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Introduction: Gastropod hemocyanins are potent immunostimulants in mammals, a trait associated with their large molecular size and unusual glycosylation patterns. While the hemocyanin from the marine snail keyhole limpet (KLH), has been widely studied and successfully employed as a carrier/adjuvant in several immunological applications, as well as a non-specific immunostimulant for bladder cancer treatment, few other gastropod hemocyanins have been biochemically and immunologically characterized. In this work, we investigated the immunogenic properties of the hemocyanin from Pomacea canaliculata (PcH), an invasive south American freshwater snail. This species, known for its high reproductive rate and easy rearing, represents a promising source of potential biomedical compounds, including hemocyanin. Methods: Employing flow cytometry, fluorescence microscopy, immunoassays, and quantitative PCR, we analysed the effects of PcH on THP-1 monocytes and their derived macrophages, as well as its ability to induce humoral response on C57BL/6 mice. Additionally, we evaluated the structural stability of PcH across a wide range of temperature and pH values. Results and discussion: Our findings demonstrate that PcH is a structurally stable protein that not only triggers a pro-inflammatory effect on THP-1 derived-macrophages by increasing IL1-β and TNF-α levels, but also promotes phenotypic changes associated with the monocyte-to-macrophage differentiation. Moreover, the humoral response induced by PcH in mice was indistinguishable from that of KLH, highlighting the promising immunostimulatory properties of this freshwater snail hemocyanin. [ABSTRACT FROM AUTHOR]

Emerging contaminants such as microplastics and pharmaceuticals in freshwater ecosystems are a growing concern, seriously affecting aquatic organisms. Ibuprofen, a widely used anti-inflammatory drug, is commonly found in rivers, streams, and water systems where it is discharged. As a result, organisms that inhabit these environments, such as snails, are affected in their natural habitats. This study examines the effects of microplastics (10 μg/L), ibuprofen (500 μg/L), and a combination of ibuprofen (500 μg/L) and microplastics (10 μg/L) on growth, movement, and reproduction in Physella acuta , a freshwater snail species. While no significant effects were observed on movement or number of egg clusters, there was a significant decrease in growth when snails were exposed to microplastics or the combination of microplastics and ibuprofen (p = 0.021). Additionally, snail egg production decreased when exposed to ibuprofen (p = 0.001) but increased when exposed to microplastics (p = 0.002). Microplastic exposure produced more eggs than ibuprofen (p < 0.001) and ibuprofen and microplastics combined (p < 0.001). Our results suggest that ibuprofen affects growth and the total number of eggs, likely due to oxidative stress, neurotoxicity, or disrupted hormonal pathways. In contrast, microplastics may have caused digestive system blockage, thus affecting energy allocation for growth and reproduction. Changes in snail fitness can directly and indirectly affect food webs and nutrient cycles, highlighting the need for research on these pollutants to understand their chronic and long-term effects on ecosystems. [ABSTRACT FROM AUTHOR]

Climate change is predicted to have significant impacts on aquatic ecosystems. When combined with other stressors such as environmental contaminants, increasing temperatures will have serious consequences to the physiology and behavior of aquatic organisms. Pharmaceuticals such as antidepressants from wastewater treatment plants have been shown to modify the behavior of non-target aquatic species. We tested over 2000 snails (Physa gyrina) from a creek in Pennsylvania, USA for their righting behavior when exposed to different combinations of temperature (12°, 20°, and 25 °C) and antidepressant (venlafaxine and fluoxetine) concentration for one week or 48 hours. Snails exposed for one week righted significantly faster in warmer temperatures and in almost all concentrations of both antidepressants compared to controls. Snails exposed for 48 hours showed similar responses to warmer temperature as they did when exposed for one week, but only at the highest antidepressant concentrations did they right significantly faster than the controls. Exposure to venlafaxine at low concentration (1.56 µg/L) for 48 hours resulted in significant inhibition of righting, indicative of a non-monotonic dose response. We discuss the possible consequences of increased water temperature combined with antidepressant contamination on snail behavior as well as the possible physiological mechanisms of action explaining non-monotonic dose responses. [ABSTRACT FROM AUTHOR]

Biological invasions threaten biodiversity and cause severe ecological and socioeconomic impacts. Freshwater snails are very diverse and many became invasive or have the potential to do so. Studies on the relationship between bioecological traits and invasiveness are needed to prevent new invasions. The tolerance to environmental stressors of the neonate, one of the most vulnerable ontogenetic phases, may be an important component of invasiveness in freshwater snails. We hypothesize that tolerance of neonates to environmental stressors increases the chances of population establishment and persistence and hence of becoming an invader. We predict that the neonates of invasive freshwater snails will show higher survival under starvation and desiccation than those of non-invasive ones and tested this experimentally for three species of each type. We also estimated neonate volume as a proxy of tolerance. We found that the desiccation stress was more severe than the starvation one. The tolerance to starvation of two of the invasive species (Melanoides tuberculata and Pomacea canaliculata) was much higher than that of remaining species but the pattern was less clear for desiccation, which was more directly related to neonate volume. None of the non-invasive species showed high tolerance to these stressors and the invasive Physella acuta groups with them in this regard. On the whole our prediction about the relationship between neonate tolerance and invasiveness stands for five out of the six species tested, indicating that the tolerance of neonates of freshwater snails merits more research effort on other stressors to gain a sounder comprehension of their invasiveness. [ABSTRACT FROM AUTHOR]

The Western Caucasus is considered a refugium for several freshwater invertebrates, but detailed phylogeographic studies are lacking. By using mitochondrial sequence data, amplified fragment length polymorphisms and distribution modelling, we study the phylogeography of the Caucasian freshwater snail Melanopsis mingrelica Mousson, 1863, and discuss the role of the Western Caucasus region as a glacial refugium. Volcanism in the Lesser Caucasus and the formation of highlands to its south in the Late Miocene and Pliocene may have effectively trapped the lineage leading to the freshwater snail M. mingrelica in the western Georgian Colchis region after its arrival there during in the Late Miocene or Early Pliocene. Our results show that the Western Caucasus region can be considered a refugium for a Melanopsis lineage at the northern margin of the range of a genus that today is otherwise mostly adapted to relatively warm climatic conditions. Our results further show that the Western Caucasus region served as a large and homogeneous refugium for M. mingrelica and that global warming may have facilitated the colonization of the Caspian Sea drainage basin by M. mingrelica. [ABSTRACT FROM AUTHOR]

The primary goal of this research is to compare the efficacy of raw freshwater snail shell (Viviparus Contectus) (FSS) and iron oxide coated calcined snail shell (IOCCSS) in removing As(V) ions from aqueous solution medium via adsorption. FTIR, XRD, EDX, BET surface area analysis and SEM image methods were used to characterise the structures of the obtained solid sorbents. The effects of solution's initial pH, initial As(V) concentration, contact time, adsorbent dose, and ambient temperature parameters on the removal of As(V) ions from aqueous solution medium with FSS and IOCCSS solid sorbents were analysed, and optimum conditions were determined. The maximum efficiency of As(V) ions adsorption was measured 94.27% at a pH value of 7.0, contact time of 60 min, initial ion concentration of 2.0 mg/L, the adsorbent dose of 2.0 g/L, and the ambient temperature of 50°C. Thermodynamic parameters ΔH, ΔG and ΔS were calculated for the removal of As(V) ions with IOCCSS solid sorbent, and the adsorption process was determined to be endothermic. The best fit was obtained by Langmuir isotherm model with maximum monolayer sorption capacity of 3.42 mg/g for arsenate. According to the obtained results, the low-cost IOCCSS solid sorbent has been proposed as a viable alternative material for the removal and preconcentration of As(V) from aqueous solutions. [ABSTRACT FROM AUTHOR]

