Ixodes Ricinus

Ectoparasites are parasites which inhabit the skin or coat of the host.

Ectoparasites are important because:

  • They may cause cutaneous lesions

  • They can induce immunopathological responses

  • They can transmit pathogens

  • They may infest people or transmit zoonotic infections

  • They may interfere with the human – animal bond

  • Their control is part of maintaining healthy pets

In addition the following factors have clinical implications:

  • Cutaneous lesions may lead to secondary bacterial or fungal infections (Malassezia spp.) and various kinds of dermatitis

  • Transmitted pathogens may cause diseases (VBDs), that are, in many cases, of more clinical relevance than the actual ectoparasite infestation

  • The immune response induced, especially by ectoparasite saliva, may lead to allergic reactions with flea allergic dermatitis being the most important

  • Ectoparasite-infested pets may be a source of infestation for owners

  • The direct health implications of ectoparasite infestation can be more than skin deep: e.g. heavy blood-sucking arthropods can cause anaemia

Ectoparasites of dogs and cats belong to one of two groups:

  • Insecta

  • Acari


The Group Insecta are parasites with:

  • chitinuous exoskeletons

  • three-part bodies (divided into head, thorax and abdomen)

  • three pairs of legs

  • compound eyes

  • two antennae

Insecta can be winged or wingless and may have further anatomical adaptations.

Insecta comprise the parasites:

(of the Order Siphonaptera)

(of the Order Phthiraptera)

(mosquitoes, sandflies and biting flies)


The group Acari are a subgroup of arachnids with:

  • a single entity body mass

  • (larval stages) three pairs of legs

  • (nymphal and adult stages) four pairs of legs

Acari comprise the parasites:



Further information about these different Ectoparasites can be found by clicking the links above.