Parasites of Gymnodactylus darwinii Gray, 1845 (Squamata, Phyllodactylidae) from an Atlantic Rainforest fragment.

Gymnodactylus darwinii is an endemic lizard from Atlantic Rainforest. Ecological aspects of your parasitic fauna are still unknown. Therefore, the goal of the present study was to know the composition of parasitic fauna of G. darwinii in an Atlantic Rainforest fragment, as well to test the influence of the size, sex and seasonality on parasitological indices. The study was carried out in two conservation units: Mata do Camucim and Mata do Tapacurá, both located in the municipality of São Lourenço da Mata, Pernambuco state, northeast region of Brazil. Sixty-five specimens were collected, of which 39 (569%) were parasitized by cystacanths of Acanthocephala (prevalence 43%; mean intensity 4 ± 9.9; mean abundance 3.82 ± 7.87), Geckobia sp. (Acari, Pterygosomatidae) (prevalence 30.7%; mean intensity 4 ± 15.0; mean abundance 3.74 ± 9.54), Physaloptera sp. larvae (Nematoda, Physalopteridae) (prevalence 4.6%; mean intensity 1 ± 0.47; mean abundance 0.06 ± 0.47) and Paradistomum rabusculum (Trematoda, Dicrocoeliidae) (prevalence 1.2%; mean intensity 1; mean abundance 0.02). Acanthocephalans presented a significant relation with the animal length (r² = 0.31, p = 0.006, n = 28). Infestation by Geckobia sp. was more frequent during the dry season (BLM: p = 0.001), while the infection by Acanthocephalans was frequent in dry and rainy seasons, with no significant variation (BLM: p = 0.78). In addition, the most prevalent parasites showed no significant difference in relation to sex: males and females showed similar infestation intensity by Geckobia sp. (BLM: p = 0.31) and infection by Acanthocephala (BLM: p = 0.34). This is the first study about the parasitic ecology of G. darwinii, representing a significant contribution to the conservation of this species and the ecosystem in which they inhabit.

Pathological and parasitological characterization of Prosthenorchis elegans in a free-ranging marmoset Callithrix geofroyi from the Brazilian Atlantic Forest / Caracterização patológica e parasitológica de Prosthenorchis elegans em Callithrix geoffroyi primate de vida livre da Mata Atlântica

Prosthenorchis elegans is an acanthocephalan intestinal parasite reported in neotropical primates. Despite parasitism by P. elegans having already been described in wild marmosets in the Brazilian Atlantic Forest, there are no reports of this infection in wild Geoffroy's marmoset (Callithrix geofroyi). The aim of this study is to report one case of P. elegans parasitism in a free-ranging C. geoffroyi from Brazilian Atlantic Forest in Espírito Santo state, and characterize the pathological and parasitological findings of this infection. One Geoffroy's marmoset necropsied at the Vila Velha University's Veterinary Pathology Laboratory presented intense chronic transmural ulcerative enteritis associated with twenty cylindrical helminths present in the jejunum and ileum. We can conclude that parasitism by P. elegans occurs in free-ranging groups of Geoffroy's marmosets. Its infection produced severe intestinal lesions even in free-ranging marmoset and therefore is a threat to this animal's survival in wildlife and can have some impact on primate conservation in the Brazilian Atlantic Forest.(AU)

Prosthenorchis elegans é um acantocéfalo intestinal descrito em primatas neotropicais. Apesar do parasitismo por P. elegans já ter sido descrito de saguis da Mata Atlântica brasileira, não há relatos da infecção em saguis-da-cara-branca (Callithrix geofroyi) de vida livre. O objetivo deste estudo é relatar um caso de parasitismo por P. elegans em um C. geoffroyi de vida livre proveniente da Mata Atlântica brasileira no Estado do Espírito Santo e caracterizar os achados patológicos e parasitológicos dessa infecção. Um sagui-da-cara-branca foi necropsiado no Laboratório de Patologia Veterinária da Universidade de Vila Velha, onde foi observada intensa enterite ulcerativa transmural crônica associada a vinte helmintos cilíndricos presentes no jejuno e íleo. Conclui-se que o parasitismo por P. elegans ocorre em grupos livres de saguis-da-cara-branca e a sua infecção leva a lesões intestinais graves; portanto, este parasita pode prejudicar a sobrevivência deste animal na vida selvagem e pode ter algum impacto na conservação de primatas na Mata Atlântica brasileira.(AU)

