The risk of infection to the animal and the need for parasiticide therapy depends on various factors, including the age of the animal, its lifestyle (e.g. access to offal or molluscs) and location (which determines which parasites are endemic), and whether the animal lives with susceptible humans (such as young children or people with immunosuppression). Animals therefore require parasiticide therapy that is tailored to their needs.

In general, cats and dogs in the UK need routine cover for fleas and roundworm. Also, depending on the animal’s lifestyle, it may need cover for ticks, tapeworm and/or lungworm. Broader parasite cover is needed for animals travelling outside the UK.

Parasiticide products

Flea and tick products

Most flea and tick products (ectoparasiticides) contain one or more ingredients that have insecticide (flea-killing) and/or acaricide (tick-killing) effects. Most products, apart from shampoos and powders and certain tablets, remain on or in the body of the animal for several weeks and can kill parasites newly acquired by the host.

This means they can prevent infestation over a period of time, usually one month. Frontline, a brand commonly stocked in pharmacies, contains fipronil, which kills fleas and ticks. It is available as a spot-on (topical) formulation and its effects last for up to four weeks.

Endoparasiticides

Worming products (known as endoparasiticides) contain one or more drugs that kill specific types of worm. Drontal tablets, a brand commonly stocked in pharmacies, contain pyrantel and praziquantel, and are used to treat roundworm and tapeworm.