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successively, and the control of all stages, both parasitic and non-parasitic. Insecticide should be routinely associated with IGR, and mechanical control measures should not be forgotten. This new approach to flea control minimises the effects of inadequacies of any one insecticide, while maintaining efficacy and slowing down possible development of resistance. In practice, use of only one product, no matter how effective, will not provide long-term control of a flea population. Control strategy needs to be adapted according to the environment and clinical situation. It can only be successful if the benefits and limitations of each method are well-understood by both vet and owner.

Treatment of the animal

Orgańophosphates and carbamates have now been rendered obsolete (whatever the presentation: systemie spot-on, drinkable solution with systemie action, collars, powders) by newer, morę effective, morę residual and less toxic produets.

Permethrin is a very effective, topical adulticide with excellent knock down and antifeeding properties. Use in the cat is the responsibility of the prescribing veterinary surgery, given the absence of a product licence for use in this species. The cat is particularly sensitive to permethrin toxicity and intoxication through overdosage is common. Its use is therefore not recommended.

Fipronil is a very effective topical adulticide and comes either in a 0.25% spray or a 10% surface-acting spot-on. Freąuency of application depends on the formulation of the product (every 6 weeks for the spray and every 4 weeks for the spot-on) and the clinical situation (presence or absence of FAD). Advantages of fipronil include its great residual activity, Iow toxicity to camivores and man, and possible use of the spray on cats aged 2 days or morę. Its efficacy depends on good compliance by the owner (correct application given at the right freąuency). Fipronil also has activity against certain non-parasitic stages (e.g. larval stages 1 and 2)^1S.

Imidacloprid is a very effective topical adulticide, used in a 10%, surface-acting, spot-on, and given every 3-4 weeks. Advantages include its residual activity, the fact that it is so safe for use in the cat and dog, and its possible use on kittens aged over 2 months. Moreover, imidacloprid is larvicidal against stage 1 larvae by virtue of sąuamous cells that become impregnated with it and get deposited in the generał environment.

Nitenpyram is a new adulticide which comes in 11.4 mg tablets. The particular advantage of this product is its extremely powerful knock down effect, within about 20 minutes. Freąuency of application is variable (on average, once weekly), depending on whether fleas are present on the cat. Nitenpyram has no residual activity. There is no risk of toxicity in either cat or dog.

Selamectin is a new avermectin, active against adult fleas. It is used monthly at 6 mg/kg in a spot-on formulation. The product becomes concentrated in the sebaceous glands and epidermal basal layer, and exerts its effects systemically. Advantages of selamectin are its residual activity, its Iow toxicity, its activity against certain helminths (e.g. toxocara cati and ankylostoma tubaeforme) and against Octodectes.

Insect Growth Regulators (IGRs) interfere with insect growth and development and have the advantage of very Iow mammalian toxicity. IGRs include Juvenile Hormone Analogues (JHAs) and Chitin Synthesis Inhibitors (CSIs). All these substances play an important role, especially in prevention of flea infestation. Delay in onset of activity (at least a week) means that they cannot be curative. JHAs, such as pyriproxyfen, affect mechanisms associated with moulting. Pyriproxyfen persists for a considerable length of time (several months) and has ovicidal and adulticide activity (after a week). It comes in various formulations including collar, spray and surface-acting spot-on. CSIs (e.g. lufenuron and flufenoxuron) affect chitin synthesis during moulting. Lufenuron prevents eggs from hatching, causing larvae to die and leading to an absence of adults emerging from the pupae. Lufenuron is given orally, every month, or by subcutaneous injection every 6 months. It is stored in the fat, then released into the blood ready for ingestion by the feeding flea.

Treatment of the environment

Control of non-parasitic stages and pre-emerged adults in the environment is vital as these stages make up 95% of the total flea population. Noting down all the potentially infested places (e.g. sleeping places, areas the animal walks through and car flooring) is the first step in a proper environmental control strategy.