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This study investigates the distribution of the Lymnaea (Radix) spp. in Pak Chong district, Nakhon Ratchasima province, northeast Thailand, where a vast cattle farming area is located and has a high prevalence of Fasciola spp. in the cattle. By random selection, 1,414 snails were collected from the natural and man-made ponds. The snails were recorded for morphology and processed for DNA isolation. The snail species were investigated by conventional PCR using a 16S rDNA-specific primer. The result demonstrated that all collected snails were R. (L.) rubiginosa. Moreover, the infection of Fasciola gigantica in the snails was investigated by PCR using a cytochrome c oxidase I (COX1)-specific primer. The results illustrated that the overall prevalence was 22.5% (318/1414), with the highest prevalence in the Nong Sa Rai subdistrict at 73.6% (81/110), which is the highest prevalence of Fasciola gigantica in the snail host that has ever been reported. The lowest prevalence existed in the Pong Ta Long subdistrict at 3.7% (4/109). Our results corresponded to the previous report on the Fasciola spp. infection in the cattle from this area, and the geographical analysis revealed that the most suspected factor would be the earth dam located in these subdistricts, where many animals live freely during the day. Our findings could be helpful for further parasite control and could trigger the study of the biology and associated factors in the future.

Biological indicators are essential for detecting contaminants globally because they can inform us about the long-term effects of many pollutants in the environment. About 80 snail individuals Physella acuta, an adult freshwater snail (Gastropod: Physidae) were collected from the Tigris River / Lower Zab near Taqtaq bridge, Erbil Province, Iraq on November 2022. In the laboratory, the animals were placed in tanks with river water for acclimatization. The 24-, 48, 72 and 96-h toxicity of two heavy metals cupper and Cadmium (CuSO4·5H2O and CdCl2.2 H2O) have been investigated using various nominal concentrations, including 0.0, 0.3, 0.5, 0.7 and 0.9 mg L−1 for Cu and 0.5, 1.0,3.0 ,5.0 and 7.0 mg L−1 for Cd. The behavioral changes and the snail’s mortality were noticed daily and the median lethal concentrations values (LC50) for 24-, 48-, 72- and 96-h were calculated. The LC50 values for the 24, 48,72 and 96- hour exposures to Cu and Cd were 0.911, 0.699, 0.462, 0.209 mg L−1 and 2.359, 1.020, 0.094 and 0.040 mg L−1, respectively. Results indicated that Cu showed noticeably greater toxicity than Cd. Also, treated groups showing significant variation in water pH value throughout the studied time. The study concluded that selected snail species can be used as a bioindicator for evaluating the hazards related to environmental pollutants.

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]

Copyright of Kirkuk Journal of Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The bioturbation potential of three freshwater operculate snails, Filopaludina bengalensis, Gabbia orcula and Melanoides tuberculata, was compared, using water column depth and sediment surface area as the explanatory variables. Assessment of nutrient fluxes from sediment to overlying water was estimated in glass microcosms, that varied in height (tall, medium, short) and base (narrow, wide), resulting in six habitat conditions. In course of movement and grazing, all the three snail species modified surface architecture of the sediment. Besides, the snails modulated NOXˉ (NO2ˉ-N + NO3ˉ-N), NH4+-N and PO43−-P concentrations and other parameters (TDS, conductivity) of the water column in significantly varying proportions. Snail-induced changes in the rate of nutrient flux were highest for F. bengalensis. Periphytic chlorophyll-a concentration was reduced in all snail-treated microcosms compared to the control. Grazing, scraping and movement of snails on sediment facilitated the release of the nutrients in a species-specific manner depending on sediment surface area and water column depth of the microcosm. Apparently, snails may be useful in mobilizing the sediment content in freshwater lakes and ponds, facilitating ecosystem processes. [ABSTRACT FROM AUTHOR]

210Po is a significant source of ionizing radiation that people are exposed to through food globally. This paper presents the wide range of accumulation level of 210Po in the organs of two species of shellfish including freshwater mussel (Sinanodonta jourdyi) and golden apple snail (Pomacea canaliculata), common freshwater species in Vietnam. There was a significant correlation between 210Po activity in muscle to their mass and size of freshwater mussels. In contrast, there was no relation between other organs of both species with their mass and size. The annual effective dose due to consumption of freshwater mussels ranged from 68.7 to 291 μSv year−1 with a mean value of 138 μSv year−1 for muscle and from 321 to 4560 μSv year−1 with a mean value of 1422 μSv year−1 for the hepatopancreas. Meanwhile, the AED for golden apple snail was recorded to be higher with values ranging from 105 to 2189 μSv year−1 with mean value of 673 μSv year−1 for muscle and from 468 to 4155 μSv year−1 with a mean value of 2332 μSv year−1 for hepatopancreas. Thus, the consumption of these two types of shellfish is considered relatively safe, but the hepatopancreas gland must be removed before processing. [ABSTRACT FROM AUTHOR]

Ecological roles of non‐native species can vary over space and time due to abiotic factors and characteristics of the invaded communities. For instance, nutrient availability, temperature, and flow regime can influence invasion outcomes in freshwaters. This variability makes it challenging to predict non‐native species' effects in newly introduced areas.New Zealand mud snails (Potamopyrgus antipodarum; NZMS) are among the most widespread aquatic invasive species globally and have recently been detected in highly productive, spring‐fed streams in the upper mid‐west U.S.A. that are important trout fisheries. We hypothesised that the nutrient‐rich, thermally stable groundwater‐fed streams would provide favourable conditions for NZMS populations, potentially amplifying their effects on native communities. We surveyed benthic macroinvertebrate community structure at 10 streams representing a gradient of NZMS densities in the Driftless Area of southern Wisconsin. At five of the streams, we quantified temporal variation in NZMS and other benthic macroinvertebrates over three seasons.NZMS populations varied considerably across sites and over time, ranging from a few hundred to over 70,000 snails/m2. NZMS numerically represented as much as 97% of the invertebrate community at the highest density sites. At two sites, NZMS increased in population density by 50‐fold and 22‐fold over the survey duration, while at other sites their densities were relatively constant. Based on a principal components analysis summarising stream environmental variables, NZMS densities were negatively associated with stream discharge and positively associated with nitrogen and phosphorus concentrations.The total density and biomass of all benthic invertebrates, and Ephemeroptera and Amphipoda in particular, were negatively associated with NZMS density and biomass. Based on multivariate analyses, overall benthic community composition differed based on NZMS invasion status, as well as across seasons.These results suggest that the environments of southern Wisconsin spring‐fed streams provide favourable conditions for NZMS populations, allowing them to dominate some benthic communities. NZMS effects are likely to vary strongly across streams and over time within streams, highlighting the importance of future work to mechanistically test biotic and abiotic factors influencing their abundance. [ABSTRACT FROM AUTHOR]

