Species Of Digenetic Trematodes Research Articles

First record of digenetic trematodes of frogsRana ridibunda ridibunda collected from Kirkuk, Iraq.

In this study which has been done between November 2005 and March 2006, 50 frogs (Rana ridibunda ridibunda ) were collected from Kirkuk governorate (Kirkuk city , Dubis , Taza and Kara injeer ) and examined for digenetic trematodes .Three species of digenetic trematodes Haematoloechus medioplexus , Pleurogenoides medians and Gorgoderina vitelliloba were observed. These species were first recorded in Iraq.

Effect of environmental change on parasites of Atlantic cod (Gadus morhua) as bioindicators of populations in the north-western Atlantic Ocean

Studies conducted in the 1980s suggested that parasites were useful in distinguishing adjacent populations of Atlantic cod Gadus morhua in the north-western Atlantic. During the mid-1980s, cod populations began to decline, culminating in closure of the fishery in 1992. A marked decrease of cod off the coast of Labrador was coincident with climatic shifts, including a decline of bottom sea temperature, and virtual absence of capelin Mallotus villosus, its main food prey. These changes in some components of the ecosystem were independent of anthropogenic influences. An initial survey of cod parasites in 2000 from coastal Labrador revealed a dramatic decline in abundance of metazoans and also a change in dominance of species of digenetic trematodes compared to 1980-1981. Comparison of metazoan parasites in three other populations of cod inhabiting the Grand (northern and southern) and St. Pierre Banks, where there was no apparent evidence of environmental changes but only commercial over-exploitation, revealed no major alterations in abundance or dominance between 1980-1981 and 2003. The results of this current study suggest that environmental changes in the food web affected the abundance of metazoan parasites only off coastal Labrador but did not influence the use of the parasites to distinguish between cod populations inhabiting the Grand or St. Pierre Banks.

PARASITES OF THE STOUT RAZOR CLAM TAGELUS PLEBEIUS (PSAMMOBIIDAE) FROM THE SOUTHWESTERN ATLANTIC OCEAN

This work describes the parasites and their respective pathologies in the stout razor clam, Tagelus plebeius (Lightfoot, 1786) (Psammobiidae) from Argentinean coasts. It represents the first report about a histopathological survey for these species in the Southwestern Atlantic. Specimens of T. plebeius were collected at Mar Chiquita coastal lagoon (37°46′S, 57°27′W) (n = 104 dissected under stereomicroscope, n = 28 histologically sectioned and microscopically examined) and from the mouth of the Quequén Salado River (38°56′S, 60°33′W) (n = 14 dissected under stereomicroscope). Tagelus plebeius was found housing two ciliate species without apparent host reaction and acting as first intermediate host for two digenetic trematode species of the families Fellodistomidae and Gymnophallidae, by hosting sporocysts (mainly in gonad and digestive gland that results in the replacement of host tissues) and as second intermediate host by housing a gymnophallid metacercaria. Likewise, T. plebeius was found parasitized by a larval spirurinae nematode encapsulated by hemocytes. The finding of two ciliate species, the gymnophallid cercaria and metacercaria, and the larval nematode represents the first record for the host. The Southwestern Atlantic populations of this clam seem to be devoid of serious pathogens in the study area.

EFFECTS OF ATRAZINE ON CERCARIAL LONGEVITY, ACTIVITY, AND INFECTIVITY

Susceptibility of free-living infective stages of parasites to contaminants is relatively understudied compared with independent effects on measures of host health or immunity, but may be important in affecting prevalence and intensity of parasite infections. We investigated whether atrazine, an herbicide commonly used in North America, affected the cercariae of 4 different species of digenetic trematodes, and found that effects of atrazine concentration on mortality and activity of cercariae varied among species. Mortality of Echinostoma trivolvis increased in a 200 microg/L atrazine solution, and a species of Alaria showed both decreased activity and increased mortality. We also examined whether the ability of E. trivolvis to infect the second intermediate host, larval amphibians, was compromised by atrazine exposure. Longevity and prevalence of E. trivolvis cercariae was affected at 200 microg/L atrazine, whereas intensity of infection in Rana clamitans tadpoles was reduced at both 20 microg/L and 200 microg/L atrazine. Our results indicate that the viability of cercariae of some species is compromised by exposure to atrazine, emphasizing the importance of considering the influence of contaminants on free-living stages of parasites in addressing how environmental degradation may relate to host parasitism.

