The purpose of the research is to study the fauna of gastrointestinal nematodes of goats in the Moscow region.
Materials and methods. The studies were carried out from December 2022 to April 2023. The object for the studies was the contents of the digestive tracts of 10 goats from small farms in the Moscow region, which were collected and fixed according to the method of K. I. Skryabin (1928). The species of detected nematodes were identified according to V. M. Ivashkin et al. (1989). A study of fecal samples was carried out, the genus of infective larvae was determined by the method of P. A. Polyakov (1953).
Results and discussion. Three species of nematodes were detected: Haemonchus contortus, Trichostrongylus colubriformis and Teladorsagia circumcincta according to the results of helminthological necropsies of goats. The highest rate of infection was noted for H. contortus and the highest intensity of infection was noted for T. colubriformis. The nematode T. circumcincta was found only in one of 10 studied goats, in the amount of 13 worms. The larvae of Trichostrongylus, Oesophagostomum and Chabertia genera were identified according to their morphology in the examined feces samples in one of the seven farms. Many larvae of the first two genera were found, and Сhabertia larvae were single. The low species diversity noted in this study may be due to the presence of anthelmintic-resistant nematode strains.

The purpose of the research is to identify the composition of fleas, and infection rates in small mammals in the northern taiga of Western Siberia; and to summarize information on fleas in the studied area.
Materials and methods. In 2008, 2010, and 2016–2021, records of small mammals and their ectoparasites (fleas) were made in the northern taiga of Western Siberia. Parasitological survey was performed for 1363 specimens of insectivores and rodents of 13 species that were recorded using trap trenches, drift fences and trap-lines. A total of 1524 fleas of 18 species were recorded. Indices widely accepted in parasitology were used to assess quantitative indicators of fleas.
Results and discussion. Based on the results of our own research and literature sources, small mammals in the northern taiga of Western Siberia were found to have specimens of 28 flea species. The flea fauna of the study area was represented by shrew fleas (Corrodopsylla birulai, Palaeopsylla sorecis), bird fleas (Ceratophyllus gallinae, C. garei), and specific species (Ceratophyllus anisus, C. indages, C. sciurorum, Megabothris walkeri, Leptopsylla segnis). Peromyscopsylla silvatica, Corrodopsylla birulai, Megabothris rectangulatus, Amalaraeus penicilliger, and Amphipsylla sibirica comprise the backbone of the flea fauna of small mammals in the northern taiga of Western Siberia.

The purpose of the research is study of chicken parasitic associations in small farms of Kotayk region, and analysis of the determined factors.
Materials and methods. Research was conducted in 2021 to 2022 in small poultry farms of Kotayk Marz. Poultry feces samples were examined at the Laboratory of Parasitology of the Research Center of Veterinary Medicine and Veterinary Sanitary Expertise, Armenian National Agrarian University. Totally 210 fecal samples were examined. Eimeria spp. oocysts and nematode eggs were detected by means of method after Darling. The results of the research were processed by statistical methods.
Results and discussion. Results of the research have shown that poultry eimeriasis had a wide prevalence in Kotayk Region (52.86%). Three species of Eimeria spp. have been detected: E. acervulina, E. tenella, and E. necatrix. E. acervulina was the most prevalence species (34.29%). The highest intensity of the infection has been registered in Nairi and Kotayk Regions of the region. The above-mentioned species of Eimeria spp. have been occurred both in mono- and poly-infection, with various combinations of the species. E. acervulina + E. tenella combination was the most common. Poultry eimeriasis occurred as a mixed-infection with ascaridiasis, heterakiasis, and capillariasis. The highest extensiveness of the poultry infection has been registered in Kotayk and Hrazdan Regions of the region (65.71% in both cases). Geographical location, as well as natural and climatic conditions of the region promote the prevalence of the mixed infection of poultry.

