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.

The aim of this study was to analyze the content of heavy metals in the shells of freshwater gastropods Viviparus sp.; to evaluate the correlation of the trace element accumulation degree in biological objects, bottom sediments, and water, and to assess the degree of pollution of minor rivers of St. Petersburg, as well as the applicability of the studied biological objects for this. Water samples, sediment samples, and gastropods were collected in July 2019 and August 2020 at seven sampling points located at five rivers in St. Petersburg. Analysis of metals in water samples, water extract from bottom sediments, was carried out with atomic emission spectrometry. Analysis of metals in the shells of molluscs Viviparus sp. carried out with atomic absorption spectrophotometry and atomic emission spectrometry. The data obtained indicate the current contamination of the Neva River Delta with a number of metals, such as Al, Mn, Fe, Cu, and Pb, and indicate a significant accumulative capacity of bottom sediments with Zn, Pb, Ni, Cu, Mn, and Fe. Gastropods showed an ability for intensive bioaccumulation, which depended on the properties of metals, the hydrology of the river, and the characteristics of bottom sediments. It was found that for the studied environmental conditions, Sr, Fe, Cr, and Mn have the best ability to bioaccumulate in gastropod shells.

Arylsulfatase and β-glucuronidase are the two substantial enzymes having a significant role in the cleavage of conjugated natural estrogens (C-NEs). The present study reports that arylsulfatase and β-glucuronidase have been abundantly found in the digestive tracts of Cipangopaludina chinensis; in which, their corresponding activities were 60 and 5 U/g wet waste, respectively. The arylsulfatase from Cipangopaludina chinensis could show high activity at low temperatures. Hence, its activity still remained at 53.2% of maximal activity even at an extremely low temperature of 4 ℃; while the corresponding activities of arylsulfatase from Helix pomatia or activated sludge were less than 20% and 10%, respectively. The arylsulfatase and β-glucuronidase from Cipangopaludina chinensis could efficiently cleave C-NEs suggesting that they could be alternative enzymes derived from Helix pomatia that are used for cleavage of conjugated compounds in environmental or biological sample analysis. Meanwhile, they might also be used to enhance the cleavage of C-NEs in municipal wastewater.

This contribution is an update to the 2014 compilation of all supra- and (infra-) specific taxa of extant and fossil Valvatidae, a group of freshwater operculate snails near the base of Heterobranchia with a nearly worldwide distribution. This update includes corrections and many additions (two replacement taxon names, 21 mainly fossil taxa previously overlooked, and 37 invalid names) to the 2014 contribution and adds all newly described species (11) during the past eight years. The extensive reference list is directly linked, where possible, to the available electronic source of the cited papers.

Schistosomiasis continues to pose significant public health problems in many developing countries. Mass drug administration (MDA) is the most adopted control option but there is increasing evidence for the development of praziquantel-resistant Schistosoma strains. This shortcoming has necessitated the search for other effective methods for the control of schistosomiasis. The breaking of Schistosoma transmission cycles through the application of molluscicides into snail infested freshwater bodies has yielded positive outcomes when integrated with MDA in some countries. However, few of such effective molluscicides are currently available, and where available, their application is restricted due to toxicity concerns. Some nanotized particles with molluscicidal activities against the different stages of snail intermediate hosts of schistosomes have been reported. Importantly, the curcumin-nisin nanoparticle synthesized by our group was very effective and it showed no significant toxicity in a mouse model and brine shrimps. This, therefore, offers the possibility of developing a molluscicide that is not only safe for man but also is environmentally friendly. This paper reviews nanoparticles with molluscicidal potential. The methods of their formulation, activities, probable mechanisms of actions, and their toxicity profiles are discussed. More research should be made in this field as it offers great potential for the development of new molluscicides.

Near Infrared Spectroscopy (NIRS) is a spectroscopic technique that evaluates the vibrational energy levels of the chemical bonds of molecules within a wavelength range of 750-2,500 nm. This simple method acquires spectra that provide qualitative and quantitative data on the chemical components of the biomass of living organisms through the interaction between the electromagnetic waves and the sample. NIRS is an innovative, rapid, and non-destructive technique that can contribute to the differentiation of species based on their chemical phenotypes. Chemical profiles were obtained by NIRS from three snail species (Biomphalaria glabrata, Biomphalaria straminea, and Biomphalaria tenagophila) that are intermediate hosts of Schistosoma mansoni in Brazil. The correct identification of these species is important from an epidemiological viewpoint, given that each species has distinct biological and physiological characteristics. The present study aimed to develop a chemometric model for the interspecific and intra-specific classification of the three species, focusing on laboratory and field populations. The data were obtained from 271 live animals, including 150 snails recently collected from the field, with the remainder being raised in the laboratory. Populations were sampled at three localities in the Brazilian state of Rio de Janeiro, in the municipalities of Sumidouro (B. glabrata) and Paracambi (B. straminea), and the borough of Jacarepaguá in the Rio de Janeiro city (B. tenagophila). The chemometric analysis was run in the Unscrambler® software. The intra-specific classification of the field and laboratory populations obtained accuracy rates of 72.5% (B. tenagophila), 77.5% (B. straminea), and 85.0% (B. glabrata). The interspecific differentiation had a hit rate of 75% for the field populations and 80% for the laboratory populations. The results indicate chemical and metabolic differences between populations of the same species from the field and the laboratory. The chemical phenotype, which is closely related to the metabolic profile of the snails, varied between environments. Overall, the NIRS technique proved to be a potentially valuable tool for medical malacology, enabling the systematic discrimination of the Biomphalaria snails that are the intermediate hosts of S. mansoni in Brazil.

The cryptic diversity of trematodes was evaluated in the Nagayama-Shinkawa River, an artificial canal of the Ishikari River System of Hokkaido, Japan. Numerous migratory waterfowls use the canal as a stopover point in every spring season. The lymnaeid snail, Radix auricularia, and the semisulcospirid snail, Semisulcospira libertina, colonize the static and flowing water areas, respectively. The trematode fauna of the two snails was assessed by molecular phylogenetic and population genetic analyses. Each of distinctive clades in mitochondrial DNA trees was arbitrarily set as a species. In total, 14 species of the families Diplostomidae, Echinostomatidae, Notocotylidae, Plagiorchiidae, and Strigeidae occurred in R. auricularia, wherease S. libertina harbored 10 species of the families Echinochasmidae, Heterophyidae, Notocotylidae, and Lecithodendridae and Cercaria creta, an unclassified species whose adult stage is still unknown. The species diversity of the larval trematodes could be recognized as a \"hot spot\", suggesting that the seasonal visit of waterfowls is very important to spread trematodes and to keep their diversity. A high intraspecific genetic diversity was observed in the echinostomatid, notocotylid, echinochasmid, and heterophyid species, whose definitive hosts include birds. It seems likely that each of the parasite populations is always disturbed by repeated visits of waterfowls.