DIFFERENCES IN SHELL SHAPE OF NATURALLY INFECTED LYMNAEA STAGNALIS (L.) INDIVIDUALS AS THE EFFECT OF THE ACTIVITY OF DIGENETIC TREMATODE LARVAE

The shells of Lymnaea stagnalis show great morphological variability. This phenomenon has been described as the result of an environmental influence. The main object of the present study was to compare some biometric data from shells of naturally infected and uninfected snails from 25 different lakes in the central part of Poland. The height of the shell, the height of the spiral, and the width of the shell were measured. Some inter- and intrapopulation differences among individuals were found. Greater variability of shell shape was observed among snails parasitized with digenean larvae than in nonparasitized ones. Snails infected with Echinoparyphium aconiatum, Echinostoma revolutum, Diplostomum pseudospathaceum, and Opisthioglyphe ranae differed in shell shape compared with uninfected individuals. Snails infected with Plagiorchis elegans did not differ from uninfected individuals. The same was true of snails in which the commensal oligochaete, Chaetogaster limnei, was found. The results of the present study support the assumption that the deformation of shells of the snails under study was in some way influenced by the presence of certain species of digenetic trematodes.

FIRST REPORT OF PARASITES FROM PINNIPEDS IN THE GALAPAGOS ISLANDS, ECUADOR, WITH A DESCRIPTION OF A NEW SPECIES OF PHILOPHTHALMUS (DIGENEA: PHILOPHTHALMIDAE)

A new species of digenetic trematode and 2 species of ectoparasites from Zalophus wollebaeki Silvertsen, 1953 (Carnivora: Otariidae) in the Galapagos Islands, Ecuador, are reported. These include an eye fluke of Philophthalmus Looss, 1899 (Echinostomata: Philophthalmidae) as well as, to our knowledge, the first report of Antarctophthirus microchir (Trouessart and Neumann, 1888) Enderlein, 1906 (Arthropoda: Anoplura) and Orthohalarachne diminuata (Doetschman, 1944) Newell, 1947 (Arthropoda: Acarina) from this host and location. Philophthalmus zalophi n. sp. differs from the 4 other marine species of Philophthalmus (P. andersoni Dronen and Penner, 1975; P. burrili Howell and Bearup, 1967; P. hegeneri Penner and Fried, 1963; and P. larsoni Penner and Trimble, 1970) by its mammalian host, large body size, lack of tegumental spines, posterior length of seminal vesicle, placement of genital pore, size ratio of oral sucker to acetabulum, shape and size of testes, and size ratio of ovary to testis.

On two new species of the trematode genera, Opisthioparorchis Wang, 1980 and Batrachotrema Dollfus and Williams, 1966 (Batrachotrematidae), wih a report of a Chinese species of Opisthoparorchis from anuran amphibian hosts in India

© Zoo Outreach Organisation; www.zoosprint.org Manuscript 1255; Received 09 September 2004; Finally accepted 23 March 2005; Date of publication 21 May 2005 1883 June 2005 | ISSN 0971-6378 During an exploratory survey of the helminth parasite fauna of anuran Amphibia in Nagaland (India) several digenetic trematode species were encountered. Two of these forms, on study, were found to be new to science and belong each to the genera Batrachotrema Dollfus and Williams, 1966 and Opisthioparorchis Wang, 1980. While the former genus has hitherto been reported from Africa (Dollfus & Williams, 1966), China (Wang, 1981; Zhang & Sha, 1985; Liang & Ke, 1988) and Vietnam (Moravec & Sey, 1989) the latter is represented so far in ranid frogs in China. The present communication deals with the description of a new species of each genus, and also forms the first record of the occurrence of these genera in the Indian subcontinent. The occurrence of O. yunnanse Li, 1996 is also reported from Rana liebigii as a new record.

