SEASONAL DYNAMICS OF CATTLE THELAZIOSIS IN NORTHERN TRANS-URAL REGION AND PATHOGENETIC MECHANISMS OF ITS CLINICAL MANIFESTATIONS

Thelaziosis of cattle is the helminthic disease caused by parasitizing of nematodes of a suborder of Spirurata, the Thelaziidae family. The purpose of our researches was detailed studying of seasonal dynamics of thelaziosis at cattle, terms of its invasive thelaziosisas well as specification of clinical implication of a disease at the cattle in the Northern Trans-Ural region. Researches were conducted in 2002-2016, surveyed 27122 heads of cattle belonging to the agricultural enterprises and citizens. It is established that in the conditions of the Northern Trans-Ural region clinical signs of thelaziosis are shown from first decade of May (EI of 3.39%), by the end of month this indicator increases more than twice (EI of 7.04%). In summer months quantity clinically sick thelaziosis animals the highest. The maximum values of extensiveness of an invasion fixed during the period from third decade of July to the first decade of August (15.83 and 15.36% respectively). In the second decade of August the number of the diseased still is at the high level – 12.23%, and then systematically decreases, and by the end of September the number of animals with clinical signs of thelaziosis made less than 5%. During the stall period the extensiveness of thelaziosis invasion was minimum - less than 1%. Clinical implication of thelaziosis is characterized by development of the catarral exudative inflammation which is quickly changing on in the beginning is purulent - catarral, then there is a loss of transparency of a cornea, fusion of tissues of eye and formation of erosion and ulcers on it. In lack of treatment there is a perforation of an iris of the eye, or formation of a white or red cataract that comes to the end with loss of sight and premature rejection of a sick animal. Key terms. Cattle, thelaziosis, seasonal dynamics, clinical implication