The prevalence and structure of parasitic diseases of dogs was studied for the first time in the conditions of Northern Trans-Urals. The dynamics of their parasitism was analyzed. The survey of dogs of different gender, age and breed was conductedin the period from 2002 till 2017. As a result of the research, it was found, that diseases with parasitic etiology were registered in dogs in 42.5±1.78% of cases. Significant role in the parasitocenosis of dogs is played by mites; among them there is

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... he class Arachnidas, divided in 2 orders: Acariformes(Otodectescynotis, Sarcoptescanis, Demodexсanis,Cheyletiellajasguri) and Parasitiformes(Ixodespersulcatus, Dermacentermarginatus,Dermacenterreticulatus).As a result of the study, we obtained information about the seasonality of otodectosisin dogs; during the study period, this disease was diagnosed in 26.1 ± 1.25% of cases. The peak of otodectosis falls on the summer period-58.33%, and the decline-for the winter period-0.78%. The analysis showed, that the greatest peak of invasion in dogs was observed in July-19.44%, in August-27.78%, and in September-19.13%. Sarcoptic mange was diagnosed in 16.4 ± 0.97% of cases. The peak of sarcoptic mange falls on the spring-summer period-21.15%, and the decline-for the winter period-0.57%. Demodecosis of dogs was diagnosed in 38.68 ± 1.32% of cases. The highest peak of invasion was observed in May-10.7%, and in August-17.2%. Among the short-haired dogs, demodectic invasion occurred in 51.1% of cases, and in long-haired dogs-in 48.9% of cases. In addition, scaly and mixed forms of demodicosis were diagnosed more often in short-haired animals;pustular and mixed forms-in long-haired animals. The analysis of parasitizing of ixodid ticks showed, that Ixodespersulcatus was revealed in 30.7 ± 1.02% of cases, Dermacentermarginatus-in 12.7±0.22% of cases, and Dermacenterreticulatus-in 56.6±1.36% of cases. Seasonal activity of ixodid ticks is very high: in spring-Ixodespersulcatus (from April to the first ten days of June), Dermacentermarginatus and Dermacenterreticulatus (from May to mid-June) and in autumn (from August to the end of September). The amount of ixodids in the biotope is directly dependent on fluctuations in the ambient temperature; the most comfortable range is from + 10°C to + 22°C.