Background: Intestinal schistosomiasis was confirmed endemic in Mangochi District, Malawi, in May of 2018 following an unexpected encounter with discreet populations of Biomphalaria spp. freshwater snails during routine malacological surveillance activities. Since then, only limited malacological surveillance of Biomphalaria has been carried out, and so the distribution of Biomphalaria populations in this area is currently unclear. Additionally, sites of active Schistosoma mansoni transmission in this area are also unknown. In the present study, through extensive malacological surveillance, we aimed to formally document the distribution of Biomphalaria in Mangochi District. We also aimed to identify active intestinal schistosomiasis transmission sites in this area through subjecting all collected Biomphalaria to a recently developed S. mansoni-specific molecular xenomonitoring PCR. Methods: Three malacological surveys were carried out along the southern shoreline of Lake Malawi, Mangochi District, Malawi, in November 2021, July 2022 and October/November 2022. All collected Biomphalaria were subjected to cercarial shedding analysis to identify active Schistosoma infections. Shed cercariae were then genotyped to species level using a standard multi-locus PCR and Sanger sequencing protocol. Following this, a subset of Biomphalaria from each collection site were also genotyped to species level using a standard PCR and Sanger sequencing protocol. All collected Biomphalaria were then subjected to a recently developed S. mansoni-specific molecular xenomonitoring PCR to identify infected, but non-shedding, Biomphalaria. Results: A total of 589 Biomphalaria were collected across all three surveys. One single Biomphalaria (0.17%) specimen was found to be actively shedding Schistosoma cercariae, which were molecularly confirmed as S. mansoni. All genotyped Biomphalaria (n = 42) were molecularly identified as B. pfeifferi. A further 19 Biomphalaria specimens, collected from four different surveillance sites, were found to be infected with S. mansoni through molecular xenomonitoring. Intestinal schistosomiasis transmission was therefore identified at four different foci in Mangochi District. Conclusions: Our study highlights the importance of molecular approaches to investigate Biomphalaria populations and monitor Biomphalaria-associated intestinal schistosomiasis transmission in endemic areas. As such, the continued development and use of such approaches, in particular the development and use of molecular xenomonitoring assays that can be carried out in resource-poor schistosomiasis-endemic settings, is encouraged. The revision of ongoing schistosomiasis control programmes in Mangochi District, in line with WHO recommendations, is also encouraged. [ABSTRACT FROM AUTHOR]

Simple Summary: Clarification of the feeding habits (i.e., feeding range and preference) of larval fireflies inhabiting various habitats (aquatic, semi-aquatic, and terrestrial) is key for the development of artificial diets and the indoor rearing of fireflies. The two aquatic species, Aquatica leii and Sclerotia substriata, prefer to prey on freshwater snails, but their feeding range presents obvious differences. The two semi-aquatic fireflies, Pygoluciola qingyu and Pygoluciola sp., show similar feeding habits, preferring freshwater snails, followed by freshwater fish meat, while the terrestrial firefly Pyrocoelia analis prefers land slugs, followed by freshwater snails. Overall, the feeding habits of larval fireflies were distinct, altering with habitat type. The common and easily accessible freshwater snail Cipangopaludina chinensis is a potential food for aquatic, semi-aquatic, and terrestrial fireflies in indoor artificial rearing, possibly circumventing the current shortage of wild-snail-derived foods. While adult fireflies are terrestrial, their larvae inhabit various habitat types, and a lack of comprehensive research on the feeding habits of these larvae across different habitats has greatly impeded the development of artificial diets. Here, we tested 14 types of foods, primarily covering gastropods, vertebrates, and fruit, to survey feed for aquatic (Aquatica leii and Sclerotia substriata), semi-aquatic (Pygoluciola qingyu and Pygoluciola sp.), and terrestrial (Pyrocoelia analis) fireflies. The results show that A. leii, S. substriata, P. qingyu, Pygoluciola sp., and P. analis fed on 12, 6, 10, 10, and 7 different foods, respectively, showing an obvious difference in feeding range among various inhabit types of fireflies. Aquatic lineages preferred to consume freshwater snails, followed by pork meat and land slugs, while semi-aquatic fireflies favored freshwater snails, followed by fish and shrimp. Favorite foods were thus freshwater snails such as Cipangopaludina chinensis for both aquatic and semi-aquatic fireflies, but feeding preference differed for second favorite foods (e.g., pork vs. fish meat). Terrestrial Pyrocoelia analis showed different feeding preferences compared withthe other two habitat lineages, with terrestrial snails and slugs as their favorite foods, followed by freshwater snails, such as C. chinensis. These findings not only uncovered larval feeding habits of fireflies across various inhabit types but also indicated that readily available and affordable C. chinensis products can serve as wild snail alternatives in the artificial feeding of fireflies. This study is the first to explore the feeding habits of firefly species inhabiting water and land habitat types, adding to the understanding of the feeding characteristics of fireflies. [ABSTRACT FROM AUTHOR]

Snails are effective bioindicators due to their prolific distribution, high level of endemism, and capacity to accumulate contaminants. Freshwater snails have unique ecological niches which are imperiled by land‐use change and the introduction of hazardous chemicals. To assess how environmental alterations affect gastropods, lab‐based studies are needed to characterize the toxicity of specific stressors. This can help guide policy decisions and remediation efforts. The aim of this research was to characterize acute toxicity of nickel (Ni) on endemic snails (Somatogyrus georgianus [Walker, 1904], Elimia cahawbensis [Lea, 1861], and Elimia spp.) and measure the accumulation of Ni and mineral elements including calcium (Ca), magnesium, potassium, and sodium (Na). Snails were exposed to six concentrations (25–800 µg/L) of Ni for 96 h. Among the studied snail species, E. cahawbensis was the most sensitive to Ni, with the lowest lethal concentration where 50% of the organisms died (LC50) at 88.88 µg/L Ni after 96 h. The LC50 at 96 h for S. georgianus was 167.78 µg/L Ni, and 393.13 μg/L Ni for Elimia spp. Except for Elimia spp., mortality of the other two snail species corresponded to the whole‐body uptake of Ni. Nickel exposure also influenced Ca and Na uptake for Elimia spp. All three endemic species are potential candidate species for evaluating localized effects of human activities, and the present study provides a first step in characterizing how snails would be affected by environmental alterations. More research could further characterize potential effects of other human stressors on these endemic snail species. Future research into subindividual responses and routes of exposure can further elucidate variations in species sensitivity. Environ Toxicol Chem 2024;43:2578–2588. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Sodium dodecyl sulfate (SDS) is a surfactant used and recommended by regulatory agencies as a reference substance in ecotoxicological analyzes. In this work, acute toxicity assays were performed with adults and embryos of the freshwater snail Biomphalaria glabrata, an endemic organism with environmental and public health importance, to evaluate the effects of the surfactant and establish a sensitivity control chart. The organisms were exposed to SDS for 24 h to a range of concentrations, as well as a control group. Six assays were performed to establish the control chart for adults (with a median LC50 of 36.87 mg L−1) and differential sensitivity was observed at each embryonic stage (EC50 = blastulae 33.03, gastrulae 35.03, trochophore 39.71 and veliger 72.55 mg L−1). The following behavioral responses were observed in exposed adult snails: release of hemolymph and mucus, body outside the shell, and penile overexposure. Embryos at the blastulae and gastrulae stages were more sensitive, and teratogenic effects were accentuated in the trochophore stage. The difference in results obtained between adults and embryos underscore the importance of carrying out analyzes at different developmental stages. The serial assays established with SDS for B. glabrata demonstrated efficiency and constancy conditions in the assays with good laboratory practice standards. The wide distribution of Biomphalaria species in several countries, their easy maintenance and cultivation in the laboratory, in addition to ecological importance, make them economical alternatives for ecotoxicological assays. [ABSTRACT FROM AUTHOR]

The freshwater snail, Bellamya bengalensis is commonly utilised as food by humans and its shells are discarded as waste and considered a nuisance. However, it is impossible to exclude its potential as a biomaterial for detoxifying heavy metals from wastewater. The present study is an attempt to eliminate heavy metals like Copper, Nickel, and Lead from synthetically prepared relevant heavy metal solutions using snail shell dust as a biosorbent. The efficacy of freshwater snail shell dust was estimated by studying various factors, viz., contact time, adsorbent dosages, size of the adsorbent, pH of test solution, and initial heavy metals concentration. The present finding thus revealed the highest percentile removal of heavy metals as 93.64%, 97.24%, and 99.98% for Copper, Nickel, and Lead, respectively. The percentile removal of heavy metals declined with a raised initial concentration of relevant heavy metals. The data was also analysed using adsorption isotherms (Langmuir and Freundlich isotherms) and was observed to follow Langmuir isotherm with a maximum adsorptive capacity of 28.95 mg/g, 29.14 mg/g and 16.35 mg/g for Copper, Nickel, and Lead, respectively, thus reflecting the monolayer mode of the adsorption mechanism. The above results thus authenticate the use of snail shell dust as a low-cost, sustainable, and green biomaterial for the eradication of heavy metals. [ABSTRACT FROM AUTHOR]

