Irritation

Arthropods damage their hosts in a variety of ways. Their feeding on the host's skin may cause intense itching, as in the case of mites. In scratching, and licking for relief, cats damage the skin. The open wound that results from the scratching and/or the original arthropod bites allow bacteria present on the skin to infect the animal and cause disease. Damage by mites causes the skin disease called mange, characterised by raw, thickened skin that has lost its hair.

Transmission of Disease

One of the damaging aspects of ectoparasites is their ability to transmit disease-carrying organisms to animals on which they feed. These diseases are often quite serious. For example, either fleas or biting lice may serve as the intermediate hosts for the tapeworm Dipylidium caninum, and fleas are intermediate hosts for the blood parasite Mycoplasma Haemofelis.