the ultrastructure of the capsule surrounding pomphorhynchus laevis (acanthocephala) in its intermediate host echinogammarus stammeri (amphipoda).the capsule or the membranous layer surrounding larvae of pomphorhynchus laevis müller, 1776 in its intermediate host, echinogammarus stammeri s. karaman, 1931, was studied by electron microscopy. some observations were also made with a light microscope. capsule components mainly show a tubular profile; capsule thickness can reach up to 8 microns. in some instances, within the hemocoel of e. stammeri, the parasite was encapsulated by amphipod hemocytes.19921339979
occurrence of pomphorhynchus laevis müller 1776 (acanthocephala) in silurus glanis (l.) from the river po.the sheatfish, silurus glanis (l.), from the terminal part of river po was examined for the presence of helminth parasites. of 182 s. glanis specimens, 95 (52.2%) were infected with the acanthocephalan pomphorhynchus laevis. mid-gut followed by fore-gut appeared to be the most infected portions of host alimentary canal. in 45 sheatfish of total length < or = 40 cm, specimens of p. laevis were found encapsulated in mesenteric and peritoneal tissues. a comparison between light and electron microsc ...19921339980
the immune response of a cyprinid fish to infections of the acanthocephalan pomphorhynchus laevis. 19724196350
the effects of temperature and other factors upon the establishment and survival of pomphorhynchus laevis (acanthocephala) in goldfish, carassius auratus. 19724680538
the importance of parasite mortality in regulating the population size of the acanthocephalan pomphorhynchus laevis in goldfish. 19744815475
[helminths in trout (fam. salmonidae) in freshwater reservoirs].a survey is made of the helminths parasitizing in representatives of family salmonidae caught mainly in the free fresh-water basins in the country. more detailed information and study concerned the american and the balkan trout--salmo irideus gairdneri and salmo trutta m. fario respectively--because of their higher economic importance. in the course of the study some corrections were made of the names of some of the species in the light of the new data obtained concerning all helminths alreay me ...19827179733
leucine aminopeptidase activity in adults of pomphorhynchus laevis (acanthocephala): a histochemical frozen sections of the acanthocephalan pomphorhynchus laevis, which is a frequent intestinal parasite of cyprinid and salmonid fishes, leucine aminopeptidase (apase) was localized histochemically in outer parts of the presomal bulbus as well as in all layers and most nuclei of the metasomal body wall. enzyme activity visualized at ph 6.5 using l-leucyl-4-methoxy-2-naphtylamide as the substrate was also associated with ovarian balls, immature larvae, and the testes. the results are discussed w ...19947809000
cyathocephalus truncatus (cestoda: spathebothridea) in its intermediate host echinogammarus stammeri (amphipoda) from the river brenta, northern italy.a study was carried out on the occurrence of the tapeworm cyathocephalus truncatus (pallas, 1781) (cestoda: spathebothridea) in its intermediate host, the amphipod echinogammarus stammeri, in the river brenta. a total of 18,860 e. stammeri was examined from july 1990 to june 1994; only 25 of them (prevalence 0.13%) were infected with tapeworm larvae (intensity of infection 1 larva/host). co-occurrence of c. truncatus larvae with the larva of the acanthocephalan pomphorhynchus laevis (müller, 177 ...19958532369
colonization and establishment of pomphorhynchus laevis (acanthocephala) in an isolated english river.the successful colonization, establishment and spread of pomphorhynchus laevis in a small, isolated, devon river 128 km from the parasite's nearest focus in dorset was followed over 11 years from 1985. the parasite was first detected in anguilla anguilla and platichthys flesus in 1988: by 1995 it had attained prevalence levels of 22.6% in a. anguilla and 43.6% in p. flesus and also occurred in 100% salmo trutta, 50% cottus gobio and noemacheilus barbatulus. as judged by prevalence, abundance, pr ...19968991914
preliminary observations on the ultrastructure of the body wall of pomphorhynchus laevis (acanthocephala). 19665336137
the fine structure of the acanthor shell of pomphorhynchus laevis (acanthocephala). 19725018475
the effect of the acanthocephalan pomphorhynchus laevis upon the respiration of its intermediate host, gammarus pulex. 19744826717
richness and diversity of parasite communities in european eels anguilla anguilla of the river rhine, germany, with special reference to helminth parasites.a total of 121 european eels (anguilla anguilla) from 2 sampling sites on the river rhine were investigated in respect of their parasite communities. special attention was given to the swim bladders, intestines, gills and fins of the fish. twelve different parasite species were found to live in and on the eels. data from each sampling site were kept separate. parasites found in descending order of prevalence were: anguillicola crassus, trypanosoma granulosum, myxobolus sp., paratenuisentis ambig ...199910503258
pomphorhynchus laevis: the intestinal acanthocephalan as a lead sink for its fish host, chub (leuciscus cephalus).aqueous lead exposure of chub (leuciscus cephalus) experimentally infected with the parasite pomphorhynchus laevis resulted in a rapid accumulation of this metal in the intestinal acanthocephalans, reaching concentrations which were significantly greater than in the host muscle, liver, and intestine and approximately 1000 times higher than the exposure con centration. parasitized chub accumulated significantly less lead in their intestinal wall than their uninfected conspecifics (mann-whitney u ...199910502468
parasite-altered behavior in a crustacean intermediate host: field and laboratory studies.the effects of the acanthocephalan parasite pomphorhynchus laevis on the behavior of its crustacean intermediate host, the amphipod echinogammarus stammeri, were studied. a drift study revealed that infected amphipods were disproportionately represented in drift samples taken throughout a 24-hr period; infection with more than 1 parasite enhanced this effect. infection also interacted with the daily timing of drift, with parasitized amphipods beginning to drift earlier in the evening. two distin ...19989920297
biodiversity of parasites in freshwater environment in relation to pollution.during 1994, 129 specimens of chub (leuciscus cephalus l.) from two localities, polluted--bolelouc, 80th river kilometer, near the city of olomouc, and unpolluted--brodské, 225th river kilometer, near the lanzhot on the morava river, were examined for metazoan parasites. altogether 38 metazoan parasite species including helminths, leeches and glochidia belonging to 14 genera were found, 34 in the case of unpolluted locality (brodské) and 28 in the polluted one (bolelouc). in both localities, 24 ...19979802067
uptake of lead by pomphorhynchus laevis cystacanths in gammarus pulex and immature worms in chub (leuciscus cephalus).the uptake of lead by cystacanths of the acanthocephalan pomphorhynchus laevis in naturally infected amphipods, gammarus pulex, and by immature parasites in experimentally infected fish, leuciscus cephalus, was examined following 3-week experimental exposures (0.01 and 0.1 mg l(-1) pb2+). both g. pulex and the cystacanths of p. laevis accumulated lead but concentrations in the parasites were lower than in the host tissues at the low lead dose and significantly lower at the high dose. p. laevis f ...19989694375