STUDIES ON SOME PARASITIC FAUNA OF CATTLE EGRET (BUBULCUS IBIS) IN KAFR EL-SHEIKH GOVERNORATE

The present study was carried out to determine the prevalence and description of parasites infecting cattle egret(B. ibis)in Kafr El-Sheikh governorate.Theobtainedresultsshowed that the overall prevalence of theparasiticfaunaamongcattleegretwas87.3%andthemost prevalent species was Nematodes followed by Digenetic trematodes and finally the ectoparasitic one(lice)with their infection rates of 74.64%,67.60% and 42.25%, respectively. Also seven species of parasites (3 species of digenetic trematodes, 3 species of nematodes and one species of lice) were recovered from this study. The recordeddigenetic trematodeswasApharyngostrigeaibis(35.2%),Nephrostomum ramosum (18.3%) and Apatemon gracilis(14.1%), while the recovered nematodes were Synhimantus invaginatus (53.5%), Porrocaecum wui (12.7%) and Heterocheilus sp.(8.5%). The latter species was recorded for the first time in cattle egret, while the detected ectoparasitic one was Menaca-nthus stramineus. The morphological description of the detected parasites was completely studied and discussed.

Phylogenetic analysis of Alloglossidium (Digenea: Macroderoididae) and related genera: life-cycle evolution and taxonomic revision.

A phylogenetic analysis was performed on 13 species of digenetic trematodes in the Macroderoididae, including 10 species of Alloglossidium, 2 species of Alloglossoides, and Hirudicolotrema richardsoni. The evolution of the unusual life-cycle patterns in the group was assessed in light of the proposed phylogeny. The results support previous hypotheses that taxa with a 3-host life cycle involving catfish as definitive hosts are basal to taxa with a 2-host life cycle involving invertebrates such as crustaceans and leeches as definitive hosts. Our results also strongly suggest that species maturing in leeches evolved from an ancestor that matured in crustaceans. Our phylogeny places Alloglossoides and Hirudicolotrema within Alloglossidium, showing Alloglossidium to be paraphyletic. To achieve a natural classification, Alloglossoides and Hirudicolotrema are synonymized with Alloglossidium, and a revised generic diagnosis for Alloglossidium is given.

Metacercárias livres de diplostomídeos (Digenea, Diplostomidae) em Loricariichthys anus (Val., 1840) (Siluriformes, Loricariidae) do estado do Rio Grande do Sul, Brasil

Free (unencysted) metacercariae of an undetermined species of digenetic trematode (Diplostomidae) were found over and in the kidney ducts, over the liver, over the peritoneum, in the abdominal cavity and in the brain, but not in the eyes of mailed catfishes, Loricariichthys anus, captured in the coastal lagoons of Peixoto and Pinguela, Osorio, RS; in the channel linking the lagoons, Imbe, RS, and in the Jacui river, Porto Alegre, RS, southern Brazil. The morphology of the metacercariae is described and pictured. They are differentiated from Diplostomum (A.) compactum and D. (A.) mardox for having an acetabulum, being identified, at present, as an undetermined species of the genus Diplostomum. The metacercariae recorded in the present study are also compared with the strigeatoid metacercariae described parasitizing subtropical fishes in Argentina, looking similar to those metacercariae described as Tylodelphylus cardiophilus from the pericardial cavity of the peixe-rei

A COMPARATIVE STUDY OF MECHANISMS UNDERLYING DIGENEAN–SNAIL SPECIFICITY: IN VITRO INTERACTIONS BETWEEN HEMOCYTES AND DIGENEAN LARVAE

