This article is from the Fleas, Ticks, and Your Pet FAQ, by tittle@zmall.com (Cindy Tittle Moore) with numerous contributions by others.
Ticks are the most important arthropod in transmitting diseases to
domestic animals and run a close second to mosquitoes in arthropod
borne human diseases. They transmit a greater variety of infectious
agents than any other type of arthropod. Ticks can cause disease and
illness directly. They are responsible for anemia due to blood loss,
dermatosis due to salivary secretions, and ascending tick paralysis
due to neurotoxins in the salivary secretions. They also can be the
vector of other diseases. Some of the more noted tick borne diseases
are babesiosis, anaplasmosis, ehrlichia, East Coast fever, relapsing
fever, rocky mountain spotted fever and, of course, Lyme disease.
 
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