Common Flea Species

The main concern about fleas and ticks is usually the distress and discomfort that their bites may cause you or your beloved pet. Learn more about the lifecycles and habits of these blood-suckers that are commonly found in Hong Kong.

Cat Flea

(Ctenocephalides felis)

Cat fleas are often unable to determine whether a host is suitable until it has been bitten. If it is deemed unsuitable, the flea soon drops off.

Appearance

  • Cat fleas are 3mm long wingless ticks, flattened from side to side with long legs enabling them to jump.
  • They have both genal and pronotal combs (ctenidia), differentiating them from most other fleas of domestic animals.

Lifecycle

  • Fleas pass through four stages: eggs, larva, pupa, adult. The eggs are small and white. These stages combined vary from two weeks to eight months.
  • The adult flea is awakened by the detection of vibration of pet or human movement, pressure, heat, noise, or carbon dioxide for potential blood meals.
  • A cat flea cannot complete its life–cycle feeding only on human blood.

Habits

  • Cat Fleas will bite humans, but they do not live on the human body. They will bite the hands and body when handling pets or pet bedding, but the most common place for flea bites are the feet and lower legs. 
  • There are usually many more fleas living on carpets and pet bedding than on the pets themselves; they will jump up and bite people as they come close.
  • Cat fleas nest where the host is in its usual resting place, for example the cat basket. This is where the young often drop to mature.

Dog Flea

(Ctenocephalides canis)

Adult Dog fleas feed on the blood of dogs and cats, and they occasionally bite humans.

It is a vector of the Dog Tapeworm, Dipylidium caninum, which can also affect humans.

Appearance

  • Adult is brownish black in colour, but appear reddish–black after a blood meal.
  • Adult dog fleas are 1 to 4 mm long. The legless larva is off–white and measures up to 5 mm long.

Lifecycle

  • The fleas go through a four–stage life cycle: eggs, larvae, pupae, adult.
  • The larvae are longer than the adults and feed on particles of dry blood, excrement, and organic substances.

Habits

  • The body is laterally flattened, which allows it to move easily through an animal’s fur. Spines project backwards from the body of the flea, which help it to hold onto the host animal during grooming.
  • As they can jump approximately 6 inches, they can move from host to host. They can also infest garden lawns.

Human Fleas

(Pulex irritans)

Human fleas have evolved to specialise on different animals, but the human flea that lives on people (and some animals with similar skin) is now uncommon in this country. The exception is around farms where human fleas are found on pigs and these can jump to humans. Human fleas will bite anywhere on the body and are associated with itchiness as fleas crawl over the skin.

Appearance

  • Adult fleas are approximately 2.5 mm long and are dark in color, ranging from brown to reddish brown. Fleas are wingless, although they are capable of jumping large distances from host to host as a result of their six long legs. Individual fleas are difficult to kill by hand and typically require chemical treatment.
  • The bodies of fleas are thin and flat, allowing for easy movement through an animal’s fur. Their bodies are also covered in hair that serves to root them to the host. Adults have mouthparts which are used to extract the host’s blood.
  • Fleas are commonly visible moving in infested pet’s fur. Their presence may be marked by reddened skin.

Lifecycle

  • 5 weeks – 1 year dependant on conditions.
  • Female fleas lay 4 to 8 eggs after each blood meal and may lay several hundred eggs in their lifetime. These may hatch in 2 – 3 days and given an adequate supply of food, larvae should pupate and weave a silken cocoon within 3 - 4 weeks, after completing 3 larval stages. 
  • Under favorable conditions, the adult emerges in a week or two, but under adverse conditions, the pupal period may be prolonged to as much as a year.

Habits

  • Are parasitic as adults and are found on dogs, rats, pigs, badgers etc. Eggs are laid on the body but are often detached. 
  • Larvae are usually found on floor or bedding of the host and often feed off the faeces of adult fleas. 
  • The adult can remain in the cocoon for long periods until vibrations indicating the presence of a possible host stimulate it to emerge and become active.

Dog Tick

(Rhipicephalus Sanguineus)

Appearance

  • Reddish–brown colour. 
  • Elongated body shape.

Lifecycle

  • The dog tick is a 3–host tick, so must change host between the 3 stages of growth (larva, nymph and adult). 
  • They require only three blood meals to complete development; once at each growth stage.

Habits

  • It is found on dogs, in kennels and houses, and occasionally on wildlife, but rarely on humans. 
  • In warm areas several generations of tick can be expected per year. 
  • The most common places for attachment on dogs are those areas the animal is unable to groom easily.

Further Information & Next Steps

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