The purpose of the research is to assess the condition of the black-backed sea shad (Alosa kessleri, Grimm, 1887) in the Lower Volga according to parasitological, microbiological, toxicological, and biochemical parameters, and to determine the correlation between the above during the spawning.
Materials and methods. The research object was the black-backed sea shad caught with a river shore seine. Sampling for comprehensive studies was performed from 15 black-backed sea shads during the spawning migration in 2017. The fish were studied by the method of partial parasitological dissection (the protozoa class was not studied). The fish were collected and dissected, and cameral treatment was performed per Bykhovskaya-Pavlovskaya method. Microbiological studies were conducted by common methods. Species identification of identified helminths and microorganisms was performed according to standard identification guides. Toxicological studies included the determination of lead, cadmium, mercury, and petroleum hydrocarbons in the muscle tissue of the studied shad specimens by atomic absorption. In fish muscles, we studied the number of total lipids by the Zollner method, and water-soluble protein by the spectrometric Warburg-Christian method. The Fulton's condition factor was used for fatness determination. The obtained results were processed statistically.
Results and discussion. The results of the comprehensive studies of commercial species of the black-backed sea shad (Alosa kessleri, Grimm, 1887) showed that the parasite fauna of fish was distinguished by a poor species composition as contracted with a qualitative microbiota biodiversity. Infection of the black-backed sea shad proceeded at the asymptomatic carrier level, which indicated a balanced relationship between parasites and the host. The levels of accumulated toxicants in shads were close to the characteristic values for fish in the Volga-Caspian basin. On average, the stock of energy resources in the studied fish had a positive trend in relation to the previous research period. The study results of the black-backed sea shad during the spawning showed the correlation of parasitological, microbiological, toxicological, and biochemical parameters that comprehensively affect the general physiological state of the studied fish.

The purpose of the research is the characterization of species composition and abundance of ixodid ticks that parasitize on horses, seasonal dynamics of ticks inhabiting natural pastures and their piroplasmid infection.
Materials and methods. The studies were performed in four Gorny Altai physiographic provinces. Ticks were manually collected from horses (1183 specimens). Ticks were counted on natural pastures every ten days with subsequent determination of the species composition (1109 specimens). Collected ticks of the genus Dermacentor (443 specimens) were examined by nested PCR in the presence of genus-specific primers for Babesia spp. and Theileria spp.; the species identification of discovered piroplasmas was determined by 18S rRNA gene sequencing.
Results and discussion. Ixodid ticks of three genera (Dermacentor, Ixodes, Haemaphysalis) and 6 species: D. nuttalli, D. silvarum, D. reticulatus, D. marginatus, H. concinna and Ix. Persulcatus, were recorded in the collections from horses and pastures. The most numerous species was D. nuttalli (56.1%), and the most common, Ix. persulcatus, that was recorded in all districts except Kosh-Agachsky in South-Eastern Altai. D. silvarum accounted for 14.9%, and other species were represented to a lesser extent. The highest species diversity, 5 species, was observed in the Northern Altai pastures and only 1 species, D. nuttalli, was recorded in the South-Eastern Altai. The seasonal dynamics of ticks in the pasture was characterized by two peaks in numbers, namely, the spring peak in the 3rd decade of April and the autumn peak in the 2nd decade of October. The spring-summer period (March-June) had 87.1% of recorded ticks, and the autumn period (September-October) had 7.2%. Three species of the examined ticks (D. silvarum, D. marginatus, D. nuttalli) were found to have DNA of three piroplasmid species (Babesia caballi, Theileria equi and Babesia sp). Piroplasmids infection rate in ticks was 2.7-25.0%, and 2.7% on average in Gorny Altai.

The purpose of the research is to review the classical methods of coprological diagnostics, taking into account modern recommendations and proposals.
Materials and methods. Literature sources on the issues of coprological methods of diagnosing parasitosis have been studied.
Results and discussion. Diagnosis during life is an important element of practical veterinary activity, the success of which largely depends on the correct choice and competent use of suitable laboratory methods. For the diagnosis of parasitic diseases, the study of feces is most often used. Coprological methods are highly informative due to the fact that they can detect not only parasites of the digestive tract, liver, pancreas, but also a number of helminths of the respiratory system and even some tissue parasites that excrete eggs or larvae with feces. Unlike existing indirect immunological and molecular genetic methods, classical research methods are based on the detection and identification of the pathogens themselves at different stages of development. At the same time, the researcher has the opportunity to study morphological features and conduct morphometric analysis. The widespread use of classical coprological methods is also associated with their availability, they are quite simple to perform and relatively inexpensive. A limitation of coprological methods is the inability to diagnose pathogens that are at a non-propagative stage. The effectiveness of diagnostics is influenced by the method of collecting samples, the terms and conditions of transportation, and the choice of an adequate method for examining samples. The article presents the rules for sampling and options for the use of fixatives, a classification of coprological methods is given, and the procedure for performing research is described. Special attention is paid to the choice of flotation solutions, the method of cultivation of strongylid larvae and the method of sporulation of coccidia oocysts. Attention is drawn to the importance of micrometric measurements of detected objects. To ensure the quality of the conducted coprological studies, it is necessary to control the stages of the studies, the technical condition of the equipment and train the personnel. The material presented in the article is intended for both students and practitioners.

