Fleas in New Zealand

  • Fleas are small, flightless insects belonging to the order Siphonaptera.
  • There are approximately 2,500 flea species and they are parasites of mammals and birds, requiring a blood meal to reproduce.
  • Although fleas are well known for their role in transmitting the bubonic plague, in developed parts of the world they are more likely to transmit typhus disease or tapeworm larvae.

Cat Flea, Ctenocephalides felis – Adult and larvae


Fleas are an occasional but annoying pest. With the wide range of pet flea control products available, infestations are far less common. However, it’s not uncommon for pet owners to forget a pet flea treatments and even homeowners without pets can suffer a flea infestation, when they are brought into the yard or home by stray pets, pest rodents and native animals.


Three of the main species are:

  • Cat flea, Ctenocephalides felis
  • Dog flea, Ctenocephalides canis
  • Human flea, Pulex irritans

Although the names of the flea suggest they are specific to an animal that is not the case. For example, the cat flea will happily live on both cats and dogs as well as other mammals, such as humans.


Fleas undergo a complete metamorphosis – a complete change in body form from the larva to the adult. Under favourable conditions the life-cycle can be completed in as little as 2 weeks. In unfavourable conditions, where there are no suitable hosts for a blood meal, the fleas can survive in their pupae stage for many months.

The main flea season is during the summer months as the warm, humid conditions are more favourable for the larvae. However, outbreaks can still occur in winter, especially in heated houses.

Flea eggs

Flea eggs are difficult to see, being no bigger than 0.5 mm and an off-white colour. The female lays eggs singly on the host, but can lay up to several thousand during her lifetime. They are not sticky and so tend to fall off the host, being spread wherever the animal moves. The biggest concentration of eggs will be around the pet’s resting places. The eggs hatch after 2-14 days.

Baby fleas

Baby fleas are more accurately called larvae. They are small, translucent worms, with small bristles, no more than 3 mm long. Outside they will live in sandy soil and in shady areas – just the places pets like to rest. Inside they will hide in the carpet, furniture and gaps in floorboards. They are negatively phototactic, which means they move away from light. They easily dry out and die, which is why they thrive in damp areas and when the weather is humid.

The larvae feed on organic material including the digested blood in adult flea droppings, dead skin and hair. They take between 4-18 days to grow to the point they are ready to spin a cocoon and develop into an adult.

More information on flea larvae.

Flea pupa

When ready to develop into an adult, the mature larva spins a cocoon. Surrounding  material (dirt, carpet fibres, etc) stick to the cocoon making it difficult to spot.

The cocoon is virtually impervious to insecticide treatments – one of the reasons why it can be difficult for homeowners to get on top of an infestation.

It can only take as little as a couple of days for the larva to develop into an adult. However, the adult will not emerge unless it knows there is a potential host (meal) nearby. They can detect the presence of a potential host through vibrations. As soon as it detects the vibrations of a large animal, the adult will burst out of the cocoon and jump onto the host.

Adult flea

As most people will know, fleas can jump! They can jump vertically up to 18 cm. This skill is particularly useful as it allows the adult to emerge from the cocoon (on the ground) and jump up onto a passing animal.

As long as the adults have access to regular blood meals, they can live for several months. The females need to have a blood meal before laying eggs.


Apart from the annoyance and irritation from bites during an infestation, fleas can transmit disease. The oriental rat flea, Xenopsylla cheopsis, is the main vector of the bacterium, Yersinia pestis, which causes the ‘black death‘ or bubonic plague. They also transmit a variety of other diseases, such as typhus and also carry parasites, including tapeworms. But actually very little is known about the full range of diseases fleas may carry.

However, for most people a flea bite is just irritating, although they can remain itchy and inflamed for up to several weeks.


To get rid of fleas, comprehensive treatment is required. A flea bomb inside the house generally doesn’t cut it, as to eliminate infestations, all the areas where the pet has been needs to be treated, both inside and outside the house. (Of course the pet needs a flea treatment too!).

A professional flea treatment

As with every professional pest treatment, a comprehensive inspection prior to treatment is essential. The pest professional will inspect areas inside and outside the home, to identify the flea hotspots.

The treatment will involve spraying all areas inside, outside and under the home where fleas have been identified – particularly the pet resting areas.

The pest professional will use a combination of long lasting insecticides and special chemicals called insect growth regulators. These chemicals break the breeding cycle and provide long lasting control, preventing re-infestation for several months.

The treatment will leave a residual layer of insecticide on the surface to take care of any adults emerging from their protective cocoons after the treatment. Some professionals will also book in a second visit, a week or two after the initial treatment, just to make sure these late emerging adults have been controlled.

From a safety point of view, any pets will need to be kept clear of the treatment areas during application and until the treatment has dried. But once the treatment has dried, the pets are free to re-enter – these professional treatments are designed for flea treatments in homes with pets.

The pest manager will also provide you will a range of other recommendations, such as speaking to your vet about updating your pet’s flea treatment, and the need to clean furnishings and throw out any pet bedding.

Our magazine article has more information on fleas and professional flea treatments.


Flea bombs or foggers are a popular treatment for homeowners. However, although a flea bomb treatment may provide temporary relief, it is very common for the problem to return.

There are two key reasons why homeowner DIY treatments using flea bombs tend to fail; firstly the treatment is not comprehensive – they have not treated all sites of the infestations both inside and outside the home and secondly, the treatment does not deal with the pupae which are resistant to insecticides – these will hatch 1-2 weeks after a treatment.

A professional flea treatment will provide both a comprehensive treatment and complete control of the infestation.


For pet owners:

  • Ensure pet flea treatments are kept up to date
  • Regularly wash pet bedding in hot soapy water

For all homeowners:

  • Ensure good hygiene – make sure living areas are regularly vacuumed
  • To prevent fleas being introduced to your property:
    • Make sure any rodent problems are dealt with promptly
    • Prevent the entry of neighbourhood cats, stray pets and any native animals into any under house areas

Check out our library for more information on pest control fleas.