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Cheliceral sensillae of the ixodid ticks Haemaphysalis punctata and Ixodes persulcatus were studied by means of scanning and transmission electron microscopy. In each chelicera of H. punctata there were found 11 sensillae which contain 29 sensory cells. In I. persulcatus there were found 12 sensillae with 34 sensory cells.

Peculiarities of activation and regularities of spatial and temporary spread of hungry larvae of D. reticulatus from the progeny of one female were studied. Activation of larvae occurs within 16 to 20 days. Under natural conditions the activation of approximately 5 to 15% of potential number of individuals produced by a single clutch takes place. A larval aggregation occupies a territory of several square metres and survives about a month. Larvae from two and more clutches feed simultaneously on small mammals. Individual larvae from the progeny of one female usually feed on one animal. The spread of larvae by the hosts occurs apparently within the limits of some hectares.

Drainage melioration in Polesye resulted in a sharp increase in the number of tundra vole (Microtus oeconomus Pall.) which quickly included into parasitocoenosis of the drained land. There were found 26 parasitic and non-parasitic species of Gamasoidea, 3 species of Ixodidae and 2 species of Trombiculidae, 10 species of Aphaniptera, 3 species of Anoplura but there was found no species specific only for the tundra vole. All found parasites occur on many hosts. This explains wide parasitic links of the tundra vole with other homoterm animals which especially extensive with the bank vole and it may have important consequences for epizootology of tularemia and tick-borne encephalitis.

985 wild small mammals and birds were serologically investigated for toxoplasmosis from 1981 to 1984 in Turkmenia: Antibodies to Toxoplasma gondii in RNGA and RIFSK according to Goldwasser and Shepard were found in 247 (25.0%), in 11 of 17 investigated species of mammals and in 13 of 22 species of birds. A sharp rise in the toxoplasmosis infection level of wild mammals was found out serologically for the first time (from 1.2% in autumn, 1982 to 72.6% in spring, 1983) followed by its reduction against the reduction in the number of animals. This must have taken place as a result of heavy toxoplasmosis epizootia in the region of investigations which is frequented by wild and domestic cats.

Four new Myxosporea species, Chloromyxum dogieli, Ch. lissosporum, Ch. schulmani, Ch. striatellus, are described from several cartilaginous fishes of the Atlantic coast of Africa. They differ from the related Ch. leydigi Mingazzini, 1890 by several morphometric characteristics: the presence or absence of striation spores or costate valves, their distribution pattern and the size of filiform appendices on the back pole of spore. Ch. ovatum Jameson, 1929 is observed in the region for the first time. Earlier suggestion about the collective character of the species Ch. leydigi is confirmed.

The effect of the antihelminthic preparation phenasal on the fine structure of tegument of the cestode Caryophyllaeus laticeps, a parasite of Cyprinidae, was studied in vitro. 10 mcg/ml concentration of phenasal causes numerous evaginations of the external cytoplasmic layer in the scolex of helminth. Inside these formations there are granules of secretion, mitochondria, vacuoles. At the same time microtrichia disappear from the surface, cytoplasmic layer gets thinner and its mitochondria degenerate. In the middle part of the body the number of microtrichia decreases, the layer of tegumental cells swells and conformational condition of its mitochondria changes. The degree of injury depends on the exposition time which was from 0 to 4 hours.

The infection of Planorbarius banaticus with sporocysts of Cotylurus cornutus is accompanied by an increase in aldolase activity of molluscs' haemolymph of 1.2 fold. In solutions of nitroammophoska (0.1, 1 and 10 mg/l) the activity of this ferment in infected individuals increases much higher than in non-infected ones. This results in fast carbohydrates expenditures by molluscs, intermediate hosts of trematodes, and their death from exhaustion.

Qualitative and quantitative collections in the populations of L. obtusata and L. saxatilis were conducted in two regions of the Kandalaksha Bay from 1981 to 1985. Molluscs staying during the falling tide on the surface of macrophytes were found to be infected more heavily than those hinding in their depth. L. saxatilis is characterized by a mosaic distribution of infection: the infection of molluscs on stones is higher than on fucoids and gravel. The ratio between age groups as well as the distribution of parasites in age groups are different on different substrata. The differences revealed are connected only with Microphallus species of the group "pygmaeus". The infection with these parasites is supposed to inhibit the ability of molluscs for tidal migrations that causes different distribution of healthy and infected individuals during the falling tide.

