Serotonergic elements in the nervous system of parasite of acipenserid fishes, Acrolichanus auriculatus (Digenea: Allocreadiidae).

The trematode Acrolichanus auriculatus is a widely distributed intestine parasite of acipenserid fishes. For the first time the localization and distribution of the serotonergic nerve elements in A. auriculatus was studied using immunocytochemical method and confocal laser scanning microscopy. The study revealed the presence of biogenic amine, serotonin, in the central and peripheral nervous systems of A. auriculatus, that is in the neurons and neurites of the brain ganglia, brain commissure, the longitudinal nerve cords, and the connective nerve commissures. The innervation of the attachment organs, pharynx, oesophagus and distal regions of the reproductive system by the serotonergic nerve elements is observed. The distribution of serotonergic neurons in A. auriculatus is schematically marked. The comparative analysis of findings obtained in A. auriculatus with those recorded for other digeneans reveals the presence of both conservative and distinctive features in the organization of the serotonergic nervous system in various representatives of trematodes.

Neuromuscular system of the causative agent of dicrocoeliosis, Dicrocoelium lanceatum. II. Neuropeptide FMRFamide immunoreactivity in nervous system.

The parasitic flatworm, trematoda Dicrocoelium lanceatum or lancet fluke is the causative agent of a widespread parasite disease of grazing ruminants, dicrocoeliosis. The aim of this work is the study of the presence and localization of neuropeptide FMRFamide immunoreactive elements in the nervous system of D. lanceatum using immunocytochemical technique and confocal scanning laser microscopy. For the first time the data on the presence and distribution of the FMRFamide-immunopositive components in the central and peripheral departments of the nervous system of D. lanceatum has been obtained. FMRFamidergic neurons and neurites were identified in paired brain ganglia, in the brain commissure, longitudinal nerve cords and connective nerve commissures. The innervation of the oral and ventral suckers by peptidergic nerve structures was revealed. The distal part of the reproductive system is innervated by FMRFamide immunopositive neurites. The data obtained suggest that the neuropeptides of FMRFamide family can be involved in the regulation of functions of the attachment organs and the reproductive system in D. lanceatum. The study of neurotransmitters and their functions in flatworms expand our knowledge on the structure and function of the nervous system of trematodes of various taxonomic groups. The results obtained on the morphological organization of D. lanceatum nervous system support the exploitation of the FMRFamidergic components as an anthelmintic target.

Musculature and neurotransmitters of internal organs of trematodes (the digestive, reproductive and excretory systems).

The article analyzes the results on the presence and organization of the muscle elements in the visceral organs of parasitic flatworms, trematodes, as well as their innervations. The different regions of the digestive, reproductive and excretory systems of trematodes contain circular, longitudinal and diagonal muscle fibers. The results of immunocytochemical investigations and confocal scanning laser microscopy show the presence of serotonin and FMRFamide-like immunoreactivity in the nervous system elements in various parts of the digestive, reproductive and excretory systems of trematodes. The data suggest that serotonergic and FMRFamide-immunopositive components of parasite's nervous system are involved in the regulation of the muscle activity of the digestive, reproductive and excretory systems. Comparative analysis of the results presented for trematodes from different taxonomic groups indicates that the organization of muscle elements in the visceral organs in trematodes and their innervation by serotonergic and peptidergic components are highly conserved.

Biodiversity of lung helminths in terrestrial mammals from Eastern Europe.

This review provides the results of many years of original studies of the authors published in different journals and compilations taking into account an analysis of literature data. The studies on biological diversity of lung helminths of terrestrial mammals were performed by the authors in Armenia, Bulgaria and Poland. Literature data on European Russia were also taken into account. Sixteen animal species from the families Cervidae (six species), Bovidae (nine species) and Leporidae (one species) were investigated. In these animal taxons 27 helminth species from the families Dictyocaulidae (five species), Protostrongylidae (20 species), and Taeniidae (two species) have been found. Lung nematodes Muellerius capillaris and Protostrongylus hobmaieri, as well as zoonotic parasite E. granulosus were found to be common for all the countries studied. Also, relatively many species appeared common between several studied regions. Taking into account morphology, ecology and life cycles, we support a validity of genera Echinococcus and Alveococcus in the structure of the subfamily Echinococcinae of family Taeniidae.