Background: The World Health Organization (WHO) has set the goal of eliminating schistosomiasis as a public health problem globally by 2030 and to interrupt transmission in selected areas. Chemical snail control is one important measure to reduce transmission and achieve local elimination. We aimed to assess the impact of several rounds of chemical snail control on the presence and number of the Schistosoma haematobium intermediate snail host (Bulinus spp.) in water bodies (WBs) on Pemba Island, Tanzania, a setting targeted for elimination of urogenital schistosomiasis. Methods: During the three annual intervention periods of the SchistoBreak study implemented in the north of Pemba from 2020 to 2024, malacological surveys were conducted up to four times per period in WBs of hotspot implementation units (IUs). Present freshwater snail species, vegetation, and WB characteristics were recorded. If Bulinus were found, the snails were inspected for Schistosoma infection and snail control with niclosamide was conducted. Results: Across the three intervention periods, a total of 112 WBs were identified in 8 hotspots IUs. The spatial distribution of WBs with Bulinus per IU was heterogeneous, ranging from 0.0% (0/15) of WBs infested in one IU in 2022 to 80.0% (8/10) of WBs infested in one IU in 2021. Bulinus presence was significantly associated with lower pH values in WBs (odds ratio: 0.2, 95% confidence interval 0.1–0.4). A total of 0.2% (6/2360) of collected Bulinus were shedding Schistosoma cercariae. Following snail control, the number of Bulinus decreased or remained absent in 56.7% (38/67) of visits at WBs when compared with the previous visit in 2021, 54.9% (28/51) in 2022, and 33.3% (32/96) in 2023. In a total of 43.1% (22/55) of initially infested WBs, no Bulinus were found in the survey round conducted a few weeks after the first application of niclosamide. However, 25.4% (14/55) of WBs showed a pattern of recurring Bulinus presence. Conclusions: The distribution of WBs containing Bulinus was very heterogeneous. The percentage of Bulinus with patent Schistosoma infection in our study area was extremely low. Repeated niclosamide application reduced the number of Bulinus in WBs, but snails often recurred after one or multiple treatments. While chemical mollusciciding can reduce snail numbers, to fully break the S. haematobium transmission cycle, timely diagnosis and treatment of infected humans, access to clean water, sanitation, and health communication remain of prime importance. Trial registration: ISRCTN, ISRCTN91431493. Registered 11 February. 2020, https://www.isrctn.com/ISRCTN91431493 [ABSTRACT FROM AUTHOR]

Optic photoreception is a critical function for animal survival. Across the evolutionary spectrum, diverse animal models have been used to investigate visual system function and potential mechanisms under physiological or pathophysiological states. However less is known on photoreceptive behaviors and retinal processing in invertebrates, especially molluscs. This study focuses on the freshwater pond snail, Lymnaea stagnalis (L. stagnalis), to explore its visual function and underlying mechanisms. Using anatomical and histological approaches we characterized the L. stagnalis eye structure and demonstrated structural connections and retinal rhodopsin-positive sensory cells potentially critical for phototransduction. To assess the snail phototactic responses, we developed a new neurobehavioral protocol and employed DeepLabCut to track and quantify animal locomotion. We demonstrated that L. stagnalis exhibits a positive locomotory response to intense focal light and has diverse photo-locomotory responses. Further, we conducted phylogenetic and protein structure analyses and demonstrated that L. stagnalis has a unique repertoire of both vertebrate and invertebrate phototransduction genes. Further characterization of a rhodopsin-like gene identified unique characteristics compared to other mollusks and vertebrates, suggesting different mechanisms of phototransduction. Taken together, our work establishes L. stagnalis as a model organism for studying optic photoreception, offering new insights into the evolution and diversity of visual function across animal species. [ABSTRACT FROM AUTHOR]

Background: Schistosomiasis is a major human disease of public health importance. Freshwater snails serving as intermediary hosts and human interaction with surface water tainted by feces or urine are both necessary components of the transmission cycle. Schistosoma haematobium, Schistosoma mansoni, and Schistosoma japonicum are the primary pathogen species. Over 250 million individuals are infected globally, according to the World Health Organization, causing significant morbidity and an estimated loss of 1.9 million disability‐adjusted life years, a number that is probably underestimated. Immunological protection is slowly built up through complex immunological systems, although innate factors also play a role. Chronic schistosomiasis affects mainly individuals residing in poor rural area. Vaccination is considered as one of the most sustainable options for the control of any pathogen, but schistosomiasis vaccine for humans or animals is not available till now despite the discovery of numerous potentially promising schistosome vaccine antigens. Objective: To provide an overview of the schistosomiasis chemotherapy, chemoprevention, and vaccines history and progress. Design: Review article. Data Sources: PubMed, ISI Web of Science, Science Direct, and the World Health Organization database. Conclusion: Favorably praziquantel (PZQ) is a medication with excellent chemopreventive treatment compliance. Due to the extensive usage of PZQ, there is a great deal of debate surrounding the emergence of drug resistance. PZQ is effective against all species of schistosomes, schistosomiasis prevalence has remained largely unaffected, due to reinfection in high transmission areas and growing juvenile worms that were not affected by the drug, even though the need for a schistosomiasis vaccine is even more pressing. [ABSTRACT FROM AUTHOR]

The Southeast Asian gastropod Tarebia granifera is an invasive freshwater snail across several continents. Our review summarises the impacts of this invasive snail on invaded aquatic ecosystems. The most important impacts are those related to their ability to reproduce quickly and reach high densities within invaded ecosystems. The snail has reportedly caused declines and local extinctions in native snail populations globally. They can further significantly reduce algal standing stocks and may have severe impacts on benthic biomass, resulting in decreased benthic biodiversity and disturbances in aquatic ecosystem function. These invasive snails also cause bioturbation that can lead to changes in the nutrient cycles of invaded aquatic ecosystems and affect food web dynamics, with unknown implications for ecosystem function. Furthermore, T. granifera is well known to harbour a diverse range of parasitic species of medical and veterinary importance both within and outside their native ranges. The effective control of invasive T. granifera remains challenging as they are not easily preyed upon, and potential control methods may have unintentional side effects on native biota. This review provides evidence that there is a need to control this invader to avoid further degradation of freshwater habitats and aquatic biodiversity. [ABSTRACT FROM AUTHOR]