Liver and intestinal flukes (LIF) are important groups of foodborne zoonotic trematodes (FZTs) in Southeast Asia, including Vietnam. Their complex life cycles require specific freshwater snail species as the obligatory first intermediate hosts. In 2019, we conducted a longitudinal study in Yen Bai and Thanh Hoa provinces in North and Central Vietnam, respectively, to investigate the diversity of LIF and their infection prevalence in relation to snail host abundance and environmental factors. Using a combination of morphological and molecular identification techniques, we identified 10 LIF species infecting 11 snail host species. We observed significant seasonal variation in the mean abundance of several snail host species, with the majority of snails collected during the spring. We also detected seasonal changes in LIF species composition, with the highest species richness reported in the spring. Clonorchis sinensis and Fasciola gigantica, two medically important human liver flukes in Asia, were found only in the spring in Yen Bai. Our study revealed that not all snail host species have the same probability of becoming infected, and we recorded seasonal variations in the prevalence of LIF infection in different snail species in relation to water parameters. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Long‐distance dispersal (LDD) is a critical process in the distribution of less‐migratory organisms. Migratory birds are considered the principal vector of LDD, especially over extremely long distances such as between continents. However, there has been no evidence of LDD spanning thousands of kilometers, even via birds. In this study, we collected a freshwater snail attached to a Latham's snipe. This snail was identified as the genus Glyptophysa through morphological and molecular identification based on four genetic regions. Considering the migration route of the bird and the distribution of the molluscan genus, we conclude that the snail was attached to a bird which migrated over 4000 km across the ocean. This finding demonstrates the LDD on an intercontinental scale of an organism via a migratory bird, which many biologists have long presumed to occur. [ABSTRACT FROM AUTHOR]

Microbial symbionts can affect host phenotypes and, thereby, ecosystem functioning. The microbiome is increasingly being recognized as an important player in the tripartite interaction between parasitic flatworms, snail intermediate hosts, and the snail microbiome. In order to better understand these interactions, transplant experiments are needed, which rely on the development of a reliable and reproducible protocol to obtain microbiome-disturbed snails. Here, we report on the first successful snail bacteriome transplants, which indicate that Biomphalaria glabrata can accrue novel bacterial assemblies depending on the available environmental bacteria obtained from donor snails. Moreover, the phylogenetic relatedness of the donor host significantly affected recipients' survival probability, corroborating the phylosymbiosis pattern in freshwater snails. The transplant technique described here, complemented by field-based studies, could facilitate future research endeavors to investigate the role of specific bacteria or bacterial communities in parasitic flatworm resistance of B. glabrata and might ultimately pave the way for microbiome-mediated control of snail-borne diseases. [ABSTRACT FROM AUTHOR]

BACKGROUND: Snail allergy is rare but can be fatal. Pila polita, a freshwater snail, was considered as a popular exotic food, particularly in tropical countries, and consumed in processed forms. Thus, the purpose of this study was to identify the major and cross‐reactive allergens of P. polita and to determine the impact of food processing on the allergen stability. RESULTS: Sodium dodecyl sulfate–polyacrylamide gel electrophoresis fractionated raw snail extract to approximately 24 protein bands, between 9 and 245 kDa. The prominent band at 33 kDa was detected in all raw and processed snail extracts. Immunoblotting tests of the raw extract demonstrated 19 immunoglobulin E (IgE)‐binding proteins, and four of them, at 30, 35, 42 and 49 kDa, were revealed as the major IgE‐binding proteins of P. polita. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry identified the 49 and 42 kDa major allergens as actin, whereas the 30 and 35 kDa major allergens were identified as tropomyosin. Immunoblotting revealed that the raw snail had more allergenic proteins than the processed snail. The degree of allergenicity in decreasing order was raw > brine pickled> boiled > roasted > fried > vinegar pickled. The presence of cross‐reactivity between P. polita and the shellfish tested was exhibited with either no, complete, or partial inhibitions. CONCLUSION: Actin and tropomyosin were identified as the major and cross‐reactive allergens of P. polita among local patients with snail allergy. Those major allergens are highly stable to high temperatures, acidic pH, and high salt, which might played a crucial role in snail allergy in Malaysia. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study presents new insights into the near-threatened endemic microsnail Sheitanok amidicus (Schütt & Şeşen, 1991), shedding light on its distribution and morphological characteristics, which have never been documented alive. Surveys conducted in 2023 uncovered two previously unknown localities where the species thrives: stenothermic springs in Tavşantepe village and a private farm in Diyarbakır, Turkey. The snail has whitish-grey body tissue, tentacles with an average length of 0.3 mm, and a foot extending up to 2 mm with grey dots on the upper part. The oval-shaped operculum has an average height and width of 0.4 and 0.3 mm, respectively. The shell width and height is 1.0 mm and 0.7 mm, respectively. The snail has unique features including an orange operculum, heart-shaped blackish mouth parts and two blackish eyes at the base of its tentacles. Previously, the species was known to inhabit seven locations in Southeast Turkey. Its near-threatened status on the IUCN Red List highlights the urgency of conservation efforts. The identification of these new locations provides hope for reducing the risk of extinction for S. amidicus. Additionally, describing the snail's external characteristics would aid in systematic classification of newly found species within this monotypic genus. [ABSTRACT FROM AUTHOR]

Background: Identification of the larval stages of Echinostoma spp. in freshwater snails is an essential guide to continue monitoring the possibility of their transmission and the potential of echinostomiasis in areas where trematodes are the primary agent of parasitic diseases. The aim of this study was investigate Echinostoma using morphological and molecular techniques. Methods: The study was conducted in Gilan and Mazandaran Provinces, northern Iran, from April 2019 to October 2021. Overall, 5300 freshwater snails were randomly collected and were identified using external shell morphology. Meanwhile, snails infected with trematodes were studied via shedding and dissecting methods. Larvae stages of Echinostoma were identified and the genomic DNA of the samples was extracted. The PCR amplification of the ITSI gene was carried out for 17 isolates and products were sequenced. Seven sequences were deposited in GenBank. Results: Totally, 3.5% of snails containing three species (Stagnicola sp., Radix sp. and Planorbis sp.) were infected with two types of cercaria, E. revolutum with 37 and Echinostoma sp. with 45 spines in the collar. Moreover, 35% of the snails were infected with Echinostoma spp. metacercaria. Phylogenetic analysis illustrated that isolates were included in two ITSI haplogroups. Conclusion: Results showed the potential hazard of a zoonotic parasite as Echinostoma in northern Iran. The potential of disease environmental relationship investigation and resource control optimization is necessary for effective disease prevention and health management. [ABSTRACT FROM AUTHOR]

