Ticks are small arachnids of order Ixodida along with mites, they constitute subclass Acarina.
Three families of ticks, 1- Nuttalliellidae comprises a single species, Nuttalliella namaqua, 2-
Ixodidae, hard ticks and 3- Argasidae, soft ticks. Ixodidae are distinguished from the Argasidae
by the presence of a scutum or hard shield. Ixodidae nymphs and adults both have a prominent
capitulum (head) which projects forwards from the body; in the Argasidae, conversely, the capitulum
is concealed beneath the body. Ticks transmit many infectious diseases to mammals including
man, birds, and some reptiles and amphibians. Toxins of various ticks caused a disease
known as tick paralysis, which can be confused with infectious and noninfectious conditions.