The purpose of the research is to develop a sandwich enzyme-linked immunosorbent assay (ELISA) for laboratory diagnosis of echinococcosis in animals.
Materials and methods. The diagnostic efficiency of the ELISA test system developed by us against cystic echinococcus infection in cattle was studied by comparing the obtained results with the data of a postmortem examination of animal carcasses. The sera from 80 animals delivered to the slaughterhouse from farms of different regions of the Republic of Azerbaijan were tested.
Results and discussion. A positive ELISA test result was obtained in 42 animals, which was 52.5% of the total number of the animals studied. The postmortem diagnosis was confirmed in 32 animals, which was 40.0%. The comparison of the ELISA diagnostic efficiency with the postmortem examination data was 68.75%. Fasciola species were found in the bile ducts in 7 animals with a positive ELISA test response to echinococcosis and a negative diagnosis in the postmortem examination, and Cysticercus tenuicollis was found in one animal.

The purpose of the research is to study the biotransformation of fenbendazole in the body of sheep after administration of fenbendazole solid dispersion (FSD) prepared by mechanochemical technique with arabinogalactan.
Materials and methods. The FSD at a dose of 2.0 mg/kg for the active substance was administered orally to sheep. Animal blood serum samples were studied by high performance liquid chromatography / tandem mass spectrometry (HPLC-TMS) to determine the concentration of fenbendazole (FBZ) and its sulfoxide and sulfone metabolites at 0, 1, 2, 4, 6, 8, 12, 24, 33, 48 and 72 hours after administered FSD and initial FBZ (substance). FBZ and its metabolite residual quantity in the organs and tissues of the sheep was determined at 1, 3, 6, 11, and 21 days after the drug administration. The prepared sample and validated method were described.
Results and discussion. A significant difference was found in the metabolism, pharmacokinetics, and timing of the FBZ and its metabolite elimination after the base drug (FBZ substance) and FSD were administered to sheep in an equal dose of 2.0 mg/kg for the active substance. FBZ and its metabolites began to be detected in blood serum 2 hours after the FSD and 4 hours after the base FBZ. Pharmacokinetic parameters of FBZ and its metabolites characterize a higher drug concentration in the blood and a longer retention time in the circulation after the FSD as compared with the base drug parameters. The FBZ and its metabolite maximum concentration was found in the organs and tissues of the sheep that received the FSD on day 3 in the liver amount of 4862.3±296.2 ng/g of FBZ; 18243.5±486.1 ng/g of sulfoxide; and 2482.3±132.4 ng/g of sulfone; and tens of times lower concentration after the base FBZ on day 6. FBZ and its metabolites were not detected in the organs and tissues of the sheep on day 16 after the base FBZ, and on day 21 after the FSD.

The purpose of the research is to study the efficacy of a solid dispersion of fenbendazole at different stages of gastrointestinal nematodes of young sheep.
Materials and methods. Evaluation of the efficacy of a solid dispersion of fenbendazole at different stages of gastrointestinal nematodes was carried out in the farms of the Samara region on 35 sheep aged 7–10 months naturally infected with gastrointestinal strongylates. Animals were divided into experimental and control groups of 8-9 animals each. A solid dispersion of fenbendazole was administered once orally at a dose of 2.0 mg/kg of active substance to the animals of the first experimental group. Animals of the 2nd group received the substance of fenbendazole at a dose of 2 mg/kg. The basic drug – Panakur was administered to the sheep of the 3rd experimental group at a dose of 5 mg/kg. Animals of the control group did not receive the drugs. The efficacy of the drugs was calculated in the experiment of «control test» based on the results of coproovoscopic examination, as well as on the results of helminthological necropsy of the digestive tract of animals, 3–5 sheep from each group.
Results and discussion. The solid dispersion of fenbendazole showed 97.8–98.2% efficacy against adult strongylates and 80.6–87.5% against larvae. The substance of fenbendazole at the same dose – 2 mg/kg revealed 33.0–41.7% and 16.1–26.9% efficacy respectively. The basic drug Panakur showed 95.4–97.3% and 46.7–73.9% efficacy against imaginal strongylates and larvae respectively at a dose of 5.0 mg/kg of active substance.