The neuroactive substances and associated muscle system in Rhipidocotyle campanula (Digenea, Bucephalidae) from the intestine of the pike Esox lucius.

We report about the muscular system and the serotonergic and FMRFamidergic components of the nervous system of the Bucephalidae trematode, Rhipidocotyle campanula, an intestinal parasite of the pike. We use immunocytochemical methods and confocal scanning laser microscopy (CLSM). The musculature is identified by histochemical staining with fluorescently labeled phalloidin. The body wall musculature of R. campanula contains three layers of muscle fibres - the outer thin circular, intermediate longitudinal and inner diagonal muscle fibres running in two opposite directions. The digestive system of R. campanula possess of a well-developed musculature: radial, longitudinal and circular muscle elements are detected in the pharynx, circular and longitudinal muscle filaments seen in the oesophagus, and longitudinal and the circular muscle fibres were found in the intestinal wall. Specific staining indicating the presence of actin muscle filaments occurs in the cirrus sac localized in the posterior body region. The frontal region of anterior attachment organ, the rhynchus, in R. campanula is represented by radial muscle fibres. The posterior part of the rhynchus comprise of radial muscles forming the organ's wall, and several strong longitudinal muscle bundles. Serotonergic and FMRFamidergic structures are detected in the central and peripheral compartments of the nervous system of R. campanula, that is, in the paired brain ganglia, the brain commissure, the longitudinal nerve cords, and connective nerve commissures. The innervations of the rhynchus, pharynx, oesophagus and distal regions of the reproductive system by the serotonergic and FMRFamidergic nervous elements are revealed. We compare our findings obtained on R. campanula with related data for other trematodes.

Nematodes of birds of Armenia.

The review provides data on species composition of nematodes in 50 species of birds from Armenia (South of Lesser Caucasus). Most of the studied birds belong to Passeriformes and Charadriiformes orders. One of the studied species of birds (Larus armenicus) is an endemic. The taxonomy and host-specificity of nematodes reported in original papers are discussed with a regard to current knowledge about this point. In total, 52 nematode species parasitizing birds in Armenia are reported. Most of the reported species of nematodes are quite common in birds outside of Armenia. One species (Desmidocercella incognita from great cormorant) was first identified in Armenia. Great snipe was recorded as a new host for Hystrichis tricolor. Zoonotic nematode Trichinella pseudospiralis was reported in Armenia from Eurasian blackbird.

Species diversity of nematodes in domestic and wild ruminants of Armenia

The review provides data on species composition of nematode parasites of cattle, sheep, goats and wild ruminants (Ovis orientalis gmelini, Capreolus capreolus, Capra aegagrus aegagrus) of Armenia. Six species of lung nematodes and 22 species of gastrointestinal ones have been registered in ruminants of Armenia. Five of the species listed in the review (Protostrongylus davtiani, Protostrongylus muraschkinzewi, Nematodirus davtiani, Trichostrongylus andreevi, Trichostrongylus skrjabini) have been first identified in Armenia. The ruminant host species most studied for this territory is a domestic sheep. Data on nematodes of goats and wild ruminants are limited to sporadic reports. Data on nematodes of cattle are limited to the only one species ­ Neoascaris vitulorum. Most of the nematode species found in Armenia are common for all ruminant host species living here and noted as widespread all over the world. Eight species of nematodes detected in ruminants of Armenia able to infect humans. The taxonomy of some rare species of nematodes reported from ruminants in Armenia is not entirely clear and should be re-evaluated basing on thorough studies.

Nematodes of rodents of Armenia

This review summarizes known data on the species composition of nematodes in 24 species of rodents inhabiting the territory of Armenia (South of Lesser Caucasus). The studied rodents include members of some cosmopolitan species (Mus musculus, Rattus norvegicus, Rattus rattus), as well as endemic and narrow-areal species (Meriones vinogradovi, Spermophilus xanthoprymnus, Microtus schidlovskii, Mesocricetus brandti, Sciurus anomalus). The taxonomical identity of the nematode species reported by previous authors is discussed with regard to present knowledge about helminth fauna of rodents. Our review concludes that 34 nematode species are present in rodents in Armenia, five of which are identified for the first time in rodents from the territory of Armenia, and three of which (Trichinella spiralis, Trichostrongylus colubriformis, Trichostrongylus skrjabini) are able to parasitize humans.