Freshwater snails of the genus Bulinus are critical hosts for Schistosoma haematobium , the causative agent of urogenital schistosomiasis. Among the 37 recognized Bulinus species, B. truncatus is a key vector. Using RNA sequencing (RNAseq), we investigated the genome-wide transcriptional responses of B. truncatus to S. haematobium infection. Our findings suggest that snails employ a complex defense strategy against the parasites by up-regulating genes involved in immune response, stress reaction, structural integrity, metabolism, and detoxification. In response, schistosome parasites appear to manipulate the snail's defense system, as evidenced by the suppression of immune-related genes such as ficolin , peptidoglycan recognition protein , and C-type lectin domain-containing protein genes. The down-regulation of biomphalysin 9 , compared to its function in Biomphalaria glabrata , indicates divergent immune strategies among snail hosts. Additionally, we compared transcriptome profiles between embryos and juveniles, providing insights into developmental processes. This study offers valuable genomic data for Bulinus snails, illuminating the molecular interactions between bulinids and schistosomes, and advancing our understanding of their developmental biology. • First genome-wide differential expression analysis of B. truncatus is presented. • B. truncatus activates complex molecular responses to S. haematobium infection. • S. haematobium may influence B. truncatus immune responses for its survival. • Genes involved in embryonic development in B. truncatus are revealed. • The study provides valuable genomic resources for studying Bulinus snails. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the infection status and species diversity of trematode cercariae in freshwater snails from canal networks in the Bangkok Metropolitan Region (BMR), Thailand. The snails were collected from 35 sites during 2 cycles of the wet (July–October) and dry (November–June) seasons in 2018–2019. A total of 29,420 snails representing 24 species/subspecies were examined for cercarial infection using shedding and crushing techniques. We found that 1,275 snails from 12 species/subspecies were infected, resulting in an overall prevalence of 4.3%. Infections were significantly higher (P<0.001) during the wet season (5.9%; 970/16,473) than during the dry season (2.4%; 305/12,947). Morphological identification revealed 37 distinct types within 15 morphotypes, with the armatae morphotype showing the highest infection rate (1.8%) and the greatest cercarial diversity (8 distinct types). This study highlights the health risk posed by the Bithynia siamensis siamensis, which was the second most prevalent (8.5%) and hosted the greatest cercarial diversity (11 morphotypes, 15 distinct types). This subspecies also displayed a wide distribution range (31 localities) with a generally high occurrence frequency in the BMR. This study firstly documents a gymnophallid digenean as a freshwater digenean, presenting evidence of a dichotoma cercarial morphotype from 4 species/subspecies (Filopaludina martensi martensi, F. sumatrensis polygramma, B. siamensis siamensis, and Wattebledia siamensis) with a low infection range (0.1–0.4%). A staggering diversity of cercariae was observed in the BMR canal networks with seasonal fluctuations. The B. siamensis siamensis displayed notable epidemiological importance in the BMR flowing-water networks. This study provides quantitative and qualitative morphological descriptions and measurement guidelines for the dichotoma cercaria in Thailand. [ABSTRACT FROM AUTHOR]

BACKGROUND: The invasive freshwater snail Pomacea canaliculata is an agricultural pest with a certain level of tolerance to abiotic stress. After the harvest of late rice, the snails usually burrow themselves into the soil surface layers to overwinter and pose a renewed threat to rice production in the following year. Revealing the response of snails to environmental stresses is crucial for developing countermeasures to control their damage and spread. RESULTS: In this study, we conducted a 120‐day in situ experiment during the winter to investigate the survival and physiological changes of hibernating snails in 0‐5 and 5‐10 cm soil depths, aiming to explore their overwintering strategies. Our results showed that 73.61%, 87.50%, and 90.28% of male, female, and juvenile snails survived after hibernation for 120 days in 0–10 cm soil depth, respectively. The differences in survival rates based on sex and size of snails potentially reflect the countermeasures of snails to rapidly reproduce after hibernation. Simultaneously, the hibernating snails exhibited the ability to maintain a certain level of body weight. During this period, the snails increased their antioxidant enzyme activities to cope with oxidative stress, and enhanced their lipid storage. The hibernation survival of snails was not significantly affected by different soil depths, indicating that they have the potential to hibernate into deeper soils. Furthermore, snails were capable of increasing their contents of bound water and glycerol to cope with sudden cold spells during hibernation. CONCLUSION: Our findings emphasize the adaptive changes of P. canaliculata snails overwintering in paddy soils. In future studies, the vulnerabilities of P. canaliculata during hibernation (e.g. shell characteristics, nutrient reserves, and dehydration tolerance, etc.,) should be investigated to develop effective control methods for this period. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study presents a thorough investigation into the microbial and mineral composition of freshwater snails, specifically Achatina fulica, Lanistes libycus, and Pomacea canaliculata, employing standard microbiological methods. Microbial assessments revealed significant variation in heterotrophic bacteria counts across the species. For Achatina fulica, counts ranged from 5.0 × 107 cfu/g to 4.45 × 109 cfu/g. In Lanistes libycus, the counts varied from 3.6 × 105 cfu/g to 2.02 × 107 cfu/g, while Pomacea canaliculata exhibited counts from 7.95 × 105 cfu/g to 2.78 × 106 cfu/g. Vibrio counts demonstrated diversity, with Achatina fulica showing a range from 1.35 × 10³ CFU/g to 1.78 × 104 cfu/g, Lanistes libycus ranging from 4.05 × 10³ cfu/g to 7.1 × 10³ cfu/g, and Pomacea canaliculata presenting counts between 1.4 × 10³ cfu/g and 8.5 × 10³ CFU/g. Staphylococcus counts varied among the species: Achatina fulica had counts ranging from 2.95 × 104 cfu/g to 2.51 × 105 cfu/g, Lanistes libycus ranged from 9.05 × 10³ cfu/g to 5.7 × 104 cfu/g, and Pomacea canaliculata exhibited counts between 9.0 × 10² cfu/g and 1.98 × 104 cfu/g. Coliform counts also demonstrated a wide range, with the highest counts observed in Achatina fulica (from 7.6 × 104 cfu/g to 2.18 × 106 cfu/g), Lanistes libycus ranging from 4.469 × 104 cfu/g to 8.356 × 105 cfu/g, and Pomacea canaliculata showing counts between 3.05 × 104 cfu/g and 1.95 × 105 cfu/g. Morphological and biochemical characterization identified thirteen genera of bacteria, including 19.2% Staphylococcus, 4.3% Micrococcus, 8.5% Bacillus, 6.2% Corynebacterium, 11.3% Escherichia coli, 5.0% Klebsiella, 10.6% Pseudomonas, 9.2% Vibrio, 5.0 Serratia, 7.1% Enterobacter, 3.6% Salmonella, 4.3% Citrobacter, and 5.7% Proteus. The proximate composition analysis revealed variations in ash content, moisture content, lipid content, crude protein, and carbohydrate levels among the species. The mineral analysis included measurements of phosphorus, calcium, and potassium content across the different snail species. These findings enhance our understanding of the microbial ecology, nutritional richness, and mineral composition of freshwater snails. This research lays a foundation for future investigations into the ecological significance of these snails and their potential applications in human nutrition, highlighting their importance in both ecological conservation and dietary considerations. [ABSTRACT FROM AUTHOR]

As costs and efforts associated with control of invasive species are often significant, data on habitat variables associated with colonization potential are needed to prioritize and target areas for prevention efforts prior to introduction. Recently, invasive New Zealand Mudsnails (Potamopyrgus antipodarum; NZMS) have undergone significant range expansions in parts of the Mid-Atlantic United States such as Pennsylvania. However, data on chemical parameters in flowing waters at risk of colonization by NZMS are largely lacking for this region. We compiled a dataset of over 400 survey sites for NZMS throughout Pennsylvania and used available water chemistry data on 57 chemical parameters for a subset of these sites to evaluate parameter-specific chemical sensitivity associated with occurrence of NZMS. We found significant associations among NZMS and chemical variables such as alkalinity, hardness, calcium, nutrients, specific conductance, bromide, osmotic pressure, strontium, and sulfate. Chemical sensitivity results were used to create a statewide chemical suitability model, which suggests several regions in Pennsylvania are at high risk for NZMS colonization. Parameters in high-risk waters are likely attributable to factors such as agriculture, urbanization, and karst geology. This model is intended as a tool for prioritizing prevention efforts and monitoring in Pennsylvania streams and rivers. Resource agencies and partners could use our study and model as a template to predict colonization risk of NZMS or other invasive aquatic mollusks in other regions. [ABSTRACT FROM AUTHOR]