A panel of 4 digenetic trematode species (Echinostoma paraensei, E. trivolvis, Schistosoma mansoni, and Schistosomatium douthitti) and 5 snail species (Biomphalaria glabrata, Helisoma trivolvis, Lymnaea stagnalis, Stagnicola elodes, and Helix aspersa) was examined to determine if known patterns of host specificity could be explained by the tendency of digenean larvae to be bound by snail hemocytes, or by the ability of larvae to influence the spreading behavior of hemocytes. In short-term (1 hr) in vitro adherence assays, there was no overall pattern to suggest that sporocysts were more likely to be bound by hemocytes from incompatible than compatible snails. Compared with the other parasites, sporocysts of E. paraensei were less likely to be bound by hemocytes from any of the snail species tested. All rediae examined, including those of another species Echinoparyphium sp., were also remarkably refractory to binding by hemocytes from any of the snails. Of all the larvae examined, only sporocysts and young daughter rediae of E. paraensei caused hemocytes to round up in their presence. This was true for hemocytes from the compatible species B. glabrata and the incompatible lymnaeid species S. elodes and L. stagnalis. The patterns of host specificity shown by this particular panel of parasites and snails were not predicted by either the extent of hemocyte adherence to digenean larvae or by the ability of larvae to affect hemocyte spreading behavior. The results of this study suggest that a role for hemocytes, although likely, may require different assays, possibly of a more prolonged nature, for its detection. Also, different parasite species (notably E. paraensei) and intramolluscan stages have distinctive interactions with host hemocytes, suggesting that the determinants of specificity vary with the host-parasite combination, and with the parasite life cycle stage.

Cold hardiness in two helminth parasites of the freeze-tolerant wood frog, Rana sylvatica

Wood frogs, Rana sylvatica, tolerate the freezing of their body tissues as an overwintering adaptation. Various parasites infect wood frogs of northern populations, but nothing is known about their strategies for surviving within a frozen host. We examined winter-conditioned wood frogs that were experimentally exposed to 0°C (nonfrozen) or –4°C (frozen) to determine whether endoparasites survive the freezing of their host. We found no differences in the prevalence or intensity of adult lungworms Rhabdias ranae (Nematoda) or of larvae of an unidentified species of digenetic trematode between these groups. Live individuals of both species were observed in hosts that recovered from experimental freezing at –4°C. Within the host, R. ranae also tolerated exposure to –5°C, a temperature near the lower limit of survival of the wood frog. Cryostage experiments showed that, like its host, R. ranae was highly susceptible to inoculative freezing and tolerant of the freezing of its tissues. Rhabdias ranae frozen in vitro in the presence or absence of 250 mM glucose, the cryoprotectant used by wood frogs, recovered from a 10-h exposure to –4°C. The mechanism of cold tolerance used by larval trematodes was not investigated; however, we hypothesize that freeze avoidance by supercooling may be important in this species. Freeze-tolerant anurans, such as the wood frog, are useful subjects in the study of coevolution of thermal tolerance in parasites and their host.

Cold hardiness in two helminth parasites of the freeze-tolerant wood frog, <i>Rana sylvatica</i>

Wood frogs, Rana sylvatica, tolerate the freezing of their body tissues as an overwintering adaptation. Various parasites infect wood frogs of northern populations, but nothing is known about their strategies for surviving within a frozen host. We examined winter-conditioned wood frogs that were experimentally exposed to 0°C (nonfrozen) or –4°C (frozen) to determine whether endoparasites survive the freezing of their host. We found no differences in the prevalence or intensity of adult lungworms Rhabdias ranae (Nematoda) or of larvae of an unidentified species of digenetic trematode between these groups. Live individuals of both species were observed in hosts that recovered from experimental freezing at –4°C. Within the host, R. ranae also tolerated exposure to –5°C, a temperature near the lower limit of survival of the wood frog. Cryostage experiments showed that, like its host, R. ranae was highly susceptible to inoculative freezing and tolerant of the freezing of its tissues. Rhabdias ranae frozen in v...

