Types of Ticks

Ixodidae (hard ticks):

Slide021

  • Typically take one blood meal in each of the three developmental stages — larval, nymphal and adult.
  • Remain attached for several days and then drop off.
  • Genera: Ixodes, Amblyomma, Dermacentor, Rhipicephalus
  • Have a scutum while soft ticks do not.
    • Males: the scutum is large, completely covering the dorsal surface.
    • Females: the scutum covers only a part of the dorsal surface and is almost obscured when she becomes engorged.
  • The capitulum of hard ticks extends forward from the anterior end of the body; bears some resemblance to a true head.
  • The spiracles lie behind the fourth pair of coxae, or basal segments of the leg.
  • Both sexes are blood feeders, but only the female becomes greatly distended during engorgement.
  • Most species feed on a different host during each stage, but there are some one-host and two-host species.

Argasidae (soft ticks)Slide032

  • Live in animal nests
  • Feed many times during their lives
  • Feed for a few minutes during the night and then drop off
  • There are four genera, of which Ornithodoros is the most important disease transmitting vector of the soft tick family.
  • Male and female soft ticks are similar in appearance, with no dorsal plate (scutum) to distinguish the sexes as in hard ticks.
  • The capitulum which bears the mouth parts is located beneath the anterior margin of the body.
  • The spiracles lie on the sides of the body above the third and fourth pairs of legs.
  • Some species of soft ticks feed on humans, but they are more common on birds and, occasionally, on bats and other small mammals.
  • Sexes are distinguished by the shape of the genital opening
    • Males is circular or crescent-shaped
    • Females is a transverse split, wider than long.
  • Example: relapsing fever tick

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