the cement apparatus of larval and adult pomphorhynchus laevis (acanthocephala: palaeacanthocephala).light and electron microscopy were used to study the ultrastructure of the cement apparatus, namely cement glands and cement ducts of mature specimens of the acanthocephalan parasite pomphorhynchus laevis müller, 1776, recovered from the digestive tracts of fish leuciscus cephalus risso, 1826. in addition, the cement glands of immature p. laevis found within the body cavity of the fish alburnus alburnus alborella de filippi, 1844 were examined. in a mature male of p. laevis the 6 cement glands a ...19989614327
proteolytic enzymes of pomphorhynchus laevis and in three other acanthocephalan species.cystacanths and adults of the acanthocephalan pomphorhynchus laevis were found to release proteolytic enzymes during in vitro culture. culture media in which cystacanths had been kept contained a trypsinlike collagenolytic proteinase exhibiting a molecular mass of 29 kda on gelatin substrate gel electrophoresis and a ph optimum at ph 9.0. samples of adults possessed a trypsinlike collagenolytic proteinase with a molecular mass of 26 kda and showed a ph optimum at 9.0. leucine aminopeptidase acti ...19948308657
lead accumulation in pomphorhynchus laevis and its host.adults of pomphorhynchus laevis were collected from the intestines of 10 chubs (leuciscus cephalus) from the river ruhr near bochum, germany. the acanthocephalans and various tissues of the fish (muscle, liver, and intestine) were analyzed for lead with electrothermal atomic absorption spectrometry. the mean lead level in the parasite was 54 micrograms/g wet weight, which was 284 times more than in the host intestine, 771 times more than in host liver, and 2,700 times more than in host muscle. t ...19948195935
pathological changes induced by pomphorhynchus laevis muller (acanthocephala) in the gut of rainbow trout, salmo gairdneri richardson.the consequences of infection of rainbow trout, salmo gairdneri richardson, by an acanthocephalan, pomphorhynchus laevis muller, have been studied using light and electron microscopy. the mucosal epithelium, of the gut adjacent to the metasoma of the worm suffered compression and abrasion. the praesoma of p. laevis penetrated the mucosal epithelium, lamina propria, stratum compactum, stratum granulosum, muscularis and serosa of the gut wall, and was invested by a fibrous capsule of inflammation ...19863962428
interactions between the acanthocephalans pomphorhynchus laevis and acanthocephalus anguillae in rainbow trout: testing an exclusion hypothesis.rainbow trout were infected simultaneously with cystacanths of the two acanthocephalan species pomphorhynchus laevis and acanthocephalus anguillae in the laboratory. infections consisted of varying proportions of the two species (from 0 to 100%) at low (20 cystacanths) and high (60 cystacanths) levels. fish were sacrificed at 7, 56 and 112 days post-infection (p.i.) and the parasites recovered. at low-level infections there was a high degree of overlap in the range of intestine occupied by the t ...19902362768
cystathionine beta-synthase and gamma-cystathionase in helminths.the activities of gamma-cystathionase and cystathionine beta-synthase were investigated in a range of gastrointestinal, free-living and entomophagous nematodes. although nematode gamma-cystathionase used the same range of substrates as the mammalian hepatic enzyme, its activity was extremely low and there were significant interspecies variations with respect to the relative order of active substrates. like the mammalian liver enzyme, nematode cystathionine beta-synthase showed activity in the di ...19911805216
the sites occupied by the acanthocephalan pomphorhynchus laevis in the alimentary canal of fish.the distribution of the acanthocephalan pomphorhynchus laevis along the alimentary tract of several species of freshwaster fish was studied in both natural and experimental infections. the parasite exhibits a clear preference for a particular region of the alimentary canal, which differs from host species to host species, but it is capable of surviving in all regions of the intestine. in some species, but not in all, its growth rate may be reduced in regions outside of the preferred site. the pa ...19761264491
heavy metal concentrations in adult acanthocephalans and cestodes compared to their fish hosts and to established free-living bioindicators.intestinal helminths of fish caught from freshwater and brackish water biotopes throughout europe were analysed by electrothermal atomic absorption spectrometry for their heavy metal (pb and cd) levels. the metal concentrations of the parasites were compared to those of different organs (muscle, liver, intestine) of the fish hosts and to those detected in the whole bodies of the respective intermediate hosts. the three acanthocephalan species analysed contained very high amounts of pb and cd. th ...19979802069
differential influence of pomphorhynchus laevis (acanthocephala) on the behaviour of native and invader gammarid species.although various species of acanthocephalan parasites can increase the vulnerability of their amphipod intermediate hosts to predation, particularly by altering their photophobic behaviour, their influence on the structure of amphipod communities and the success of invader species has so far received little attention. we compared the prevalence and behavioural influence of a fish acanthocephalan parasite, pomphorhynchus laevis, in two species of amphipods, gammarus pulex and gammarus roeseli in ...200011428335
metazoan parasite community structure in brown trout from two lakes in western ireland.a total of 549 brown trout were caught from two lakes, lough feeagh and bunaveela lake, in the burrishoole system, co. mayo, ireland. seven species of metazoan parasite were detected but only four species occurred in > or = 10% of the sample. the parasite community of the trout was dominated by a single species, pomphorhynchus laevis, with a prevalence if 58%. only one allogenic helminth species was recorded from the trout, diphyllobothrium ditremum, with the community mainly comprising autogeni ...19958522767
population biology of pomphorhynchus laevis in brown trout from two lakes in the west of ireland.since ireland is the only country in which pomphorhynchus laevis (acanthocephala) uses brown trout (salmo trutta) as its preferred definitive host, the population biology of the parasite in this host was investigated thus enabling a comparison to be made with data collected on p. laevis from other hosts, particularly the cyprinids, chub and barbel. over a period of 12 months, 549 brown trout were caught from two lakes, lough feeagh and bunaveela lake, in the burrishoole river system, co. mayo, i ...19958522766
conflict between co-occurring manipulative parasites? an experimental study of the joint influence of two acanthocephalan parasites on the behaviour of gammarus pulex.when two parasite species are manipulators and have different definitive hosts, there is a potential for conflict between them. selection may then exist for either avoiding hosts infected with conflicting parasites, or for hijacking, i.e. competitive processes to gain control of the intermediate host. the evidence for both phenomena depends largely on the study of the relative competitive abilities of parasites within their common intermediate host. we studied the effects of simultaneous infecti ...200010874725
