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The most common flea found on dogs is the cat flea (Ctenocephalides felis). These microscopic insects suck blood, causing irritation and, in some cases, severe itching. Some pets can also suffer from flea allergy dermatitis (hypersensitivity to a flea's saliva) that may cause intense skin inflammation from a single flea bite.
A common myth is that only pets in poor condition become infested with fleas. While it's true that pets with an impaired immune system are more likely to succumb to parasites, even pets in the best of health are at risk.
None of us want to use more chemicals than absolutely necessary, and there are a number of alternative treatments for flea infestations. Some of these are traditional methods that were used to eliminate fleas before the advent of modern pharmaceuticals, whereas others are championed as natural, non-chemical methods for flea control. It's important to remember, though, that 'natural' does not always mean safe.
The first thing to note about essential oils is that they are produced by distillation and are highly concentrated, so they could actually be toxic to your pet if used carelessly or incorrectly. It also means they often have strong fragrances, which could irritate your pet's airways.
You can try applying small drops of oils such as lavender, cedar and lemon to your pet's collar, or diluted and sprayed over their fur. The active component of lemon, limonene, is extracted from citrus peel and is an effective insect repellent and home cleanser - but be aware that limonene can lead to liver damage and has been known to cause skin irritation in pets as well as people.
Overall, be very careful when using limonene or any other essential oils as a flea treatment.
Apple cider vinegar has been heralded by many as being able to provide health benefits for many pet ailments when added to their water or food.1 Some even advocate using it as a rinse after shampooing. However, there have been very few scientific studies investigating its efficacy or any side effects it may cause. As a result, we don't really know how much is safe to use, or at what frequency, when treating any pet-related disease, including flea infestations.
Garlic has no lasting health benefits for your pet and can be very dangerous, even toxic, when given in large doses. Advocates of garlic do feed small amounts daily for a number of purported benefits, but its use as a flea treatment has recently been debunked.2
Commercially available prescription treatments are the result of rigorous scientific research and testing to ensure that your pet receives the safest and most efficacious medication available. On the other hand, concerns have recently been raised about the environmental impact of the active ingredients, causing some pet owners to re-consider.
Imidacloprid is an active insecticide known to kill adult fleas and the larval stages of the flea. As well as fleas, medications containing imidacloprid can be applied if your pet has an infestation with biting lice, mange, or ear mites. It is used in solutions designed for monthly application to a dog’s skin (usually between the shoulder blades) and has minimal side effects – although there have been rare occurrences of itching, skin rashes and vomiting, with occasional hypersensitivity reactions at the site of application.3
You should avoid bathing your dog (or allowing your dog to swim) for 48 hours after application.
Commercial products often combine imidacloprid with moxidectin in order to also treat worm infections in a single application, but there has been some resistance to this. If your pet is a Collie, Old English Sheepdog or a related breed, special care should be taken to correctly administer the product, as well as monitor for any adverse effects.
By spreading across the body of your dog through the natural oils of their hair and skin, fipronil stays on for up to month – killing all fleas and any ticks within 24 to 48 hours and also making sure none of the larvae survive.
Fipronil-containing medications can also be used to treat infestations with lice and a variety of ticks and mites in dogs, while sprays can be used to treat your pet's bedding and environment. If your pet has skin damage from scratching, speak to your veterinarian before using topical pesticides.
A recent study, published in the journal 'Science of the Total Environment', discovered that highly toxic insecticides – including fipronil and imidacloprid – are poisoning rivers across England.
Fipronil was found in 99% of samples from 20 rivers across the UK, at an average concentration five times higher than the chronic toxicity limit. Imidacloprid was found in 66% of samples. Scientists said it was 'extremely concerning' for water insects, as well as the fish and birds that depend on them.4
Environmentalists and scientists are calling on pet owners and veterinarians to reconsider the month-in, month-out treatment of pets, particularly in winter months when fleas are less common.
Fluralaner is available in chewable tablet form for dogs and is given at 12-week intervals for the treatment and prevention of fleas. Essentially, fluralaner prevents messages from traveling between nerves in the flea, causing the paralysis and death of the flea before they can lay eggs.5 It is also licensed for the treatment and control of a number of ticks that can transmit disease to your pet, albeit for a shorter time. If your pet is younger than six months old, this medication is still safe, however it may not remain in their system for as long as 12 weeks.
Side effects in dogs are uncommon but may include short term diarrhoea and excess saliva production after dosing. If your pet is pregnant, you should discuss the use of fluralaner with your vet before administration, due to the possible effect on unborn puppies.
A key advantage of a tablet format is that you can be sure your pet has taken their medication. There is also no need to restrict bathing after treatment.
Spinosad was the first oral flea medication available. As with other medications, it interferes with the flea's central nervous system, causing the paralysis and death of fleas within thirty minutes of ingestion. Generally available in tablet form and used in monthly doses, it is advisable to give it to your dog after feeding to maximise the medication's absorption.
If your pet suffers from flea allergy dermatitis, a flea bite allergy causing intense skin irritation, preparations of spinosad have been used to help reduce the symptoms.6 As with oral fluralaner, you can be sure your pet has received his or her treatment and you can bathe your pet as normal. However, as it’s difficult to accurately dose very small pets, vets don't recommend using medications containing spinosad in dogs weighing less than 1.5kg.
There are many more flea treatments available for your pet, on and off prescription. Treating fleas is perfectly manageable for any pet owner, as long as you understand how to do it safely. It's always advised that you discuss any treatments with your veterinarian.
1The Benefits of Apple Cider Vinegar to Dogs, Whole Dog
2Can Garlic Help Keep My Dog's Fleas Away?, Vetstreet
3The Use of Imidacloprid (Advantage®) in Dogs and Cats, Pet Education
4Contamination of English rivers with pesticides commonly used as flea treatments University of Sussex
5Williams, H at al. (2014). Fluralaner, a novel isoxazoline, prevents flea (Ctenocephalides felis) reproduction in vitro and in a simulated home environment, Parasites & Vectors
6Dryden M. Flea Allergy Dermatitis MSD Manual
Healthspan pet supplements are not intended to replace a well-balanced diet for your pet.