. The present study identified a transcript in Biomphalaria alexandrina that encodes a peptide belonging to the gonadotropin-releasing hormone (GnRH) superfamily. The precursor and the predicted mature peptide, pQIHFTPDWGNN-NH (designated Biom-GnRH), share features with peptides identified in other molluscan species, including panpulmonates, opisthobranchs, and cephalopods. An antibody generated against Biom-GnRH labeled neurons in the cerebral, pedal, and visceral ganglia of Biomphalaria glabrata. GnRH-like immunoreactive fiber systems projected to all central ganglia. In the periphery, immunoreactive material was detected in the ovotestis, oviduct, albumen gland, and nidamental gland. As these structures serve crucial roles in the production, transport, nourishment, and encapsulation of eggs, disruption of the GnRH system of Biomphalaria could contribute to reduced reproductive activity in infected snails.
Topics: Amino Acid Sequence; Animals; Biomphalaria; Gonadotropin-Releasing Hormone; Host-Parasite Interactions; Neuropeptides; Schistosoma mansoni; Schistosomiasis mansoni
PubMed: 33368267
DOI: 10.1002/cne.25099 -
Fish & Shellfish Immunology Sep 2015This review summarizes the research progress made over the past decade in the field of gastropod immunity resulting from investigations of the interaction between the... (Review)
Review
Advances in gastropod immunity from the study of the interaction between the snail Biomphalaria glabrata and its parasites: A review of research progress over the last decade.
This review summarizes the research progress made over the past decade in the field of gastropod immunity resulting from investigations of the interaction between the snail Biomphalaria glabrata and its trematode parasites. A combination of integrated approaches, including cellular, genetic and comparative molecular and proteomic approaches have revealed novel molecular components involved in mediating Biomphalaria immune responses that provide insights into the nature of host-parasite compatibility and the mechanisms involved in parasite recognition and killing. The current overview emphasizes that the interaction between B. glabrata and its trematode parasites involves a complex molecular crosstalk between numerous antigens, immune receptors, effectors and anti-effector systems that are highly diverse structurally and extremely variable in expression between and within host and parasite populations. Ultimately, integration of these molecular signals will determine the outcome of a specific interaction between a B. glabrata individual and its interacting trematodes. Understanding these complex molecular interactions and identifying key factors that may be targeted to impairment of schistosome development in the snail host is crucial to generating new alternative schistosomiasis control strategies.
Topics: Animals; Biomphalaria; Host-Parasite Interactions; Signal Transduction; Trematoda
PubMed: 25662712
DOI: 10.1016/j.fsi.2015.01.036 -
Microbiology Spectrum Apr 2022transmits schistosomiasis mansoni which poses considerable risks to hundreds of thousands of people worldwide, and is widely used as a model organism for studies on the...
transmits schistosomiasis mansoni which poses considerable risks to hundreds of thousands of people worldwide, and is widely used as a model organism for studies on the snail-schistosome relationship. Gut microbiota plays important roles in multiple aspects of host including development, metabolism, immunity, and even behavior; however, detailed information on the complete diversity and functional profiles of gut microbiota is still limited. This study is the first to reveal the gut microbiome of based on metagenome-assembled genome (MAG). A total of 28 gut samples spanning diet and age were sequenced and 84 individual microbial genomes with ≥ 70% completeness and ≤ 5% contamination were constructed. and were the dominant bacteria in the freshwater snail, unlike terrestrial organisms harboring many species of and . The microbial consortia in helped in the digestion of complex polysaccharide such as starch, hemicellulose, and chitin for energy supply, and protected the snail from food poisoning and nitrate toxicity. Both microbial community and metabolism of were significantly altered by diet. The polysaccharide-degrading bacterium was enriched in the gut of snails fed with high-digestibility protein and high polysaccharide diet (HPHP). Notably, as a mobile repository can escalate biosafety issues regarding transmission of various pathogens such as Acinetobacter nosocomialis and Vibrio parahaemolyticus as well as multiple antibiotic resistance genes in the environment and to other organisms. The spread of aquatic gastropod , an intermediate host of Schistosoma mansoni, exacerbates the burden of schistosomiasis disease worldwide. This study provides insights into the importance of microbiome for basic biological activities of freshwater snails, and offers a valuable microbial genome resource to fill the gap in the analysis of the snail-microbiota-parasite relationship. The results of this study clarified the reasons for the high adaptability of to diverse environments, and further illustrated the role of a in accumulation of antibiotic resistance in the environment and spread of various pathogens. These findings have important implications for further exploration of the control of snail dissemination and schistosomiasis from a microbial perspective.
