• Cats can have internal parasites (intestinal worms and, less commonly, heartworm) and external parasites (fleas, ticks and mites).
• Prevention should be risk based: strictly indoor cats generally have a lower parasite risk than outdoor or hunting cats.
• Fleas are common and can trigger flea allergy dermatitis (significant itch and skin inflammation), even if you rarely see fleas.
• If you live in a tick risk area (including parts of Australia’s east coast), tick prevention is critical and needs to be discussed with your vet.
• Intestinal worms can be zoonotic (some can infect people). Households with children, pregnant people, or immunocompromised people may need a more intensive plan.
• Avoid using dog-only parasite products on cats. Some are toxic to cats.

Common intestinal worms in cats include:

• Roundworm (Toxocara): can cause pot belly, poor growth in kittens, vomiting or diarrhoea; can infect people.
• Hookworm: can cause diarrhoea and anaemia; can infect people through skin contact with contaminated environments.
• Tapeworm: often linked with flea ingestion or hunting; owners may notice small “rice grain” segments near the tail or in bedding. 

• Kittens can be infected early in life.
• Outdoor cats may be exposed through contaminated soil, eating prey (rodents, lizards), or ingesting fleas.
• Indoor cats can still be exposed through fleas brought into the home, shared environments, or new pets. 

Heartworm is spread by mosquito bites. Cats are less commonly affected than dogs, but infection can still cause significant respiratory disease. Because diagnosis and treatment can be challenging, prevention is usually the safest approach for cats at risk.

Cats that may be higher risk include:

• cats that go outdoors (especially at dusk and dawn when mosquitoes are active)
• cats living in mosquito-prone environments (near waterways or after heavy rain seasons)
• cats that travel with their owners to areas with higher mosquito activity

Your vet can advise whether heartworm prevention is recommended where you live and whether it should be seasonal or year-round.

Fleas can cause:

• itch and overgrooming
• scabs, hair loss, and skin infection
• flea allergy dermatitis (a strong allergic skin reaction to flea saliva)
• tapeworm infection (from ingesting fleas)

Important point: you may not see fleas even when they are present. Some cats groom them off quickly.

Reducing flea burden at home

• Wash bedding regularly.
• Vacuum carpets and soft furnishings, especially areas where cats sleep.
• Treat in-contact pets in the household if advised by your vet. 

In parts of Australia, ticks can cause serious illness, including tick paralysis, which is a veterinary emergency. Tick risk varies by region and can change with weather patterns.

If you live in a tick risk area, your prevention plan should include:

• an effective tick prevention product suitable for cats (your vet will advise)
• routine tick checks (especially after outdoor exposure) 

Ear mites can cause:

• itchy ears and head shaking
• dark, crumbly ear discharge
• skin inflammation around the ears and neck

Ear mites spread readily between cats (and can affect dogs). Cats with persistent ear irritation should be examined, as ear infections, foreign bodies, allergies and polyps can mimic mites.

Examples: strictly indoor cats, no hunting, no new pets entering the home.

Typical approach (to discuss with your vet):

• Intestinal worm treatment 1 to 2 times per year
• Flea prevention based on household risk (for example, if fleas are detected in the home or pets regularly visit grooming/boarding) 

Examples: indoor cats with occasional supervised outdoor time, households with other pets, or regular visitors’ pets.

Typical approach (to discuss with your vet):

• Intestinal worm treatment every 3 months
• Flea prevention monthly during higher-risk periods, or year-round if fleas are persistent locally 

Examples: outdoor cats, hunting cats, multi-cat households with frequent new cats, households with young children, or known flea/tick exposure.

Typical approach (to discuss with your vet):

• Intestinal worm treatment monthly
• Flea prevention monthly year-round
• Tick prevention according to local risk (often year-round in tick-endemic areas) 

Kittens and newly adopted cats often need a different plan from adult cats. If you have a kitten, refer to the Kitten health: Parasites and prevention calendar page and confirm timing with your vet.