[Distribution, species composition and seasonal dynamics of ticks of the Ixodidate family in northwest Bulgaria].

It has been established that a total of 7 species of Ixodes ticks parasitize in farm animals in the northwest region of the country. The prevailing species is Rh. bursa, which constitutes 67.07 per cent of all ticks that have been collected and plays a basic role in the epizootiology of hemosporidioses. Described are the basic biotopes of the prevailing species. It has been demonstrated that altitude influences the durat-on of the seasonal activity of the parasites as well as the period during which farm animals harbour the parasites.