A total of 4754 snails were collected from four sites (Qandil, Kawergosk, Khabat, and Sufaia) on Greater Zab River, Kurdistan Region, Iraq, identified morphologically and the distribution results made up of 2764 (58.14%) of Physella acuta, 919 (19.33%) of Radix auricularia, 416 (8.75%) of Radix euphratica, 180 (3.79%) of Radix sp., 255 (5.36) of Melanopsis praemorsa and 220 (4.63%) of Gyraulus huwaizahensis. Statistical analysis of species distribution showed significant (p

Background: Identification of the larval stages of Echinostoma spp. in freshwater snails is an essential guide to continue monitoring the possibility of their transmission and the potential of echinostomiasis in areas where trematodes are the primary agent of parasitic diseases. The aim of this study was investigate Echinostoma using morphological and molecular techniques.Methods: The study was conducted in Gilan and Mazandaran Provinces, northern Iran, from April 2019 to October 2021. Overall, 5300 freshwater snails were randomly collected and were identified using external shell morphology. Meanwhile, snails infected with trematodes were studied via shedding and dissecting methods. Larvae stages of Echinostoma were identified and the genomic DNA of the samples was extracted. The PCR amplification of the ITSI gene was carried out for 17 isolates and products were sequenced. Seven sequences were deposited in GenBank.Results: Totally, 3.5% of snails containing three species (Stagnicola sp., Radix sp. and Planorbis sp.) were infected with two types of cercaria, E. revolutum with 37 and Echinostoma sp. with 45 spines in the collar. Moreover, 35% of the snails were infected with Echinostoma spp. metacercaria. Phylogenetic analysis illustrated that isolates were included in two ITSI haplogroups. Conclusion: Results showed the potential hazard of a zoonotic parasite as Echinostoma in northern Iran. The potential of disease environmental relationship investigation and resource control optimization is necessary for effective disease prevention and health management.

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Salinization is of global concern, threatening freshwater biodiversity. Salinity tolerance is highly variable and therefore needs to be evaluated on a species-specific basis. An estuarine population of Chilina dombeiana, a freshwater gastropod endemic to Chile and classified as vulnerable, has been recently found in the Biobío River's mouth, suggesting some degree of tolerance to brackish waters. This study evaluated the survival, behaviour (medium preference) and physiology of C. dombeiana when exposed to salinities higher than freshwater, thus elucidating the potential mechanisms used to survive salinization. Chilina dombeiana belongs to the Pulmonate group;, so we evaluated oxygen uptake in air and water, aiming to evaluate emersion as a potential avoidance response to a progressive salinity increase. Complete embryo development was observed for salinities ≤ 16 PSU (practical salinity units) but hatching rates above 50% were only achieved in freshwater (0 PSU). It was also found that salinity had stage-specific effects during embryonic development. In adults, acute exposure to brackish water (12 PSU) caused a decrease in oxygen consumption (compared to freshwater), in the ammonium excretion rates and in the percentage of muscular water content. Although C. dombeiana was able to take up oxygen in both mediums, survival in air decreased over time (days), which correlates with the behavioural preference to remain submerged, even at elevated salinities. Considering the survival of adults and embryos decreased as salinity increased and the lack of an avoidance behaviour or a physiological ability to maintain homeostasis at salinities higher than freshwater, our results suggest this snail could be adversely affected by salinization in the long term. Furthermore, given the ability of C. dombeiana to uptake oxygen in both mediums, it should be considered as a facultative air breather snail, rather than a strictly aquatic species. [ABSTRACT FROM AUTHOR]

This study aims to investigate whether the assassin snail Anentome helena may serve as a biological control agent of Bithynia siamensis goniomphalos, the 1st intermediate host of Opisthorchis viverrini. Experiments were carried out in the laboratory, and the results found that A. helena showed the variation and selection of mollusc prey. A. helena can consume B. siamensis goniomphalos, which is remarkable because this snail can compete with other snails and could be used as a biological control. The consumption rate of the predator was compared, and it was found that A. helena prefers to consume Indoplanorbis exustus, followed by Pomacea canaliculata, Melanoides tuberculata, Filopaludina sumatrensis speciosa, Lymnaea sp., and B. siamensis goniomphalos. This is the first report of an experimental study controlling B. siamensis goniomphalos using A. helena. Our data imply that A. helena can control the B. siamensis goniomphalos population with good results, especially in the absence of other snail species. [ABSTRACT FROM AUTHOR]

Abstract Background Parasitic conjunctivitis caused by Philophthalmus spp. is a common ophthalmic disease in birds, with localized outbreaks occurring worldwide. There is no consensus on treating this disease; mechanical removal is considered a standard recommendation, but is associated with disease relapses within days or weeks. Methods From 2015 to 2020, we examined 4295 Larus michahellis and Larus fuscus gulls in southern Portugal for the presence of Philophthalmus spp. Due to the need to treat dozens of infected gulls in the rescue station, we tested three treatment regimens aimed at targeting Philophthalmus lucipetus in the infected gulls: (I) the ophthalmic application of levamisole; (II) the oral application of milbemycin in combination with praziquantel; and (III) the subcutaneous application of ivermectin. Results The outbreak of philophthalmosis in gulls in southern Portugal has been ongoing since the first cases were reported in 2015–2016. The prevalence of philophthalmosis has fluctuated annually, peaking a maximum of 10.3% in L. fuscus in 2017 and at 2.1% in L. michahellis in 2016. The infection intensity peaked at a median of 11.5 eye-flukes per host bird in L. fuscus in 2016 and a median of six eye-flukes per host bird in L. michahellis in 2017. Nine gulls were infected with >50 eye-flukes. None of the treatment options were effective at treating P. lucipetus infections: the numbers of eye-flukes in the infected birds did not decrease, and the clinical signs of the disease did not change. Conclusions An outbreak of philophthalmosis in southern Portugal has massively affected two species of gulls in the region. Two previously suggested philophthalmosis treatments (ocular levamisole and praziquantel given orally), as well as a third mode of treatment with a previously failed compound (ivermectin administered subcutaneously) were used. However, the treatments did not affect the numbers of P. lucipetus in the eyes of the treated gulls. Further research should address ophthalmic gel formulations or sub-conjunctival delivery mode for antihelminthic drugs that are effective against Philophthalmus spp. in vitro. Graphical abstract