Nickel ferrite nanoparticles (NiF NPs) have growing applications in biomedical and nanomedicine fields. However, knowledge concerning their ecotoxicity during the early developmental stages of invertebrates, such as gastropods, remains scarce. Thus, the current study aimed to evaluate whether NiF NPs and nickel chloride (NiCl2) induce toxic effects on embryos and newly hatched snails of freshwater species Biomphalaria glabrata (Say, 1818). NiF NPs were synthesized and characterized by multiple techniques, and their ecotoxicity was assessed by Biomphalaria embryotoxicity test (BET) during 144 h of exposure and an acute toxicity test (96 h) using newly hatched snails. NiF NPs induced mortality, developmental delay, reduced hatching rate, and promoted morphological changes in B. glabrata. Also, NiF NPs induced higher toxicity in embryos than in newly hatched B. glabrata. Overall, results showed that the early developmental stages of gastropods are a target group for nanoparticle toxicity in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: Giant water bugs play an important role as top predators in wetland ecosystems, helping to control freshwater snails and mosquitoes. In this study, we used MaxEnt models to predict how climate change might affect the distribution of two Korean species, Appasus japonicus and Diplonychus esakii. Our findings suggest that A. japonicus may lose habitat and shift northward, while D. esakii is expected to expand its range, potentially causing occupancy turnover between the two species. The range shifts of the two species are primarily driven by different factors—elevation for A. japonicus and annual mean temperature for D. esakii. This research helps us understand how climate change could affect two giant water bugs and supports efforts to manage and conserve wetland ecosystems in South Korea. Giant water bugs (Hemiptera: Belostomatidae) are top predators in wetland ecosystems, serving as biological indicators of the health of lentic ecosystems and as effective biological control agents for freshwater snails and mosquitoes. This study aimed to predict the current and future distribution of two Korean giant water bugs, Appasus japonicus and Diplonychus esakii, under three climate change scenarios, contributing to the sustainable management of wetland ecosystems in South Korea. Using MaxEnt models, we employed seven climatic and three non-climatic variables to investigate the habitat preferences and distribution patterns of the species. The results revealed that A. japonicus is likely to experience a northward range contraction due to climate change, while D. esakii is predicted to expand its distribution northward without losing its current range. These responses may lead to occupancy turnover between the two species, potentially driving reassembly in aquatic organism community. Elevation was the primary factor influencing the distribution of A. japonicus, whereas annual mean temperature was the most informative variable for D. esakii, both factors derived under the current climate conditions. These findings suggest that both species are highly sensitive to climate change, with potential range shifts toward higher latitudes and elevations. This study provides insights into how climate change could impact two giant water bugs, thereby supporting future efforts to manage and conserve wetland ecosystems in this country. [ABSTRACT FROM AUTHOR]

Freshwater snails that act as intermediate host and some abiotic environmental factors plays a prominent roles in these infections. The objective of this paper as to assess the composition and distribution of the snail fauna in water bodies around irrigation schemes in the Benue River Valley, Yola area of Adamawa state, Nigeria using appropriate techniques. Data obtained reveals that the distribution of freshwater snails species, showed that a total of 1,620 snails were sampled, Njoboliyo had the highest number of snails with 373, followed by Lake Geriyo with 287, Dasin Hausa with 266, Rugange with 255, Dasin Bwattiye with 235, while Boronji had the least with 204 freshwater snails. The species include B. globosus, P. ovata, B. truncatus and B. reticulatus. The diversity index showed that H fell below the 1.5-3.5 range while the Evenness E showed a potential evenness between freshwater snail species in all sites of the communities with no exception. [ABSTRACT FROM AUTHOR]

Fascioliasis is an often-neglected zoonotic disease caused by liver fluke Fasciola hepatica and Fasciolagigantica[1]. The life cycle of this parasite starts when eggs in mammalian stool are deposited in tepid water (22-26°C) and hatch in within two weeks, miracidia appear and develop. These miracidia invade many species of freshwater snails, in which they further develop to sporocyst and redia for 4-7 weeks. They leave as free-swimming single tailed cercaria that subsequently attach to watercress, water lettuce, mint, parsley, or khat [2, 3]. They encyst within few hours and wait to be eaten by the definite host, humans [4]. The metacercariae exist in the small intestine is releasing the young parasites, which rapidly penetrate the intestinal wall and enter the peritoneal cavity. The immature flukes penetrate the capsule of Glisson after 48h and enter the liver then migrate throughout the hepatic parenchyma till they reach the biliary system where they become adults within 3 to 4 months from the initial infection and lay eggs [4]. World health organization now recognizes human Fascioliasis as a significant public health problem and a neglected tropical disease with a great impact on human development [4]. The burden of infection is unclear, and studies have shown the geographic expansion of fascioliasis in human and livestock likely related to climate change[5]. This study aims to highlight the sociodemographic characteristics of human fascioliasis in a newly emerged endemic area at north of Iraq. [ABSTRACT FROM AUTHOR]

Potamopyrgus antipodarum (Gray, 1843) has been considered one of the most successful and widespread invasive freshwater molluscs worldwide. This snail has been present in mainland Portugal since the 1960s, but there is only scarce information regarding its presence in Madeira or Azores archipelagos. In this work, macroinvertebrate communities were sampled in six Madeira Island streams. P. antipodarum was found in all sampled sites, with abundances ranging from 3 to 3528 individuals per sampling area, indicating that the species arrived at Madeira recently and is now in a clear spreading phase. Our results indicate no relationship between the abundance of P. antipodarum and macroinvertebrates' biodiversity indices. Nevertheless, the abundance of P. antipodarum was extremely high in some locations, representing more than 30% of all benthic invertebrates, which triggered alterations in the food web and community structure. The future impacts of this invasion are for now unpredictable, but given P. antipodarum parthenogenetic reproduction and fast spread, its presence can potentially affect Madeira Island's aquatic ecosystems' ecological status and services. These results can inform environmental agencies on the importance of monitoring the presence and spread of this invasive species and call for management strategies focused on early detection and control measures. Given the endemicity and insularity of Madeira macroinvertebrate communities, the spread of P. antipodarum should be limited to mitigate its ecological impacts and biodiversity loss. [ABSTRACT FROM AUTHOR]

The dependence of freshwater snails on the availability of ions through their ambient water varies widely across species and deficiencies may limit reproduction and other physiological functions. Nevertheless, in many studies on the New Zealand mud snail (NZMS) Potamopyrgus antipodarum, where reactions on components dissolved in the water are not the focus, the composition of the water the snails are kept in is not specified. We tested the sensitivity of reproduction to three types of artificial fresh water in three parthenogenetic lineages invasive to Europe. The three lineages descended each from a single mother collected in the same population in northern Germany. Reproduction was measured as the number of offspring sired within 12 weeks and varied across water types, however, lineages differed in their reaction norms. This indicates 1) that reproduction of the NZMS is indeed sensitive to the composition of the water and 2) that there is fitness relevant genetic variation which probably has arisen only within the 160-180 years the NZMS is present in Europe, i.e. we witness clonal evolution. For experiments, this means that the water composition should not be neglected and that potential genetic variation even among closely related clonal lineages has to be accounted for in order to ensure comparability and reproducibility. [ABSTRACT FROM AUTHOR]

Pomacea canaliculata, a freshwater snail native to South America, has become widely naturalised in many countries, causing serious damage to agricultural and native ecosystems. Although climate warming is likely to expand the distribution of this species, limited information exists regarding its impact on feeding activities. In this study, we examined the effects of temperature on the feeding activity of this species and estimated the impact of climate warming on its feeding potential. The feeding activity was determined by measuring the amount of standard food (Japanese mustard spinach, komatsuna) ingested at different temperatures. It tended to increase from 15 to 25 °C but became almost stable from 25 to 35 °C. The respiration rate determined by the O2 consumption rate, showed a similar response to temperature. Based on these findings, we constructed a simple model to estimate the relative feeding activity using climatic data recorded at meteorological stations throughout the Japanese Archipelago. The model estimated that, with warming of + 2 °C, annual feeding potential (relative value) increased by 21.1% at the present northern distribution limit of this species. The effect of warming on percentage increase in feeding potential was estimated to be smaller at the southern distribution limit (9.9%), although the absolute feeding potential was larger than that at the northern sites. The model also suggested that if this species expanded its northern distribution range as a result of climate warming, it would have a high feeding potential comparable to that of the southern regions. [ABSTRACT FROM AUTHOR]