[remarks on pomphorhynchus laevis (zoega, muller 1776) as a parasite in pleuronectes flesus and pleuronectes platessa]. 195713457088
species associations among larval helminths in an amphipod intermediate host.larval helminths that share the same intermediate host may or may not also share the same definitive hosts. if one or more of these helminth species can manipulate the phenotype of the intermediate host, there can be great advantages or severe costs for other helminths resulting from co-occurring with a manipulator, depending on whether they have the same definitive host or not. among 2372 specimens of the amphipod echinogammarus stammeri collected from the river brenta, northern italy, there wa ...200011027778
the effect of the acanthocephalan parasite pomphorhynchus laevis on the lipid and glycogen content of its intermediate host gammarus pulex.besides conspicuous changes in behaviour, manipulative parasites may also induce subtle physiological effects in the host that may also be favourable to the parasite. in particular, parasites may be able to influence the re-allocation of resources in their own favour. we studied the association between the presence of the acanthocephalan parasite, pomphorhynchus laevis, and inter-individual variation in the lipid and glycogen content of its crustacean host, gammarus pulex (amphipoda). infected g ...200111306112
populations of acanthocephalus anguillaepomphorhynchus laevis in rivers with different pollution levelsthe distribution of two acanthocephalan species (pomphorhynchus laevisacanthocephalus anguillae) in the chub (leuciscus cephalus) was studied in four river reaches characterized by different levels of pollution: the river ticino near abbiategrasso (unpolluted), the naviglio grande canal, in milano (slightly polluted), the river lambro near merone village (polluted) and the river lambro near monza (severely polluted).pomphorhynchus laevis was restricted to the unpolluted and the slightly polluted ...19989858630
interspecific interactions between acanthocephala in the intestine of brown trout: are they more frequent in ireland?the aim of this paper was to test the hypothesis that when the 2 species of acanthocephalan pomphorhynchus laevis and acanthocephalus clavula are found concurrently within the intestine of brown trout under field conditions, they have the potential to interact negatively. evidence has shown that acanthocephala are more likely to exhibit negative interactions with their own and other species, under both field and experimental conditions. furthermore, the likelihood of these interactions is increa ...200314636026
pomphorhynchus laevis (palaeacanthocephala) in the intestine of chub (leuciscus cephalus) as an indicator of metal pollution.chub experimentally infected with the acanthocephalan parasite pomphorhynchus laevis were exposed to 0.01 mg l(-1) pb(2+) over 5 weeks. lead was rapidly accumulated in the intestinal worms reaching a steady-state concentration after 4 weeks. this concentration was significantly greater than in the host muscle, liver and intestine and more than 9,000 times higher than the exposure concentration. lead accumulation in p. laevis increased at a higher exposure concentration but was not correlated wit ...200312547347
comparison between lead accumulation of pomphorhynchus laevis (palaeacanthocephala) in the intestine of chub (leuciscus cephalus) and in the body cavity of goldfish (carassius auratus auratus).this experimental study assessed the role of the microhabitat in the uptake of metals by adult acanthocephalans. we examined the accumulation of lead by adult pomphorhynchus laevis in the intestine of chub (leuciscus cephalus) and compared it with that in goldfish, carassius auratus auratus, in which the parasites penetrate the intestinal wall and enter the body cavity. chub and goldfish experimentally infected with adult pomphorhynchus laevis were exposed to 0.01 mg l(-1) pb(2+) over 3 weeks. l ...200111336747
a predator's dilemma: prey choice and parasite susceptibility in three-spined sticklebacks.the acanthocephalan parasite pomphorhynchus laevis is transmitted by a suitable intermediate host such as the amphipod gammarus pulex to its definitive fish host. parasite-induced alterations in both appearance and behaviour concur to render infected gammarids more vulnerable to predation, thus promoting parasite transmission. experimental infection of laboratory bred full- and half-sib groups of three-spined sticklebacks (gasterosteus aculeatus) provided evidence that the parasite imposes a sur ...200312741513
a comparison of freshwater and marine/estuarine strains of pomphorhynchus laevis occurring sympatrically in flounder, platichthys flesus, in the tidal thames.collections of flounder, platichthys flesus, at two sites on the tidal river thames in 1994 and 1995 have, for the first time, revealed the sympatric occurrence of the freshwater and marine/estuarine strains of the acanthocephalan parasite pomphorhynchus laevis. this natural co-occurrence of the strains has been employed to compare infection levels and a range of parasite attributes of the two strains under conditions of sympatry. at both lots road (chelsea) and tilbury the marine/estuarine stra ...200111551313
effects of conspecifics and heterospecifics on individual worm mass in four helminth species parasitic in fish.intraspecific and interspecific effects on the growth and body size of helminths are rarely studied in natural situations, yet knowing what determines helminth sizes and thus fecundity is crucial to our understanding of helminth ecology and epidemiology. the determinants of average individual worm mass were investigated in four common species of helminths parasitic in trout, salmo trutta. in the acanthocephalan echinorhynchus truttae, there was a negative relationship between the intensity of in ...200312756550
influence of enteric helminths on the distribution of intestinal endocrine cells belonging to the diffuse endocrine system in brown trout, salmo trutta l.the presence of intestinal helminths in the alimentary canal of brown trout, salmo trutta l., can alter the number of cells that synthesize modulatory peptides. a total of 167 brown trout were collected from tributaries of the river brenta (northern italy), of which 119 (71.3%) specimens were infected with enteric helminths, 28 with the acanthocephalan pomphorhynchus laevis müller, 1776 with intensity of infection ranging from 1 to 162 (18.57 +/- 30.79) worms per host and 67 fish with the cestod ...200312962225
patterns of intermediate host use and levels of association between two conflicting manipulative parasites.for many parasites with complex life cycles, manipulation of intermediate host phenotypes is often regarded as an adaptation to increase the probability of successful transmission. this phenomenon creates opportunities for either synergistic or conflicting interests between different parasite species sharing the same intermediate host. when more than one manipulative parasite infect the same intermediate host, but differ in their definitive host, selection should favour the establishment of a ne ...200211796118