Abstract To clarify the effect of niche conservatism on evolutionary history, we focused on freshwater snails, which have different ecological and phylogenetic properties from previously tested taxa. We conducted a phylogenetic analysis using 750 lymnaeid individuals from 357 sites of eleven Radix species. Then, we estimated the ancestral distribution using the geographic coordinates and colonization routes. In addition, a statistical test of the colonization distances in the latitudinal and longitudinal directions was performed. We also conducted ecological niche modeling for two widely distributed species using climatic data. Ancestral geographic reconstruction estimated the origin of the genus to be around the Indian subcontinental region and showed that latitudinal immigration distances were shorter than longitudinal immigration distances in the diversification process. Ecological niche models suggested that the current distribution was restricted by climate, with annual mean temperature and precipitation of the driest month as particularly strong factors. Niche conservatism to the climate can affect the diversification of freshwater snails.

The history of a lineage is intertwined with the history of the landscape it inhabits. Here we showcase how the geo-tectonic and climatic evolution of South Asia and surrounding landmasses have shaped the biogeographical history of Indoplanorbis exustus , a tropical Asian, freshwater snail. We amplified partial COI gene fragments from all over India and combined this with a larger dataset from South and Southeast Asia to carry out phylogenetic reconstruction, species delimitation analysis and population genetic analyses. Two nuclear genes were also amplified from a few individuals per putative species to carry out divergence dating and ancestral area reconstruction analyses. The results suggest that I. exustus dispersed out of Africa into India during the Eocene. Furthermore, molecular data suggest I. exustus is a species complex consisting of multiple putative species. Primary diversification took place in the Northern Indian plains or in Northeast India. The speciation events appear to be primarily allopatric caused by a series of aridification events starting from the late Miocene to early Pleistocene. None of the species appears to have any underlying genetic structure suggestive of high vagility. All the species underwent population fluctuations during the Pleistocene, probably driven by the Quaternary climatic fluctuations. [ABSTRACT FROM AUTHOR]

This study investigates the distribution of the Lymnaea ( Radix ) spp. in Pak Chong district, Nakhon Ratchasima province, northeast Thailand, where a vast cattle farming area is located and has a high prevalence of Fasciola spp. in the cattle. By random selection, 1,414 snails were collected from the natural and man-made ponds. The snails were recorded for morphology and processed for DNA isolation. The snail species were investigated by conventional PCR using a 16S rDNA-specific primer. The result demonstrated that all collected snails were R . ( L .) rubiginosa . Moreover, the infection of Fasciola gigantica in the snails was investigated by PCR using a cytochrome c oxidase I (COX1)-specific primer. The results illustrated that the overall prevalence was 22.5% (318/1414), with the highest prevalence in the Nong Sa Rai subdistrict at 73.6% (81/110), which is the highest prevalence of Fasciola gigantica in the snail host that has ever been reported. The lowest prevalence existed in the Pong Ta Long subdistrict at 3.7% (4/109). Our results corresponded to the previous report on the Fasciola spp. infection in the cattle from this area, and the geographical analysis revealed that the most suspected factor would be the earth dam located in these subdistricts, where many animals live freely during the day. Our findings could be helpful for further parasite control and could trigger the study of the biology and associated factors in the future., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Potamopyrgus antipodarum is a New Zealand freshwater snail that is invasive worldwide. While native P. antipodarum populations are characterized by frequent coexistence between obligately sexual and obligately asexual individuals, only the asexual snails are known to invade other ecosystems. Despite low genetic diversity and the absence of sex, invasive asexual P. antipodarum are highly successful. Here, we quantified variation in three key life-history traits across invasive P. antipodarum lineages and compared this variation to already documented variation in these same traits in asexual native lineages to provide a deeper understanding of why some lineages become invasive. In particular, we evaluated if invasive lineages of P. antipodarum could be successful because they represent life-history variation from native ancestors that could facilitate invasion. We found that invasive snails displayed a non-representative sample of native diversity, with invasive snails growing more slowly and maturing more rapidly than their native counterparts. These results are consistent with expectations of a scenario where invasive lineages represent a subset of native variation that is beneficial in the setting of invasion. Together, these results help illuminate the mechanisms driving the worldwide expansion of invasive populations of these snails. [ABSTRACT FROM AUTHOR]

Rapid diversification is a way of responding to environmental change for freshwater organisms. This work examined the physicochemical changes and abundance of freshwater snails in Anambra River (Nigeria) during the rainy season. Field studies were conducted fortnightly from June to August 2019 at three stations of the river namely: Otuocha (station I), Otunsugbe (station II), and Ukwubili (station III) about 8.35 kilometers apart from each other. A scoop net of 2 cm mesh size and handpicking was used to sample freshwater snails randomly and water samples were taken to the laboratory for physicochemical analysis. A total of 896 freshwater snails belonging to 6 species (Afropomus balanoidea, Pomacea maculata, Lymnea stagnalis, Lanistes ovum, Pila wernei, and Saulea vitrea) were collected. Pomacea maculata was the most dominant species with a relative abundance of 45.87 %, while Saulea vitrea was the least dominant species with a relative abundance of 2.34 %. There was a significant negative correlation between dissolved oxygen and Pomacea maculate (r = –0.877, p = 0.002) and a positive correlation between dissolved oxygen and Stagnalis lymnea (r = 0.840, p = 0.005). The diversity of species was highest at Otuocha (1.171) followed by Ukwubili (1.133) and Otunsugbe (0.856) with average mean temperatures of (23.1 ±0.1) °C, (27.30 ±0.00) °C, and (26.80 ±0.03) °C respectively. The distribution of freshwater snails was influenced by the physicochemical variability of Anambra River during the rainy season. Therefore, further studies for a longer time and different seasons to examine the impact of physicochemical changes on the snail distribution are encouraged. [ABSTRACT FROM AUTHOR]