Transcriptome data reveal Syndermatan relationships and suggest the evolution of endoparasitism in Acanthocephala via an epizoic stage.

The taxon Syndermata comprises the biologically interesting wheel animals ("Rotifera": Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparasitism. Here, we report the first phylogenomic analysis that includes all four higher-ranked groups of Syndermata. The analyzed data sets comprise new transcriptome data for Seison spec. (Seisonidea), Brachionus manjavacas (Monogononta), Adineta vaga (Bdelloidea), and Paratenuisentis ambiguus (Acanthocephala). Maximum likelihood and Bayesian trees for a total of 19 metazoan species were reconstructed from up to 410 functionally diverse proteins. The results unanimously place Monogononta basally within Syndermata, and Bdelloidea appear as the sister group to a clade comprising epizoic Seisonidea and endoparasitic Acanthocephala. Our results support monophyly of Syndermata, Hemirotifera (Bdelloidea + Seisonidea + Acanthocephala), and Pararotatoria (Seisonidea + Acanthocephala), rejecting monophyly of traditional Rotifera and Eurotatoria. This serves as an indication that early acanthocephalans lived epizoically or as ectoparasites on arthropods, before their complex lifecycle with arthropod intermediate and vertebrate definite hosts evolved.

Acetylcholinesterase activity in the host-parasite system of the cod Gadus morhua and acanthocephalan Echinorhynchus gadi from the southern Baltic Sea.

Acetylcholinesterase (AChE) activity measurement is widely used as a specific biomarker of neurotoxic effects. The aim of this study was to evaluate AChE activity in a host fish (the cod) and its acanthocephalan parasite Echinorhynchus gadi from the southern Baltic. AChE activity in hosts and parasites was inversely related: the highest cod AChE activity corresponded to the lowest E. gadi enzymatic activity and vice versa ("mirror effect"). This is the first report on the simultaneous application of this biomarker in cod and its acanthocephalan parasites. Results obtained for the host-parasite system are complementary and provide comprehensive information about the response of this biomarker. Analysis of the system allows for detection of a greater number of factors influencing AChE activity in the marine environment than separate analysis of the host and parasites. Thus, AChE activity measurement in a host-parasite system may be considered to be a promising tool for biomonitoring.

Parasite effects on isopod feeding rates can alter the host's functional role in a natural stream ecosystem.

Changes to host behaviour as a consequence of infection are common in many parasite-host associations, but their effects on the functional role hosts play within ecosystems are rarely quantified. This study reports that helminth parasites significantly decrease consumption of detritus by their isopod hosts in laboratory experiments. Natural host and parasite densities across eight contiguous seasons were used to estimate effects on the amount of stream detritus-energy processed. Extrapolations using mass-specific processing rates from laboratory results to field patterns suggest that the effects of the parasites occur year round but the greatest impact on the amount of detritus processed by isopods occurs in the autumn when the bulk of leaf detritus enters the stream, and when parasite prevalence in the isopod population is high. Parasites have a lesser impact on the amount of detritus processed in spring and summer when isopods are most abundant, when parasite prevalence is not high, and when fish predation on isopods is high. These results support the idea that parasites can affect the availability of resources critical to other species by altering behaviours related to the functional role hosts play in ecosystems, and suggest that seasonality may be an important factor to consider in the dynamics of these parasite-host interactions.

