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 epidemiological
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 Hyalomma marginatummarginatum
in winter quarters and in summer pasture; Dermacentor
marginatus 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-cypermethrin deeping 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.