Background: Parasitic conjunctivitis caused by Philophthalmus spp. is a common ophthalmic disease in birds, with localized outbreaks occurring worldwide. There is no consensus on treating this disease; mechanical removal is considered a standard recommendation, but is associated with disease relapses within days or weeks. Methods: From 2015 to 2020, we examined 4295 Larus michahellis and Larus fuscus gulls in southern Portugal for the presence of Philophthalmus spp. Due to the need to treat dozens of infected gulls in the rescue station, we tested three treatment regimens aimed at targeting Philophthalmus lucipetus in the infected gulls: (I) the ophthalmic application of levamisole; (II) the oral application of milbemycin in combination with praziquantel; and (III) the subcutaneous application of ivermectin. Results: The outbreak of philophthalmosis in gulls in southern Portugal has been ongoing since the first cases were reported in 2015–2016. The prevalence of philophthalmosis has fluctuated annually, peaking a maximum of 10.3% in L. fuscus in 2017 and at 2.1% in L. michahellis in 2016. The infection intensity peaked at a median of 11.5 eye-flukes per host bird in L. fuscus in 2016 and a median of six eye-flukes per host bird in L. michahellis in 2017. Nine gulls were infected with >50 eye-flukes. None of the treatment options were effective at treating P. lucipetus infections: the numbers of eye-flukes in the infected birds did not decrease, and the clinical signs of the disease did not change. Conclusions: An outbreak of philophthalmosis in southern Portugal has massively affected two species of gulls in the region. Two previously suggested philophthalmosis treatments (ocular levamisole and praziquantel given orally), as well as a third mode of treatment with a previously failed compound (ivermectin administered subcutaneously) were used. However, the treatments did not affect the numbers of P. lucipetus in the eyes of the treated gulls. Further research should address ophthalmic gel formulations or sub-conjunctival delivery mode for antihelminthic drugs that are effective against Philophthalmus spp. in vitro. [ABSTRACT FROM AUTHOR]

Background: Freshwater snails serve as intermediate hosts for a variety of trematodes that cause illness in the human and animal populations. Several species of freshwater snails in Thailand have been found to have larval trematode infections. We aimed to investigate a freshwater snail in Phitsanulok Province and report on its current status of larval trematode infection. Methods: Freshwater snails were collected from six localities (rice field and irrigation canal) by handpicking and using a count per unit of time sampling approach. The snails were identified by their external shell morphology. The shedding method was applied to observe the cercariae, which were photographed under a light microscope to determine their morphological types. Results: A total of 211 snails were classified into seven genera. The most abundant snail species was Lymnaea sp., representing 31.3% of the sample, followed by Physella sp., Bithynia sp., Pomacea canaliculata, Filopaludina martensi, Indoplanorbis exustus, and Melanoides tuberculata, in that order. From the sample, 21 snails (9.95%), including Bithynia sp., Lymnaea sp., I. exustus, and M. tuberculata, were infected with cercarial trematodes, which could be categorized into four types, namely amphistome, parapleurolophocercous, echinostome, and xiphidiocercaria. Amphistome emerged from Bithynia sp., and I. exustus was the most common cercaria to be recovered, representing 80.9% of all infected snails. Conclusion: This study presents the current prevalence of cercariae in infected snails within the studied area. It is important to manage intermediate host snails in order to restrict trematode life cycle completion. [ABSTRACT FROM AUTHOR]

Background: Freshwater snails serve as intermediate hosts for a variety of trematodes that cause illness in the human and animal populations. Several species of freshwater snails in Thailand have been found to have larval trematode infections. We aimed to investigate a freshwater snail in Phitsanulok Province and report on its current status of larval trematode infection. Methods: Freshwater snails were collected from six localities (rice field and irrigation canal) by handpicking and using a count per unit of time sampling approach. The snails were identified by their external shell morphology. The shedding method was applied to observe the cercariae, which were photographed under a light microscope to determine their morphological types. Results: A total of 211 snails were classified into seven genera. The most abundant snail species was Lymnaea sp., representing 31.3% of the sample, followed by Physella sp., Bithynia sp., Pomacea canaliculata, Filopaludina martensi, Indoplanorbis exustus, and Melanoides tuberculata, in that order. From the sample, 21 snails (9.95%), including Bithynia sp., Lymnaea sp., I. exustus, and M. tuberculata, were infected with cercarial trematodes, which could be categorized into four types, namely amphistome, parapleurolophocercous, echinostome, and xiphidiocercaria. Amphistome emerged from Bithynia sp., and I. exustus was the most common cercaria to be recovered, representing 80.9% of all infected snails. Conclusion: This study presents the current prevalence of cercariae in infected snails within the studied area. It is important to manage intermediate host snails in order to restrict trematode life cycle completion.

Fasciolosis and paramphistomosis are a major health problem for the livestock economy worldwide. In Colombia, both distomatosis are reported in cattle, particularly in high Andean tropics, with annual economic losses close to COP 40 billion. The goal of this study was to determine the prevalence of fasciolosis and paramphistomosis in cattle from La Candelaria farm, Caucasia (Colombia), and the presence of intermediate host snails. A descriptive cross-sectional study was carried out with non-probability convenience sampling. Stool samples were collected from the animals and the diagnosis was made using the modified Dennis technique. Digenea prevalence were determined according to sex, weight, age, and race. Freshwater snails were collected in the studied area and were identified by morphology. 400 and 66 fecal samples from 178 bovines of the Zebu (Bos indicus), BON (white-eared white) breeds and the cross between them were analyzed. Fasciola hepatica and Paramphistomidae were diagnosed with a prevalence of 2,2% and 30,9%, respectively. Coinfection was diagnosed in 1,1% of the cattle. Both trematodosis were most frequent in females (p = 0,03). Freshwater molluscs Ampullariidae, Physidae and Planorbidae without digenea larval stages were identified. It was concluded that dual-purpose cattle from La Candelaria farm are exposed to F. hepatica and Paramphistomidae and are probably infected on the farm grounds. Paramphistomidae was more prevalent than F. hepatica, which agrees with other studies in herds from the Colombian high Andean tropics. Paramphistomidae was found in all age groups. [ABSTRACT FROM AUTHOR]

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To clarify the effect of niche conservatism on evolutionary history, we focused on freshwater snails, which have different ecological and phylogenetic properties from previously tested taxa. We conducted a phylogenetic analysis using 750 lymnaeid individuals from 357 sites of eleven Radix species. Then, we estimated the ancestral distribution using the geographic coordinates and colonization routes. In addition, a statistical test of the colonization distances in the latitudinal and longitudinal directions was performed. We also conducted ecological niche modeling for two widely distributed species using climatic data. Ancestral geographic reconstruction estimated the origin of the genus to be around the Indian subcontinental region and showed that latitudinal immigration distances were shorter than longitudinal immigration distances in the diversification process. Ecological niche models suggested that the current distribution was restricted by climate, with annual mean temperature and precipitation of the driest month as particularly strong factors. Niche conservatism to the climate can affect the diversification of freshwater snails. [ABSTRACT FROM AUTHOR]

