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Monday 5 June 2006

Definition: Tick is the common name for the small arachnids that, along with mites, constitute the order Acarina.



Ticks are ectoparasites (external parasites), living by hematophagy on the blood of mammals, birds, and occasionally reptiles and amphibians.

Ticks are important vectors of a number of animal and human diseases, as Lyme disease.

Tick-borne diseases

Ticks are second only to mosquitoes as vectors of human disease.

- hard ticks

  • relapsing fever
  • Lyme disease
  • Rickettsioses (Rickettsiosis)
  • Rocky Mountain spotted fever
  • tularemia
  • equine encephalitis
  • Colorado tick fever
  • ehrlichiosis

Generally, tick-borne diseases correspond to a specific tick-host combination, and are limited in their geographical extent. For example, nearly 90% of all Lyme disease cases have been reported in the Northeastern part of the US,[2] only specific deer ticks carry that disease.[3] According to the Rhode Island Department of Health, roughly 70% of people who develop Lyme disease in that part of North America catch it from ticks in their own yard.

See also

- tick-bite