As ecosystem disruptors and intermediate hosts for various parasites, freshwater snails have significant socioeconomic impacts on human health, livestock production, and aquaculture. Although traditional molluscicides have been widely used to mitigate these effects, their environmental impact has encouraged research into alternative, biologically based strategies to create safer, more effective molluscicides and diminish the susceptibility of snails to parasites. This review focuses on alterations in glucose metabolism in snails under the multifaceted stressors of parasitic infections, drug exposure, and environmental changes and proposes a novel approach for snail management. Key enzymes within the glycolytic pathway, such as hexokinase and pyruvate kinase; tricarboxylic acid (TCA) cycle; and electron transport chains, such as succinate dehydrogenase and cytochrome c oxidase, are innovative targets for molluscicide development. These targets can affect both snails and parasites and provide an important direction for parasitic disease prevention research. For the first time, this review summarises the reverse TCA cycle and alternative oxidase pathway, which are unique metabolic bypasses in invertebrates that have emerged as suitable targets for the formulation of low-toxicity molluscicides. Additionally, it highlights the importance of other metabolic pathways, including lactate, alanine, glycogenolysis, and pentose phosphate pathways, in snail energy supply, antioxidant stress responses, and drug evasion mechanisms. By analysing the alterations in key metabolic enzymes and their products in stressed snails, this review deepens our understanding of glucose metabolic alterations in snails and provides valuable insights for identifying new pharmacological targets.

Relative to the numerous studies focused on mammalian schistosomes, fewer include avian schistosomatids particularly in the southern hemisphere. This is changing and current research emerging from the Neotropics shows a remarkable diversity of endemic taxa. To contribute to this effort, nine ducks (Spatula cyanoptera, S.versicolor, Netta peposaca), 12 swans (Cygnus melancoryphus) and 1,400 Physa spp. snails from Chile and Argentina were collected for adults and larval schistosomatids, respectively. Isolated schistosomatids were preserved for morphological and molecular analyses (28S and COI genes). Four different schistosomatid taxa were retrieved from birds: Trichobilharzia sp. in N. peposaca and S. cyanoptera that formed a clade; S.cyanoptera and S. versicolor hosted Trichobilharzia querquedulae; Cygnus melancoryphus hosted the nasal schistosomatid, Nasusbilharzia melancorhypha; and one visceral, Schistosomatidae gen. sp., which formed a clade with furcocercariae from Argentina and Chile from previous work. Of the physid snails, only one from Argentina had schistosomatid furcocercariae that based on molecular analyses grouped with T. querquedulae. This study represents the first description of adult schistosomatids from Chile as well as the elucidation of the life cycles of N.melancorhypha and T. querquedulae in Chile and Neotropics, respectively. Without well-preserved adults, the putative new genus Schistosomatidae gen. sp. could not be described, but its life cycle involves Chilina spp. and C. melancoryphus. Scanning electron microscopy of T. querquedulae revealed additional, undescribed morphological traits, highlighting its diagnostic importance. Authors stress the need for additional surveys of avian schistosomatids from the Neotropics to better understand their evolutionary history.

Avian schistosomes inhabit the blood stream of domestic and wild birds with aquatic snails as their intermediate hosts. In the Neotropics there is an emerging effort to describe species from these hosts, including Chile, although the knowledge about their pathological consequences is mostly understudied. This study aimed to describe the pathological changes associated with the parasitism of a native schistosomatid restricted to the Southern Cone of Neotropics. To achieve this, a total of 401 Chilina dombeiana snails (Chilinidae) were collected in two locations from Southern Chile. All of them were disposed to cercarial release procedure for three consecutive days. Furcocercariae released were stained and characterized by microscopic evaluation. Then, all snails were dissected under stereomicroscope and preserved in 10 % buffered formalin until histopathological analysis was performed. Eight out 401 (P = 2 %) snails were found parasitized with avian schistosomes. The released furcocercariae were identified as Schistosomatidae gen. sp. Lineage II which was previously reported in the same host. The main pathological change was an atrophy of ovotestes and an absence or mild infiltration of hemocytes in the surrounding tissues. Besides, a co-infection with echinostomes was found which was associated with a moderate hemocyte infiltration, granuloma-like lesion, and a reduced presence of schistosome\' sporocysts. The latter would suggest an antagonistic interaction between these two digeneans, as has been proposed in the Echinostoma spp.-Schistosoma mansoni model. Despite the above, the release of furcocercariae was present but reduced, in contrast with the non-release of echinocercariae. This interaction requires further attention. This study represents the first attempt to characterize the pathological consequences of parasitism by a native, yet undescribed, avian schistosome in an endemic snail. Future studies should consider experimental infections to understand the dynamics of single infections in other Chilina species, including inter- and intra-specific parasitism as previous studies have found, including this study.

