tick infestation rate of sheep and their distribution in abdanan county, ilam province, iran, 2007-2008

background: ticks are hematophagous arthropod belonging to the class of arachnids. ticks are also one of the major vectors of pathogens to animal and human. this study was conducted to determine tick infestation rate of sheep in abdanan during 2007 – 2008. methods: sampling was performed seasonally in 19 villages during spring 2007 until winter 2008. a total of 1095 sheep were selected and tested for tick infestation.   after collection, all ticks were transported to laboratory of medi­cal entomology and were identified with appropriate identification keys. results: totally, 864 hard ticks were collected. the ticks were classified into two genera and 5 species including: hyalomma marginatum (44.67%), hy. anatolicum (43.17%), hy.asiaticum (6.37%), hy. dromedarii (5.55%), hea­maphysalis sulcata (0.24%). the highest seasonal activity was observed in spring (36.46 %) and the lowest seasonal was in winter (11.57%). the rate of tick frequency in mountainous region was 48.15% and it was 51.85% in plateau regions. in this study, tick infestation of sheep was 11.41%. conclusion: hy.marginatum has the more frequent density in the study area.