This study focuses on developing a sustainable and biocompatible polycaprolactone (PCL)‐based scaffold for bone tissue engineering through electrospinning, utilizing calcium carbonate (CaCO3) from Pomacea canaliculata shells and keratin from human hair, known for stimulating bone regeneration. The isolated CaCO3 has been identified to demonstrate two polymorphs, vaterite and calcite, as determined by X‐ray diffraction. The isolation of keratin from human hair was confirmed through sodium dodecyl sulfate polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy analysis, revealing the presence of α‐keratin structures around 45–50 kDa and β‐keratin structures around 55–60 kDa. According to scanning electron microscope observations, the addition of keratin to PCL fibers reduced their diameter from 457 ± 345 to 371 ± 103 nm. Further addition of calcium carbonate led to a mean diameter of 258 ± 76 nm. The melting temperature of PCL fibers containing keratin and CaCO3 was determined to be 76.17 °C via differential scanning calorimetry, while thermogravimetric analysis, conducted at temperatures up to 600 °C, revealed a remaining ash content of 9.59%. Calcium phosphate accumulation was observed to initiate on PCL fibers containing keratin and CaCO3 following a 7‐day exposure to simulated body fluid. The fibers exhibit cytocompatibility, showing no toxicity while supporting the growth and proliferation of Saos‐2 osteosarcoma cells. The results suggest that the innovative incorporation of keratin and CaCO3 into PCL nanofibers could serve as a bioactive matrix compared to pure PCL matrices, thereby offering enhanced potential for bone tissue engineering applications. © 2024 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: The transmission cycle of Schistosoma is remarkably complex, including sexual reproduction in human hosts and asexual reproduction in the intermediate host (freshwater snails). Patterns of rapid recrudescence after treatment and stable low transmission are often observed, hampering the achievement of control targets. Current mathematical models commonly assume regulation of transmission to occur at worm level through density-dependent egg production. However, conclusive evidence on this regulating mechanism is weak, especially for S. mansoni. In this study, we explore the interplay of different regulating mechanisms and their ability to explain observed patterns in S. mansoni epidemiology. Methodology/Principal findings: We developed SchiSTOP: a hybrid stochastic agent-based and deterministic modelling framework for S. mansoni transmission in an age-structured human population. We implemented different models with regulating mechanisms at: i) worm-level (density-dependent egg production), ii) human-level (anti-reinfection immunity), and iii) snail-level (density-dependent snail dynamics). Additionally, we considered two functional choices for the age-specific relative exposure to infection. We assessed the ability of each model to reproduce observed epidemiological patterns pre- and post-control, and compared successful models in their predictions of the impact of school-based and community-wide treatment. Simulations confirmed that assuming at least one regulating mechanism is required to reproduce a stable endemic equilibrium. Snail-level regulation was necessary to explain stable low transmission, while models combining snail- and human-level regulation with an age-exposure function informed with water contact data were successful in reproducing a rapid rebound after treatment. However, the predicted probability of reaching the control targets varied largely across models. Conclusions/Significance: The choice of regulating mechanisms in schistosomiasis modelling largely determines the expected impact of control interventions. Overall, this work suggests that reaching the control targets solely through mass drug administration may be more challenging than currently thought. We highlight the importance of regulating mechanisms to be included in transmission models used for policy. Author summary: Schistosomiasis is a neglected tropical disease estimated to affect 250 million people worldwide and causing severe morbidity in endemic countries. The transmission of Schistosoma is complicated by the multiplication of parasites within freshwater snails that act as obligate intermediate hosts. Rapid rebound of infection after mass treatment is commonly observed, as well as stable low transmission. Several mathematical models are currently employed to inform policy decisions, building on the predominant assumption of worm-level regulation through density-dependent egg production. We explored the interplay of different regulating mechanisms assumed at worm-, human-, and snail-level and their ability to explain observed epidemiological patterns. To this end, we developed SchiSTOP, a new modelling framework for S. mansoni transmission dynamics and considered 162 model variants. Results show that snail-level regulation is required to explain stable low transmission, while the combination of snail- and human-level regulation is necessary to reproduce a rapid rebound after control. We further show that assumptions on the regulating mechanisms heavily influence conclusions about the feasibility to reach control targets. In particular, the models that successfully explain observed patterns for S. mansoni suggest that achieving control targets solely through mass drug administration may be more challenging than currently thought. [ABSTRACT FROM AUTHOR]

Background: Freshwater snails are the first obligatory intermediate hosts in the trematode life cycle. Several parasitic diseases transmitted by these snails are endemic in Africa, and their distribution closely follows that of the intermediate hosts. These diseases represent a major public health problem and cause significant socio-economic losses in Africa, particularly schistosomiasis and fascioliasis. In this review, we will describe the main roles of freshwater snails in the life cycle of trematode parasites, and the geographical distribution of these diseases in Africa. We will also discuss the different techniques for detecting parasitic infections in snails, as well as the various methods of controlling snails and the larval stages of parasites. Methods: We carried out a literature search for articles dealing with parasitic diseases transmitted by freshwater snail hosts in Africa. The search was conducted in databases such as PubMed, Web of Science and Google Scholar using various search terms combined by Boolean operators. Our search was limited to peer-reviewed articles less than 10 years old. Articles published to date in the fields of control of parasitic diseases transmitted by freshwater snails were included. Results were presented in narrative and in table format. Results: The results of the database search identified 1007 records. We included 84 studies in this review. These studies generally focused on freshwater snails and the diseases they transmit. We described the geographical distribution of 43 freshwater species belonging to nine snail families, as well as the parasites that infect them. Several methods for diagnosing parasites in their snail hosts have been described, including microscopic and molecular methods, as well as antibody and protein barcode-based techniques. Molluscicides have been described as the main strategy for snail control. Conclusion: This study highlights several elements of knowledge about diseases transmitted by freshwater snails and their distribution. A good understanding of snail infection detection techniques and existing control methods is an essential component in adapting control strategies for these diseases. [ABSTRACT FROM AUTHOR]

The presence of the freshwater snail Oncomelania hupensis lindoensis in their habitats is influenced by abiotic environmental factors (nutri- ents, water salinity, and predators) that play a crucial role in maintaining snail survival. The objective of this study is to determine the relationship between environmental factors and the presence of O. hupensis lindoensis snails in the Napu Valley, one of the Schistosomia-sis-endemic areas in Indonesia. Eight environmental factors were measured in three different habitats: a seepage, a ditch, and a pond. The study found O. hupensis lindoensis snails in all three habitats, with significant differences in their numbers (p, 0.05). The seepage habitat had the highest snail density (762.22 snails per m²) compared to the other habitats. Phosphorus levels were highest in the seepage habitat compared to the other habitats, while nitrogen levels were highest in the pond habitat. Pearson correlation analysis found a significant posi- tive correlation between O. hupensis lindoensis snails and water salinity in the ditch habitat (p, 0.05). In addition to environmental factors, the presence of snails can also be influenced by other factors, such as the presence of snail predators, the presence of snail nutrients, and the population of snail host niche competitors. [ABSTRACT FROM AUTHOR]

China is a hotspot for species' discovery nowadays and harbours some of the most threatened environments in the world due to human activities. Here we describe a new remarkable gastropod species from an ancient freshwater lake in Yunnan, south-west China, Squamapex taiji gen. et sp. nov. within a new monospecific family of Truncatelloidea, Squamapicidae fam. nov.. The highly ornamented protoconch of Squamapicidae, with a microstructure distinct from that of the teleoconch, has rarely been found in true freshwater gastropods, being previously mostly known from marine or migratory gastropods with veliger larvae. The most complete family-level and first-dated phylogeny of Truncatelloidea, the largest and most diverse superfamily within Mollusca, based on two mitochondrial and three nuclear markers, shows that Squamapicidae belong to a distinct ancient lineage with Cretaceous origin. Its sister-group, unique protoconch, and distribution suggest a Tethys Ocean origin of this new family. [ABSTRACT FROM AUTHOR]