Topics: Animals; Biomphalaria; Carbohydrates; Host-Parasite Interactions; Humans; Metagenome; Nitrogen; Schistosomiasis
PubMed: 35254167
DOI: 10.1128/spectrum.01843-21 -
Proceedings of the National Academy of... Mar 2021Temperature constrains the transmission of many pathogens. Interventions that target temperature-sensitive life stages, such as vector control measures that kill...
Temperature constrains the transmission of many pathogens. Interventions that target temperature-sensitive life stages, such as vector control measures that kill intermediate hosts, could shift the thermal optimum of transmission, thereby altering seasonal disease dynamics and rendering interventions less effective at certain times of the year and with global climate change. To test these hypotheses, we integrated an epidemiological model of schistosomiasis with empirically determined temperature-dependent traits of the human parasite and its intermediate snail host ( spp.). We show that transmission risk peaks at 21.7 °C ( ), and simulated interventions targeting snails and free-living parasite larvae increased by up to 1.3 °C because intervention-related mortality overrode thermal constraints on transmission. This shift suggests that snail control is more effective at lower temperatures, and global climate change will increase schistosomiasis risk in regions that move closer to Considering regional transmission phenologies and timing of interventions when local conditions approach will maximize human health outcomes.
Topics: Animals; Biomphalaria; Host-Parasite Interactions; Humans; Schistosoma mansoni; Schistosomiasis mansoni; Temperature
PubMed: 33836584
DOI: 10.1073/pnas.2017537118 -
Journal of Invertebrate Pathology Jan 2014The effect of concurrent infection by Echinostoma paraensei and Angiostrongylus cantonensis on the activity of the enzymes alanine aminotransferase (ALT) and aspartate...
The effect of concurrent infection by Echinostoma paraensei and Angiostrongylus cantonensis on the activity of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the concentration of total proteins, uric acid and urea in the hemolymph of Biomphalaria glabrata were investigated. Additionally, histopathological studies were conducted to better understand the dynamics of ontogenic development of both helminths in the host and the possible biochemical effects. Co-infections by helminths and other parasites often occur due to the wide distribution of helminths and the chronic nature of the infection. The biochemical parameters were measured at the end of the seventh week after exposure. The co-infection resulted in a significant decrease in the total proteins concentration in the hemolymph of snails as well as an increase in the nitrogen excretion products, these results showed that the infection leads to exhaustion of free circulating and stored carbohydrates and the infected snails make use alternative substrates, such as free amino acids. So, the protein degradation to release free amino acids causes a decrease in the content of total proteins in the snail host and an amino acids deamination process, increasing the content of ammonium, which needs to be detoxified. This occurs by increasing the urea and uric acid contents. This observation is corroborated by the increase of ALT and AST activities, enzymes directly related to amino group from an amino acid to an α- ketoacid an important step to generate new carbon skeleton for glucose synthesis de novo, as well as new intermediates to the Krebs cycle. Additionally, reduction in the recovery of L3 from the co-infected group (A + E) was observed, since in this association the burden was higher than in the other. Histopathological results showed a change in the distribution of A. cantonensis in the presence of E. paraensei, indicating that the presence of this trematode impairs the dynamic transmission of A. cantonensis.
Topics: Angiostrongylus cantonensis; Animals; Biomphalaria; Echinostoma; Echinostomiasis; Strongylida Infections
PubMed: 24513030
DOI: 10.1016/j.jip.2013.10.005 -
Parasites & Vectors Sep 2020Freshwater snails are the intermediate hosts of a large variety of trematode flukes such as Schistosoma mansoni responsible for one of the most important parasitic...
