Fleas make life miserable for many of our canine family members. They are the most common external parasite of dogs and have bothered animals for a very long time: they are thought to have been in existence for around 60 million years.
These little blood sucking insects have a number of effects on dogs. The most easily recognised is that fleas irritate their skin and make them scratch. They also spread the flea tapeworm, Dipylidium Caninum, and if there are a lot of fleas on a dog, they may well drink enough blood to cause anaemia. This can be fatal in puppies. But with the right knowledge, and an awareness of your dog’s vulnerabilities, it needn’t be anything to worry about.
Where do fleas come from?
Fleas don’t always spread directly from dog to dog, so this means that your pooch might not just be picking them up from their canine playmate or by coming in contact with the dogs next door. Dogs can also acquire a flea infestation from the environment they’re in.
Mature fleas lay eggs on their canine host, which fall off onto the ground or into the carpet. They then hatch into larvae. These larvae spin a cocoon and turn into pupae. When the young adult fleas emerge from their cocoon, they start looking for a dog to jump onto, and when they find one, they start feeding within a few minutes.
It can be seen from the flea’s lifecycle that there are a number of scenarios where a dog may pick up a flea or two. You could walk your dog through a park or reserve where there are immature fleas in the ground. Your neighbour’s pets could have an infestation; fleas aren’t bothered by fences and the newly hatched adults could make their way into your garden. If you move into a new home, there could be immature fleas in the carpet and lawn just waiting to pounce on your pooch.
How you can control fleas on your dog
There are two aspects to flea control in dogs. Firstly, it’s essential to kill adult fleas that are living and feeding on your pet. Secondly, if you can control the immature flea stages in the environment then you can reduce the number of newly hatched fleas that jump onto your dog.
To treat the fleas already on your dog, there is quite a selection of products to choose from. Shampoos usually contain pyrethrins which do kill fleas, but the killing effect is lost when the lather is rinsed off. Flea collars are not commonly used these days because there are better alternatives available.
One of the most popular types of product that pet owners use to control fleas on dogs is the monthly spot-on treatment where liquid is applied to the skin of the dog’s neck and back. They’re particularly useful for dogs that are fussy eaters and won’t take an oral medication.
The oral flea control products are very effective and will kill fleas for between one and three months. Some products control other parasites at the same time.
Some pet owners prefer to use more natural products to control fleas but this isn’t ideal. Natural products aren’t necessarily effective and can actually cause harm to your pet1,2.
Whatever product you use, it’s essential that it’s used according to directions. This means that you should choose the appropriate sized product for your pet, and use it as frequently as recommended. By doing this, you make sure that it does the job while avoiding side effects. There have been concerns that fleas are becoming resistant to insecticides, but one study has suggested that this is likely to be because flea control products haven’t been used correctly3.
When it comes to controlling fleas in your pet’s environment, you can really only manage that which is under your control. You can’t do anything about fleas in the park or in your neighbour’s lawn. However, it’s still worthwhile making the effort to keep your own home flea free. This involves frequently vacuuming carpets, rugs, and soft furnishing to remove flea eggs, larvae, and pupae. Your dog’s bedding should be washed in hot water regularly. Flea foggers can be used indoors to kill fleas and also to break their lifecycle — these products interfere with the intermediate life stages’ development into young adult fleas. Consider your garden too. You may wish to use a lawn spray to kill fleas, or at least keep your dog away from dry dusty patches of your yard where fleas may be more likely to be found.
When flea control doesn’t work
There may be times when you think that your flea control products aren’t working because you can still see fleas on your dog’s coat. There are a few reasons why this might happen, and it’s not because the product is faulty.
Firstly, you may have a new batch of adult fleas emerge from pupae that have lain dormant in your dog’s environment. It’s possible for adult fleas to emerge as much as one year after the larvae have pupated. Pupae are very resistant to chemicals and can survive an insecticidal assault, so it’s not surprising fleas can survive and continue to emerge from their pupae for some time after you’ve sprayed your home and yard. But all is not lost. The young adult fleas that then jump on your dog will soon die if you’re using a reliable spot-on product.
Secondly, if you walk your dog at all they’re very likely to pick up more fleas from the park or forest. You may even have an ongoing reservoir of fleas in your own yard if you have stray animals wandering through. This is unavoidable but can be well managed if you use a good flea control product on a regular basis.
The treatment of fleas in dogs has changed over recent years. There’s now a better understanding of the flea lifecycle and how it can be interrupted. Newer products are more effective, easier to use and safer for our pets. An integrated flea control program involves killing fleas on your pet and removing fleas from the environment to prevent re-infestation. By following both these steps, you’ll effectively protect your dog from the adverse effects of these annoying little parasites.
For more information on flea prevention and treatments, head on over to our expert advice centre.
1Genovese, AG, McLean, MK, Khan, SA, 2012. Adverse reactions from essential oil-containing natural flea products exempted from Environmental Protection Agency regulations in dogs and cats. J Vet Emerg Crit Care., 22(4), 470-5. 2Villar, D, Knight, MJ, Hansen, SR, Buck, WB, 1994. Toxicity of melaleuca oil and related essential oils applied topically on dogs and cats. Vet Hum Toxicol., 36(2), 139-42. 3Rust, MK, 2016. Insecticide Resistance in Fleas. Insects, 7(1), 10.
Author info: Dr Audrey Harvey is a graduate of the University of Queensland, Australia, and has worked in small animal practices for 25 years. She is particularly interested in obesity management and the role of exercise in resolving behaviour problems in dogs.