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The data available in the literature show that 1.5-3% of Russia's population is carriers of cryptosporidium oocysts. Cryptosporidia are ascertained to be able to cause diarrhea of varying severity in preschool children. However, cryptosporidiosis in the latter is not frequently diagnosed. The urgency of the problem of cryptosporidiosis is also due to the practically ubiquitous prevalence of the causative agent in nature and to the role of this infection in the development of perinatal diseases, as well as complications in immunocompetent patients (infected and uninfected with AIDS virus). Cryptosporidiasis is an HIV-associated infection and of great importance for the diagnosis of AIDS.

Fungi of the genus Paecilomyces, a causative agent of the fungal disease paecilomycosis, have been found in the blood of productive animals (sheep, cattle, pigs, goats) that are carriers of Echinococcus larvocysts. In the Republic of Uzbekistan, the echinococcosis affection of sheep, cattle, pigs, and goats continues to remain high. Domestic fowls (chickens, turkeys, and gooses) have been established to be blood carriers of Paecilomyces fungi, which is also true for wild birds, such as my-lady's-belts, quails, chukars, and crows. The degree of fungal affection has been also established for birds.

Experiments were carried out on 35 lambs infected with echinococcus eggs taken from canine donors, 5 lambs with echinococcosis, 5 lambs with echinococcosis + paecilomycosis, 5 lambs with coenurosis, 5 with cysticercosis ovis, 5 with alveococcosis, 5 with paecilomycosis, inoculated by the material taken from patients; and 5 healthy lambs formed a control group. Cystic hydatidosis was found to induce substantial cardiovascular changes.

The fauna of Ixodidae ticks was studied in Bishkek in 1998-2004. The city is situated in the center of the Chuisk valley, at the foot of the Kirghiz ridge, at the boundary of a submountain-plain-arid region and a plain-piedmont-semiarid one with steppe fragments. The ticks were gathered on a flag from small mammalians caught by Gero traps, from birds, domestic and agricultural animals. A total of 648 animals of 13 species were examined. The bites of ticks were registered in 98 persons in the city. A total of 1085 ticks of all developmental phases were gathered. The faunal complex of Ixodidae ticks was represented by the following species: Ixodes persulcatus Sch (domination index (DI) = 0.45), Haemaphysalis punctata Can. Et Fanz (DI = 21.93), Haemaphysalis erinacei Paves (DI = 1.0), Dermacentor marginatus Sulter (DI = 0.27), Rhipicephaluspumilio Sch. (DI = 0.84), Rhipicephalus sanguineus Latr. (DI = 0.56), Rhipicephalus turanicus Pom (DI = 74.85), Hyalomma anatolicum Koch (DI = 0.87). The regional and climatic conditions of Bishkek and the presence of profeeders in the private sector (domestic and agricultural animals, synanthropic rodents, and birds) favor the existence of the R. turanicus population. The mosaic pattern of a cultural region in the center of the city permits small populations of several species of ticks to exist.

Spirometrosis (sparganosis) in animals and man is a serious ecological problem in Russia, which requires the constant attention of veterinary and medical services. The paper presents data on the biology of the parasite Spirometra erinacei europaei Muller, 1937, an account and diagram of a developmental cycle, and original photos of parasitic eggs, plerocercoids, strobiles, and cestode joint from animals.

Results of studies of clonorchiasis in the region of the Upper Amur and its tributaries are presented. Biological features of the pathogen and its epidemiology are outlined. Clinical symptoms were studied in 112 patients. In case of death, a pathoanatomic picture is given.

Domestic and wild mammals in Byelorussian Polesye have been found to have 3 species of echinostomatates known as human parasites: Echinochasmus perfoliatus (Ratz, 1908), Echinostoma revolutum (Froelich, 1802) and Isthmiophora (= Euraryphium) melis (Schrank, 1788). Human beings may be infected on ingestion of mollusks, fish, and Amphibia (frogs) invaded with larvae of these helminths. Although, cases of human invasion have not been recorded in Byelarus, there is an infection risk group, this should be borne in mind by medical workers.

