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It was found out by the methods of large scale cartography and mathematics modelling, that the distribution of Ixodes persulcatus ticks around the point of clutch is still aggregated both on stages of hungry larvae and nymphs and on a stage of hungry imago. It is proposed to use the number of hungry imago aggregates as the criterium for the estimation of clatch number per square unit. Wild animals living in foothill taiga forests of the central part of Krasnoyarsk region support 9-10 female ticks per 10 000 square meters, and among them 5-6 females rise a full-bodied offspring, which completes the life cycle.

Collection materials and cited data on the Ischnopsyllidae of the Middle Asia and Kazakhstan are summarized. The geographical coordinates of the 86 localities and main hosts of the fleas are listed. The fauna of the secribed region consists of five group of species. The species of the first group (Ischnopsyllus obscurus, I. elongatus and I. hexactenus) have transpalearctic areas. They are known from Vespertilio murinus, Nyctalus noctula and Plecotus austriacus respectively. The second group (Ischnopsyllus intermedius and I. variabilis) is represented by the species with westpalearctic areas. Their presence in the region in question is result of the season migrations of the hosts. The species of the third group (I. octactenus, Rhinolophopsylla unipectinata unipectinata and Nycteridopsylla trigona trigona) have west-centralpalearctic areas. The hosts of these species are Pipistrellus pipistrellus, Rhinolophus ferrumequinum and Barbastella leucomelas respectively. The Araeopsylla gestroi, which was found in the Indo-Malayan Region belongs to this group as well. The species of the fourth group (Ischnopsyllus plumatus, I. petropolitanus, Nycteridopsylla calceata, N. oligochaeta, N. singula and Rhinolophopsylla unipectinata turkestanica) have centralpalearctic areas. The species of the genus Nycteridopsylla preponderate among the endemic species. Imago of the genus parasitize on hibernate bats. Ischnopsyllus plumatus parasitize on Eptesicus serotinus distributed in Palaearctic. Fleas of Rhinolophopsylla unipectinata turkestanica are the parasites of Myotis blythi and Rhinolophus ferrumequinum, which often settle the same shelter. The fifth group includes only one species - Myodopsylla trisellis. This species is known from the Central and the Eastern Palaearctic and we recorded it in the Eastern and North-Eastern Kazakhstan. In conclusion it may be point out, that bats of the genus Myotis play the main role as host of the fleas in the north part of Kazakhstan. To south of the region in question Plecotus austriacus, Pipistrellus pipistrellus and Barbastella leucomelas are the hosts of the fleas of the family Ischnopsyllidae.

During the summer season of 1994 the symbiotic and parasitic crustaceans on benthic invertebrates were collected by the author from some localities of the White Sea. A list on 28 species of the symbiotic and parasitic crustaceans on invertebrates from the White Sea is given for the first time. The revision of the literature sourses on symbiotic and parasitic crustaceans of the benthic invertebrates from the Arctic Seas of Russia revealed 44 crustacean species. Among them only 7 species are common for the White Sea and the Arctic Seas: Sphaeronella decorata, Herpyllobius polynoes, Peltogaster paguri, Воруroides hippolytes, Phryxus abdominales, Andaniella pectinata, Metopa glacialis. Thus total number of the symbiotic crustacean forms for the Arctic Seas and the White Sea is 65. Among them the copepods are the dominants (42 species or 64.6% of the fauna).

The distribution specificity of fungi and microsporidies in natural population of Anopheles messeae Fall, and A. beklemishevi Stegny et Kab. and those wich survived after treatment them by Bacillus thuringiensis israelensis (Bti) were observed. Parasitic fungus nonselectively affected individuals of both species and all inversion genotypes of A. messeae. Microsporidia Parathelohania messeae affected males and it has not species and genotypic specificity. The 4-th instar larvae of both species infected by parasitic fungus after treatment them by Bti did not survive. The level of microsporidian infection of A. messeae and A. beklemishevi after Bti treatment was reduced from 1.1 ±0.5 to 0.5 ± 0.3% and from 1.3 ± 1.3 to 0.7 ± 0.5% accordingly. A. beklemishevi was registered as Parathelohania messeae host for the first time. The harmonious relationships between malaria mosquitoes and their parasites in natural populations may be destructed by the Bti treatments.

We have used the polymerase chain reaction (PCR) and random amplified polymorphic DNA (RAPD) method to identify DNA polymorphism in three classes of helminths, Cestoda, Nematoda and Trematoda. In this study, RAPD markers have been used for a description of the genetic variability between the families, genera, species and isolates of helminths. We optimized the conditions of the RAPD analysis and revealed the genetic variability of helminths belonging to different taxonomic groups. These results show that the RAPD-PCR method can be considered as a suitable technic for a phylogenetic study of helminths. The problem of an age variability and host specificity of RAPDs markers is discussed.

An influence of trematode infection and different concentrations of potassium bichromic (20, 50, 80 mg/l) on physical and chemical characteristics of the orb snail haemolymph was studied. Low and moderate rates of infection does not show reliable differences in haemolymph characteristics. In case of hard infection the haemolymph becomes acid, and contents of haemoglobin increases. In infected orb snails the intoxication processus is clear displayed and a letal result is observed more often than in non infected orb snails.

The characteristics of interspecies differences between 22 cestode species of genus Proteocephalus with an apical sucker at the cephalic end was given by the multidimensional statistic analysis methods. The peculiarity of the North-American and the Euro-asiatic species was revealed, groups of morphologically similar species were singled out, non-validity of P. fallax, P. dubius, P. osburni was confirmed. P. scoricovi was classified as an ecoform of P. osculatus. The relation of the group formation to the history of the Palaearctic and Neoarctic faunas was traced.

A helmintological material from 5 seal species (361 specimens) captured in the Pacific sector of Antarctica was examined. The host-parasite associations of cestodes, peculiarities of their locations, extensive and intensive infection rate were studied. Parasitological data are compared with the data on a host feeding.

The gradient of some chemical characteristics along the strobila of the cestode E. rugosum living in the intestine of burbot was studied. It is shown, that the contents of proteins, carbohydrates and an intensity of glucose uptake is changed in dependence upon the gravidity of gonades in segments. The contents of glucose decreases and the contents of glycogen increases from the anterior end of strobila to posterior one. The maximum intensity of the glucose accumulation is observed in the zone of scolex and neck and in the zone of developing proglottids, while in the zone of gravid proglottids the intensity of this processus is low. These indices depend upon the age of the worm. There is a similarity of characteristics between anterior part of adult worms and whole young worms. The adult worms with gravid proglottids differ from young helminths by the fact, that they do not show any clear gradient in contents of glucose and intensity of glucose accumulation; the contents of glycogen in young worms is significantly higher, than in adult worms.