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Fleas can be extremely irritating for both pet and owner. Sydney’s hot humid climate means fleas thrive in the environment and all cats and dogs will be exposed. It is important to use regular flea prevention all year round, on your pet and household, to kill adult fleas and prevent a house infestation.

All year round use of flea treatment is recommend to keep fleas under control and always treat all pets in the household.  Due to be being in a high tick risk area on the Northern Beaches we recommend using a flea & tick product all year.

Flea Population 

The adult fleas you see on your pet only make up 5% of the flea population. The other 95% are hiding in carpets, rugs or cracks in floorboards in the form of eggs, larvae and pupae - waiting for the right conditions/timing to emerge as adult fleas. Adult female fleas lay 50 eggs a day. These eggs are shed from your pet into the home environment.

There can also be extra reservoir sources of fleas just outside your door. Fleas thrive in damp, shady areas in your garden and especially under the house. Their eggs can be shed from neighbourhood pets, rodents or native wildlife that has access to your garden or home.

The aim of flea prevention for your pet is to break the flea life cycle by killing adult fleas on your pet and preventing them from breeding or laying fertile eggs.


There is a confusing array of products available on the market for treatment of fleas. Poor understanding of the flea population and how the products work can lead to failure, or perception of failure, of the product.

Whichever product(s) you choose there are a few simple rules to adhere to, to make sure that you get the best result.

  • Read the instructions and apply the product correctly. This may sound obvious but it is a common reason flea control fails. You must ensure that you are using the correct size for your pet’s bodyweight, that you are applying it in the correct way, and that, if appropriate for the product, you have not bathed your pet 48 hours either side of applying it.

  • Treat all pets within the household. Even if you are only seeing fleas on one pet, it is important that you treat all animals in the household, even if they don’t venture outside, otherwise fleas will easily survive on these untreated pets, acting as a reservoir and constant source of reinfestation.

  • Treat your pets all year round. Although in lower numbers during winter, favourable conditions within the home allows fleas to develop all year round. If fertile eggs are laid during winter, they can remain dormant for up to 6 months waiting for warmer weather, with a sudden outbreak occurring in spring. Bomb every room in the house on the same day. Move furniture so that as the flea bombs settle, larvae/ pupae are not protected from the bomb.

  • Treat your house environment with flea bombs or fumigation if you are having an outbreak. Prevent access to areas where fleas could be harbouring such as under the house, basement and bushy areas in the garden where native wildlife such as possums are.

  • Remove eggs and stimulate fleas to emerge by regularly vacuuming and washing the pets’ bedding in hot water (>60 C).

  • Tapeworms can be spread by fleas so make sure you use tapeworm or all-worm prevention on your pet regularly and particularly if you are having a flea outbreak.


There are many flea & tick products on the market.  Finding the best combination for you depends on your circumstances.  Effective products can be bought from veterinary clinics and pet shops.  They consist of tasty chews, spot ons, spray or tablets.  Below is a list of some products we recommend.


Nexgard / Nexgard Spectra Chew  - 1 chew every 4 weeks, will kill fleas & ticks for 4 weeks once given.  Must be given on a full stomach

Bravecto Chew - 1 chew every 3 months, will kill fleas & ticks for 3 months once given.  Must be given on a full stomach

Bravecto Spot On - 1 spot on every 6 months, will kill fleas & ticks for 6 months once applied

Advantix Spot On - apply every 2 weeks for tick or every 4 weeks for fleas

This is toxic to cats - use with caution in households with cats


Frontline Spot On - apply every 2 weeks for ticks or every 4 weeks for fleas

Frontline Spray - apply every 3 weeks.

Apply 4 pumps per kg bodyweight, all over the body - this means the animal is soaked in the product

Seresto Tick/Flea Collar - lasts 4 months for ticks and 8 months for fleas. 

This is water-resistant and remains effective following a shampoo treatment, swimming or after exposure to rain or sunlight. Under normal conditions, effectiveness lasts for 8 months. To maintain an eight-month duration, dogs must not be bathed more than once per month.