The larval form of nematode known under the name Vogeloides zorillae is a widely distributed parasite of reptiles and hedgehogs in Turkmenia. After infecting the nestlings of Athene noctua with these larvae the obtained mature form is referred to the genus Procyrnea. The III stage larvae of P. zorillae from intermediate hosts (beetles of the fam. Tenebrionidae) are considerably smaller than those from vertebrates. The growth of larvae in reservoire (paratenic) hosts was established experimentally. Descriptions and figures of larvae from intermediate and reservoire hosts and first description of mature form are given.

Larvae of Anisakis schupakovi were recorded, with regard for published data, from 40 species and subspecies of marine anadromous and semianadromous Caspian fishes, one species of marine mammals, one species of ichthyophagous birds and one species of ichthyophagous reptiles. The infection rate with these helminths is most high in Clupeidae (excluding 3 species of Clupeonella, which are not infected). In Acipenseridae, Salmonidae, Cyprinidae, Siluridae and Percoidea larvae of Anisakis are rare. The Anisakis infection of fishes inhabiting the southern and middle Caspian Sea is as a rule higher than that of fishes from the northern Caspian. Definitive host of A. schupakovi is Caspian seal, intermediate hosts are not established (apparently crustaceans), reservoir hosts are fishes and ichthyophagous reptiles.

The ixodid tick Anomalohimalaya lotozkyi Fil. et Panova, 1978, which was known by its single find from the ridge Peter I (the West Pamirs), is recorded from Zeravshansky and Gissarsky ridges. The absence of eyes in larvae is confirmed. The genus diagnosis by the nymphal phase is added with the following character: lateral processes of the gnathosoma basis are flattened in the frontal plane.

When treating the material on parasitic isopodes of fishes from the North Atlantic a new member of the new species of the genus Lironeca (Isopoda, Cymothoidae) was found in the gill cavity of Cepola macrophthalma from the Bay of Biscay.

On the basis of the author's material and literary data the identity of the species Paraergasilus rylovi and P. markevichi is proved. P. rylovi females were first found to be parasitic mainly on Ariodonta piscinalis (Mollusca, Bivalvia) and to penetrate sometimes into nasal fossa of Cyprinidae when approaching shallow waters near molluscs' habitats.

A representative of the genus Leptomonas found in the intestine of the bug Camptopus lateralis from Kirgizia is described.

On the basis of the material collected on East Pamir (hot spring Shaimak, 800 m above sea level) a new species, Myxobolus montanus sp. n., from gills of Schizopygopsis stoliczkai is described. This is the third species of Myxobolus with ridges on the valves. A detailed morphological description of spores supplied with figures and differential diagnosis is given.

The ability to form aggregations or groups was studied in Dactylogyrus chranilowi isolated from gills or present on them. It was found that under experimental conditions dactylogyrids form aggregations only on exposure to light; in the dark this phenomenon was not observed. It was observed that the more the number of parasites in the group the greater the number of eggs laid by them. This dependence is of curvilinear character and is approximated quite satisfactorily by parabolic function. The aggregation of D. chranilowi on gills of Abramis ballerus takes place only when the intensity of infection is comparatively low and there are portions free of parasites on the gill filoments. The ability to group formation was recorded only in sexually mature dactylogyrids. Apparently localisation in groups favours allogamy in D. chranilowi under natural conditions.

The activity of α-amylase in haemolymph of Planorbarius corneus and P. purpura, collected from various biotopes, infected and non-infected with Cercaria pseudogracilis parthenites, was determined. The specific and biotopical variability of the character investigated was observed. The activity of α-amylase in the haemolymph of P. corneus, collected in one of the biotopes, decreases with infection. In most cases the trematode infection does not affect the activity of the ferment studied.

Summary is absent.

Summary is absent.

Summary is absent.