cercaria laramiensis sp. n., a freshwater zygocercous cercaria from physa gyrina say, with a discussion of cercarial aggregation. 19744430945
failure of transmission of low-pathogenic avian influenza virus between mallards and freshwater snails: an experimental aquatic bird populations, the ability of avian influenza (ai) viruses to remain infectious in water for extended periods provides a mechanism that allows viral transmission to occur long after shedding birds have left the area. however, this also exposes other aquatic organisms, including freshwater invertebrates, to ai viruses. previous researchers found that ai viral rna can be sequestered in snail tissues. using an experimental approach, we determined whether freshwater snails (physa acuta ...201324502718
new intermediate host records for the avian schistosomes dendritobilharzia pulverulenta, gigantobilharzia huronensis and trichobilharzia querquedulae from north america.abstract here, we provide the first north american report of a naturally infected snail, gyraulus parvus, harboring the larval stages of the cosmopolitan, arterial schistosome, dendritobilharzia pulverulenta. the relatively small cercariae of this species are shed in the early morning, are sticky, and adhere to the water's surface film. we also provide a report of the snail host, physa gyrina, of the widespread north american passerine schistosome, gigantobilharzia huronensis. finally, we provid ...201121506803
comparative life histories of two diplostomid trematodes, ornithodiplostomum ptychocheilus and posthodiplostomum minimum.a lack of comparative studies limits our understanding of interspecific variation in parasite life histories, especially for species that incorporate asexual and resting stages into their life cycles. ornithodiplostomum ptychocheilus and posthodiplostomum minimum are sympatric diplostomid trematodes that share the same first (pond snail, physa gyrina) and second (fathead minnow, pimephales promelas) intermediate hosts within lakes in alberta, canada. interspecific differences in the body sizes o ...200415715233
intermediate host availability masks the strength of experimentally-derived colonisation patterns in echinostome trematodes.a fundamental goal of parasite evolutionary ecology is to elucidate patterns of host use and determine the underlying mechanisms of parasite colonisation. in order to distinguish the relative contributions of host encounter rates and host compatibility to infection outcomes, we compared host use in both field and experimental laboratory settings. two years of bi-weekly snail sampling at a freshwater pond demonstrated fluctuating availability among three potential second intermediate snail host s ...200919026653
species- and size-specific infection of snails by cyclocoelum mutabile (digenea: cyclocoelidae).infectivity of cyclocoelum mutabile miracidia to 9 species and up to 4 size classes of pulmonate snails at 14, 16, and 20 c was studied under laboratory conditions. of the 9 species examined, 6 (stagnicola elodes, lymnaea stagnalis, gyraulus parvus, gyraulus circumstriatus, promenetus exacuous, and armiger crista) were highly susceptible (infection success > or = 25%), 2 (physa jennessi and helisoma trivolvis) had low susceptibility (infection success < 25%, > 0), and 1 (physa gyrina) was not su ...19957623190
trematode community structure in the pulmonate snail physa gyrina.trematode community structure was examined in the pulmonate snail physa gyrina over a 12-mo period. a total of 1,181 snails was collected from charlie's pond, north carolina, and was found to be parasitized by 6 trematode species. infracommunities were relatively species rich when compared to previous studies, with 18.4% of infected snails having multi-species infections. halipegus eccentricus was found in 88.4% of multiple infections, usually with 1 of 2 other autogenic, egg-transmitted species ...19938459331
survival and growth of freshwater pulmonate and nonpulmonate snails in 28-day exposures to copper, ammonia, and pentachlorophenol.we performed toxicity tests with two species of pulmonate snails (lymnaea stagnalis and physa gyrina) and four taxa of nonpulmonate snails in the family hydrobiidae (pyrgulopsis robusta, taylorconcha serpenticola, fluminicola sp., and fontigens aldrichi). snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for toxicity testing. this method successfully produced offspring for both species of pulmonate snails an ...201626747374
the role of damselflies (odonata: zygoptera) as paratenic hosts in the transmission of halipegus eccentricus (digenea: hemiuridae) to anurans.halipegus eccentricus is a common hemiurid trematode in the eustachian tubes of north america frogs. however, the life cycle of this species has never been completely elucidated. studies on h. eccentricus suggest that it has a 3-host life cycle. here, we show through fieldwork and host specificity experimental infections that the life cycle of halipegus eccentricus utilizes 4 hosts. metamorphosed anurans become infected with h. eccentricus by feeding on infected damselflies; worms reside in the ...201020738199
comparative observations on cercariae and metacercariae of echinostoma trivolvis and echinoparyphium sp.comparative observations were made on cercariae of echinoparyphium sp. from physa gyrina in charlie's pond, stokes county, north carolina and cercariae of echinostoma trivolvis from helisoma trivolvis in northampton county, pennsylvania. the cercaria of echinoparyphium sp. has 43 collar spines, lacks penetration and paraesophageal glands, and has a conical tail without fin folds. the cercaria of e. trivolvis has 37 collar spines, penetration and paraesophageal glands, a finger-like process at th ...19989645871
acute sensitivity of the vernal pool fairy shrimp, branchinecta lynchi (anostraca; branchinectidae), and surrogate species to 10 chemicals.vernal pool fairy shrimp, branchinecta lynchi, (branchiopoda; anostraca) and other fairy shrimp species have been listed as threatened or endangered under the us endangered species act. because few data exist about the sensitivity of branchinecta spp. to toxic effects of contaminants, it is difficult to determine whether they are adequately protected by water quality criteria. a series of acute (24-h) lethality/immobilization tests was conducted with 3 species of fairy shrimp (b. lynchi, branchi ...201728019706
catastrophic collapse of the larval trematode component community in charlie's pond (north carolina).in 1984, work on the parasite population and community ecology in the pulmonate snail, helisoma anceps , was initiated in charlie's pond (north carolina). similar research on physa gyrina was started in 1986. when study in the pond began in 1984, 8 species of larval trematodes were being shed from hel. anceps. by far, the dominant species was halipegus occidualis , with prevalences generally ∼60%, except during midsummer, when older snails were dying. for the other 7 trematode species being shed ...201525313595
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