ISSN 2398-2942      

Ctenocephalides felis


Rosanna Marsella

Synonym(s): C. felis felis, cat flea




  • Class: Insecta.
  • Order: Siphoneptera.

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Clinical Effects



Adult fleas

  • Parasitic - in hair coat of dog, cat or other animal.
  • Non-parasitic - in the absence of a host can survive few days to a few weeks (if has recently fed) in a cool, moist environment.
  • Pre-emerged adults in their cocoon - in the absence of stimuli to emerge (pressure, temperature, possibly vibration) - can remain in the cocoon <1 year, particularly in cool temperatures.
  • Laid on the animal but not sticky; eggs fall off within about 8 hours.
  • Majority fall where animal spends most of its time sleeping/resting (in the bedding, on the owner's bed, etc).
Larvae and pupae
  • Larvae hatch where eggs accumulate in the environment and do not move very much, although capable of moving up to 46 cm.
  • Require blood protein found in the feces of fleas.
  • Negatively phototactic, positively geotactic → found at the base of the carpet pile.


  • Adult → egg → larva → pupa → pre-emergent adult → adult Lifecycle Ctenocephalides canis - diagram.
  • Become active and breed at temperatures >10-15°C.
  • Pre-emergent adults will emerge in the spring, or at preferred temperature and humidity, eg when central heating is turned on.
  • Eggs, larvae and pupae develop slowly at spring temperatures, but the speed of development of subsequent generations increases, reaching about 5 weeks in the late summer.
  • Development slows down as temperatures fall, and ceases in winter in an unheated house.
  • Development can continue in a centrally heated house if microenvironmental humidity is adequate.
  • Marked variation in temperatures, eg heating off at night, will increase mortality.


  • Animals become infected by:
    • Newly emerged adults in their own environment.
    • Newly emerged adults in visited environment, eg homes, gardens of other animals.
    • Adult fleas, in particular males, will transfer from one animal to another; less significant.

Pathological effects

  • There are at least 15 allergens in flea saliva. One is a hapten (4-7 kDa) that binds to collagen; others have been identified in MWs 14-150kDa.

Classical progression of the hypersensitivity response

  • Period of hypersensitization with no response.
  • Type IV nodular DTHS reaction appearing about 6-12 hours after the bite.
  • Type I wheal and flare ITHS reaction within 15 min to a few hours of the bite; this is then followed by a DTHS reaction.
  • ITHS reaction only.
  • Possible desensitization.

Response in the dog

  • The response of the dog has not been as well characterized but ITHS, DTHS and type III basophil hypersensitivity are all described in the same or different individual dogs.

Immunological response of individual dogs

  • Unexposed and asymptomatic.
  • Infested and asymptomatic (in a period of sensitization or desensitization).
  • Infested showing flea bite dermatitis.
  • Infested showing flea allergic hypersensitivity.
  • Flea infestation → chronic flea bites → hypersensitivity to flea allergens, eg salivary chemicals → pruritus and self-trauma.
  • Alopecia predominantly on the dorsum of the back at the tail base.

Other Host Effects

  • Depends on blood meals - the female ingests large volumes of blood ( → enlarged abdomen) to maintain high fecal output (provides food in environment for larvae); the male feeds less → less susceptible to systemic insecticides.
  • C. felis not single-host specific, so it can breed if it feeds on dogs, cats and some wild mammals, eg foxes and badgers.
  • If hungry, the flea will feed, but not breed, on other hosts such as farm animals.
  • Body is streamlined for moving quickly through animal coat.
  • Specialized mouthparts for piercing skin, sucking blood, and injecting saliva as an anticoagulant.


Control via animal

  • Three point strategy to control:
    • Eliminate adult flea population on animal.
    • Protect animal against reinfection.
    • Eliminate environmental reservoir of fleas.
  • See Flea Control for more detail Flea: control.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lee S E, Johnstone I P, Lee R P et al (1999) Putative salivary allergens of the cat flea, Ctenocephalides felis felis. Vet Immunol Immunopathol 69 (2-4), 229-237 PubMed.
  • Marsella R (1999) Advances in flea control. Vet Clin North Am Small Anim Pract 29 (6), 1407-1424 PubMed.
  • Dryden M W & Rust M K (1994) The cat flea - biology, ecology and control. Vet Parasitol 52 (1-2), 1-19 PubMed.
  • Heath A W, Arfsten A, Yamanaka M et al (1994) Vaccination against the cat flea Ctenocephalides felis felis. Parasite Immunol 16 (4), 187-191 PubMed.
  • Rust M K (1994) Interhost movement of adult cat fleas (Siphonaptera - Pulicidae). J Med Entomol 31 (3), 486-489 PubMed.

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