Why is it important?
Fleas are the biggest cause of skin disease for UK pets - even now, with so many great products on the market, they're still present living on cats across the country! There are two reasons they're hard to get rid of - firstly, they can jump from cat to dog to rabbit to human to cat and so evade us; and second, 95% of the fleas aren't living on the animal, but hiding away in your home, waiting for their chance.
OK, let's look at the details...
There are a number of phases to getting your home "Flea Free", but they sit easily into two categories. Firstly, kill the adults, then break the life-cycle!
(1) Herbal and homeopathic remedies
Herbal flea remedies are notoriously unreliable - what works in one cat fails completely in another. We do not recommend homeopathic remedies alone, as they are complementary, not alternative, medicines.
(2) Over-the-Counter Flea Drops and Powders
There are a wide range available, at very cheap prices. However, remember that, with medicines as with everything else, you get what you pay for. Over-the-counter products from pet shops or supermarkets are unlikely to be as effective as prescription-only or vet/pharmacist only products - not least because these often do not need to prove their effectiveness. There have also been MAJOR problems in recent years with unscrupulous manufacturers rebranding dog medications for cats, with fatal effects - many dog flea treatments contain permethrin which, while safe in canines, is fatal to cats.
(3) Prescription Flea Spot-Ons
There are a lot of different spot-on medications, containing different ingredients, but they all work by killing the fleas. The most common contain fipronil, selamectin or imidacloprid, but there are others as well. These medications have to prove their effectiveness before being given a license; however, remember that many aren't waterproof and will wash out if you give your cat a bath or even if they spend a lot of time outdoors in wet undergrowth. On the other hand, these are often effective against other parasites, such as ticks or mange mites. Of course, you can only get these from, or with a prescription from, your vet.
(4) Flea Tablets
There are a number of different brands, and different active ingredients available now; these have the advantage that they cannot be washed off. They do still need to be repeated periodically though - like all medications, they won't last for ever! Some over-the-counter tablets only last for 24 hours, whereas some of the prescription-only products last a whole month.
(5) Medicated Collars
Available as a prescription-only medication, these are effective for up to eight months, and also treat and repel ticks. The collars also contain a safety-catch so the cat cannot become hung-up or injured by - instead, the collar will open allowing the cat to escape.
(6) Environmental Control Medications
Some flea products contain ingredients called Insect Growth Regulators, that effectively put the fleas on the pill so they only lay non-viable eggs. Others contain ingredients that directly act to kill flea larvae in the environment. These are invaluable for preventing a household infestation, but may not completely control one that is already established (or at least, not quickly). These are most commonly given either mixed in with a spot-on; or as an injection.
(7) Environmental insecticides
These can be sprayed onto soft furnishings throughout the home to kill larvae and eggs. Bear in mind that, although generally effective, you need to follow the label instructions, as these can be toxic to cats if you don't allow enough airing time after application! In addition, flea pupae are immune to any form of chemical warfare we can practically employ! That said, be sure to follow the instructions carefully - some can be quite bad for cats if not used appropriately.
(8) Vacuuming
Yes, the humble vacuumed cleaner is your secret weapon in the war on fleas! It will suck up eggs, and the flea-droppings that the larvae feed on, but more importantly, it will stimulate the pupae to hatch, releasing new hungry adults. In this state, they an easily be killed with an insecticide spray!
In conclusion...
No one medication or intervention will control a severe infestation - instead, you'll need to attack them on several fronts, usually with an adult-killing medication, and environmental control spray or medication, and spotless hygiene in the home. If you need help, call your vets' for personalised advice!