Parasitism and invasive species:effects of digenetic trematodes on mussels

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 169:149-163 (1998) - doi:10.3354/meps169149 Parasitism and invasive species: effects of digenetic trematodes on mussels G. Calvo-Ugarteburu, C. D. McQuaid* Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa *Addressee for correspondence. E-mail: zocm@hippo.ru.ac.za ABSTRACT: The brown mussel Perna perna in South Africa is threatened by the introduction of the invasive Mediterranean mussel Mytilus galloprovincialis. Whilst the indigenous P. perna has been found to be commonly infected by digenetic trematodes, the invasive M. galloprovincialis is free of trematodes, which may give it a competitive advantage in direct or indirect interactions between the 2 mussels. The most common parasites infecting P. perna are 2 species of digenetic trematodes: metacercariae of the genus Proctoeces and bucephalid sporocysts. The influence of these 2 parasites on the ecological fitness of their host was tested by examining their effects on survival and competitive ability of P. perna. The results showed significant negative effects. Both parasites significantly depressed condition, but only after spawning, when the mussels were already stressed. Neither parasite affected mortality rate or gaping behaviour of P. perna exposed to air. Proctoeces did not affect the force required to open mussels or the amount of water lost by mussels in air. In contrast, mussels infected with bucephalid sporocysts were easier to open and lost significantly more water than non-infected individuals, possibly because their valves did not seal properly. There were no significant differences in either number or size of oocytes in females infected with Proctoeces compared with non-infected females. However, bucephalid sporocysts had a dramatic effect on reproduction by castrating the host. Proctoeces reduced growth both in summer and in winter, whilst bucephalid sporocysts had no significant effect on growth. Neither parasite had a significant effect on filtration rates or oxygen consumption of the host. All these results indicate that both Proctoeces and the bucephalid sporocysts have detrimental effects on P. perna. Proctoeces affects primarily growth, while bucephalid sporocysts affect reproduction, adductor muscle strength and water loss. The effects of both parasites are concentrated on those size classes of mussel which channel most energy into the portion of the energy budget affected by the parasite. Proctoeces affects growth only in the smaller individuals, which in normal conditions would put most energy into growth; bucephalid sporocysts castrate the bigger mussels, which would expend most energy on reproduction. In energetic terms, the absence of effects on filtration and respiration indicates that there was neither re-allocation nor compensation for the energy lost from production, but that it was simply re-routed to the parasite. These negative effects, together with the high prevalence of both parasites in P. perna along the South African coast and their absence in M. galloprovincialis, suggest that lack of these parasites may contribute to the success of M. galloprovincialis. KEY WORDS: Mussels · Invasive · Indigenous · Trematodes · Ecological fitness · Condition · Water loss · Survival · Adductor muscle strength · Reproduction · Growth · Filtration · Respiration Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 169. Publication date: August 06, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.

Helminth parasite communities of kangaroos and wallabies (Macropus spp. and Wallabia bicolor) from north and central Queensland

The occurrence of gastrointestinal helminth parasites in 40 Macropus agilis, 12 M. antilopinus, 39 M. dorsalis, 28 M. giganteus, 29 M. parryi, 30 M. robustus and 26 Wallabia bicolor from north and central Queensland was examined. A total of 124 morphologically defined species of helminth was encountered, comprising 103 species of strongyloid nematodes, 6 species of trichostrongyloid nematodes, 2 species of spiruroid nematodes, 4 species of oxyuroid nematodes, 7 species of anoplocephalid cestodes and 2 species of digenetic trematodes. Helminth communities in each macropodid host species exhibited a high level of diversity, and were dominated numerically by strongyloid nematodes. A high proportion of the helminth species was restricted to a single host species and there was a low level of similarity between helminth communities in different host species. Similarities that did occur were not apparently related to the phylogenetic relationships between hosts and are best explained by host switching between hosts sharing overlapping habitats and feeding preferences. There was poor separation of the helminth species into ‘core’, ‘secondary’ and ‘satellite’ members of communities.

Intra- and interspecific pairing of rediae and sporocysts of five species of digenetic trematodes

AbstractIn vitro pairing studies on rediae of Echinostoma trivolvis, E. caproni, Zygocotyle lunata, Ribeiroia sp. and sporocysts from a species of armatae cercaria were undertaken at 22°C in a Petri dish bioassay containing an agar substratum and a Locke's 1:1 overlay. Pairing was arbitrarily defined as larvae in contact or within 1 mm of each other. Intraspecific and interspecific pairing occurred in the bioassay using several larval combinations initially placed 5 or 10 mm apart. Intraspecific pairing occurred with the rediae of Ribeiroia sp. and interspecific pairing was seen between E. trivolvis or E. caproni and Ribeiroia sp. A previous study documented intraspecific and interspecific pairing between rediae of E. trivolvis and E. caproni. Armatae sporocysts did not pair intraspecifically or interspecifically when matched with either E. caproni or E. trivolvis rediae. Intraspecific pairing of Z. lunata or interspecific pairing between Z. lunata rediae and echinostome rediae did not occur. The significance of redial pairing remains unclear.

