Prevalence, intensity and associated risk factors for ovine tick infestation in two districts of Semnan area

BACKGROUND: Ticks are the most important vectors whichtransmit several arthropod-borne diseases such as theileriosis,babesiosis, and anaplasmosis. OBJECTIVES: An epidemiologicalstudy was conducted in Semnan area to determine thecurrent situation of tick infestation in sheep and assess theefficacy of usage of CIS-cypermethrin against tick infestationunder field condition. METHODES: Sampling was done monthlyon 5% of a sheep herd in a population of 1000 sheep for one year.Ticks were collected, counted, and diagnosed. RESULTS: Ticksspecies affecting sheep were Hyalomma marginatummarginatumin winter quarters and in summer pasture; Dermacentormarginatus and D. raskemensis were the prominent ticks. In themiddle of autumn and during the winter, no ticks were detectedfrom the animals. The preferred sites of tick attachment toinfested animals were perineal region and ears in winter quarters;however, in the summer pastures, the ticks were found only underthe neck area and on the sternum. There was a significantdifference between the numbers of male ticks on ewe and lamb;however, these phenomena were not recorded for female ticks.In this regard, CIS-cypermethrin deeping treatment reduced therate of infestion (almost 100%) after one day of treatment.Nonetheless, in the next sampling after 4 weeks, the rate ofinfestation increased again and reached 50%. CONCLUSIONS:Inorder to control the tick infestation, it is recommended thatspraying be done monthly on the infected areas.