On the life cycle andmorphology of metacestodes Dioecocestus asper (Cyclophyllidea: Dioecocestidae). P. 3-22.
Metacestodes Dioecocestus asper (Cyclophyllidea) habe been found in larvae of dragonflies Aeshna spp. (Odonata, Anisoptera) from the lakes of the Upper Kolyma and northern Okhotsk seaboard basins (3.8 ± 0.46 % of n = 1730 and 0.09 ± 0.09 % of n = 1065, respectively) for the first time. Thus, participation of dragonflies in lifecycle of Dioecocestidae has been proved. Larvagenesis of D. asper (from spontaneously infested hosts) have been retraced from the stage of primary lacuna up to fully-developed metacestode. Process of development of the metacestode D. asper includes two invaginations. The first one follows the start of exogenous formation of undifferentiated anlage of the cystoscolex; as the result, the latter settles to the bottom of the forming two-layered exocyst homologous to the cercomer. Subsequent development of the prospecive part and the endocyst occurs in the closed amniotic cavity of the sacciform exocyst, the back pole of which preserves embryonic hooks and the front pole possesses the invaginational channel. At the stage of early scolexogenesis, the endocyst with the anlage of the strobila and the scolex separates from the exocyst. and the excretory atrium forms on the back pole of endocyst. At the stage of late scolexogenesis, the formation of the larval strobila (differentiation of the sex) is completed and the second invagination starts. Strong retractors pull bottom of the stribila into the endocyst; simultaneously, the front part of it is also turned inside. The invaginational pore of the endocyst of fully-developed metacestode D. asper remains open; the scolex with the most part of the strobila is located outside the endocyst in the cavity of the exocyst. The encystment of the metacestode occurs when the temperature rises up to 40 °С (i. e., reaching the temperature of the definitive host). Morphogenesis of the uniquely large (among the cyclophyllid metacestodes developing in the invertebrate intermediate host) metacestode D. asper lasts for about two—three years and is associated with the developmental terms of the intermediate host, the larva of the Aeshna dragonfly, in climatic conditions of the Far North-East of Asia. Early stages of morphogenesis of D. asper were noted at the dragonfly larvae of the age of 0+ (at September) and 1+ (at June), and fully-developed metacestodes, only at elder ages. Owing to the extremely large size of D. asper metacestodes we refer them as a specific modification of cysticercoids: a megalocercus (Megalocercus). Common features were noted in the structure and morphogenesis of D. asper megalocercus and ascocerci of Schistotaeniidae. High morphological similarity of these metacestodes and their development in relative taxonomic groups of intermediate hosts, larvae of amphibiotic insects (the dragonfly larvae, and occasionally the larvae of mayflies or water-bugs), prove their belonging to the same philogenetically related group of metacestodes Cyclophyllidea, emerging independently from other groups of cysticercoids. We suggest naming this morpho-ecological group of larvocysts as ascocerci (or ascocysticercoids). The use of the name "ascocercus" as nominal nomenclature for group of larvocysts supposes the change of the name "ascocercus Schistotaeniidae" to "euascocercus".
A case study of singular spectrum analysis application in parasitology: dynamics of prevalence of Cryptocotyle concavum and Bunocotyle progenetica trematode parthenitae in Hydrobia ventrosa snails at the White Sea. P. 23-37.
In this study parasitological data were analyzed by different methods of revealing the structure of time series, namely, auto-correlation analysis (ACA), Fourier spectrum analysis (SA) and singular spectrum analysis (SSA), and the results of these analysis were compared (SSA makes it possible to present non-stationary time series as a sum of independent components and to determine the contribution of each component into the dispersion of the initial series — Golyandina et al., 2001). This case study was based on the result of 10-year-long monitoring of changes in the prevalence of Cryptocotyle concavum and Bunocotyle progenetica trematode parthenitae in intertidal snails Hydrobia ventrosa at the White Sea (in total, 45 observations). ACA did not reveal any statistically significant oscillations in the analyzed series. The application of SSA and SA allowed us to reveal at least two quasi-periodical components. In addition, SSA made it possible to reveal a significant dome-shaped trend in the prevalence of B. progenetica parthenitae, which were described by SA as an oscillation with a period equal to the duration of the study, as well as to give proof that there was no trend in the changes of C. concavum parthenitae prevalence. The components (modes) extracted by the SSA described the changes in the prevalence better that the harmonics extracted by the SA. In particular, SSA modes (contrary to SA harmonics) reflected that the amplitude of oscillations of the B. progenetica prevalence increased as the prevalence grew. The sums of SSA modes correlated more with initial prevalence series that the sums of SA harmonics. A possible interpretation of the trends and modes extracted by the SSA in the light of the transmission features of the investigated trematode species in the study area was proposed.
