[Age-related dynamics of roach infection rate with Ligula intestinalis (Cestoda: Ligulidae) plerocercoids and probability of its usage for the calculation of host death rate].

Results of special parasitological dissections of roach samples from catches with the same fishing gear and at the same station (Monakhovo Cove, Chivyrkui Bay of the Lake Baikal) and at the same time in different years (1998-2002) are given. Stability of age-related dynamics of roach infection rate with Ligula intestinalisis in different years with the maximum of prevalence and mean abundance in fish of 3+ age, and the following sharp decrease in these rates in elder age groups, was revealed. Basing on prevalence decreasing of a single roach generation, the rate of fish mortality during its growth from age group 3+ to 4+ was estimated as 15.9-20.7%.

[Localization of crustaceans--fish parasites and nose capsules as the habitat of the genus Salmincola (Podoplea: Lernaeopodidae) mesoparasites].

Copepoda parasitica of Baikal fishes (16 species) is divided into 7 groups according to their localization: parasites of the gill apparatus, gill covers, gill and buccal cavities, nasal fossa, cutaneous covering, and fins. It was proposed to separate nasal fossa parasites as the special ecological group ofmesoparasites. Typical speciemens of the group include crustaceans Salmincola longimanus complex--parasites of grayling and cisco fishes consist of three species (S. longimanus, S. svetlanovi, S. lavaretus) and one subspecies (S. longimanus sibirica).

[Dynamics of parasite communities in an age series of Arctic Cisco Coregonus migratorius (Georgi, 1775)].

Parasite communities of Arctic cisco from Chivyrkui Bay of Lake Baikal have been analyzed at levels of a host individual (infracommunity), a individual age group of a host-(assemblages of infracommunities), and a host population (component community). Significant positive correlations of parameters of species richness (number of parasite species, Margalef and Menhinick indices) with the age of Arctic cisco were recorded only at the level of parasite inffacommunities. The absence of linear positive correlations between the parameters of species richness and the age of Arctic cisco at the level of assemblages of parasite infracommunities were revealed for the first time for fish of Lake Baikal. The peculiarity of the dynamics of parasite communities of. Arctic cisco is determined by specific features of the host physiology and ecology, primarily by the age dynamics of the feeding spectrum.

[Variability of myxospores in the myxosporidian genus Henneguya depending on host and geography in the transect "Khubsugul Lake (Mongolia)--Baikal Lake--Laptev Sea (Russia)"].

Analysis of variability and estimation of significance of the differences in morphometric parameters of spores have been carried out for three species of the genus Henneguya (Myxosporidia). Representatives of these species collected both in the same water body (but from different host species) and in geographically distant localities were compared. Thus, we compared samples of Henneguya zschokkei from different host species in Chivyrkui Bay of Baical Lake and in Laptev Sea, and also we compared samples of this species from Baikal Lake with those from Laptev Sea. Materials on Henneguya cerebralis from Baikal Lake were compared with those from Khubsugul Lake; samples of H. cutanea from one host species (Siberian dace) but from water bodies of different type (lake or river) were compared.

[Composition of leucocytes of the head kidney of the crucian carp Carassius auratus gibelio (Cypriniformes: Cyprinidae) as affected by invasion of cestode Digramma interrupta (Cestoda; Pseudophyllidea)].

The composition of leucocytes of the head kidney is studied in the crucian carps (Carassius auratus) either contaminated or uncontaminated with Digramma interrupta. The composition of leucocytes in the pronephros of the crucian carp from Lake Baikal basin has a lymphoid character. Compared to the crucian carp from the European part of Russia, in the fish from Baikal the granulocytopoetic processes are more pronounced. This is proved by the high content of young forms of granulocytes. In the fish infected with digramma, the immune suppression of proliferation of blasts and young forms of eosinophils was revealed. On the other hand, the inflammatory and humoral specific immune reactions are enhanced. Partial suppression of the immune response of C. auratus to invasion by D. interrupta facilitates development of the parasite.

[Baikal whitefish Coregonus baicalensis Dybowski, 1874 parasite communities and host age].