The purpose of the research is to test the efficacy of triclafascid and two solid dispersion complex preparations based on the triclabendazole substance against fasciolosis in cattle and sheep.
Materials and methods. Complex preparations of triclabendazole (TCB) formulations: Succinic Acid (SA): Polyvinylpyrrolidone (PVP) (1: 1 : 8) and TCB: SA: Arabinogalactan (AG) (1: 1 : 8) were obtained by combined solid-stategrinding of the components in a fiber drum on an LE-101 ball mill at a roll rotation speed of 60 rpm with a process module of 1: 17 for 1 to 6 hours with sampling for analysis (HPLC) for changes in the TCB solubility. A comparative test of the efficacy of triclafascid and new solid dispersions (SD) of TCB complexes with SA against fascioliasis of sheep and cattle was conducted in the North-Eastern Federal District of the Caucasus in March-April 2023. To determine the Fasciola infection rate in animals, fecal samples were individually taken and examined by the Fülleborn methods using saturated aqueous NaCL solution and sequential washing. The drug efficacy was recorded at 25-30 days after deworming in analogy with "critical test". The results were statistically processed by the Student-Fisher method using Microsoft Excel 2007.
Results and discussion. The resulting TCB and SA complexes with polymers had an increased solubility (up to 59–70 times) that depended on the polymer nature. The efficacy of new TCB dosage forms against fascioliasis in sheep at a dose of 1.5 mg/kg, i.e. 0.5 mg/kg less than the therapeutic dose as compared with oral triclafascid was 90.0 and 100%, respectively, and 85.7% in cattle at a dose of 2.0 mg/kg for the active substance.

The purpose of the research is to assess foreign potato varieties for resistance to potato tuber nematode by different methods: in laboratory setting, greenhouse experiment, and field experiment.
Materials and methods. A potato tuber nematode suspension was added to each tuber with 100 and 40 specimens in the laboratory and greenhouse experiments, respectively. At 3 months of storage in a refrigerator at 6–7 ºC in the greenhouse experiment, at 70 days of potato plant growing, nematodes were isolated from tubers using the phytohelminthological method. Twelve potato varieties were planted with 15 tubers of each variety in the field experiment. During planting, halves of tubers affected by Ditylenchus infection were placed in each hole. After growing and harvesting, tubers of 10 plants of each variety were placed in bags and stored at 10–15 ºC for 60 days. The infection rate of each sample was determined by the ratio of potato tubers infected and uninfected by the potato tuber nematode, as well as by the percentage of Ditylenchus-infected tubers.
Results and discussion. In evaluating foreign potato varieties for susceptibility to the potato tuber nematode by three methods, it was found that all tested potato varieties were infected with Ditylenchus destructor nematodes to a greater or lesser extent. In terms of susceptibility to the potato tuber nematode, the varieties were classified as highly susceptible (Riviera, Excellence, Bellarosa, Roco), moderately susceptible (Arizona, Evolution, Impala, Picasso, Arrow) and weakly susceptible (Vineta, Collette) potato varieties. No potato tuber nematode-resistant varieties were identified. All three tested evaluation methods of potato varieties for susceptibility to potato tuber nematode showed that they could be used in the testing of variety resistance to the potato tuber nematode. When the first two methods were conducted in the controlled environment, the field evaluation method depended on agrometeorological growing conditions of the tested potato varieties. In storage, the disease developed in D. destructor-infected tubers, and the Ditylenchus infection signs increased, and the nematode reproduced. This technique should be used in evaluating potato varieties for resistance to the potato tuber nematode D. destructor.