With any topical products the animal must not be bathed 48 hours either side of applying the product.


Bravecto / Bravecto Plus Spot On - 1 spot on every 3 months, will kill fleas & ticks for 4 weeks once applied.

Frontline Spot On - apply every 2 weeks for ticks or every 4 weeks for fleas.

Frontline Spray - apply every 3 weeks for ticks or every 8 weeks for fleas.

Apply 4 pumps per kg bodyweight, all over the body - this means the animal is soaked in the product

Seresto Flea Collar - lasts 8 months for fleas.  This is not registered for use for ticks in cats.

Frontline Spray - apply every 3 weeks for ticks or every 6 weeks for fleas.

Apply 4 pumps per kg bodyweight, all over the body - this means the animal is soaked in the product

Comfortis tablets – 1 tablet given every 4 weeks for fleas only.  Kills fleas within 4 hours of giving. 


Never use a dog products on your cat without checking with a vet first. These products have varying efficacy in cats and can be toxic.

Indoor environmental products

Flea bombs or professional extermination are the only ways of treating a house infestation. Once you have an infestation it can take up to 6 months for all the eggs present to mature to adults and come out of the environment naturally.

Your pet(s) will need to be out of the house for the day when the extermination/ bombing is happening, so you often need to prepare for it in advance. While waiting to flea bomb or exterminate the house regularly vacuuming (not sweeping), washing bedding in hot temperatures (>60 C) and using crawling insect sprays under shelves etc can help minimise numbers.

My pet has fleas and I can’t get rid of them. What do I do?  

If you have applied one of the flea products above and you are still seeing fleas on your pet it is understandable to think that the flea product has not worked or has resistance. There is no scientific evidence that there is resistance to any of the products described above, most commonly the problem is due to poor environmental flea control (indoors or outdoors) or product failure due to it being infrequently or incorrectly applied.

If you have a flea infestation, it usually takes at least 2-3 months to get in under control. The key is persistence and consistency. Think about all contributing factors i.e. you must control fleas on your pet and in its environment. Of course preventing an infestation is easier than treating it, so year round flea treatment is advised. If you only start treatment after you are seeing fleas, the flea population will already be difficult to control.

Checklist for controlling fleas and infestations

1. Check if you applied the flea product correctly - was it the right dose for your pet? Had you bathed/or did your pet swim just before or after applying it and the product therefore was not absorbed? Was it out of date?

2. Have you treated all pets in the household? If you have other people’s pets visiting make sure they are up to date with flea treatment too, as they could be shedding fertile eggs into your home environment.

3. Does your pet have access to areas that could be harbouring fleas such as under you house, basements and bushy areas in the garden? Ideally prevent your pet getting access to these areas. Also keep your lawn short (fleas, larvae and pupae live in the top surface layers of the soil, and don’t like being dried out by the sun). Also control rodents as these can a source of fleas.

4. Have you treated the indoor environment? Flea bomb/ have an exterminator treat the house. Make sure all rooms are done, and use a crawling insect surface spray under cupboards/ shelves. To keep numbers down in the mean time you can vacuum, wash bedding in hot water (>60 C) or throw it out. Until the environment is treated, you will continue to see fleas on your pet(s) even if you have applied a topspot/ spray. This is because flea products can take up to 24 hours to kill adult fleas, so you are seeing the new adults coming out of the environment before the product has had time to kill them. This does not mean that the product is not working- as a general rule if you are able to pick off the fleas, they are already in the process of dying- healthy fleas are too fast to catch.

5. Until you can treat the environment as in section 4, we advise using a flea tablet such as Capstar or Comfortis. These will kill adult fleas more quickly than a topspot product, helping to kill fleas on your pet as rapidly as possible to aid in their comfort.

6. Tapeworm or all-worm all your pets as fleas can carry tapeworm larvae.

If you have more questions please don’t hesitate to contact us at Northern Districts Veterinary Hospital for further advice, or to book in for a complimentary nurse consult.

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