In the author's opinion, the recent taxonomic revision of the genus Trichinella Railliet, 1895 (Pozio et al., 1992 and others) seems to be hasty and insufficiently substantiated. The proposed criteria for identification of new species, such as production of new-born larvae (PNBL) by Trichinella females in vitro, periods of development of nurse cells (DNC), index of reproductive capacity (IRC), resistance to freezing (RF), firstly, have a sufficient dispersion and are frequently very close (PNBL) to T. britovi, T. nativa, T. nelsoni, and T. pseudospiralis, DNC for these species. Secondly, these criteria are not always precise (one cannot agree with the fact that T. spiralis are not resistant to freezing). And, finally, it is impossible to be guided seriously by such criteria as the low or high significance of IRC or RF. According to the fifth criterion--the number of unique allozymic markers--two species are obviously distinguished: T. spiralis (6 markers) and T. pseudospiralis (12 markers). If the absence of capsule formation in case of T. psuedospiralis and the participation of birds in the life cycle of this parasite will be added to the above-mentioned, two species are again clearly distinguished: T. spiralis and T. pseudospiralis. Presently, it is necessary to classify the remaining species as varieties of subspecies of T. spiralis and to designate T. spiralis nativa, T. spiralis nelsoni, T. spiralis britovi, as recommended by the "Guidelines on Surveillance, Prevention, and Control of Trichinellosis" published by the WHO in 1988.

The prevalence of trichinosis was analyzed among human beings and animals in Moscow Province over 50 years (1946-1996). A total of 7022 domestic, synanthropic, and wild carnivorous animals were incompletely helminthologically dissected. Enzyme immunoassay revealed diagnostic Trichinella antigen antibody titers in 45.4% of 544 examinees during outbreaks and at their intervals, as well as in 0.58% of domestic pigs of different property forms. Trichinella larvae were found in domestic pigs (0.13%), dogs (12.3%), cats (12.9%), hunting and fur-bearing (wild boars (2.0%), wolves (38.8%), red foxes (32.0%), raccoon-like dogs (20.0%)) animals and rats (2.4%). Criteria were developed and epidemiological and epizootic division of the districts near Moscow was made. Three unfavourable (hyperendemic, mesoendemic, hypoendemic) and one favourable areas were identified. A trichinosis control programme was worked out.

A hundred and forty-six isolates of Trichinella from various regions of Eurasia have been identified by the crossbreeding method (1 male + 1 female). Three independent species of Trichinella: T. nativa, T. nelsoni, and T. pseudospiralis were found to parasite on the animals of this continent. The former two are dominant species of different territories. T. nativa occupies the whole continental zone to the north and the north-east of the isotherm minus 5-6 degrees C in January and T. nelsoni populate to the west and the south of this line. The both strains are registered in the borders of active zones of the isotherms mentioned above. T. pseudospiralis is autochthonous for the Australian region. Due to its plasticity, this species has also been found in the tropical part of Asia. Birds seem to be the carriers of this nematode to temperate latitudes.

The fleas of wild and commensal small mammals, domestic animals (dogs, cats) and free-living flea forms in houses have been collected in plague nidi of Tay Nguyen plate, Dak-Lak province, Vietnam. Pulex irritans, Ctenocephalides felis felis, Ct. felis orientis were found in the houses on dogs, cats and on the ground floor. Commensal rats in populated areas were infested by Xenopsylla cheopis and rarely by Lentistivalius klossi. The agricultural zone was inhabited by both home and wild animals such as commensal, savannah and forest-dwelling small mammals. The flea fauna of this zone is presented by X. cheopis and L. klossi. In the tropical forest surrounding villages four of the flea species were found: X. vexabilis, a specific parasite of the forest-dwelling rat Berylmys berdmorei, L. klossi found on six species of forest small mammals, Acropsylla girshami from Berylmys bowersii and Pariodontis subjugis from Hystrix brachyura. The agricultural zone is the most possible place of commensal and forest-dwelling small mammals contact, where the latter can get plague microbe.

Hypothesis on the origin of Sporozoa from Spiromonadida ancestors is discussed on the basis of the data on their ultrastructure. The phylum Sporozoa comprises three large distinct groups of organisms as follows: Perkinsemorpha, Gregarinomorpha and Coccidiomorpha. Advanced Coccidiomorpha have not descended directly from Gregarinomorpha. Gregarinomorpha and Coccidiomorpha have common ancestors, Protospiromonadida. Heteroxeny is quite common among Coccidiomorpha. The formation of heteroxeny in Coccidiomorpha proceeded in different ways and at different time in different groups. Cystoisospora, Toxoplasma, Aggregata, Atoxoplasma, Schellackia have primary definitive hosts while Sarcocystis, Karyolysus, Haemogregarina, Hepatozoon, Plasmodium, Haemaproteus, Leucocytozoon, Akiba, Babesiosoma, Theileria, Babesia have primary intermediate hosts.