Data on the taxonomic diversity of Baikal whitefish parasites are summarized in the study. Significant correlations of some parasite species' relative abundance and parasite communities' (infracommunities and component communities) parameters with host age were found during the study of parasite distribution in the host's age groups in the Baikal whitefish population from Chivyrkui Bay of Lake Baikal. Study of morphobiological and genetic features which have arisen due to long-term geographic isolation allowed confirming the initial specific independence of lake whitefishes of Lake Baikal as Coregonus baicalensis Dybowski, 1874, i.e., the Baikal whitefish (Sukhanova et al., 2000). The main habitats of this Baikal endemic are Barguzin and Chivyrkui bays, Selenga shallow, and Little Sea strait (Pronin et al., 2007). Local populations from these habitats were previously considered to be independent stocks (Krogius, 1933).

[Parasite fauna and features of the parasite community structure in the minnow Phoxinus phoxinus (Linnaeus) from Yenisei and Kacha rivers].

Phoxinus phoxinus is a species widely distributed throughout Palaearctic and is a good model for investigation of parasite communities. Species composition and structure of parasite communities in the minnow from the streams if different types, namely Yenisei river near Krasnoyarsk City and its left affluent Kacha River, were examined. Indices of Shannon, Simpson, and Berger-Parker were used to describe the component parasite communities. Twenty five parasite species of seven classes were revealed, and ectoparasite were found to be dominating among them. The host-specific parasite species Paratrichodina phoxini (Infusoria), Dactylogyrus borealis (Monogenea), Parahemiurus merus and Diplostomum phoxini (Digenea) constitute the peculiarity of the parasite fauna in minnow. Parasite community of minnow in the Kacha river is the most various one. It is caused by the following factors--favorable temperature conditions, composition of ichthyofauna, and a high density of fish population in the Kacha river. Metacercaria of Diplostomum phoxini, the specific parasites of minnow's brain, are dominating in both streams.

[Morphofunctional characteristics of thymus and immunological parameters in golden hamster under experimental invasion with the cestode Diphyllobothrium dendriticum].

Morphofunctional changes induced by the tapeworm in the thymus and blood of its definitive host, by an example of the experimental model "Diphyllobothrium dendriticum--Mesocricetus auratus", have been investigated. The morphofunctional changes in the thymus and immunological transformations in the organism of infested hamster are evidences of rather high immunogenic effect of the D. dendriticum antigens on the definitive host at the period of active growth of the parasites.

[Hematological and immunological properties of herring gull (Larus argentatus) nestlings experimentally infected with Diphyllobothrium dendriticum (Cestoda: Pseudophyllidae)].

The morphological structure of the blood in herring gull nestlings and their immune system response to experimental infection with tapeworm Diphyllobothrium dendriticum have been studied. The leukocyte reaction pattern and the dynamics of immunoglobulin synthesis and populations of immunocompetent cells in the blood of nestlings during early invasion indicated a short duration of the cellular immune response and an insignificant humoral immune response. A pronounced trend to decrease in the hemoglobin level in the blood of infected nestlings has been revealed and this reduction was in part compensated by intensified erythropoiesis. It is shown, that the changes in hematologic and immune responses of the obligate definitive host provide for the mutual host-parasite adaptation.

[Survival of helminth eggs in the wastewater mud in the sludge beds of Chita waterworks].

The species composition, size, and survival of human and domestic animal helminth eggs was determined in the wastewater mud in the sludge beds of the waterworks of Chita. It was shown that when the wastewater mud was little dried in the sludge beds under distinctly continental climatic conditions for three years, their complete disinvasion did not take place. The eggs of seat-worms (Enterobius vermicularis), whipworms (Trichuris trichiura), broad tapeworms (Diphylobotrium latum), and teniae were undetectable in the mud samples after the second and third year of drying. Surviving Ascaris eggs may develop in the soil to the invasion stage under the climatic conditions of Chita, by creating a risk for new infections.

Dynamics of egg production of the cestode Diphyllobothrium dendriticum (Nitzsch, 1824) (Cestoda: Pseudophyllidea) and the concept of fecundity in helminths.

The dynamics of egg production of the tapeworm D. dendriticum has been estimated experimentally in nestlings of the herring gull Larus argentatus per day and per reproductive period. Numbers of eggs in strobilae have been estimated for the maturation period. Mean egg production, of one tapeworm per day (10.42 +/- 2.72 mln) is two orders of magnitude as high as the maximal number of eggs in a mature strobila (0.206 +/- 0.007). It is proposed to estimate the coefficient of reproduction intensity as the ratio of egg output per unit of time and maximum egg numbers in a mature strobila.