Abstract Background Gut microbes can contribute to their hosts in food digestion, nutrient absorption, and inhibiting the growth of pathogens. However, only limited studies have focused on the gut microbiota of freshwater snails. Pomacea canaliculata is considered one of the worst invasive alien species in the world. Elucidating the diversity and composition of the microbiota in the gut of P. canaliculata snails may be helpful for better understanding the widespread invasion of this snail species. In this study, the buccal masses, stomachs, and intestines were isolated from seven P. canaliculata snails. The diversity and composition of the microbiota in the three gut sections were then investigated based on high-throughput Illumina sequencing targeting the V3-V4 regions of the 16S rRNA gene. Results The diversity of the microbiota was highest in the intestine but lowest in the buccal mass. A total of 29 phyla and 111 genera of bacteria were identified in all of the samples. In general, Ochrobactrum, a genus of putative cellulose-degrading bacteria, was the most abundant (overall relative abundance: 13.6%), followed by Sediminibacterium (9.7%), Desulfovibrio (7.8%), an unclassified genus in the family Aeromonadaceae (5.4%), and Cloacibacterium (5.4%). The composition of the microbiota was diverse among the different gut sections. Ochrobactrum (relative abundance: 23.15% ± 7.92%) and Sediminibacterium (16.95 ± 5.70%) were most abundant in the stomach, an unclassified genus in the family Porphyromonadaceae (14.28 ± 7.29%) and Leptotrichia (8.70 ± 4.46%) were highest in the buccal mass, and two genera in the families Aeromonadaceae (7.55 ± 4.53%) and Mollicutes (13.47 ± 13.03%) were highest in the intestine. Conclusions The diversity and composition of the microbiome vary among different gut sections of P. canaliculata snails. Putative cellulose-degrading bacteria are enriched in the gut of P. canaliculata.

Snails are creatures present in various ecosystems that, in addition to being present in human surroundings, some of them are also important in veterinary medicine and medicine as the intermediate hosts of Digenean trematodes. The present study was conducted to identify and determine the geographical distribution of freshwater snails and investigate the relationship of variables, such as season and geographical region, with snail species and dispersion in Lorestan in the west of Iran. A total of 4400 samples of freshwater snails were collected using the multistage sampling method (i.e., stratified, cluster, and randomized) from 110 points in five geographical regions in four seasons and then identified based on their morphological characteristics by diagnostic keys. The ArcGIS software (version 10.3) was used to evaluate the spatial distribution of the freshwater snails. In this study, seven species of freshwater snails were identified in six families belonging to six genera, namely Melanopsis doriae (6.30% of the variation in species), Theodoxus doriae (5.55%), Bithynia tentaculata (43.22%, the dominant species), Physa acuta (24.98%), Lymnaea truncatula (9.75%), Gyraulus euphraticus (8.18%), and Lymnaea gedrosiana (2.02%). The geographic distribution of freshwater snails was recorded across five regions in 22 points per region for every season. The spatial distribution maps showed that the distribution of freshwater snails varies according to region and season (P

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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Shi, Yao, Chen, Chen, Zhang, Guo, Zhang and Zhang.)

Biological invasions are common among freshwater molluscs, with the North American planorbid gastropod Gyraulus parvus being reported from Europe (Germany) by the 1970s. It has since spread across Central and Western Europe, mostly living in artificial and highly modified habitats. However, considerable conchological and anatomical similarity exists between it and the native European G. laevis. Using four other European and one North American Gyraulus species as outgroups, separate phylogenetic analyses using mitochondrial and nuclear DNA sequences show that G. parvus and G. laevis are in fact part of the same species-level clade, with the former having nomenclatural priority. However, the structure within the mitochondrial tree suggests a North American origin of the invasive populations. It also makes it possible to track down the distribution of both races. Although native and non-native races in Europe tend to possess some differences in conchology and ecology, the degree of overlap makes it impossible to accurately distinguish between them without the DNA barcode data. Our results change the outlook on the conservation of the rare native race. While interspecific competition among snail species is rare, invasion on an intraspecific level may represent a serious threat for native populations. [ABSTRACT FROM AUTHOR]

Abstract The reproductive system has a fundamental role in population dynamics and several reproduction strategies have been shaped by the environment over time. Many environmental pressures are generated by releasing pollutants, as endocrine disruptors, that can affect the reproductive system of individuals, among them invertebrates. The freshwater snails Biomphalaria spp. are used as biomonitor in several ecotoxicological studies; however, there are few studies about gametogenesis and morphology of reproductive snail cells, which could be used as a new biomarker. In this sense, the current study aims to characterize Biomphalaria glabrata gametogenesis, bringing new histomorphometric parameters for germinative cells. Results showed that the hermaphrodite tissue is formed by several acini with simple pavement epithelium with germinative and somatic cells. Oogenesis was classified into five developmental stages (OI to OV) according to diameter, nucleus area, total area, and follicular cell development, and then classified into previtellogenic and vitellogenic oocytes. The spermatogenesis was classified into spermatogonia (Spg), spermatocytes (Spc) and spermatids that were subdivided into five stages (Spt I to Spt V) according to cytoplasm losing, and nucleus spiralization along with Sertoli cells development. Thus, the present study highlights the gametogenesis of B. glabrata with new histomorphometric parameters, which can be an important tool for ecotoxicological and molluscicidal developmental further studies.

Abstract This study presents a four-year follow-up of an introduced population of Physa acuta Draparnaud, 1805, from initial stages to an established population. This introduction occurred on a small impacted stream of Vila do Abraão, the main village of Ilha Grande (Angra dos Reis, Rio de Janeiro, Brazil). The population size increased during the study, and presented a relationship to environmental factors, especially with rainfall. On the initial stages of introduction prevailed the smaller specimens, but on the overall, predominated the intermediate size classes. After less than a year, P. acuta becomes established on this stream and was possibly affecting the other species found on the stream. The information presented here is useful to understand the invasion process of invasive snails, as well as directing conservation efforts.