Molluscicidal and parasiticidal activities of Eryngium triquetrum essential oil on Schistosoma mansoni and its intermediate snail host Biomphalaria glabrata, a double impact.
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% (LC) and 90% (LC). 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 LC and LC 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.
Topics: Animals; Anthelmintics; Biomphalaria; Disease Vectors; Eryngium; Humans; Lethal Dose 50; Molluscacides; Oils, Volatile; Plant Extracts; Plant Oils; Schistosoma mansoni; Schistosomiasis mansoni
PubMed: 32967724
DOI: 10.1186/s13071-020-04367-w -
Epigenetics & Chromatin Oct 20215-Methylcytosine (5mC) is an important epigenetic mark in eukaryotes. Little information about its role exists for invertebrates. To investigate the contribution of 5mC...
BACKGROUND
5-Methylcytosine (5mC) is an important epigenetic mark in eukaryotes. Little information about its role exists for invertebrates. To investigate the contribution of 5mC to phenotypic variation in invertebrates, alteration of methylation patterns needs to be produced. Here, we apply new non-nucleoside DNA methyltransferase inhibitors (DNMTi) to introduce aleatory changes into the methylome of mollusk species.
RESULTS
Flavanone inhibitor Flv1 was efficient in reducing 5mC in the freshwater snails Biomphalaria glabrata and Physa acuta, and to a lesser degree, probably due to lower stability in sea water, in the oyster Crassostrea gigas. Flv1 has no toxic effects and significantly decreased the 5mC level in the treated B. glabrata and in its offspring. Drug treatment triggers significant variation in the shell height in both generations. A reduced representation bisulfite-sequencing method called epiGBS corroborates hypomethylation effect of Flv1 in both B. glabrata generations and identifies seven Differential Methylated Regions (DMR) out of 32 found both in Flv1-exposed snails and its progeny, from which 5 were hypomethylated, demonstrating a multigenerational effect. By targeted bisulfite sequencing, we confirmed hypomethylation in a locus and show that it is associated with reduced gene expression.
CONCLUSIONS
Flv1 is a new and efficient DNMTi that can be used to induce transient and heritable modifications of the epigenetic landscape and phenotypic traits in mollusks, a phylum of the invertebrates in which epigenetics is understudied.
Topics: Animals; Biomphalaria; DNA Methylation; Epigenesis, Genetic; Epigenome; Mollusca
PubMed: 34702322
DOI: 10.1186/s13072-021-00422-7 -
Developmental and Comparative Immunology Feb 2015Gastropod immunology is informed importantly by the study of the frequent encounters snails endure with digeneans (digenetic trematodes). One of the hallmarks of... (Review)
Review
Gastropod immunology is informed importantly by the study of the frequent encounters snails endure with digeneans (digenetic trematodes). One of the hallmarks of gastropod-digenean associations is their specificity: any particular digenean parasite species is transmitted by a limited subset of snail taxa. We discuss the nature of this specificity, including its immunological basis. We then review studies of the model gastropod Biomphalaria glabrata indicating that the baseline responses of snails to digeneans can be elevated in a specific manner. Studies incorporating molecular and functional approaches are then highlighted, and are further suggestive of the capacity for specific gastropod immune responses. These studies have led to the compatibility polymorphism hypothesis: the interactions between diversified fibrinogen-related proteins (FREPs) and diverse carbohydrate-decorated polymorphic parasite antigens determine recognition and trigger specific immunity. Complex glycan structures are also likely to play a role in the host specificity typifying snail-digenean interactions. We conclude by noting the dynamic and consequential interactions between snails and digeneans can be considered as drivers of diversification of digenean parasites and in the development and maintenance of specific immunity in gastropods.
Topics: Animals; Biomphalaria; Host Specificity; Host-Parasite Interactions; Immunity, Innate; Trematoda
PubMed: 25034871
DOI: 10.1016/j.dci.2014.06.014