Insecta Siphonaptera

What are Fleas?

Some may have heard of the fantastic flea circus, but fleas are generally better known for their annoying, itchy and sometimes painful bites. Fleas are parasites and feed on the blood of warm-blooded animals, including humans.

Fleas can spread diseases and parasites. In the 14th Century, fleas were responsible for the spread of the Bubonic Plague, killing more than 200 million people. Nowadays, cat-fleas can transmit tapeworms from dogs and cats to humans; and in rare cases, rat-fleas can transmit the disease typhus from rats to humans. Some people have allergic reactions to flea bites, or may even develop secondary skin infections. Dogs can be vulnerable to severely itchy dermatitis caused by flea bites.

Given the risks of fleas to human and pet health (and comfort), it’s important to prevent and control fleas in the home.


The most common flea is the cat-flea (Ctenocephalides felis) which can live and breed on cats or dogs and also feed on humans.

Fleas are very small insects and depending on the species and age of flea, range in size from 1 to 10 mm long. After engorging themselves on the blood of their host, fleas can swell up to 30% larger than their original size.

The body of the adult is flattened from side-to-side so as to appear very thin and long from above, but mostly oval shaped when viewed from the side. The body is heavily segmented and covered in hairs which face backward. Fleas come in colours of light-browns, reddish-browns and dark-browns.

The head is small with a rounded front. On either side of the head are two, very small, simple eyes. At the front and underside of the head is a row of downward facing comb-like structures which resembles a moustache. At the front and underside of the head are needle-like mouthparts used to pierce the skin of their host, inject a special form of saliva (to prevent blood coagulation) and suck out blood. While fleas do have antennae, they are difficult to see as they are short and often sit into little grooves on either side of the head and behind the eyes. On the back of the neck is a row of back-ward facing comb-like structures. Body hairs, combs and spines help fleas remain safe and secure on their host.

Behind the head, on the underside and middle section of the body (thorax), are three pairs of spiny legs. The hind pair are used for jumping allowing the flea to jump up to three hundred times its height. At the tip of the legs are strong claws used for holding tightly on to their host. Fleas are wingless.

Flea larvae are grub-like, eyeless, legless and hairy. The head is brown and the body is a white-to-cream colour. After feeding on remnant or excreted blood from adults, larvae take on a reddish colour.


After emerging from the pupal stage and feeding on their first bloodmeal, adults are ready for mating. After mating and feeding on blood, females deposit up to 4 eggs at a time. One female can lay up to 100 eggs in her lifetime. Eggs are oval, cream-coloured and very small. Eggs are generally less than 0.5 mm long and similar in appearance to grains of salt. Eggs are laid directly on to a host in a nest and hatch within 1 week. Unlike adult fleas which feed on blood, larvae feed on dead skin; remnant and excreted blood from adult feeding; and other material available on the host. At each of the 4 stages of growth development (instar) larvae shed their skin (moult). After 1 to 3 weeks of feeding and moulting, larvae spin a silk cocoon for pupation which is often covered in skin, animal fur/hair or carpet fibre for camouflage. After pupating, fleas emerge as the adult form. Depending on the species and environmental conditions, the flea life cycle is approximately 2 weeks to 8 months.


Fleas are found anytime of year however peak season is spring and early summer, when conditions are warm and humid, favouring larvae and adult growth and development.

Fleas can be found living and feeding on warm-blooded animals such as humans, cats, dogs, rabbits, rats, mice, birds and various other animals. Fleas can be specialist feeders, feeding primarily on one type of animal; or generalist feeders, feeding on a variety of different animals.

Places fleas can be found:

  • animal bedding and housing such as kennels and chicken coups.
  • carpets, especially along the fringes.
  • along skirting boards, window sills, and other areas of the house where dust and other particles collect.
  • soft furnishings, especially in crevices and seams, underneath pillows and cushions, beds and bedding.
  • outside where it is warm, humid and shady. Fleas are often found in long grass, under bushy plants, open areas under the house, woodpiles and under piles of leaves.


Fleas are attracted to heat, vibrations, humidity and carbon dioxide, most of which are detected using their antennae. Fleas can remain dormant in the larval and pupal stage for many months without feeding. After disturbance, larvae awaken from a state of hibernation and pupae emerge as adults.

On humans, fleas more commonly bite feet, ankles and legs, whereas on pets, fleas will attack areas where it is warm and moist such as armpits, groin and ear, however bites can occur almost anywhere on the body. Fleas are often found on cats and dogs behind the neck and at the base of the tail.