The adults and larvae of some groups in the coleopteran family Carabidae are known to prey on snails (Mollusca: Gastropoda). Most species of the carabid tribe Licinini are believed to feed on live snails. However, the snail-eating behavior of only a few species has been studied. Whether adults of the licinine genus Badister can prey on live snails was tested by providing 155 live snails of 20 species (eleven terrestrial and nine aquatic species) to adults of Badister pictus Bates, 1873, and observing their behavior under laboratory conditions. Six of the 20 snail species have an operculum that can close the aperture of the shell. Each B. pictus adult attacked all of the snails provided. Badister pictus successfully preyed on ten terrestrial and six aquatic snail species. These beetles used their strikingly asymmetrical mandibles to break the dextral shells along the dorsal part of the whorls from the outer lip of the aperture towards the apex, allowing subsequent consumption of the soft bodies. However, 41.9% of snails could not be eaten by B. pictus adults. The rate of predation success by B. pictus decreased with increasing shell size and thickness of snails. In addition, the presence of an operculum decreased the rate of predation success by B. pictus. The results show that the shell size, thickness, and operculum of some snail species could play important roles in preventing B. pictus mandibles from breaking the shells. Therefore, Badister beetles may exert selective pressure on the evolution of defensive shell structures in small-sized snails. [ABSTRACT FROM AUTHOR]

Elodea nuttallii (Planch.) H. St John is an invasive alien submerged macrophyte, which grows very fast and dominates in many Chinese waters. Bellamya aeruginosa (Reeve) is a widely distributed benthonic organism in China. This snail species rarely grazes submerged macrophytes and may promote their growth by feeding on epiphyte and phytoplankton. The above two species can commonly be found together in nature waters and their interaction may promote the growth of both species, which could disturb the ecological balance. In this paper, effects of different densities of B. aeruginosa at two different nutrient stages on water quality and the growth of E. nuttallii were studied. The results showed that the growth rates (GRs) of E. nuttallii were not significantly affected by different B. aeruginosa densities in the low nutrient (LN) stage. However, in the high nutrient (HN) stage, the GRs of the aboveground parts of E. nuttallii in the high density (HD) groups were considerably higher than the control (CK) and low density (LD) groups. The water chlorophyll (Chl) and nitrate-nitrogen (NO3-N) contents increased substantially with increasing B. aeruginosa density in the LN stage, while the Chl and NO3-N contents in the LD groups were significantly higher than in the HD and CK groups in the HN stage. The results of this paper indicated that B. aeruginosa could promote the growth of E. nuttallii by reducing the Chl contents in the water in high-nutrient environment rather than in low-nutrient environment, which highlighted that B. aeruginosa may strengthen the invisibility of E. nuttallii in eutrophic water caused by human activities.

Background: Avian schistosomes are considered as main causative agents of human cercarial dermatitis (HCD) in Iran. The study was conducted to determine bird schistosomes in their final and intermediate hosts, in main wetlands of Mazandaran. Methods: A total of 255 domestic and wild ducks were collected and the infection of nasal tissues of five (Anas platyrhynchos domesticus, Aythya ferina, Cairina moschata, Anas platyrhynchos and Spatula clypeata) species were analyzed using morphological techniques. Also, 1687 freshwater snails were collected and surveyed by cercarial shedding and crushing tests. Detection of HCD was performed for the presence of clinical symptoms of itching and maculopapular rashs by physical examination. Results: Of 255 ducks, in 41 (16%) infection with nasal Trichibilarizia spp. were recognized by observing eggs and/or adult worms. The most infected ducks were Anas clypeata and Anas platyrhynchos domesticus. Overall, 0.17% of snails were infected with avian schistosomes. Also, clinical examination of 951 rice farmers revealed that 588 (61.82%) of them were suffered from HCD. Conclusion: Our data suggest that domestic ducks could play a prominent role as a reservoir host for establishing life cycle of Trichobilharzia in the area. Also, existence of domestic reservoir ducks and suitable snail hosts in ponds and paddy fields of this area, climate conditions of the wetlands in Mazandaran leads to a high incidence of HCD.

A new snail-eating leech, Batracobdelloides bangkhenensis sp. n., was discovered at Kasetsart University, Bangkhen Campus, Bangkok, Thailand. This species is found free living in the benthic zone of ponds; feeds on freshwater snails, including Bithynia siamensis siamensis, Indoplanorbis exustus, Radix rubiginosa, Physella acuta, and Pomacea canaliculata; and uses a shell as a shelter during the parental care period, with a colony of 7-15 juvenile individuals held on the venter inside the shell of host. Batracobdelloides bangkhenensis displays distinct morphological characters, including a rice-shaped body showing transparency, cephalization, two eye pairs merged on somite III, an anterior sucker twice as large as the cephalic region, a central mouth in the anterior sucker, seven light brown transverse rows in the neck region, absent dorsal papillae, rich green pigments on the dorsum, a male gonopore on XIIa2/XIIa3 (27-28), a female gonopore on XIIIa1/XIIIa2 (29-30), and diffuse aggregations of minute, spherical salivary glands in the neck region. Comparisons of the COI and COI-ND1 genes showed a monophyletic clade for Batracobdelloides, and the phylogenetic tree of the COI gene also indicated that B. bangkhenensis is distinct from other species in the genus, with strong support values. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the potential risk of transmission of angiostrongyliasis by common freshwater snails in Dali Bai Autonomous Prefecture, Yunnan Province, so as to provide insights into local surveillance of angiostrongyliasis., Methods: Common freshwater snails were collected from Dali Bai Autonomous Prefecture, Yunnan Province from March to April, 2020, and identified and bred in laboratory. SD rats were infected with third-stage larvae of Angiostrongylus cantonensis that were isolated from commercially available Pomacea canaliculata snails in Dali Bai Autonomous Prefecture, and freshwater snails were infected with the first-stage larvae of A. cantonensis that were isolated from the feces of SD rats 39 days post-infection at room temperature. The developmental process and morphological characteristics of worms in hosts were observed, and the percentages of A. cantonensis infections in different species of freshwater snails were calculated. Then, SD rats were infected with the third-stage larvae of A. cantonensis that were isolated from A. cantonensis -infected freshwater snails, and the larval development and reproduction was observed., Results: More than 3 000 freshwater snail samples were collected from farmlands, ditches and wetlands around Erhai Lake in Dali Bai Autonomous Prefecture, and Cipangopaludina chinensis , P. canaliculata , Parafossarulus striatulus , Oncomelania hupensis robertsoni , Galba pervia , Physa acuta , Radix swinhoei , Assiminea spp., Tricula spp. and Bellamya spp. were morphologically identified. A total of 105 commercially available P. canaliculata snails were tested for A. cantonensis infections, and 2 P. canaliculata snails were found to be infected with A. cantonensis , in which the third-stage larvae of A. cantonensis were isolated. Ten species of freshwater snails were artificially infected with the third-stage larvae of A. cantonensis , and all 10 species of freshwater snails were found to be infected with A. cantonensis , with the highest positive rate of A. cantonensis infections in Bellamya spp. (62.3%, 137/204), and the lowest in C. chinensis (35.5%, 11/31). After SD rats were infected with the third-stage larvae of A. cantonensis isolated from different species of freshwater snails, mature adult worms of A. cantonensis were yielded., Conclusions: Multiple species of freshwater snails may serve as intermediate hosts of A. cantonensis under laboratory conditions in Dali Bai Autonomous Prefecture of Yunnan Province. Further investigations on natural infection of A. cantonensis in wild snails in Dali Bai Autonomous Prefecture seem justified.