the origin and function of cement gland secretion in pomphorhynchus laevis (acanthocephala).cement gland protein in male and inseminated female individuals of an acanthocephalan parasite of fish, pomphorhynchus laevis (müller, 1776), was localized by immunohistochemistry using an antibody specific for cement protein. male p. laevis possess 3 pairs of round to oval cement glands ranging from 0.5 to 0.9 mm in length and from 0.3 to 0.7 mm in width. each gland has an outer portion containing nuclear fragments and other cellular organelles surrounding a space for storage of gland products. ...199910633927
the life cycle and seasonal changes in the occurrence of pomphorhynchus laevis (palaeacanthocephala, pomphorhynchidae) in a small isolated a small isolated lake in slovakia, the fish acanthocephalan pomphorhynchus laevis using gammarus balcanicus and the minnow phoxinus phoxinus, respectively, as its intermediate and final hosts, represented a dominant helminth species. its prevalence and intensity of infection in fish showed no significant variation during a year fluctuating above the mean values of 89% and 6.6 worms per fish. the mean prevalence of p. laevis larvae in gammarus was 41.4% with a maximum in the late summer and au ...200314535165
comparison of the macroparasite communities of wild and stocked brown trout (salmo trutta l.) in the west of ireland.the aim of the present study was to compare the helminth infra and component communities of wild and stocked brown trout in lough feeagh, in the west of ireland, and also to examine the establishment and development of helminth communities in stocked brown trout. fish were sampled in may, august and november 1997 and 1998 and an additional sample of wild brown trout was examined in april 1997. in total 217 wild trout and 122 stocked trout were examined. the acanthocephalans acanthocephalus clavu ...200212003067
histopathology in leuciscus cephalus (pisces: cyprinidae) resulting from infection with pomphorhynchus laevis (acanthocephala).the histopathology present in leuciscus cephalus risso 1826 from the river po, naturally infected with the acanthocephalan pomphorhynchus laevis müller 1776, was studied and described. the parasite was only found within the host's digestive tract, and a density of 10 p. laevis per square centimeter was common. on histological examination it was noticed that both male and female parasites penetrated deeply through all the layers of the host digestive tract by means of their slender neck, bulb and ...19911844504
effects of two acanthocephalan parasites on the fecundity and pairing status of female gammarus pulex (crustacea: amphipoda).acanthocephalan parasites are known to alter the reproductive biology and physiology of their hosts in various ways. in this study we investigated the influence of two acanthocephalan parasites, pomphorhynchus laevis and polymorphus minutus, on the fecundity and pairing success of female gammarus pulex. the results show that p. laevis and p. minutus affect female intermediate host reproduction in different ways. females infected with p. minutus were totally castrated, whereas those infected with ...200212095239
comparative investigations of the morphology and chemical composition of the eggshells of acanthocephala. ii. palaeacanthocephala.eggshells of the palaeacanthocephalans acanthocephalus anguillae, pomphorhynchus laevis and polymorphus minutus were investigated for their fine structure as well as their chemical composition. the acanthor larvae are surrounded by four eggshells (e1-e4) separated by interstices (g1-g4). immature eggs do not exhibit the complete set of eggshells. the chemical composition of the outermost, thin eggshell (e1) remains unknown. e2 is supplied by outer filaments of different strength; it contains ker ...19921379711
effect of pomphorhynchus laevis (acanthocephala) on putative neuromodulators in the intestine of naturally infected salmo trutta.immunohistochemical and pathological studies were carried out on the digestive tract of parasitized and uninfected specimens of salmo trutta (l.). a total of 124 brown trout were collected on several occasions from 3 tributaries of the brenta river, northern italy. twenty-eight individuals of s. trutta (22.6%) were parasitized with pomphorhynchus laevis (miller, 1776). the occurrence of p. laevis in the trout gut significantly increased the number of endocrine cells immunoreactive to calcitonin ...200212240968
helminth communities of european eels anguilla anguilla (linnaeus, 1758) from the vistula lagoon and puck bay, poland.within 2001-2002 a total of 621 eel anguilla anguilla (l., 1758) (488 from the vistula lagoon and 133 from the puck bay) were examined. fifteen parasite taxa were recovered: pseudodactylogyrus anguillae (yin et sproston, 1948), brachyphallus crenatus (rudolphi, 1802), deropristis inflata (molin, 1859), diplostomum spp., bothriocephalus claviceps (goeze, 1782), proteocephalus macrocephalus (creplin, 1825), anguillicola crassus (kuwahara, niimi et itagaki, 1974), camallanus lacustris (zoega, 1776) ...200516838624
associations and interactions among intestinal helminths of the brown trout, salmo trutta, in northern italy.species co-occurrences and interspecific associations between intensity of infection were studied in helminth communities of three populations of brown trout, salmo trutta, from northern italy. of the eight helminth species, only four were common enough to be included in the analyses: pomphorhynchus laevis, acanthocephalus anguillae, echinorhynchus truttae and cyathocephalus truncatus. the observed frequencies of co-occurrences of the different species, based on presence/absence data, did not di ...200111818049
parasitic infection and developmental stability: fluctuating asymmetry in gammarus pulex infected with two acanthocephalan species.several studies have reported a negative association between developmental stability and parasitic infection. however, the host-parasite associations examined so far consist only of a limited number of parasite taxa, and developmental stability was appraised on definitive hosts. the present study examines the association between infection by 2 acanthocephalan parasites. pomphorhynchus laevis and polymorphus minutus, and the developmental stability of their common intermediate host gammarus pulex ...200212053979
activity levels and predator detection by amphipods infected with an acanthocephalan parasite, pomphorhynchus laevis.the acanthocephalan parasite pomphorhynchus laevis (müller, 1776) uses freshwater amphipods as its intermediate host. in order to complete the life cycle, the infected amphipod must be consumed by a fish, where the acanthocephalan will mature and reproduce. parasite transmission, and therefore fitness, could be enhanced if infected amphipods fail to detect or avoid predatory fish. we compared the activity levels of infected and non-infected amphipods, echinogammarus stammeri (karaman, 1931), in ...200314560974
costs of intraspecific and interspecific host sharing in acanthocephalan cystacanths.larval helminths often share individual intermediate hosts with other larval worms of the same or different species. in the case of immature acanthocephalans capable of altering the phenotype of their intermediate hosts, the benefits or costs of host sharing can be evaluated in terms of increased or decreased probability of transmission to a suitable definitive host. competitive interactions among the immature stages of acanthocephalans within the intermediate host could create additional costs ...200111315182