Monitoring of the helminth fauna of small rodents of land reclamation canal banks in Belorussian Polesie. P. 38-46.
The results of monitoring of the helminth fauna of small rodents dwelling in land reclamation canal banks performed in 2005—2010 in Belorussian Polesie are presented. A total of 38 helminth species were revealed, and the total infestation rate constituted 56.0 %. The data are compared with similar observations performed in 1996—1999.
Trematodes of birds (Aves) from the Middle Volga region. 1. Orders Brachylaimidae, Cyclocoelida, Echinostomatida, Notocotylida, and Opisthorchiida. P. 47-76.
The data on trematodes of the orders Brachylaimidae, Cyclocoelida, Echinostomatida, Notocotylida, and Opisthorchiida from the Middle Volga region are given. Records of different authors are supplemented with the results of our own research. Reliable records are confirmed for 61 trematode species. The following characteristics for each parasite species are given: the systematic position, the host spectrum, locality, collecting sites, biology, degree of host specificity, and the geographical range. Morphological descriptions and original figures of 3 trematodes species are given.
New data on parasite fauna of the Chinese sleeper Perccottus glenii (Actinopterygii: Odontobutidae) in Primorsky Territory with the description of a new myxozoan species from the genus Myxidium (Myxozoa: Myxidiidae). P. 77-99.
Examination of 116 individuals of Perccottus glenii from water bodies of Primorsky Territory of Russia (the Khanka Lake basin and the Peter the Great Bay basin) revealed the presence of 35 species/taxa of parasites. We give a description of a new species, Myxidium shedkoae sp. nov. Spherical plasmodoa of M. shedkoa sp. nov. are located in the gall bladder; spores are fusiform, with protrusive, pointed, or truncated-cone-shaped poles. The length of spores constitutes 12.6—14.9 (13.4) µm; width 7.1—8.6 (7.9) µm; shell valves possess 8—10 ridges forming "papillary" pattern. Drawings and descriptions of parasites species poorly studied and recorded from Russia for the first time are given together with drawings and descriptions of some parasites determined only as genera: Triangula perccotti, Gyrodactylus sp., Phyllodistomum sp., Paracoenogonimus ussuriensis (metacercaria), Cyathocotylidae gen. sp. (metacercaria) and Spiroxys japonicus (third-stage juvenile). Parasite fauna of P. glenii in Primorsky Territory comprises 66 % of species/forms known for P. glenii in the native part of its range.
Peculiarities of the distribution of Cryptosporidia (Coccidia, Cryptosporydiidae) in monkeys in an apery. P. 100-107.
A total of 520 monkeys belonging to 6 species (Macaca mullata, M. fascicularis, M. nemestrina, Cercopithecus aethiops, Papio anubis, and P. hamadrias) were investigated. Total frequency of occurrence of the protozoan Cryptosporidium in the Adler apery constituted 13.8 %. The majority of parasites were found in animals with intestinal disorders such as diarrhea. The lowest frequency of cryptosporidias occurrence was revealed in clinically healthy monkeys. Among sick monkeys, the invasion was most common in infants under one year of age. Cryptosporidiosis is rarely found just as it is, and, as a rule, it accompanied by other parasitogenic and bacterial infections.
Review of the monograph: A.A. Kirillov, N.Yu. Kirillova, I.V. Chikhlyaev. Trematodes of terrestrial vertebrates of the Middle Volga region. P. 108-111.