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.

Schistosomiasis, a prevalent water-borne disease second only to malaria, significantly impacts impoverished rural communities, primarily in Sub-Saharan Africa where over 90% of the severely affected population resides. The disease, majorly caused by Schistosoma mansoni and S. haematobium parasites, relies on freshwater snails, specifically Biomphalaria and Bulinus species, as crucial intermediate host (IH) snails. Targeted snail control is advisable, however, there is still limited knowledge about the community structure of the two genera especially in East Africa. Utilizing a machine learning approach, we employed random forest to identify key features influencing the distribution of both IH snails in this region. Our results reveal geography and climate as primary factors for Biomphalaria, while Bulinus occurrence is additionally influenced by soil clay content and nitrogen concentration. Favorable climate conditions indicate a high prevalence of IHs in East Africa, while the intricate connection with geography might signify either dispersal limitations or environmental filtering. Predicted probabilities demonstrate non-linear patterns, with Bulinus being more likely to occur than Biomphalaria in the region. This study provides foundational framework insights for targeted schistosomiasis prevention and control strategies in the region, assisting health workers and policymakers in their efforts.

In order to investigate and study the species and distribution of freshwater snails in Ordos area of Inner Mongolia, as well as the trematode infection in different periods, and to provide a scientific basis for the effective prevention and control of livestock trematodiasis. In this paper, freshwater snails distributed in Ordos were widely collected for morphological identification, and PCR amplification of freshwater snails COI gene and ITS2 gene was carried out with the help of molecular biology. At the same time, microscopic examination was used to observe the trematode infection of freshwater snails in two different periods from May to July and July to September, and the molecular biology of the trematodes was identified. The results showed that the 1796 freshwater snails collected belonged to two orders, three families and four genera, i.e. Bellamya, Radix, Galba, and Gyraulus. Microscopic examination of snails showed that the infection rate of trematode larvae from July to September was significantly higher than that from May to July. The collected trematodes were identified as five species, namely Cotylurus marcogliesei, Fasciola hepatica, Fasciola gigantica, Paramphistomum cervi, and Parastrigea robusta. The combination of freshwater snail species in Ordos and the infection of trematode in snails showed that a large number of freshwater snails were infected with trematodes, especially from July to September, when there is more rain and suitable climate, which causes serious harm to local livestock.

Angiostrongyliasis is a parasitic disease and a leading cause of human eosinophilic meningoencephalitis caused by rat lungworm Angiostrongylus cantonensis. This parasite infects a wide range of animal hosts, including snails and rats, which plays a significant role in zoonotic transmission. The study was conducted to determine the prevalence of A. cantonensis infection in freshwater snails and definitive rat hosts in the agricultural area in Ampayon, Butuan City, Philippines. A total of 54 rat samples and 719 snail individuals were collected in June and July 2020. An overall 2.36% prevalence rate of A. cantonensis snail infection was recorded, consisting of Pomacea canaliculata and Melanoides tuberculata, with a prevalence rate of 4.05% and 1.38%, respectively. Results revealed an overall prevalence of 38.9% in rat infection. Rattus tanezumi (48.48%) showed a higher infection than Rattus norvegicus (23.80%). Higher infection rates were found in rice field environments than residential houses, with 44.12% and 30% prevalence rates, respectively. Moreover, male rats showed higher infection rates (50%) than female rats (26.92%). Among age classes, adult rats had significantly higher infection rates (48.57%) than juvenile rats (21.05%). Correlation analysis showed a significant positive correlation between A. cantonensis infection intensity to the body length (r = 0.603; p = 0.001) and body weight (r = 0.715; p = 0.000) of rats. The study exemplifies the critical role of intermediate and definitive hosts for angiostrongyliasis. Infected freshwater snails and rats in rice fields make these agricultural areas a venue for A. cantonensis emergence. Integrated actions, health education campaigns, surveillance, hygiene, and good farming practices will help prevent the potential risk of the transmission of angiostrongyliasis in the area.