Aquatic invasive species are a significant threat to global freshwater biodiversity. This study focuses on the banded mystery snail, Callinina georgiana, an invasive species in the Adirondack region of northern New York—an important section of the New York Great Lakes Basin. This project aims to explore the genetic connectivity of C. georgiana within its invasive range using a combination of mitochondrial and nuclear markers.Sampling was conducted in the Raquette River and adjacent waterways, with a total of 229 snails collected from 16 distinct populations distributed across eight different waterbodies. Also included were two populations from the species' native range in the southern U.S.A. DNA was extracted, and a 710‐bp fragment of the mitochondrial DNA marker cytochrome c oxidase 1 and a 351‐bp fragment of nuclear marker histone‐3 were amplified. Population genetic analyses including haplotype patterning, AMOVA and genetic diversity estimates, neutrality tests and tests for isolation by distance were performed to assess connectivity patterns.Results showed moderate to high levels of genetic admixture within the snail's invasive range as indicated by the lack of geographic patterning of haplotypes and low to moderate levels of genetic differentiation across multiple sites. Demographic analyses combined with high numbers of private haplotypes indicate historic population expansion. Interestingly, a case of mitonuclear discordance was detected for native and invasive populations as evident by incongruent haplotype patterns for the cytochrome c oxidase 1 and histone‐3 markers.Callinina georgiana exhibits a high level of genetic connectivity in its invasive range. The presence of dams does not significantly affect apparent gene flow, indicating that anthropogenic activities, such as boat traffic might be key in dispersing the snails across this fragmented freshwater system.This study offers new insights into the dispersal and genetic structure of an invasive freshwater snail. It highlights the importance of considering anthropogenic factors when confronting complex patterns of genetic diversity. The findings are significant for biodiversity conservation and provide a basis for developing strategies to manage and contain the spread of aquatic invasive species such as C. georgiana, especially in regions with high human activity. [ABSTRACT FROM AUTHOR]

The genus Pseudamnicola Paulucci, 1878, is commonly found throughout the Mediterranean region. The genus displays considerable levels of endemism, accompanied by notable systematic and taxonomic ambiguity. However, the application of molecular data has proven highly effective in clarifying taxonomy and unveiling the diversity of cryptic species within the genus. Therefore, we employed all cytochrome c oxidase subunit I sequence data available and generated new ones from Greece to infer the phylogeny of the genus throughout its Mediterranean range and estimate the divergence times as well as the ancestral area of diversification. Our phylogenetic and time‐estimate analyses demonstrate that with 36 to 38 extant Pseudamnicola species and genetic divergences across species ranging from 0.5% to 11.9% on average, the genus underwent relatively recent diversification during late Miocene (6.53 Ma), and the primary speciation events occurred during Plio‐Pleistocene. The Italian Peninsula and Islands and the Ionian Drainages as defined by the Freshwater Ecoregions of the World are the ancestral regions of the genus following two different dispersal routes. Our study contributes to deepening our understanding of Pseudamnicola phylogeny by using data from throughout its range for the first time. This phylogeny provides evidence and confirms previous studies that relatively recent habitat isolation, followed by founder and dispersal events, has been one of the primary reasons for the evolution of the genus Pseudamnicola in the Mediterranean basin. [ABSTRACT FROM AUTHOR]

Schistosoma mansoni is a parasitic flatworm that causes the major neglected tropical disease schistosomiasis. The miracidium is the first larval stage of the life cycle. It swims and infects a freshwater snail, transforms into a mother sporocyst, where its stem cells generate daughter sporocysts that give rise to human-infective cercariae larvae. To understand the miracidium at cellular and molecular levels, we created a whole-body atlas of its ~365 cells. Single-cell RNA sequencing identified 19 transcriptionally distinct cell clusters. In situ hybridisation of tissue-specific genes revealed that 93% of the cells in the larva are somatic (57% neural, 19% muscle, 13% epidermal or tegument, 2% parenchyma, and 2% protonephridia) and 7% are stem. Whereas neurons represent the most diverse somatic cell types, trajectory analysis of the two main stem cell populations indicates that one of them is the origin of the tegument lineage and the other likely contains pluripotent cells. Furthermore, unlike the somatic cells, each of these stem populations shows sex-biased transcriptional signatures suggesting a cell-type-specific gene dosage compensation for sex chromosomelinked loci. The miracidium represents a simple developmental stage with which to gain a fundamental understanding of the molecular biology and spatial architecture of schistosome cells. [ABSTRACT FROM AUTHOR]

Three new populations of the invasive New Zealand mud snail, Potamopyrgus antipodarum, have been discovered in central Chile, increasing the documented records in the country to 23. Only females were observed in the present study. Significant differences in shell length and fecundity were found among populations. The size of the snails was less than 6 mm, while fecundity varied from 0 to 45 offspring per snail. A significant correlation was found between adult shell length and brood size in one of the three populations discovered. In these localities, Potamopyrgus antipodarum coexists with native and possibly other invasive gastropods. [ABSTRACT FROM AUTHOR]

Genetic drift, gene flow, and natural selection commonly influence population genetic diversity. In populations of self‐compatible hermaphrodites, the mating system (e.g., self‐fertilization) further reduces individual heterozygosity. Furthermore, selfing, as a form of inbreeding, significantly impacts genetic drift by reducing effective population size (Ne). This can potentially accelerate genetic drift, particularly in small populations where self‐fertilization is likely during founder events. To investigate the roles of genetic drift and contemporary mating system in populations of the freshwater snail Lymnaea stagnalis, we examined their effective population sizes (Ne) and Tajima's D values, which reflect genetic drift over extended time periods, as well as estimates of within‐population selfing rates and pairwise relatedness reflecting contemporary mating system. We used 4054 SNP markers obtained using restriction site associated DNA (RAD) sequencing from individuals in five snail populations originating from geographically closely located ponds. We found strong population genetic structure and differences in genetic diversity among populations. Covariation between genetic diversity and Ne estimates and Tajima's D values suggested drift being an important determinant of genetic diversity and structure in these populations. However, this effect was independent of the contemporary mating system, as indicated by the similarity of selfing rates and relatedness estimates among populations. Thus, founder events (possibly including historical inbreeding) and/or drift due to small sizes of L. stagnalis populations are likely to explain their genetic structure and limit within‐population genetic diversity. [ABSTRACT FROM AUTHOR]

The freshwater snails and mussels are recognized as ecosystem engineers owing to their ability to influence the ecological processes. We investigated the effect of the snail Filopaludina bengalensis and the mussel Lamellidens marginalis alone and in interaction with the macrophyte Lemna minor on the ecological processes (nutrient dynamics, microbial account, sediment properties and periphytic algal growth) of the freshwater ecosystem through a mesocosm experiment. Both the snail and mussel promoted the growth rate of L. minor; however, the presence of snail negatively influenced the growth of periphyton. The biogeochemical process was affected by the presence of snails and mussels. Macrophyte association further influenced this biogeochemical process. Snail and mussel enhance the growth of heterotrophic bacteria and phosphate solubilising bacteria in the sediment. Likewise, the presence of macrophyte also positively influences the microbial growth. The activities of the benthic fauna like the mussels and the snails can be considered a useful process for the sustenance of the microbes and the macrophytes representing a pattern of bottom-up regulation. [ABSTRACT FROM AUTHOR]

The freshwater snail Bulinus truncatus is an important intermediate host for trematode parasites causing urogenital schistosomiasis, a tropical disease affecting over 150 million people. Despite its medical importance, uncertainty remains about its global distribution and the potential impacts of climate change on its future spread. Here, we investigate the distribution of B. truncatus, combining the outputs of correlative and mechanistic modelling methods to fully capitalize on both experimental and occurrence data of the species and to create a more reliable distribution forecast than ever constructed. We constructed ensemble correlative species distribution models using 273 occurrence points collected from different sources and a combination of climatic and (bio)physical environmental variables. Additionally, a mechanistic thermal suitability model was constructed, parameterized by recent life‐history data obtained through extensive lab‐based snail‐temperature experiments and supplemented with an extensive literature review. Our findings reveal that the current suitable habitat for B. truncatus encompasses the Sahel region, the Middle East, and the Mediterranean segment of Africa, stretching from Southern Europe to Mozambique. Regions identified as suitable by both methods generally coincide with areas exhibiting high urogenital schistosomiasis prevalence. Model projections into the future suggest an overall net increase in suitable area of up to 17%. New suitable habitat is in Southern Europe, the Middle East, and large parts of Central Africa, while suitable habitat will be lost in the Sahel region. The change in snail habitat suitability may substantially increase the risk of urogenital schistosomiasis transmission in parts of Africa and Southern Europe while reducing it in the Sahel region. [ABSTRACT FROM AUTHOR]

