Parasite control is often called a “parasite vaccine”, and it is worth correcting that: parasites are not prevented by a vaccine. They are prevented and treated by antiparasitic medication, given at intervals, because the protection wears off and reinfection is always possible.

Internal parasites

Roundworms. The most common in cats. Kittens are frequently infected through their mother’s milk. Heavy burdens cause a pot bellied kitten with a dull coat, vomiting and diarrhoea. Roundworm larvae can infect people, particularly children, which is why regular worming matters in households with young children.

Tapeworms. Usually acquired by swallowing an infected flea while grooming, or by hunting. You may see rice grain segments around the anus or in bedding. Treating tapeworm without treating fleas simply lets it come back.

Hookworms and whipworms, less common but relevant in cats with outdoor access.

Giardia and coccidia, protozoa that cause persistent diarrhoea, particularly in kittens.

External parasites

Fleas. The most common skin parasite and the most common cause of allergic skin disease in cats. Adult fleas on the cat are a small fraction of the problem; the eggs, larvae and pupae are in the carpet and the bedding.

Ticks. Picked up outdoors. Remove them with a proper tick hook, twisting rather than pulling, and never with a lit match or petroleum jelly.

Ear mites. Very common in kittens. Dark crumbly discharge in the ears and persistent head shaking and scratching.

Mange mites and lice, less common, usually in weakened or neglected cats.

How often

There is no single answer. It depends on:

Whether the cat goes outdoors
Whether it hunts
Whether there are children or immunocompromised people in the household
Whether other animals live there
The season, though in heated homes fleas persist year round

An indoor only cat and a hunting cat do not need the same schedule. We set it for your cat.

Forms

Tablets given by mouth, spot on liquid applied to the skin at the back of the neck, collars, and injections. Which one suits depends on the cat’s temperament, its age and weight, and which parasites are being targeted.

One critical warning

Never use a dog product on a cat. Spot on treatments for dogs containing permethrin cause tremors, seizures and death in cats. Always read which species the product is for, and keep a treated dog away from the cat until the application has dried.

Doing it properly

Treat every animal in the household on the same schedule. Weigh the cat and dose to the actual weight. Wash bedding hot and vacuum thoroughly when treating fleas. Keep to the interval; a treatment given late leaves a gap.