the intestinal parasite pomphorhynchus laevis (acanthocephala) interferes with the uptake and accumulation of lead (210pb) in its fish host chub (leuciscus cephalus).uninfected chub as well as fish experimentally infected with the acanthocephalan parasite pomphorhynchus laevis were exposed to (210)pb(2+) for up to 38 days and the uptake and distribution of lead within different fish organs and the parasites was determined at various time points. highest metal concentrations were detected in the acanthocephalans, followed by intestine, bile, liver, gill and muscle of the fish host. infected chub had significantly lower (210)pb levels in the gills on day 17 (p ...200314636677
the intestinal parasite pomphorhynchus laevis (acanthocephala) from barbel as a bioindicator for metal pollution in the danube river near budapest, hungary.concentrations of as, al, ag, ba, bi, cd, co, cr, cu, fe, ga, mg, mn, ni, pb, sb, sn, sr, tl, v and zn were analyzed by inductively coupled mass spectrometry (icp-ms) in the intestinal helminth pomphorhynchus laevis and its host barbus barbus. the fish were caught in the danube river downstream of the city of budapest (hungary). ten out of twenty one elements analyzed were found at higher concentrations in the acanthocephalan than in different tissues (muscle, intestine, liver and kidney) of bar ...200415016463
intestinal helminth parasites in flounder platichthys flesus from the river thames: an infracommunity analysis was undertaken of intestinal helminth communities in flounder platichthys flesus from two sites on the river thames. a comparison was made between helminth community richness and diversity from these sites at the component and infracommunity levels. at the component community level, a richer and more diverse parasite community was found in flounder from the tilbury location (marine influence) than that from the lots road location (freshwater influence). at the infracommunity level, m ...200415575985
differential influence of pomphorhynchus laevis (acanthocephala) on brain serotonergic activity in two congeneric host species.the physiological mechanisms by which parasites with complex life cycles manipulate the behaviour of their intermediate hosts are still poorly understood. in burgundy, eastern france, the acanthocephalan parasite pomphorhynchus laevis inverses reaction to light in its amphipod host gammarus pulex, but not in gammarus roeseli, a recent invasive species. here, we show that this difference in manipulation actually reflects a difference in the ability of the parasite to alter brain serotonergic (5-h ...200717443968
the parasite community infecting flounders, platichthys flesus, in the tidal thames.the composition of the parasite fauna of the flounder, platichthys flesus, retrieved from two locations in the tidal thames is described in detail for the first time. the combined parasite species list of the flounders from lots road in the upper tideway and west thurrock in the middle tideway consisted of one protozoan (glugea stephani), one monogenean (gyrodactylus sp.), four larval digeneans (cryptocotyle concava, timoniella imbutiforme, t. praeterita, and labratrema minimus), five adult dige ...199910526412
fish acanthocephalans of the genus pomphorhynchus sp. as globally applicable bioindicators for metal pollution in the aquatic environment?intestinal helminths of fish, especially the acanthocephalans, have become increasingly interesting as potential bioindicators for heavy metal contamination in aquatic habitats. pomphorhynchus laevis from chub and barbel has been investigated frequently for its ability to take up and bioconcentrate metals within its body. this papers summarizes the present knowledge on p. laevis and its metal bioaccumulation properties in order to evaluate the applicability of species of the pomphorhynchus genus ...200415683038
site availability and density-dependent constraints on the acanthocephalan pomphorhynchus laevis in rainbow trout, oncorhynchus mykiss (walbaum).threshold density levels were investigated experimentally in rainbow trout, oncorhynchus mykiss, for the acanthocephalan pomphorhynchus laevis. fifty small fish 120-150 mm long were infected with 50 cystacanths each every 4 weeks for 16 weeks, and samples of up to 10 fish examined at 1, 5, 9, 13 and 17 weeks after the original infection. the mean intestinal length was found to have increased significantly over this period, from a mean of 125 to 173 mm and the mean number of parasites recovered i ...19911866187
helminth communities of the barbel barbus barbus from large river systems in austria.the composition and diversity of the total and intestinal component endohelminth communities were determined in the cyprinid barbel from three study areas in two large river systems in austria. two sample sites in the danube and one site in the river drau are the only free flowing stretches of these rivers in austria. nine helminth species were identified, with the acanthocephalan pomphorhynchus laevis being dominant in the danube, with up to 100% prevalence. in the drau, where the dominant spec ...200515946396
its rdna sequences of pomphorhynchus laevis (zoega in müller, 1776) and p. lucyi williams and rogers, 1984 (acanthocephala: palaeacanthocephala).the internal transcribed spacers (its-1 and its-2) of the ribosomal rna gene of pomphorhynchus laevis (zoega in müller, 1776) (acanthocephala) isolated from various fish species across central and southern europe were compared with those of p. lucyi williams and rogers, 1984 collected from the largemouth bass micropterus salmonoides boulenger from the usa. the nucleotide sequences of its regions of p. laevis from minnows phoxinus phoxinus (l.) and chub leuciscus cephalus (l.) from two distant lo ...200314574091
fish macroparasites as indicators of heavy metal pollution in river sites in austria.this paper describes two approaches to evaluate the use of fish macroparasites as bioindicators of heavy metal pollution at selected river stretches in austria. firstly changes in the diversity and richness of endoparasites of the cyprinid barbel, barbrus barbuls (l.), were tested in relation to heavy metal contents in the aquatic system. secondly, the bioaccumulation potential of cadmium, lead and zinc was assessed in the acanthocephalan, pomphorhynchus laevis (miller, 1776), and compared with ...200314667173
larval morphology, genetic divergence, and contrasting levels of host manipulation between forms of pomphorhynchus laevis (acanthocephala).studies on parasite species with a wide geographic and ecological range may be confounded by still equivocal taxonomic identification. here, we investigated genetic polymorphism and behavioural changes induced in a common intermediate host, in two different forms of pomphorhynchus laevis based on the morphology of the larval infective stage (cystacanth). a 'smooth type' (s) and a 'wrinkled type' (w) of cystacanth were distinguished based on their surface and shape. we analysed sequence divergenc ...200414711589
colonization of the round goby, neogobius melanostomus (gobiidae) by parasites in the new environment of the gulf of gdańsk (southern baltic).the round goby (neogobius melanostomus) is a non-indigenous species in the baltic sea, introduced to its waters (the gulf of gdańsk) from the black, azov, and caspian seas. for this reason, an attempt was made to determine the species' parasitic fauna in its new environment. within 1994-2000, a total of 201 round goby specimens caught in the gulf of gdańsk were examined. the parasites found represented protozoans (trichodina domerguei domerguei), digeneans (diplostomum spp. metacercariae), cesto ...200216888941