We show that the globally invasive, human-infectious flatworm, Haplorchis pumilio, possesses the most physically specialized soldier caste yet documented in trematodes. Soldiers occur in colonies infecting the first intermediate host, the freshwater snail Melanoides tuberculata, and are readily distinguishable from immature and mature reproductive worms. Soldiers possess a pharynx five times absolutely larger than those of immature and mature reproductives, lack a germinal mass, and have a different developmental trajectory than reproductives, indicating that H. pumilio soldiers constitute a reproductively sterile physical caste. Neither immature nor mature reproductives showed aggression in in vitro trials, but soldiers readily attacked heterospecific trematodes that coinfect their host. Ecologically, we calculate that H. pumilio caused ~94% of the competitive deaths in the guild of trematodes infecting its host snail in its invasive range in southern California. Despite being a dominant competitor, H. pumilio soldiers did not attack conspecifics from other colonies. All prior reports documenting division of labor and a trematode soldier caste have involved soldiers that may be able to metamorphose to the reproductive stage and have been from nonhuman-infectious marine species; this study provides clear evidence for an obligately sterile trematode soldier, while extending the phenomenon of a trematode soldier caste to freshwater and to an invasive species of global public health concern. [ABSTRACT FROM AUTHOR]

Background: Biological invasions pose risks to the normal functioning of ecosystems by altering the structure and composition of several communities. Molluscs stand out as an extensively studied group given their long history of introduction by either natural or anthropogenic dispersal events. An alien population of the lymnaeid species Orientogalba viridis was first sighted in 2009 in southern Spain. In its native range (Australasian), this species is one of the main intermediate hosts of Fasciola hepatica, a major worldwide trematode parasite largely affecting humans, domestic animals and wildlife. Methods: We collected field populations of O. viridis from its native (Malaysia) and invaded (Spain) ranges. We performed detailed morphoanatomical drawings of the species and screened for natural infection of parasites. Individuals were molecularly characterized using ITS2 for comparison with existing sequences in a fine phylogeography study. We founded experimental populations at two different conditions (tropical, 26 °C and temperate, 21 °C) to study the life-history traits of exposed and non-exposed individuals to different F. hepatica isolates. Results: We found a 9% natural prevalence of trematode infection (98% similarity with a sequence of Hypoderaeum conoideum [Echinostomatidae]) in the Spanish field population. The haplotypes of O. viridis found in our study from Spain clustered with Australian haplotypes. Experimental infection with F. hepatica was successful in both experimental conditions but higher in tropical (87% prevalence) than in temperate (73%). Overall lifespan, however, was higher in temperate conditions (mean 32.5 ± 7.4 weeks versus 23.3 ± 6.5) and survivorship remained above 70% during the first 20 weeks. In parasite-exposed populations, life expectancy dropped from an overall 37.75 weeks to 11.35 weeks but still doubled the time for initial cercariae shedding. Cercariae shedding started at day 23 post-exposure and peaked between days 53 and 67 with an average of 106 metacercariae per snail. Conclusions: Whether O. viridis will succeed in Europe is unknown, but the odds are for a scenario in which a major snail host of F. hepatica occupy all available habitats of potential transmission foci, ravelling the epidemiology of fasciolosis. This research provides a comprehensive understanding of O. viridis biology, interactions with parasites and potential implications for disease transmission dynamics, offering valuable insights for further research and surveillance. [ABSTRACT FROM AUTHOR]

Growing evidence has suggested a strong link between gut microbiota and host fitness, yet our understanding of the assembly mechanisms governing gut microbiota remains limited. Here, we collected invasive and native freshwater snails coexisting at four independent sites in Guangdong, China. We used high-throughput sequencing to study the assembly processes of their gut microbiota. Our results revealed significant differences in the diversity and composition of gut microbiota between invasive and native snails. Specifically, the gut microbiota of invasive snails exhibited lower alpha diversity and fewer enriched bacteria, with a significant phylogenetic signal identified in the microbes that were enriched or depleted. Both the phylogenetic normalized stochasticity ratio (pNST) and the phylogenetic-bin-based null model analysis (iCAMP) showed that the assembly process of gut microbiota in invasive snails was more deterministic compared with that in native snails, primarily driven by homogeneous selection. The linear mixed-effects model revealed a significant negative correlation between deterministic processes (homogeneous selection) and alpha diversity of snail gut microbiota, especially where phylogenetic diversity explained the most variance. This indicates that homogeneous selection acts as a filter by the host for specific microbial lineages, constraining the diversity of gut microbiota in invasive freshwater snails. Overall, our study suggests that deterministic assembly-mediated lineage filtering is a potential mechanism for maintaining the diversity of gut microbiota in freshwater snails [ABSTRACT FROM AUTHOR]

Since time immemorial, molluscs have been a popular source of food in North East India. Given the historical importance of snail consumption in the region, the current investigation was carried out to assess the nutritional properties of mollusc meat/tissue and shell. Three species of freshwater snails (Cipangopaludina sp. Brotia costula, Filopaludina bengalensis) and the bivalve Lamellidens sp. were identified from five states of North East India. Proximate and elemental analyses of mollusc meat revealed high amounts of nutrients (more crude protein (range 26.75–22.83%) and low fat (3.82–2.70%)) and minerals (especially calcium). Additionally, high levels of polyunsaturated fatty acids were observed (maximum 1.95% in B. costula). [ABSTRACT FROM AUTHOR]

Trematodes of the family Cyclocoelidae are parasites mainly of the respiratory system of birds and present a cosmopolitan distribution. Although infection with these flukes can result in pathological changes and even bird death, information on their life cycles is scarce and almost entirely based on experimental infection data. Thus, the generation of knowledge on the mollusks that act as natural intermediate hosts of cyclocoelids is necessary and can aid control measures against these air sac trematodes. In the present study, gastropod mollusks collected in an urban stream from Belo Horizonte, Minas Gerais, Brazil, were subjected to the compression technique for the detection of non-emerging larval trematodes. Tailless cercariae with confluent ceca were found in 8/30 (26.7%) specimens of Biomphalaria glabrata and 3/33 (9.1%) specimen of Physella acuta. Samples of the cercariae were subjected to morphological characterization and genetic study (28S, Cox-1, and Nad-1). For comparative purposes, adult trematodes previously collected in the air sac of a common gallinule (Gallinula galeata) found dead in another waterbody from the same region were also characterized. The molecular sequences obtained revealed a high degree of similarity (100% in 28S, 99.2% in Cox-1, and 99.5% in Nad-1) between larval stages found in mollusks and adult parasites found in G. galeata and morphologically identified as Cyclocoelum mutabile. The conspecificity with this widely distributed cyclocoelid was also corroborated by phylogenetic analysis and comparison with isolates of this species previously characterized in Peru and the Czech Republic (99.4–100% and 96.7–97.0% of similarity in Nad-1, respectively). Thus, the integrative analysis carried out in the present work enabled us to identify C. mutabile in mollusks in South America for the first time. The finding of B. glabrata and P. acuta as new intermediate hosts corroborates the importance of freshwater gastropods in the transmission of C. mutabile, as well as the low specificity to the mollusk group, as previously characterized through experimental studies. [ABSTRACT FROM AUTHOR]

Valvata (Cincinna) piscinalis (Müller, 1774) is a widespread and variable Palaearctic freshwater snail species. Some authors have separated more depressed forms with a wider umbilicus as a distinct species, Valvata (Cincinna) ambigua Westerlund, 1873. The latter species was described from Scandinavia and has also been reported from Siberia and Kazakhstan and more recently from Central Europe. We conducted an integrative study of the delimitation and relationships of V. ambigua and V. piscinalis using both morphometric and molecular genetic analyses. Analyses of the morphometric data did not reveal differentiation into distinct clusters. Rather, the shell characteristics used to distinguish V. ambigua and V. piscinalis showed continuous variation. There is little variability in mitochondrial DNA sequences in the V. piscinalis complex. A median-joining network based on cytochrome oxidase sequences showed that the morphological character states supposedly characteristic of V. ambigua and V. piscinalis did not correlate with the genetic relationships of the individuals studied. We therefore consider V. ambigua to be synonymous with V. piscinalis. [ABSTRACT FROM AUTHOR]