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The purpose of the research is to model the pathogen Uncinaria stenocephala in laboratory rodents.Materials and methods. The material for research was the nematode U. stenocephala. The source of the infection was a domestic dog from the Stupinsky district of the Moscow region. In fecal samples, from 90 to 360 helminth eggs were recorded in 1 g of feces. Helminth eggs were obtained by flotation using the Fulleborn and McMaster method. A suspension of larvae was taken into an insulin syringe to a volume of 1 ml and each dose was counted in a watch glass with a diameter of 8 cm. DBA mice and laboratory Beagle dogs were used in the experiments.Results and discussion. An oral challenge dose of 100 U. stenocephala (L3) larvae was fatal to laboratory mice. Over the 6th day of life, the animals decreased their body weight by 3 g. With a reduced oral dose, for 7–14 days the animals showed ruffled hair and, in isolated cases, dyspepsia. When the infective material was administered subcutaneously, no clinical signs of infection were observed in experimental rodents. After infecttion of Beagle dogs with U. stenocephala larvae, no clinical picture of nematode parasitism was observed. After 21 days, the first helminth eggs appeared in the feces of carnivorous animals. On the 28th day and beyond, the release of helminth eggs in dogs increased. From 360 to 2370 U. stenocephala eggs were found in 1 g of feces.

The purpose of the research is to study the morphological changes in the capsules of Trichinella spiralis larvae and their distribution in muscles.Materials and methods. In the experiment, 12 white rats were used, divided into 3 groups of 4 animals each. Rats of the first group were infected with T. spiralis larvae at a dose of 5 larvae per 1 g of body weight, the second – at a dose of 40 larvae per 1 g, rats of the 3rd group served as control and were not infected. The selective dispersal of larvae was studied by determining the intensity of infection in post-mortem studies of the main muscle groups of the animal and measuring the capsules of larvae in different muscle groups.Results and discussion. In the entire muscle mass, 45±10 T. spiralis larvae/animal were found in the 1st group, in the 2nd group the number of larvae was 2250±180, in the control group no T. spiralis larvae were found. It has been established that the distribution of T. spiralis larvae in the muscles of infected animals depends on the dose of infection: at low doses, the largest number was found in the gastrocnemius muscles and diaphragm, at high doses, the number of larvae in the muscles of the head sharply increases.

The purpose of the research is studying of Cysticercus tenuicollis protoscolexes extract effects on cell division at different routes of administration to mice and evaluation of the associated negative effects.Materials and methods. C. tenuicollis were obtained from spontaneously infected sheep in Kabardino-Balkarian Republic. C. tenuicollis protoscolexes were washed, crushed and homogenized. Protein extraction was performed with phosphate buffered saline pH 7.2–7.4. C. tenuicollis extract was administered intraperitoneally and intravenously to mice males at the dose level of 80 μg protein/animal. The control group of mice was intravenously injected with 0.1 ml of saline. At hours 3; 6; 24 and 48 post extract administration mice were euthanized. Bone marrow samples were taken from experimental and control mice for preparation of microscopic preparations to assess mitotic activity in a given cell population. The mitotic index was determined, all stages of mitosis were recorded. At the above time points blood samples were taken from mice to determine the main hematological parameters post intravenous and intraperitoneal administration of C. tenuicollis extract. The main hematological parameters of mice were determined using hematological analyzer MicroCC-20 Plus (High Technology, Inc. (USA)); leukocyte formula – by the generally accepted method. Samples of liver, kidneys, spleen, mesenteric lymph nodes and testes were taken from experimental and control animals for macroscopic and microscopic studies.Results and discussion. C. tenuicollis protoscolices extract leads to inhibition of cell division in the population bone marrow and testes cells in mice when administered intravenously and intraperitoneally at the dose level of 80 μg/animal manifested in accumulation of metaphases and decrease of other stages. At both routes of administration a decrease in leukocyte counts was noted. The observed microscopic changes in testes, spleen and lymph nodes either reflect the consequences of extract antimitotic effect or the immune response to the administration of C. tenuicollis extract.

The purpose of the research is to study effects of Trichinella spiralis and Echinococcus multilocularis extracts on mitosis in a bone marrow cell population, and on hematological and biochemical blood parameters of mice after single and multiple intraperitoneal injections.Materials and methods. The experiment was conducted on outbred male mice. The T. spiralis and E. multilocularis extracts were administered intraperitoneally once or multiple times daily for 10 days at a dose of 80 μg/mouse. Bone marrow cell isolation, microscopic preparations, mitotic index and individual stage determination were made as described in the literature (Ford C. E., Hamerton J. L., 1956). The mouse main peripheral blood parameters were determined with a MicroCC-20 Plus hematological analyzer, and the leucogram was determined by a conventional method. Biochemical blood parameters of the mice were determined with a Clima MC-15 analyzer.Results and discussion. The T. spiralis and E. multilocularis extracts after a single intraperitoneal injection at a dose of 80 μg/ mouse had a pronounced negative effect on the mouse bone marrow cell mitosis with the cell division terminated in the metaphase and a decreased proportion of other mitosis stages. Characteristics were detected of the effects made by the T. spiralis and E. multilocularis extracts on the mouse bone marrow cell mitosis after multiple administration for 10 days. In the reinjection mode of the test extracts to the mice, hematological and biochemical parameters did not change.

