Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.047.
Section : Killing Flies, Fleas, and Lice.
‘Ata was asked by a man about the fleas or ants that vexed him while he was in the state of ihram. He replied: “You may throw away what does not belong to you.” Ibn ‘Abbas said: “A muhrim may kill lice and ticks.”
A muhrim may also remove fleas from his camel. ‘Ikrimah reported that Ibn ‘Abbas once ordered him to kill the ticks off his camel while they were both in the state of ihram. ‘Ikrimah, disliked doing so. Then, Ibn ‘Abbas commanded Ikrimah to slaughter a camel, which he willingly did. Thereupon Ibn ‘Abbas asked him, “Do you know how many ticks you just killed?”