UNASSIGNED: Lymnaea gedrosiana snails are hosts to a variety of trematode cercaria of public and veterinary health importance. In Guilan Province, Iran, a region with a high level of fish and bird farming and wetlands important for migratory birds, little is known about the trematode cercaria from L. gedrosiana.
UNASSIGNED: From April 2020 to October 2021, six freshwater sites in Guilan Province were sampled for Lymnaeidae snails three times per season (spring, summer, autumn and winter). Snails were exposed to light and heat to induce cercaria shedding and shredded cercaria were identified morphologically and molecularly.
UNASSIGNED: In total, 5,712 Lymnaeidae snails were collected of which 3,288 (57.6%) were identified to be L. gedrosiana with 54.3% containing trematode cercaria. Snail and cercaria recovery were highest in the spring and summer. Trematode cercaria identified included Telorchis assula, Hypoderaeum conoideum, Apharyngostrigea pipientis, Sanguinicola cf. inermis, Opisthioglyphe ranae, Diplostomum pseudospathaceum, and Australapatemon burti.
UNASSIGNED: The four trematodes D. pseudospathaceum, S. inermis, A. burti, and A. pipientis have not been previously reported in Iran; all four of these can infect migratory birds. The most common cercaria found, H. conoideum (18.3% of the snails) is of zoonotic importance. The third most common cercaria found, S. inermis (10.0% of the snails) is detrimental to fish production. Given the importance of the wetlands in the region for wildlife and migratory birds as well as the number of fish and bird farms in the area, efforts to control L. gedrosiana snails are needed to protect wildlife and human health. In addition, monitoring programs should be implemented to identify and prevent introductions of new trematode species.

Trematodiases are diseases caused by snail-borne trematode parasites that infect both animals and humans. Fascioliasis, schistosomiasis and paramphistomosis are some of these diseases and they affect millions of livestock, leading to significant economic losses. The aim of the study was to document freshwater snails occurring in selected study sites in the Free State and Gauteng provinces as well as identify and detect larval trematodes that they harbour. Samples were collected from a total of five study sites within two provinces of South Africa. Morphological features were used to identify snail species and were further confirmed genetically by polymerase chain reaction (PCR), sequencing and phylogenetic analysis. The larval trematodes were also detected by PCR, PCR-Restriction Length Fragment Polymorphism (PCR-RLFP), sequencing and phylogenetic analysis. A total of 887 freshwater snails were collected from Free State (n = 343) and Gauteng (n = 544). Five different genera of snails as well as species in the Succineidae family were documented. The snails in descending order of abundance were identified as: Physa (P.) spp. (51%), Succineidae spp. (20%), Galba (G.) truncatula (12%), Pseudosuccinea (Ps.) columella (10%), Planorbella (Pl.) duryi (6%) and Bulinus (B.) truncatus (1%). Approximately 272 DNA pools were created for genetic identification of snails and detection of trematode parasites. Schistosoma species were not detected from any of the snail species. A total prevalence of 46% was obtained for Fasciola hepatica in the identified snail species across all study sites. Overall, the highest prevalence of F. hepatica was obtained in Physa species (24%), whilst the lowest was observed in B. truncatus snails (1%). Forty three percent (43%) of the snail samples were PCR positive for Paramphistomum DNA. This is the first report of P. mexicana in South Africa. Fasciola hepatica was confirmed from all obtained snail species per study site. This is the first reported detection of F. hepatica in Pl. duryi and P. mexicana snails as well as the first confirmation of natural infection from P. acuta in South Africa.

Early life stages are commonly thought to be highly sensitive to environmental contaminants and may offer insight into the future health of a population. Despite the importance of studying early life stages, very few standard protocols for benthic invertebrates commonly used in ecotoxicological assessments measure developmental endpoints. The goal of the present study was to develop and optimize a robust standard protocol for studying embryonic endpoints in freshwater gastropods. The developed method was then used to characterize the sensitivity of four embryonic endpoints (viability, hatching, deformities, and biomass production), in conjunction with juvenile and adult mortality, for the snail Planorbella pilsbryi exposed to three metals (copper [Cu], cadmium [Cd], and nickel [Ni]). Biomass production was typically the most sensitive endpoint but was relatively variable, while embryo hatching was slightly less sensitive but highly consistent for all three metals. However, no single embryonic endpoint was consistently the most sensitive, which demonstrates the importance of assessing a broad range of endpoints and life stages in ecotoxicological risk assessment. Interestingly, the embryonic life stage of P. pilsbryi was considerably less sensitive to Cu exposure compared with juvenile and adult mortality. However, for Cd exposure, embryonic endpoints were the most sensitive, and for Ni exposure, embryonic endpoints were similar in sensitivity to juvenile and adult mortality. The present study has valuable applications in conducting developmental toxicity research with organisms lacking standardized testing protocol as well as future applications in multigenerational and in silico toxicity research. Environ Toxicol Chem 2023;42:1791-1805. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.