Flea control
Wednesday, April 15 2009
There is a bewildering choice of products to combat fleas. How can you tell the good from the bad, and avoid joining the ranks of owners who have spent a fortune without controlling the problem? Or the unfortunate few whose efforts have only resulted in poisoning a pet?
By far and away the safest and most effective route to administering an effective flea control programme is to consult your vet. However, flea control is a complex and frustrating issue, which requires repeated treatments and you may want to shop around for the best price on products.
This is a guide to what’s available. But there is no magic easy cure – fleas have been around for thousands of years and they have evolved strategies to evade our efforts to eliminate them.
Shampoo, powder, spray or spot-on?
There are a variety of forms of flea control. Generally speaking, powders and shampoos are not very effective. They lose their ability to kill fleas a few days after application. The same also applies to many of the commonly available sprays. Some sprays also have the disadvantage that you need to apply the correct amount for the size of the animal or they won’t work or may be dangerous. Quality flea control nowadays usually means using a spot-on – regularly – but they are not all the same and you really do need to know what chemical they contain to make your choice.
Understanding the label
The most important step in flea control is reading the label. Without this, not only do you not know what you are applying, but you may not be applying it correctly, so it won’t even have a chance to work – or worse still, could harm your pet.
Flea infestation or flea allergy?
Many animals have a few fleas without showing any signs at all. A few animals – and people - are allergic to flea saliva, which means that they can become very itchy, scabby and sore following flea bites. Flea control for flea allergic animals can be problematic. There is no flea control product that will kill a flea before it bites, although there are some that will repel fleas. Unfortunately, a single bite can trigger an allergic response.
Points to bear in mind
- The lifecycle of the flea is like a butterfly. Eggs hatch into larvae which then pupate. The adult flea emerges from the pupa.
- Fleas start to feed within minutes of arriving on a host
- They start laying eggs 24-48h after they jump onto an animal
- Flea eggs are very resistant to most chemical methods of treatment
- Flea larvae crawl away from light, down cracks in the floorboards, under furniture or deep in the carpet.
- Dogs, cats and rabbits can share fleas, even if they don’t come into direct contact.
- You can reduce the number of fleas on your pet by regular combing but you won’t completely get rid of them
- Washing your pets bedding weekly helps reduce flea numbers
- Regular vacuuming physically removes some flea eggs and larvae.. The mechanical vibration also encourages hatching of the resistant eggs into vulnerable larvae prior to chemical treatment. Throw away the hoover bag afterwards.
- Fleas – adults, eggs and larvae – can survive outside, especially in the summer months. Drying and direct sunlight reduce numbers, so regular cutting of the lawn can be helpful
Ten Steps to flea control
- Read all label instructions with care. Ensure that you only use a cat product on a cat and a dog product on a dog, and that you do not use a treatment intended for the household environment on the pet.
- Be particularly cautious with tiny or young pets – many products are not suitable for use on kittens or puppies. If your pet is pregnant or feeding pups or kittens, check that the product is safe to use.
- Treat all household dogs and cats with a low toxicity product which will retain its activity for several weeks. Fipronil, imidacloprid, metaflumizone or selamectin are some examples of good choices. Try to get a formulation that also includes a growth inhibitor, or buy one for separate use. Using a growth inhibitor prevents the development of any eggs laid during the “lag” period, from when the flea jumps on the pet to its kill by the insecticide.
- It is best to wait until children are in bed before application. Owners should not sleep with recently treated pets.
- Exclude untreated animals from the house. Ask your vet for advice on treating small pets such as rabbits or ferrets.
- Wash or discard pet bedding, at the highest possible temperature.
- Hoover well, and throw away the bag contents outside the house.
- Apply a product which will kill adult fleas and larvae, and contains a growth inhibitor, to every room in the house.
- Repeat all treatments at the minimum intervals recommended on the label. Most products applied to the animal need doing monthly.
- If your pet is flea allergic, consider using a daily nitenpyram tablet. This won’t prevent flea bites, but it is one of the most rapid ways of getting fleas to jump off your pet.
FAQs
- Why did I find a flea on my pet 3 days after applying a fipronil spot-on? After fleas jump on your pet, it can take 24 hours for the product to kill them. They may have come from outside or from eggs or larvae in an inaccessible area in the home
- Is there anything I can do to completely stop my pet from being bitten? It’s pretty much impossible to completely prevent a bite but you can drastically reduce exposure by treating the house, treating the pet regularly and using a growth inhibitor. This ensures that if fleas are acquired outside, any eggs they lay before they are killed don’t develop.
Table of flea control products
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Chemical name
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Available forms
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Advantages
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Disadvantages
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Fipronil
Imidacloprid
Metaflumizone
Selamectin
Pyriprole (for dogs only)
Note that these are not chemically related, but have similar actions, interfering with the nervous system of the flea to cause paralysis and death.
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Spot-ons, pump action spray for fipronil
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Relatively safe with low mammalian toxicity
Kills fleas within 24h of their arrival on the animal
Retains high activity for 30 days
Selamectin has some activity against flea eggs
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Can cause skin irritation at the site of application, also can leave oiliness or spiking of hair
Can cause excessive drooling or mild tummy upset if incorrectly applied so animal can lick it
Bathing or swimming can reduce efficacy
Fipronil, imidacloprid and pyriprole are
toxic to fish, bees and some birds.
Owners should not sleep with recently treated animals
Some formulations of metaflumizone
are combined with amitraz, which must not be used on cats
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Pyrethrins and pyrethroids – e.g permethrin, transallethrin, resmethrin, fenvalerate, and many other chemicals ending in “thrin”, often mixed with piperonyl butoxide, to increase their potency
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Found in shampoos, powders, sprays, collars, spot-ons, household sprays, powders and foggers, etc
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Rapid kill on contact
Pyrethrins are extracted from chrysanthemums, so a “natural product”
Pyrethroids are the manufactured form of the same chemical.
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Frequent cause of poisoning in dogs and cats, can be fatal. Potentially very toxic to cats, great care required with their use, contact with a recently treated dog can be dangerous for a cat . Lose their strength in sunlight so poor residual action.
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Lufneron, s-Methoprene, pyriproxifen, cyromazine, etc
Not a chemical group, but all inhibit insect development – known as “IGRs”
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Tablets or medicines, spot-ons, household sprays, foggers, and powders, injectable form of lufneron available from vets
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Appear very safe, prevent flea development so are an vital part of flea control
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Don’t kill adult fleas, only prevent development of eggs
Need repeating regularly, usually monthly
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Organophosphates e.g. chlorpyrifos, diazinon, fenthion, dichlorvos, malathion and phosmet
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Collars, environmental sprays
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Some have rapid onset of action
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Concerns about their toxicity to people
Potentially toxic to animals, especially cats
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Carbamates e.g. propoxur
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Collars, environmental sprays
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Similar to organophosphates but less toxic
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Still potential for toxicity
Little residual action
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Nitenpyram
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tablets
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May be helpful for flea allergic animals as they start to work within 15 minutes, and have eliminated most (but not all) fleas within 6 hours
Low toxicity to dogs and cats
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Need daily dosing
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Garlic, brewers yeast, Vitamin B
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tablets
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Not proven to be effective against fleas
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Garlic is potentially toxic to cats
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citronella
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Oil or cream
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Not proven to be effective against fleas
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Potentially toxic
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D-limonene and other essential oils
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Shampoo, soap or dip
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“Natural” products
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Potentially toxic and poisonings have occurred in both dogs and cats. Cats especially are at risk.
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Boric acid or diatomaceous earth
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Household powder
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Variable efficacy and some safety concerns
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Courtesy of Caroline Reay