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, 1776) was recorded in 15 amphipods. Tapeworms were localized in the anterior portion of each amphipod's hemocoel, in intimate contact with E. stammeri internal organs such as the alimentary canal, and frequently induced its displacement. No differences in integumental pigmentation were noticed between infected and non-infected amphipods, and some infected E. stammeri females were ovigerous.

Infección humana con Falsifilicollis Sphaerocephalus (Acanthocephala) en Trujillo, Perú / Human infection with Falsifilicollis Sphacrocephalus (Acanthocephala) in Trujillo city, Peru

En el curso de 20 años (1963-1983) se colectó cuatro especímenes de Acanthocephala Rudolphi, 1808; dos de heces humanas y dos del intestino de pacientes sometidos a intervenciones quirúrgicas en el hospital Regional de Trujillo-Perú. Los referidos acantocéfalos fueron identificados como Falsifilicollis sphaerocephalus (Bremser. 1821) parásito normal de aves, que ocurrentemente se registra por primera vez en el hombre

Parasitological study of a population of Tiber River eels (Anguilla anguilla).

A study was conducted on the parasitofauna of Anguilla anguilla caught in the section of the Tiber river south of Rome (Italy). The sample examined consisted of 417 specimens that were classified by stage (elver, young yellow eel, yellow eel and silver eel) and season of sampling. The following species were identified: Trypanosoma granulosum, Eimeria anguillae, Myxidium giardi, Sphaerospora reichenowi, Myxobolus sp., Trichodina anguilli, Ichthyohodo sp., Gyrodactylus anguillae, Bothriocephalus claviceps, Proteocephalus macrocephalus, Raphidascaris acus, Acanthocephalus clavula. Each parasite species was considered in its prevalence according to stage and season. For some parasite the pathogenic effect was also examined in a histological study of serial sections. The results of the statistical analysis of the single parasitic infection as related to different seasons pointed to marked seasonal trends only in some species (Trypanosoma granulosum and Gyrodactylus anguillae). The intensity of infection assessed for acanthocephalan infection only was found to affect neither weight nor condition index (weight/length3). No difference in weight or condition index was found to be ascribable to the presence or absence of a species. An attempt to find a rule-of-thumb algorithm to gauge the overall effect to parasitic diseases failed to give sufficiently significant results.

[Morphological variability of thorny-headed worms of the genus Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) that parasitize fishes of the Arctic Ocean province in the boundaries of the USSR]. / Morfologicheskaia izmenchivost' skrebnei roda Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae), parazitiruiushchikh u ryb Ledovitomorskoi provintsii v predelakh SSSR.

Study of the morphology of 602 specimens of N. rutili (Müller, 1780) and N. crassus Van Cleave, 1919 collected in 10 species of fishes from waterbodies of the Kola Peninsular, the Ob, Yenisei, Lena, Kolyma and Chauna rivers has shown that all absolute specific characters considered (13 in female and 17 in male) have a considerable range of variations due to the modificational individual and age variability. Differences have been revealed in morphometric indexes of some characters in members of the European and Siberian populations of N. rutili that is due to a geographic variability of the species. It has been established that most constant characters of all species studied are the length of the proboscis and its hooks.

[Proboscis worm, Echinorhynchus gadi (Zoega) from a relict cod of Lake Mogil'noye]. / Skreben' Echinorhynchus gadi (Zoega) iz repliktovoi treski ozera Mogil'noe.

Data on the extensiveness and intensity of infection of Kildin island cod with Echinorhynchus gadi in various seasons are given. E. gadi was proved to have a one-year life cycle and Gammarus duebeni as an intermediate host in the lake. A change of the parasite generations occurs in late summer--autumn. A high extensiveness (100%) and intensity of Kildin cod infection with E. gadi depends on the feeding habits (monophagy) and narrow distribution range of the host. Infection intensity is directly correlated with the fish age. Selfregulation of the parasite quantity in the host's intenstine is an important factor affecting the existence of E. gadi population in Lake Mogilnoye.