[Trends in Ixodides fauna along the Black Sea in the south].

A total of 55726 Ixodes ticks were collected from farm and wild animals on the territory of Bourgas district in the 1958-1964 period and were specifically differentiated. At a later study in the region of the town of Michourin other 26722 ticks were collected from sheep. A total of 15 species were determined. It was found that Ixodes ricinus in the East Balkan Mountain to the north of the town of Nessebur develops after a three-year pattern in pure populations of larvae, nymphs, and imagoes, the peak periods being autumn and spring. The tick-induced paralyses in sheep and goats in this region were due to I. ricinus. A year-round occurrence was established of ticks of the H. plumbeum, I. ricinus, H. punctata, and R. bursa species parasitising in animals. The Ixodes fauna in the Michourin region, where the pastures in 1971 were grazed only by sheep, shows the following trends: H. punctata and R. turanicus ticks, which are preferably parasitising in sheep, increase their relative share. R. bursa, D. marginatus and I. ricinus, which, besides sheep, have also other hosts among farm animals, have lowered their relative share, however, still remain at a comparatively high level. No further decrease is expected in this respect. The H. plumbeum species occurs less frequently, and its level may drop further or remain as it is now. H. inermis has strongly decreased in numbers. It is expected, however, to persist at the present level. B calcaratus has not been found in sheep in the Michourin region. Maybe sporadic cases in single sheep would not be an exception provided it parasitises in wild animals (does).