How to get rid of Fleas

To properly control fleas in the home, ensure all pets and humans, plus all areas in and around the house and garden, have been thoroughly treated simultaneously. In only one area is focused on at a time, fleas will move from one area to the next, resulting in reinfestation. Repeat the same protocol within a few weeks of initial treatment to ensure any remaining eggs do not hatch and pupating larvae do not emerge as adults.

Control Fleas in the home:

  • To control fleas outside and prevent fleas from entering the home, try Blitzem! Ant, Flea & Tick Killer. Pour the easy-to-apply sand formulation around the outside of buildings including gardens, lawns and around animal/pet housing. Flea larvae develop in the soil of shaded areas that are accessible and frequented by pets or other animals. Apply to these areas and for best results thoroughly water the treated area immediately after application. Use higher application rates when treating areas with dense groundcover or heavy leaf litter.
  • Thoroughly clean the house. Vacuum and steam-clean carpet and soft furnishings. Clean inside cupboards. Please read below section on “How to prevent Fleas appearing” for more handy tips for controlling and preventing fleas in and around the home.
  • Wash all infested items in hot water in the washing machine. To dry, place items in the dryer or outside on a hot and sunny day.

Control fleas on pets and in animal houses:

  • Ensure pets are treated using veterinary approved and animal specific flea killer and preventative products such as shampoos, sprays, dusts and medication. Contact your vet for further information and advice.
  • Wash pet bedding and mats in the washing machine, preferably on hot.  Dry in the dryer or outside on a hot and sunny day.
  • To stop the spread of fleas, do not allow the pet to go near other animals until the pet has been cleared of infection. Avoid having infested pets inside the home, especially in the bedroom.

First aid and safety:

  • Apply an ice-pack and visit your local chemist for suggestions on topical treatments and/or pain relievers.
  • Avoid scratching to prevent potential secondary skin infections.
  • If symptoms worsen or if allergic, seek urgent medical assistance. 


Symptoms of Flea damage


In humans and pets, flea bites can present as itchy, red, swollen and/or lumps on the skin, typically occurring within 30 minutes. In some cases, a bite may further develop into a blister or wound, sometimes leading to infection. Constant scratching may result in hair loss.

Flea infestation cannot be identified based on the evidence of bites alone. Bites are nearly indistinguishable from other pest attack such as Bed Bugs, Mosquitoes, Spiders, Ticks and Lice. Check pets and all areas fleas are known to inhabit (see habitat).

Further evidence of flea infestation includes:

  • Living adult or larvae. On pets, these can be found using a special comb.
  • Faeces - black to brown coloured, very small and granular looking, similar in appearance to grains of pepper. On pets, part the hair/fur and place a moistened piece of white tissue onto exposed skin having dusty specks.  If it is flea faeces, specks will develop into red rings on the tissue. Similarly, to identify flea faeces in the home, use the same method but with a moistened white sock.
  • Eggs - oval, cream-coloured and very small. Eggs are generally less than 0.5 mm long and similar in appearance to grains of salt.


How to prevent Fleas appearing

  • Control hosts such as Rats and Mice in and around the home.
  • Stop pets and other animals from going under the house or going into the roof by closing off areas using a barrier.
  • Remove any bird, rodent or other animal nests from in and around the home.
  • Regularly check pets for signs and symptoms of fleas.
  • Where possible, avoid having infested pets inside the home, especially in the bedroom.
  • Regularly wash pet bedding and mats.
  • Regularly clean indoor areas including vacuuming along skirting boards, inside cupboards and under furniture. Dispose of vacuumed material into a plastic bag, seal, then dispose of in the rubbish bin.
  • Steam clean fabric furniture and carpets.
  • If moving into a new house, especially when pets were previously living in the residence, thoroughly vacuum and clean the house prior to moving in. Apply Blitzem! Ant, Flea & Tick Killer around the outside of buildings including gardens, lawns and around animal/pet housing.
  • Avoid purchasing second-hand furniture, clothing and accessories, otherwise thoroughly inspect for signs of flea eggs, larvae and adults, prior to bringing into the home.
  • Avoid having debris around the home such as piles of wood or leaves where fleas are known to inhabit.
  • Ensure the lawn is regularly mown.

Recommended products

Blitzem! Ant, Flea & Tick Killer

Sand formulation which provides a barrier on outdoor surfaces, controlling ants before they get inside the house. Ideal for paths & pavers.

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