potential interactions between acanthocephalus anguillae and pomphorhynchus laevis in their natural hosts chub, leuciscus cephalus and the european eel, anguilla anguilla.chub and eels were experimentally infected via intermediate hosts harbouring cystacanths, with pomphorhynchus laevis alone, or acanthocephalus anguillae alone, or simultaneously with mixtures of both species in varying proportions, and sampled at 7, 56 or 112 days post-infection. examination of chub revealed that both species showed low establishment and growth rates, differing markedly from british field data, where chub is apparently one of the most important hosts, and preventing further mean ...19911852495
histochemistry of glycoconjugates in mucous cells of salmo trutta uninfected and naturally parasitized with intestinal helminths.mucus secreted onto the surface of the intestine forms a physical barrier to invading parasites so that a possible attachment of helminths to the surface is prevented and their expulsion by peristalsis facilitated. in mammals, intestinal parasites induce hyperplasia and hypertrophy of intestine goblet cells and provoke changes in the mucus composition. in fish, this topic has received less attention. in the present investigation, histochemical methods were employed to compose intestinal mucous c ...200515900687
differential phenoloxidase activity between native and invasive gammarids infected by local acanthocephalans: differential immunosuppression?manipulative endoparasites can alter the behaviour and the physiology of their intermediate hosts in ways that increase the probability of successful transmission to the final host. this requires that the parasite is able to circumvent its host's immune defence. successful immune evasion may depend on host-parasite coevolutionary history and the appearance of new hosts invading the local host population may promote local parasite maladaptation. to test this hypothesis, we examined the effect of ...200314700193
comparison of morphological characters in irish and english populations of the acanthocephalan pomphorhynchus laevis (müller, 1776).pomphorhynchus laevis is believed on ecological evidence to exist as three strains in the british isles. however, the strains have never been shown to be capable of being distinguished using morphological characters. a morphological comparison was made between a sample of p. laevis from salmo trutta in l. feeagh in the west of ireland and a sample from leuciscus cephalus in r. culm in the south of england. the length and width of the trunk, neck, bulb, proboscis and hooks were measured. the numb ...200415477755
how parasitism and pollution affect the physiological homeostasis of aquatic hosts.parasitism poses a serious threat to hosts under certain circumstances, while the well-being of organisms is also negatively affected by environmental pollution. little information is available on the simultaneous effects of parasites and pollutants on the physiological homeostasis of organisms. the present paper demonstrates that parasites: (i) may influence the metabolism of pollutants in infected hosts, (ii) interact with pollution in synergistic or antagonistic ways, and (iii) may induce phy ...200616768858
[a study on the helminth fauna linked to seasonal changes and size of the fish host, leuciscus cephalus l., from lake dam orenler, afyonkarahisar].in this study, the presence of helminths on 103 leuciscus cephalus from the orenler dam lake, turkey was investigated from july 2007 to may 2008. five parasite species were found in the host fish: of these species dactylogyrus vistuale was found in the gills (42.7%, 10.6+/-14.8 parasite/fish), diplostomum sp. in the lens of eyes (12.6%, 4.1+/-4.0), bothriocephalus acheilognathi in the intestine (23.3%, 4.8+/-10.4), ligula intestinalis in the body cavity (12.6%, 2.1+/-1.2), and pomphorhynchus lae ...200919851976
the intestinal parasite pomphorhynchus laevis as a sensitive accumulation indicator for the platinum group metals pt, pd, and rh.concentrations of the platinum group elements pt, pd, and rh were analyzed by adsorptive cathodic stripping voltammetry (pt, rh) and total-reflection x-ray fluorescence (pd) in the intestinal helminth pomphorhynchus laevis and its host barbus barbus. the fish were caught in the danube river south of the city of budapest (hungary) and were exposed to ground catalytic material for 28 days. following exposure all three precious metals were taken up and accumulated in host organs and the parasites. ...200515721887
metazoa parasites of the invasive round goby apollonia melanostoma (neogobius melanostomus) (pallas) (gobiidae: osteichthyes) in the gulf of gdańsk, baltic sea, poland: a comparison with the black sea.the known metazoa parasite fauna of the invasive round goby apollonia melanostoma (formerly neogobius melanostomus) consists of 12 species. the core of the parasite fauna comprises two species: cryptocotyle concavum and diplostomum spathaceum; secondary species are absent; satellite species include cercariae gen. sp. and ergasilus sieboldi; rare species are acanthocephalus lucii, anguillicola crassus, bothriocephalus sp., dichelyne minutus, hysterothylacium aduncum, pomphorhynchus laevis, piscic ...200717048001
is metal accumulation in pomphorhynchus laevis dependent on parasite sex or infrapopulation size?concentrations of the elements as, cd, co, cu, fe, mn, mo, ni, pb, sn, v, zn were analysed by inductively coupled plasma mass spectrometry (icp-ms) in the acanthocephalan pomphorhynchus laevis and its fish host barbus barbus. a total of 27 barbels were collected from the danube river in autumn 2006 close to the town kozloduy (685 river kilometer) on the bulgarian river bank. fish were divided into 3 groups. according to their p. laevis infrapopulation size hosts were considered as heavily infect ...201020380766
crustacean-acanthocephalan interaction and host cell-mediated immunity: parasite encapsulation and interactions of pomphorhynchus laevis (müller, 1776) in naturally infected amphipod, echinogammarus stammeri (karaman), from the brenta river (northern italy) are described. a fully developed acanthocephalan larva occupies a large portion of an amphipod's haemocoelic space; thus, the parasite frequently induces displacement of host digestive tract and other internal organs. however, no apparent damage to the host's internal structures was observed. within the haemocoel of e. stamme ...200818578167
infection with an acanthocephalan manipulates an amphipod's reaction to a fish predator's odours.many parasites with complex life cycles increase the chances of reaching a final host by adapting strategies to manipulate their intermediate host's appearance, condition or behaviour. the acanthocephalan parasite pomphorhynchus laevis uses freshwater amphipods as intermediate hosts before reaching sexual maturity in predatory fish. we performed a series of choice experiments with infected and uninfected gammarus pulex in order to distinguish between the effects of visual and olfactory predator ...200717049528