The purpose of the research is analyze the localization of Trichinella sp. in animals muscle and to evaluate the methods of intravital and post-mortem diagnosis of trichinellosis in domestic, wild and game animals.Materials and methods. In order to prevent trichinellosis in human population and animals, life-time and post-mortem diagnosis methods for trichinellosis are widely used. Life-time diagnosis of trichinellosis is based on detection of specific antibodies in blood serum of sick animals. Modern immunological assays allow detecting specific antibodies (immunoglobulins J and M) at 10–12 days after infection. Enzyme-linked immunosorbent assay (ELISA) with fractionated antigen has the greatest real possibility of application for individual and mass seroepizootic studies of pigs and horses; ELISA is a highly sensitive and specific test. Veterinary and sanitary examination is conducted by methods of compressor trichinelloscopy and peptolysis (muscle tissue digested in artificial gastric juice). For the compression research method, in particular for pig carcasses, 2 samples of the diaphragmatic peduncles of 60 g each are taken. It is also possible to study samples from masticatory muscles, tongue, intercostal space or esophagus. Twelve sections are made from each sample (24 in total). A more sensitive and productive method is the digestion of muscle tissue using a set of diagnostic devices and instruments such as AVT. The method is based on peptolysis of crushed muscle tissue in technological reactors. Diagnosis of trichinellosis using such devices makes it possible to automate and mechanize all processes associated with the isolation of Trichinella larvae. The main application areas of the devices are meat processing factories, fur farms or veterinary and sanitary examination laboratories in the markets.Results and discussion. We presented data on the role of veterinary and sanitary examination for trichinellosis in susceptible animals as the core measure in the system of measures to prevent this infection. We analyzed indicators of diagnostic efficiency, performance and usability of methods of compressor trichinelloscopy and digestion of muscle tissue in artificial gastric juice. Factors of diagnostic efficiency, performance and usability of methods of compressor trichinelloscopy and digestion of muscle tissue in artificial gastric juice were analyzed. Information was given on localization of Trichinella larvae in various species of domestic and wild animals, optimal sampling sites and volumes of muscle tissue samples with the existing methods of examination for trichinellosis. To study fresh carcasses for trichinellosis at meat processing factories, the peptolysis method is recommended.

The purpose of the research is identification of the current parasitological situation for Eurasian beavers inhabiting the Central Russia.Materials and methods. The work was carried out on hunting farms and in specially protected areas of the Central Russia. Potentially infective material was collected, recorded and preserved from animals during 2015–2021. The age of the animals was determined by their weight and physiological state of the rodents’ teeth and internal organs, and the sex was determined by their genitals. The animals were examined according to the method of complete and partial helminthological dissection per Skryabin.Results and discussion. A total of 41 animals were examined. Three forms of parasitism on animals were identified in natural habitat, namely, the trematode Stichorchis subtriquetrus, the nematode Travassosius rufus, and the ectoparasite Platypsyllus castoris. The stichorchosis causative agent localized in the animal’s large intestine was diagnosed in 35 rodents (85.4%). The helminth infection was 96% in the Eurasian beaver and 68.7% in the Canadian beaver. The nematode infection in stomach was detected in 31 animals (75.6%). The infection by T. rufus was 88% in the Eurasian beaver, and 56.3% in the Canadian beaver. The infected animals were delivered from the Vladimir, Moscow, Ryazan, Tula and Yaroslavl Regions. The beaver beetle P. castoris was found in 6 animals (14.6%). The infection rate was 8% in the Eurasian beaver, and 25% in the Canadian beaver. Animals with wingless arthropods have been identified in the Moscow and Ryazan Regions.

Commercially exploited predator animal species are considered as a final host for multiple biohelminths posing a threat both to human and other animals. Fight against pathogens of dangerous helminthozoonoses should be based on combining efforts of scientific and practical centers, various state departments, executive authorities, law enforcement authorities as well as country residents. Examining parasitic fauna in commercially exploited predator animals is of special priority in the Midland Russia with high population density, wherein people have been engaged in hunting closely contacting both with fur animals as well as domestic pets (dogs, cats). Alveococcosis is a natural focal disease caused by Echinococcus multilocularis. The study was aimed at examining dynamics of E. multilocularis recording in the Midland Russia commercially exploited predator animals. 2007—2018 Cestode spread was examined. A research material for (corpses, carcasses, body and tissue fragments) was obtained hunting reserves located in the Vladimir, Nizhny Novgorod, Moscow, Tver, Oryol and Bryansk regions of the Midland Russia as well as the Republic of Karelia. Complete or partial helminthological autopsy carried out in accordance with K.I. Scriabin technique (1928) was performed in 262 animals, including 193 common red foxes, 28 domestic and 16 raccoon dogs, 16 domestic cats, 6 wolves, 2 brown bears and one lynx. It was shown that cestodes E. multilocularis was found in 46 foxes (23.8%), 3 raccoon dogs (18.7%), 3 wolves (50%) and one domestic dog (3.6%). Moreover, the peak tapeworm prevalence in carnivorous animals was noted for foxes and raccoon dogs in 2010—2011 (42.4%), 2011— 2012 (37.1%) and 2012—2013 (42.1%). On the other hand, no tapeworm invasion in carnivores was noted during 2009—2010 and 2013—2014 sports hunting seasons. However, a causative agent of alveococcosis is routinely detected in the Ryazan and Vladimir regions. The prevalence of invasion in animals differs in foxes, raccoon dogs, wolves ranging from 12 to 40,000, in raccoon dogs — from 37 to 112, in wolves — from 12 to 318 tapeworms per animal, and in domestic dog reaching 19 worms per animal. The data of 2007—2018 personal studies point at spread of alveococcosis foci in the Midland Russia.

Fauna of helminths of boars in Ryazan region is presented by 6 types of helminths: 2 types trematodes – Fasciola hepatica, Alaria spp. and 4 types of nematodes – Metastrongylus elongatus, M. pudendotectus, Ascaris suum, Globocephalus longemucronatus.