The results of many years' observations and literature data allowed one to determine the species of wild and domestic mammalians, vectors of trichinelliasis in Kamchatka. The variability of trichinelliasis prevalence in individual mammalian species were found in relation to their habitation place. Significant fluctuations of the index are presented by years. Cases of trichinelliasis in wild American minks (acclimatized species) and in pigs were noted.

Some aspects of dwelling of Echinococcus multilocularis and E. granulosus populations in the Kamchatka Peninsula were considered. Transformation of their natural foci to natural synanthropic due to enrichment of mammalian fauna, increased human density and rural development was noticed. Main quantitative characteristics of infectivity of the worm definitive and intermediate hosts are presented using literature and the author's own data. A correlation was noted between host density and their infectivity with Echinococcus.

101 species of oribatid mites and 12 species of helminths--anoplocephalids, transmitted by these mites, were found out by Soviet-Vietnam studies in agroecosystems and tropical forests of northern and southern Vietnam. Helminths were recorded from graminivorous mammals as follows: horses, zebu, sheep, goats, buffaloes, deer, hares, elephant, 2 species of rates, 5 species of monkeys and 11 species of birds.

21 species of bloodsuckling midges were recorded from the Kishert region of the Perm district. During the period of investigation the group obsoletus was most abundant, then the group pulicaris and fascipennis. There was noted a poor adaptation of midges to different biotopes and high ecological plasticity of mass species. Specific composition of midges attacking man and domestic animals is more diverse as compared to species attacking birds. Food specialisation is more distinct in ornithophilous species.

A redescription of female and male of the little-known species Dermacentor raskemensis Pomerantzev has been made on the holotype (male, West China, Sinkiang) and on collection material of Zoological Institute of the Academy of Sciences of the USSR and Institute of Zoology of Armenian SSR: three females and males from Armenia and western Pakistan. Despite a considerable remoteness of their distribution areas all studied specimens show stability of their specific characters and differ distinctly from the close species D. niveus Neumann and D. everestianus Hirst. The both sexes (especially female) of D. raskemensis differ in having peculiar, most complete (in the ranges of the genus) filing of the dorsal shield area with dense light pigment and by prevalence of very small punctation and the lack of contrast between it and larger punctation. Peritreme of D. raskemensis male has a long narrow dorsal process which is at the right angel to its longitudinal axis and slightly concave along the hind edge. The dorsal process of the female is well developed and is at the right or acute angles to the longitudinal axis. In addition the both sexes have a wide smooth thickening along the anterior edge of the process, the proportions of peritreme are specific in species. In close species the dorsal process of peritreme is at the blunt angle to its longitudinal axis, in D. everestianus the thickening along the anterior edge is missing. Female of D. raskemensis lacks wing-shaped appendages of the genital opening while in D. niveus they are distinct (the structure is not mentioned in the description of D everestianus). D. raskenmensis apparently inhabits highlands and meadow-steppe, steppe and mountain sparce forest zones most part of which is covered by rocks and screes. In Armenia it was recorded from Armenian mouflon and wild goat; in other countries (Iran, Afghanistan, western Pakistan, India and China) it occurs on sheep and goats from alpine pastures. Most collections were done in autumn, winter and spring.

Investigations carried out in Pavlodar Province have shown that 7 species of ixodid ticks, Ixodes crenulatus, I. lividus, I. persulcatus, I. laguri laguri, Dermacentor marginatus, D. reticulatus, Haemaphysalis concinna, and one brought species, Hyalomma asiaticum, parasitize domestic animals and wild mammals. Maximum activity of pasture ticks of the genus Dermacentor falls on the end of April--beginning of May, that of H. concinna on the beginning of June. The growth in the abundance of pasture ticks, recorded during the last years, is favoured by the increase in the cattle live stock, its seasonal movements and pasture area reduction. Natural nidi of tularemia become more active. Since 1977 221 cultures of tularemia agent have been isolatid from pasture ticks. H. concinna takes the most active part in the infection circulation.