Parasitism of Gobius bucchichii Steindachner, 1870 (Teleostei, Gobiidae) in protected and unprotected marine environments.

We collected 396 Gobius bucchichii, Steindachner, 1870 (Teleostei, Gobiidae) in and around the marine reserve of Cerbère-Banyuls, in the southeast of France, between March and July 1994. Five species of adult parasites were found: one acanthocephalan, Acanthocephaloides propinquus Dujardin, 1845 (Acanthocephala, Arhythmacanthidae); one nematode, Cucullanus sp. (Nematoda, Cucullanidae); and three species of digenetic trematodes, Helicometra sp. (Digenea, Opecoelidae), Derogenes sp. (Digenea, Hemiuridae) and Deretrema scorpaenicola Bartoli, 1990 (Digenea, Zoogonidae). Fishes collected in a protected area were on average, larger, older, had a higher percentage of regenerated scales, and harbored more parasites.

Parasites, Morphology, and Habitat Use in a Bluegill Sunfish (Lepomis macrochirus) Population

In some lakes, bluegill sunfish (Lepomis macrochirus, family Centrarchidae) captured from the open water and littoral zone are morphologically and behaviorally specialized for foraging in their respective habitats. Here, we examine the degree to which individuals move between habitats of a single lake by using parasites as an indicator of long-term habitat use. Fish captured from the open water and littoral zone of Holcomb Lake, Michigan, were morphologically different, confirming the results of an earlier study. Twelve parasite species infected bluegill from the littoral zone whereas seven species infected fish from the open water. Two digenetic trematode species (Neascus sp. and Posthodiplostomum minimum) that utilize snails as intermediate hosts were over five times more abundant in littoral-zone fish than in open-water fish, whereas one cestode species (Proteocephalus ambloplitis) that utilizes copepods as intermediate hosts was almost twice as abundant in open-water fish than in littoral-zone fish. Within habitats, there was no relationship between morphology and parasite abundance. Our results suggest that most fish (including those with intermediate morphology) commit themselves to one habitat or the other and that open-water specialists seldom visit the littoral zone.

Stephanostomum lophii sp. nov. (Digenea: Acanthocolpidae), intestinal parasite of Lophius piscatorius, with reference to seasonal fluctuations of metacercariae in intermediate second hosts (Gadidae)

We describe the adult and metacercaria of a new species of digenetic trematode, Stephanostomum lophii sp. nov., an intestinal parasite of the angler fish, Lophius piscatorius. The species is distinguished from the similar Stephanostomum kovalevi by the numerous peristomial spines in the latter and from S. baccatum by the oral sucker being larger than the ventral sucker and by the fact that the principal intermediate hosts are gadids, not pleuronectids as in the case of Stephanostomum baccatum. We also report the prevalence of S. lophii metacercariae in various potential angler fish prey species caught off the coast of Galicia (NW Spain).

Trématodes parasites de poissons marins du littoral de Rio de Janeiro, Brésil

Les Trématodes de 35 espèces de poissons marins, d'importance commerciale, collectés dans le littoral de Rio de Janeiro, ont été étudiés. Dix-sept espèces de Trématodes appartenant à 13 familles ont été recensées. Quatre de ces espèces sont référés pour la première fois au Brésil: Diphtherostomum americanum, Diplomonorchis floridensis, Pancreadium otagoensis et Neomegasolena chaetodipteri, neuf dans de nouveaux hôtes: D. americanum, Diplangus paxillus, Hurleytrema shorti, Lecithochirium microstomum, Morascus filiformis, Neolebouria multilobatus, P. otagoensis, Pleorchis mollis et Opechona bacillaris, une a été recontrée dans un hôte mentionné pour la première fois au Brésil: Vitellibaculum spinosum et cinq autres espècies sont déjà répertoriées: Acanthocollaritrema umbilicatum, Bucephalopsis calliocotyle, Bucephalus varicus, Parahemiurus merus et Tergestia pauca. Tergestia selenei est consideré synonyme de T. pauca. Les principales mesures sont données pour chaque espèce.