Parazitologiia最新文献

The analysis of taxonomical and ecological diversity of acanthocephalans in fishes ofAsiatic sub-Arctic region freshwaters, summarizing changes in modern views on speciescomposition, life cycles, and ecology of background groups of these parasites is given.A priority role of studies provided by O. N. Bauer and his scientific school in organizationand development of these aspects of acanthocephalology is demonstrated. Special attentionis paid to the assessment of acanthocephalan biodiversity of the genus Neoechinorhynchus,the background group of freshwater fish parasites of the Asiatic sub-Arctic region,and an original key for their species is given. The distribution of acanthocephalans of thegenus Acanthocephalus in northeastern Asia is analyzed and prospective study of this parasitegroup, evolutionary associated with freshwater isopods of the genus Asellus as intermediatehosts, is outlined. The absence of documented evidences on intermediate hosts ofother background parasites of freshwater fishes in the region, acanthocephalans of the genusMetechinorhynchus, is revealed. It is assumed that subsequent taxonomic revisions basedboth on morphological and molecular genetic studies are necessary for the reliable revealingof species composition in each genus of the background acanthocephalans fromfreshwater fishes of Northern Asia. Theoretical significance of the study of acanthocephalanlife cycles and revealing their natural intermediate hosts for the reliable estimation ofstructural and functional organization of their host-parasite systems in different parts ofthe range is substantiated and the possibility of the distribution of taxonomic conclusionsin new territories is analyzed. A brief annotated taxonomical list of freshwater acanthocephalansof the Asiatic sub-Arctic region is given.

The native population of the Arctic char in the Lake Mushtalampi was studied. The dwarf form of the Arctic char inhabiting the lake was revealed. The fish is characterized by extremely low growth rate and by early maturation. Twelve parasite species were found in the arctic char. The parasite fauna is typical of representatives of Salmonidae. Distinguishing features of this fauna include the absence of narrowly specialized char parasite species. High intensity of infection with nematodes Philonema oncorhynchi allows estimating the epizootic state of the studied char population as insufficient.

The spatial structure and seasonal aspects in the number distribution of the cestodeProteocephalus longicollis population, maintained by trophic connections of specializedplankton-feeders (the vendace Coregonus albula L. and the smelt Osmerus eperlanus L.)in the Lake Onego were studied. Differences in the distribution of number of cestode populationin host population, size-age structure, and pre-reproductive/reproductive stagesratio of the studied parasites were revealed. It was demonstrated that the spatial structureof P. longicollis was shaped by the specific characteristics of vendace and smelt populationsin the Lake Onego. These species possess partially overlapping ecological niches anddifferences in the use of food resources, significantly determining the infection dynamicsof the examined fish species.

The material was collected according to commonly accepted methods in 1992—2013from the following sites: the Lake Krivoye (Kolguev Island); Volonga, Schapkina, Kolva,More-Yu, Vorkuta, Kara, and Khalmer-Yu Rivers; Lakes Nikaramata (the Kara River basin)and Mercempertato (Yamal Peninsula). A total of 436 of the minnow Phoxinus phoxinuswith age 1+—3+ were examined. In the examined water bodies, excluding the KolvaRiver, the parasite fauna of the minnow is impoverished, and, to a greater extent, possessesan occasional character. In rivers Kolpina and Shapkina Rivers, component communitiesof minnow parasites are mature (balanced, according to Pugachev, 1999). These minnowparasite communities consist of three groups of species separated according to the ratio oftheir biomasses. In More-Yu, Vorkuta, Kara, and Khalmer-Yu Rivers, and in Lakes Nikaramata,and probably, Mercempertato, parasite communities are immature (unbalanced).These minnow parasite communities consist of 1—3 groups of species separated accordingthe ratio of their biomass. Characteristics of communities from the Volonga Riverneed clarification. Associations between the state of the described minnow parasite communitiesand their geological age (Quaternary history) are traced.324

Metacercarial development of most Diplostomum species including D. pseudospathaceumoccurs in the eye lenses of their fish hosts and is accompanied by radical morphologicalchanges often referred to as metamorphosis. One of the structures undergoing substantialchanges in D. pseudospathacewn are tegumental spines. The present study used phalloidinstaining and confocal microscopy to examine these changes in D. pseudospathaceumover the course of development from 3-day-old to infective metacercariae. Although thegeneral pattern of spination remained essentially unchanged, most larval spines continuedgrowing in size until late in metacercarial development. From day 10 of development, larvalspination was gradually replaced by small incipient definitive spines and the infectivemetacercariae had only definitive spination. The possible adaptive role of spines in developingmetacercariae is discussed.

Infestation of bee colonies and apiaries by representatives of the genus Nosema, microsporidian protozoans of European honeybees (Apis mellifera L.), causing nosemosis, in Tomsk Province was investigated. In 2012—2015, nosemosis was detected in 32 out of 124 honeybee colonies (31.3 %) and in 20 out of 64 studied apiaries (25.8 %). The maximal infestation rate of bee colonies and apiaries constituted more than 40 % in 2014—2015. N. apis pathogen was registered in 84.4 % of infected bee colonies (16 apiaries); N. ceranae was identified in 9.4 % of infected bee colonies (2 apiaries); and co-infection (N. apis and N. ceranae) was detected in 6.3 % of infected bee colonies (2 apiaries). The reasons of the spreading of the nosemosis, such as climatic conditions, control ofimported bee colonies on the presence of Nosema infection, and some others are discussed.

Two new species of virgulous cercariae are described. Morphological descriptions and differential diagnoses are given. Each description is supplemented with a detailed picture.

Acanthocephalans Prosthenorchis cf. elegans were found in primates in the Moscow Zoo. The larvae of these parasites (cistacanths) were found in cockroaches Blattella germanica that had been captured near aviaries of infected animals. Descriptions and drawings of adult parasites and their larvae are given. Analysis of Prosthenorchis cf. elegans genes ITS 1 rDNA and CO 1 mtDNA shows phylogenetic relations of these parasites with several representatives of the class Archiacanthocephala. The obtained molecular data, however, do not support the monophyly of the family Oligacanthorhynchidae and the orderOligacanthorhynchida.