[Finding of the subarctic leeches, Acanthobdella peledina and Cystobranchus mammillatus, in the Lake Baikal basin and the reasons for their absence in Lake Baikal itself]. / Nakhozhdenie subarkticheskikh piiavok Acanthobdella peledina i Cystobranchus mammillatus v basseine ozera Baikal i prichiny otsutstvii ikh v Baikale.

Acanthobdella peledina was first found in the basin of Lake Baikal on the fluvial form of the Balkal grayling Thymallus arcticus baicalensis and Coregonus lavaretus pidschian from the Upper Angara. Cystobranchus mammillatus, a parasite of burbot, is widely distributed in the tributaries of Baikal. The absence of these subarctic leeches from Baikal itself is explained by their rheophily.

[Cytochemical characteristics of the myxosporidian Henneguya cerebralis (Myxosporidia, Myxobolidae) and pathohistological changes in the Kosogol grayling in myxosporidiasis]. / Tsitokhimicheskaia kharakteristika miksosporidii Henneguya cerebralis (Myxosporidia, Myxobolidae) i patogistologicheskie izmeneniia u kosogol'skogo khariusa pri miksosporidoze.

Content and distribution of RNA, protein, DNA, glycogen and carbohydrate components in spores and vegetative sporeforming stages plasmodium of Henneguya cerebralis were described. Pathohistological changes in head tissus of Thymallus arcticus nigrescens are discussed. The conclusion on the relative youth of parasite system "H. cerebralis--Thymallus arcticus nigrescens" is made.

[New species of myxosporidians (Myxosporea: Cnidosporidia) from the oilfishes (Comephorus spp.) of Baikal lake]. / Novye vidy miksosporidii (Myxosporea: Cnidosporidia) ot golomianok (Comephorus ssp.) ozera Baikal.

Two new species of Myxosporidia, Henneguya bayerii sp. n. and Myxobolus korjakovii sp. n. from the kidney of the Comephorus baicalensis (Pallas, 1776) and C. dybowskii Korotneff, 1905 from the Baikal lake are described.

[Ecological and micromorphological aspects of interrelations in myxosporidian--fish parasitic systems]. / Ekologicheskie i mikromorfologicheskie aspekty vzaimootnoshenii v parazitarnykh sistemakh miksosporidii--ryby.

A comparative analysis of the character of interactions in five parasitic systems myxosporidians--fishes (Myxobolus mülleri-Perca fluviatilis, Myxobolus ellipsoides-Phoxinus percnurus, Henneguya zschokkei-Coregonus autumnalis migratoris, Henneguya cerebralis-Thymalus articus nigrescens, Sphaerospora pectinacea-Perca fluviatilis) is given.

[Cestode egg production dynamics and fertility in Diphyllobothrium dendriticum (Cestoda, Pseudophyllidea)]. / Dinamika iaitseproduktsii i plodovitost' tsestody Diphyllobothrium dendriticum (Cestoda, Pseudophyllidea).

Dynamics of egg production of the tapeworm Diphyllobothrium dendriticum has been estimated experimentally in nestlings of the herring gull Larus argentatus per day and per reproductive period. The number of eggs in strobiles has been estimated for the maturation period. Mean egg production of the tapeworm per day (10.43 +/- 2.72 mln) is two orders of magnitude as high as the maximum number of eggs in a mature strobile (0.206 +/- 0.007). It is proposed to estimate coefficient of reproduction intensity as the ratio of egg output per unit of time and maximum egg number in a mature strobile.

[The survival of Diphyllobothrium dendriticum pleurocercoids during the processing of fish and sanitary helminthologic evaluation of the product]. / Vyzhivaemost' plerotserkoidov Diphyllobothrium dendriticum pri pererabotke ryby i sanitarno-gel'mintologicheskaia otsenka produktsii.

Diphyllobothrium dendriticum plerocercoids' survival in salt water solutions of various concentrations and at various temperature was assessed. Conditions of salt treatment and freezing of the Baikal salmon assuring total release of fish from D. dendriticum plerocercoids are determined. The authors suggested differentiation in sanitary helminthological assessment of fish invasion rate by D. latum and D. dendriticum plerocercoids.