Sanitary parasitological study of the contamination of environmental objects as factors of parasitosis transmission is an important element of sanitary and hygienic monitoring. Using sanitary-parasitological methods of research of environmental objects in 2018, wastewater and its sediments, soil and water of open surface water bodies as the main factors of parasitosis transmission were studied in the territory of the Rostov region and the Republic of Adygea. Screening works were carried out to indicate 137 objects of the surrounding environment that the parasitosis pathogens infected. Extensive and intensive indicators of the contamination of objects with the ascertained viability of the identified parasitic pathogens were determined. Wastewater and its sediments turned out to be the most epidemiologically significant objects, as evidenced by the level of contamination of these substrates with parasitic pathogens and to a greater degree the share of viable helminth eggs detected among them. The spectrum of parasitic pathogens detected in both territories in sewage and sediments was as follows: tokocar eggs (more than 50%), ascaris eggs, pinworms, taeniid oncospheres, ankylostomid eggs, dicrocelium, diphyllobotriid. The soil remains one of the main components of the environment, of great importance in the spread of parasitic invasions. In the studied areas, the ovogram of detected parasitic pathogens in the soil was almost identical: eggs of ascaris, tokocar, pinworms, etc. In addition, the maximum epidemiological significance of the soil was established for geo-and contact helminth infections in respect of the territories of residential areas of settlements, pre-school institutions. The investigated water samples of open surface reservoirs contained only non-viable helminth eggs with low contamination intensity (1–2 specimens / 25 l.).

We analyzed data reflected in the records of the epidemiological screening of cases with echinococcosis in 2019 in some constituent entities of the Russian Federation. It was noted that both rural people and urban residents suffered from the disease equally, while women suffered a little more than men (54.4%). It is found that the most common localization of echinococcal cysts, both in men and women, is the liver (79.5%), and the lesion of the lungs caused by echinococcal cysts (9.1) is in the second place. We presented multiple localization of echinococcal cysts affecting several organs simultaneously to a lesser extent. Two cases of hydatidosis and two cases of multilocular hydatid cyst in the liver were accompanied by a fatal outcome. In some territories, alveococcosis was diagnosed in 14 (8.75%) cases. Contacts with dogs, work on livestock farms, caring for pets, picking wild berries or mushrooms in the forest and eating them without thermal treatment, use of raw river water in housekeeping, eating unwashed vegetables and berries, activities in natural environment, hunting and dressing of wild animals, or failure to observe the rules of personal hygiene have great importance in the spread of this disease among the population, according to epidemiological records.

In the structure of parasitic diseases, helminthiasis traditionally accounts for about 90%. Among them, a special role belongs to larval or tissue helminthiasis. In order to further predict the level of endemic helminthiases in specific administrative territories and develop appropriate proposals for planning and implementing preventive and antiepidemic measures, an analysis of the incidence of larval helminthiases in the population was carried out. The data of official statistics (information on infectious and parasitic diseases – form No. 2) on the incidence of larval helminthiases in the period 2016– 2020, as well as maps of epidemiological survey of cases of echinococcosis, trichinosis, toxocariasis and dirofilariasis, received by the Reference Center by monitoring of larval helminthiases, functioning on the basis of the FBSI "Rostov Research Institute of Microbiology and Parasitology" of Rospotrebnadzor. It is noted that the most unfavorable administrative territories in terms of the incidence of larval helminthiases are currently: echinococcosis – the territories of the North Caucasus, Volga and Ural federal districts; toxocariasis – the territories of the Ural and Siberian federal districts, trichinosis – the territories of the Siberian and Far Eastern federal districts. Dirofilariasis was recorded more often in the territories of the Southern and Volga federal districts.

Toxocariasis is a widespread socially significant zoonotic helminthiasis. Infestation with human toxocariasis occurs through the ingestion of infected Toxocara eggs, which mainly accumulate in the soil. The aim of our study was long-term sanitaryparasitological and immunological observations of toxocariasis in a number of territories in southern Russia. For sanitary and parasitological analysis of soil from 2002 to 2019 in the territory of the Rostov region and the Republic of Adygea, 1664 samples were taken and examined. Determination of indicators of contamination of soil samples with eggs of helminths and invasiveness of Toxocara spp. carried out using the methods outlined in 4.2.2661-10 "Methods of sanitary and parasitological research". During the same period of time, an enzyme-linked immunosorbent assay (ELISA) of 6831 blood serum of a conventionally healthy population of the Rostov region and the Republic of Adygea was carried out using the diagnostic test systems "Toksokara-IgG-IFA-BEST". According to the results of ELISA, high seroprevalence values were obtained, indicating the frequency of contact of the population with the causative agent of toxocariasis and indicating a possibly higher incidence rate than the officially registered one. The results of the conducted sanitary and parasitological studies, which showed a consistently high degree of contamination of the soils of the studied territories of southern Russia, indicate the continuing risk of infection of the population and animals with toxocariasis.