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

Abstract

BACKGROUND: Ticks are the most important vectors which<br />transmit several arthropod-borne diseases such as theileriosis,<br />babesiosis, and anaplasmosis. OBJECTIVES: An epidemiological<br />study was conducted in Semnan area to determine the<br />current situation of tick infestation in sheep and assess the<br />efficacy of usage of CIS-cypermethrin against tick infestation<br />under field condition. METHODES: Sampling was done monthly<br />on 5% of a sheep herd in a population of 1000 sheep for one year.<br />Ticks were collected, counted, and diagnosed. RESULTS: Ticks<br />species affecting sheep were Hyalomma marginatummarginatum<br />in winter quarters and in summer pasture; Dermacentor<br />marginatus and D. raskemensis were the prominent ticks. In the<br />middle of autumn and during the winter, no ticks were detected<br />from the animals. The preferred sites of tick attachment to<br />infested animals were perineal region and ears in winter quarters;<br />however, in the summer pastures, the ticks were found only under<br />the neck area and on the sternum. There was a significant<br />difference between the numbers of male ticks on ewe and lamb;<br />however, these phenomena were not recorded for female ticks.<br />In this regard, CIS-cypermethrin deeping treatment reduced the<br />rate of infestion (almost 100%) after one day of treatment.<br />Nonetheless, in the next sampling after 4 weeks, the rate of<br />infestation increased again and reached 50%. CONCLUSIONS:In<br />order to control the tick infestation, it is recommended that<br />spraying be done monthly on the infected areas.