Objective: To investigate the population distribution of intermediate host snails and crabs of Paragonimus along the Jiulongjiang River, Zhangjiang River, and Dongxi River basins in Bopingling Mountain, southern Fujian Province, so as to provide baseline data for researches on parasitic disease prevention and control and enlargement of samples in the parasitic resource bank., Methods: A total of 23 villages in 8 counties (districts) along the Jiulong River, Zhangjiang River, and Dongxi River basins in Zhangzhou City, Fujian Province were selected as survey sites during the period from November 2020 through March 2023, and snail and freshwater crabs were sampled from 1 to 3 streams and ditches neighboring residential areas in each village. Morphological identification of snails was performed according to the external morphological characteristics of collected snail shells, and the unidentified snail species sampled from the natural foci of paragonimiasis in Yunxiao County were subjected to se-quence analysis of the mitochondrial cytochrome oxidase 1 ( CO1 ) gene. The crab species was identified by observing the morphological characteristics of the terminal segment of the first pleopod of male crabs, and Paragonimus cercariae and metacercariae were detected in collected snails., Results: The shells of the unidentified snails sampled from the natural foci of paragonimiasis in Yunxiao County were approximately 50 mm in height and 18 mm in width, thick and solid, long tower cone-shaped, and had 8 to 10 whorls. CO1 gene sequence analysis identified the snail species as Sulcospira hainanensis . A total of 6 freshwater snail species belonging to 5 genera within 3 families, identified 23 survey sites, including Semisulcospira libertina , Paludomus zhangchouensis and S. hainanensis that belonged to the Family Pleurceridae, Tricula fujianensis and T. huaanensis that belonged to the subfamily Triculinae, Family Pomatiopsidae, and Melanoides tuberculata (Family Thiaridae), and 11 species of freshwater crabs belonging to 5 genera within 2 families were identified, including Sinopotamon genus of S. jianglense , S. pinheense , and S. zhangzhouense , Huananpotamon genus of H. planopodum and H. zhangzhouense , Nanhaipotamon genus of N. huaanense and N. longhaiense , and Minpotamon genus of M. nasicum and M. auritum that belonged to the Family Potamidae, and Somanniathelphusa genus of S. huaanensis and S. zhangpuensis (Family Parathelphusidae). In addition, the prevalence of P. westermani cercariae infections was 0.08% (2/2 317) in P. zhangchouensis from Danyan Village in Changtai District and 0.09% (1/1 039) in S. hainanensis from Jinkeng Village in Yunxiao County, and the prevalence of P. westermani metacercariae infections was 25.81% (8/31) in S. jianglense from Danyan Village in Changtai District, and 26.31% (5/19) in S. zhangzhouense from Jinkeng Village in Yunxiao County, respectively., Conclusions: There is a population diversity in the intermediate host snails and crabs along the Jiulongjiang River, Zhangjiang River, and Dongxi River basins in Bopingling Mountain, southern Fujian Province, and P. zhangzhouensis and S. hainanensis are, for the first time, confirmed as the first intermediate hosts of P. westermani .

Abstract Background Islands have traditionally been the centre of evolutionary biological research, but the dynamics of immigration and differentiation at continental islands have not been well studied. Therefore, we focused on the Japanese archipelago, the continental islands located at the eastern end of the Eurasian continent. While the Japanese archipelago is characterised by high biodiversity and rich freshwater habitats, the origin and formation mechanisms of its freshwater organisms are not clear. In order to clarify the history of the planorbid gastropod fauna, we conducted phylogenetic analysis, divergence time estimation, ancestral state reconstruction, and lineage diversity estimations. Results Our analyses revealed the formation process of the planorbid fauna in the Japanese archipelago. Most lineages in the Japanese archipelago have closely related lineages on the continent, and the divergence within the Japanese lineages presumably occurred after the late Pliocene. In addition, each lineage is characterised by different phylogeographical patterns, suggesting that immigration routes from the continent to the Japanese archipelago differ among lineages. Furthermore, a regional lineage diversity plot showed that the present diversity in the Japanese archipelago potentially reflects the differentiation of lineages within the islands after the development of the Japanese archipelago. Conclusions Although additional taxon sampling and genetic analysis focused on each lineage are needed, our results suggest that immigration from multiple routes just prior to the development of the Japanese archipelago and subsequent diversification within the islands are major causes of the present-day diversity of the Japanese planorbid fauna.

Objective: To investigate the parasitic infection of Anentome helena (A. helena) and determine the validity of species boundaries for A. helena by combining molecular phylogeny and morphological approaches. Methods: A total of 325 individuals of A. helena were collected throughout northern Thailand. Shells were measured and compared by t-test. Radulae were investigated by using light and scanning electron microscope. Two partial mitochondrial DNA sequences of COI and 16S rRNA from 36 specimens of A. helena and related species were used to test the validity of the morphospecies. Phylogenetic trees were constructed using neighbour joining, maximum likelihood and Bayesian inference. Infection of A. helena with trematode larva was examined and observed. Results: Morphological examination of A. helena revealed 2 distinct morphospecies. Genetic divergences supported the separation of the two morphotypes into two distinct groups. Both individual and combined analyses of the two nucleotide fragments revealed two phylogroups that corresponded with shell and radula characteristics. In addition, A. helena was found infected with 37-collar spined echinostome metacercariae. The prevalence and intensity of metacercariae was highest in the San Kamphaeng district, Chiang Mai province, with 7.5% and 1.670±0.577, respectively. Conclusions: These findings suggest that comprehensive taxonomic revision of this unrecognised species complex is needed. This study represents the preliminary step to reveal new data on the recent distribution of trematode infection in A. helena. This information may be useful for developing conservation management of the snail and the practice of targeted regimes to reduce anthelmintic resistance in the future.