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

Background: ticks are the most important vectors which transmit several arthropod-borne diseases such as theileriosis, babesiosis, and anaplasmosis. objectives: an epidemio-logical study was conducted in semnan area to determine the current situation of tick infestation in sheep and assess the efficacy of usage of cis-cypermethrin against tick infestation under field condition. methodes: sampling was done monthly on 5% of a sheep herd in a population of 1000 sheep for one year. ticks were collected, counted, and diagnosed. results: ticks species affecting sheep were hyalommamarginatummarginatum in winter quarters and in summer pasture; dermacentormarginatus and d. raskemensis were the prominent ticks. in the middle of autumn and during the winter, no ticks were detected from the animals. the preferred sites of tick attachment to infested animals were perineal region and ears in winter quarters; however, in the summer pastures, the ticks were found only under the neck area and on the sternum. there was a significant difference between the numbers of male ticks on ewe and lamb; however, these phenomena were not recorded for female ticks. in this regard, cis-cypermethrindeeping treatment reduced the rate of infestion (almost 100%) after one day of treatment. nonetheless, in the next sampling after 4 weeks, the rate of infestation increased again and reached 50%. conclusions: in order to control the tick infestation, it is recommended that spraying be done monthly on the infected areas.