divergent location of ribosomal genes in chromosomes of fish thorny-headed worms, pomphorhynchus laevis and pomphorhynchus tereticollis (acanthocephala).we studied distribution of ribosomal dna (rdna) sequences along with chromosomal location of the nucleolar organizer regions (nors) in males of two fish parasites, pomphorhynchus laevis and pomphorhynchus tereticollis (acanthocephala). fluorescence in situ hybridization with 18s rdna probe identified two clusters of rdna in each species, but revealed a remarkable difference in their location on chromosomes. in p. laevis, the rdna-fish signals were found in long arms of the first chromosome pair ...200717143651
immune depression induced by acanthocephalan parasites in their intermediate crustacean host: consequences for the risk of super-infection and links with host behavioural manipulation.parasite survival in hosts mainly depends on the capacity to circumvent the host immune response. acanthocephalan infections in gammarids are linked with decreased activity of the prophenoloxidase (propo) system, suggesting an active immunosuppression process. nevertheless, experimental evidence for this hypothesis is lacking: whether these parasites affect several immune pathways is unknown and the consequences of such immune change have not been investigated. in particular, the consequences fo ...200918708062
variation and covariation in infectivity, virulence and immunodepression in the host-parasite association gammarus pulex-pomphorhynchus laevis.parasites often manipulate host immunity for their own benefit, either by exacerbating or suppressing the immune response and this may directly affect the expression of parasite virulence. however, genetic variation in immunodepression, which is a prerequisite to its evolution, and the relationship between immunodepression and virulence, have rarely been studied. here, we investigated the variation among sibships of the acanthocephalan parasite, pomphorhynchus laevis, in infecting and in immunod ...200919726474
carotenoid-based colour of acanthocephalan cystacanths plays no role in host manipulation.manipulation by parasites is a catchy concept that has been applied to a large range of phenotypic alterations brought about by parasites in their hosts. it has, for instance, been suggested that the carotenoid-based colour of acanthocephalan cystacanths is adaptive through increasing the conspicuousness of infected intermediate hosts and, hence, their vulnerability to appropriate final hosts such as fish predators. we revisited the evidence in favour of adaptive coloration of acanthocephalan pa ...200918796399
is the host or the parasite the most locally adapted in an amphipod-acanthocephalan relationship? a case study in a biological invasion context.manipulative endoparasites with complex life cycles can alter their intermediate host immunity and behaviour in ways that increase survival probability within the host body cavity and enhance successful transmission to the definitive host. these parasitic manipulations are variable among and within parasite species and may result from co-evolutionary processes, in which the parasite is constrained for adaptation to the local intermediate host. hence, arrival of a new host species in a local host ...200717266962
evidence for the hypothesis of strain formation in pomphorhynchus laevis (acanthocephala): an investigation using mitochondrial dna sequences.a hypothesis has been erected stating that in the british isles the acanthocephalan, pomphorhynchus laevis can be separated into 3 strains, an english, irish and marine strain. ecological and morphological evidence exists in support of this hypothesis. an investigation at the molecular level was conducted in order to test the validity of the existing evidence. a mitochondrial gene, subunit i of cytochrome c oxidase was partially sequenced from 3 irish populations of p. laevis, 1 scottish populat ...200415471009
biological invasion and parasitism: invaders do not suffer from physiological alterations of the acanthocephalan pomphorhynchus laevis.biological invasions expose parasites to new invasive hosts in addition to their local hosts. however, local parasites are often less successful in infecting and exploiting their new hosts. this may have major consequences for the competitive ability of hosts, and finally on the fate of the parasite-host community. in burgundy (eastern france), the acanthocephalan parasite, pomphorhynchus laevis, infects 2 amphipod species living in sympatry: the native gammarus pulex and the invasive gammarus r ...201019765338
do eel parasites reflect the local crustacean community? a case study from the rhine river 2003, the parasite fauna of 197 european eels anguilla anguilla, captured at three different locations (laufenburg, karlsruhe and beneeden leeuwen) in the river rhine, was analysed. the eels harboured a total of 18 species, among them the protozoa (myxidium giardi, myxobolus kotlani and trypanosoma granulosum), acanthocephalans (acanthocephalus anguillae, acanthocephalus lucii, echinorhynchus truttae, pomphorhynchus laevis), nematodes (paraquimperia tenerrima, pseudocapillaria tomentosa, cama ...200717578598
est based phylogenomics of syndermata questions monophyly of eurotatoria.the metazoan taxon syndermata comprising rotifera (in the classical sense of monogononta+bdelloidea+seisonidea) and acanthocephala has raised several hypotheses connected to the phylogeny of these animal groups and the included subtaxa. while the monophyletic origin of syndermata and acanthocephala is well established based on morphological and molecular data, the phylogenetic position of syndermata within spiralia, the monophyletic origin of monogononta, bdelloidea, and seisonidea and the acant ...200819113997
lipids of fish parasites and their hosts: fatty acid fingerprints of four species of acanthocephalans and of their hosts' intestinal tissues.the fatty acid fingerprints of total lipid extracts from the four fish parasites acanthocephalus lucii, neoechinorhynchus rutili, paratenuisentis ambiguus, and pomphorhynchus laevis were investigated by capillary gas-liquid chromatography (glc). the fatty acid patterns of the parasites were compared with those of their respective host tissue, viz., intestinal tract tissue of infected perch, brown trout, eel, and chub. the highly complex gas chromatograms revealed significant differences not only ...19957567912
understanding trophic interactions in host-parasite associations using stable isotopes of carbon and nitrogen.stable isotope analysis of carbon and nitrogen can deliver insights into trophic interactions between organisms. while many studies on free-living organisms are available, the number of those focusing on trophic interactions between hosts and their associated parasites still remains scarce. in some cases information about taxa (e.g. acanthocephalans) is completely missing. additionally, available data revealed different and occasionally contrasting patterns, depending on the parasite's taxonomic ...201728212669
cadmium concentrations in two adult acanthocephalans, pomphorhynchus laevis and acanthocephalus lucii, as compared with their fish hosts and cadmium and lead levels in larvae of a. lucii as compared with their crustacean host.adults of pomphorhynchus laevis and acanthocephalus lucii were analyzed for cadmium by atomic absorption spectrometry. their cadmium concentrations were compared with those found in different tissues (muscle, liver, and intestine) of their final hosts the chub and perch. additionally, the cadmium and lead concentrations in larvae of a. lucii and their intermediate host asellus aquaticus were determined. regarding the adult acanthocephalans, the parasites showed several times more cadmium than di ...19957567908
