Helminth biodiversity and spread peculiarities of helminthiasis of domestic artiodactyls in the Caspian Depression ecosystems

The Caspian Depression is situated on the flat eastern territory of the North Caucasus. According to the soil and climatic conditions, different ecosystems are neighboring in the Caspian Depression: lowland moistened areas (up to 30% of the territories), plat steppes (more than 50%), salt marshes (up to 10%), and semi-deserts (up to 10%). The majority of the Caspian Depression territories are used for domestic animal grazing, where more than 3 million sheep, goats and up to 150 thousand heads of cattle are contained. 46 nosological units of helminthiasis agents are parasitized on domestic ruminants, including 37 species of sheep and 38 of cattle. The average temperature in winter is up to +12°С; in summer – up to +45°С (210-220 days a year). This region is characterized by year-round use of land and an increase in zootechnical standards for keeping animals per unit of pasture (up to 8 heads of sheep and 3 heads of cattle). Moreover, it has a rich variety of pathogens of helminthiasis, the similarity of most types of helminths for domestic ruminants, a high number of invasive stages in biotopes, and up to 95% of the prevalence of mixed invasions of dangerous parasitoses.