field evidence of host size-dependent parasitism in two manipulative parasites.the distribution of parasites within host natural populations has often been found to be host age-dependent. host mortality induced by parasites is the commonest hypothesis proposed for explaining this pattern. despite its potential importance in ecology, the parasitism intensity in relation with the host age has rarely been studied in the field. the 2 manipulative acanthocephalans, polymorphus minutus and pomphorhynchus laevis, use the amphipod gammarus pulex as an intermediate host, and their ...200717918352
modification of hosts' behavior by a parasite: field evidence for adaptive manipulation.parasites relying on trophic transmission to complete their life cycles often induce modifications of their host's behavior in ways that may increase their susceptibility to predation by final hosts. these modifications have often been interpreted as parasite adaptations, but very few studies have demonstrated that host manipulation has fitness benefits for the parasite. the aim of the present study was to address the adaptive significance of parasite manipulation by coupling observations of beh ...200718051653
parasite virulence when the infection reduces the host immune response.parasite infections often induce a reduction in host immune response either because of a direct manipulation of the immune system by the parasite or because of energy depletion. although infection-induced immunodepression can favour the establishment of the parasite within the host, a too severe immunodepression may increase the risk of infection with opportunistic pathogens, stopping the period over which the parasite can be transmitted to other hosts. here, we explore how the risk of contracti ...201020200031
response of the gut neuroendocrine system of leuciscus cephalus (l.) to the presence of pomphorhynchus laevis müller, 1776 (acanthocephala).immunohistochemical tests were applied to sections of intestine of uninfected and pomphorhynchus laevis muller-infected chub, leuciscus cephalus (l.) using 15 different antisera. nerve cell bodies and fibres immunoreactive (ir) to the anti-bombesin, -cholecystokinin-8 (cck-8), -galanin, -gastrin-releasing peptide (-grp), -nitric oxide synthase (-nos), -substance p (-sp), and -vasoactive intestinal peptide (-vip) sera were observed in the myenteric plexus of uninfected chub. the density of nerve ...200515736056
altered host behaviour and brain serotonergic activity caused by acanthocephalans: evidence for specificity.manipulative parasites can alter the phenotype of intermediate hosts in various ways. however, it is unclear whether such changes are just by-products of infection or adaptive and enhance transmission to the final host. here, we show that the alteration of serotonergic activity is functionally linked to the alteration of specific behaviour in the amphipod gammarus pulex infected with acanthocephalan parasites. pomphorhynchus laevis and, to a lesser extent, pomphorhynchus tereticollis altered pho ...200617015346
the effects of parasite age and intensity on variability in acanthocephalan-induced behavioural manipulation.numerous parasites with complex life cycles are able to manipulate the behaviour of their intermediate host in a way that increases their trophic transmission to the definitive host. pomphorhynchus laevis, an acanthocephalan parasite, is known to reverse the phototactic behaviour of its amphipod intermediate host, gammarus pulex, leading to an increased predation by fish hosts. however, levels of behavioural manipulation exhibited by naturally-infected gammarids are extremely variable, with some ...200818314127
the endohelminth fauna of barbel ( barbus barbus) correlates with water quality of the danube river in bulgaria.summary: infection of barbel with 10 species of metazoan parasites including 3 trematodes, 3 acanthocephalans and 4 nematodes was observed in fish collected from 3 localities in the bulgarian part of the river danube between summer 2004 and summer 2007. the composition as well as the diversity characteristics of the parasite communities were analysed seasonally and showed a clear correlation with the composition of the invertebrate fauna and water quality. the most prevalent species was the acan ...200919250599
the interaction between an introduced fish host and local parasite fauna: neogobius kessleri in the middle danube river.parasite communities of introduced fish neogobius kessleri günther (gobiidae) were studied at five localities in the slovak section of the danube river during 2002-2005. thirty-three metazoan parasite species were identified. all fish were infected with at least two parasite species; most of the parasite species were generalists. at all sampling sites, high susceptibility to local parasites was observed. the parasite community was dominated by three parasite species: glochidia of anodonta anatin ...200919288135
infection with acanthocephalans increases the vulnerability of gammarus pulex (crustacea, amphipoda) to non-host invertebrate predators.phenotypic alterations induced by parasites in their intermediate hosts often result in enhanced trophic transmission to appropriate final hosts. however, such alterations may also increase the vulnerability of intermediate hosts to predation by non-host species. we studied the influence of both infection with 3 different acanthocephalan parasites (pomphorhynchus laevis, p. tereticollis, and polymorphus minutus) and the availability of refuges on the susceptibility of the amphipod gammarus pulex ...200818371238
telomere analysis of platyhelminths and acanthocephalans by fish and southern hybridization.we examined the composition of telomeres in chromosomes of parasitic worms, representatives of the flatworm groups monogenea and cestoda (platyhelminthes), and thorny-headed worms (syndermata: acanthocephala) by fluorescence in situ hybridization (fish) with different telomeric repeat probes. our results show that the (ttaggg)n sequence, supposed to be the ancestral telomeric repeat motif of metazoa, is conserved in monogenea (paradiplozoon homoion) and cestoda (caryophyllaeus laticeps, caryophy ...200919935913
[helminths fauna of fishes in the mała panew river drainage basin].a parasitological investigation was made at 420 fishes from 10 species: perca fluviatilis l., gymnocephalus cernuus (l.), gobio gobio (l.), tinca tinca (l.), leuciscus idus (l), noemacheilus barbatulus (l.), lota lota (l.), leucaspisus delineatus (heckell 843), blicca biorkna (l.) and rhodeus sericeus amarus (bloch 1782). the fishes were caught over one year period (1995-1996) in the mała panew river drainage basin (south poland). in examined fishes the following parasite species were found: dip ...200016886354
variation between populations and local adaptation in acanthocephalan-induced parasite manipulation.many trophically transmitted parasites manipulate their intermediate host phenotype, resulting in higher transmission to the final host. however, it is not known if manipulation is a fixed adaptation of the parasite or a dynamic process upon which selection still acts. in particular, local adaptation has never been tested in manipulating parasites. in this study, using experimental infections between six populations of the acanthocephalan parasite pomphorhynchus laevis and its amphipod host gamm ...201020394670
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