Cat Parasites: Fleas, Worms, Ticks and Ear Mites

Parasites are one of the most common health problems in cats — and some can spread to people. Most are easy to prevent with regular treatment. Your vet will recommend a plan based on your cat's age, lifestyle (indoor or outdoor, hunting or not) and where you live.

Fleas

Signs: scratching, over-grooming, hair loss (often on the back near the tail), small scabs, "flea dirt" (black specks that turn red on damp paper), or seeing fleas themselves. Some cats develop an allergy to flea saliva (flea allergy dermatitis), with intense itching.

Why they matter: fleas cause itching and anemia in kittens, and they transmit the common tapeworm Dipylidium caninum and bacteria such as Bartonella (cat scratch disease).

Treatment and prevention:

• Use a vet-recommended cat product — spot-ons, oral tablets or collars — regularly, as directed.
• Treat every pet in the home at the same time, even if only one is scratching.
• Treat the home too: only about 5% of a flea population lives on the pet — the rest are eggs, larvae and pupae in carpets and bedding. Vacuum daily for a few weeks (empty the vacuum outside) and wash bedding hot. Household flea sprays can help; keep cats and fish away as directed.
• It can take 2–3 months to clear an infestation completely because pupae keep hatching.

Intestinal worms

Roundworms

Very common in kittens, which can be infected through their mother's milk. Signs include a pot belly, poor growth, diarrhea, vomiting (sometimes with spaghetti-like worms). Roundworm eggs can infect people, especially children.

Tapeworms

Spread by swallowing fleas (while grooming) or by eating rodents. Look for rice-grain-like segments around the tail or in feces.

Hookworms and others

Less common in many regions, but can cause anemia and diarrhea.

Prevention:

• Kittens are usually dewormed frequently — often every 2 weeks from a few weeks of age until about 8 weeks, then monthly until 6 months (your vet will advise).
• Adults: frequency depends on risk. Hunting and outdoor cats may need treatment every 1–3 months; strictly indoor cats less often. Your vet may suggest fecal testing instead.
• Always pick up litter daily and wash hands after cleaning the box.

Ticks

Outdoor cats can pick up ticks, especially in wooded or grassy areas. Ticks can transmit diseases in some regions.

• Removing a tick: use a tick-removal tool, twist gently without squeezing the body, and don't apply chemicals or heat. Check the area over the following days.
• Use a cat-specific tick product if your vet recommends one.

Ear mites

Otodectes cynotis are tiny mites common in kittens and shelter cats. Signs: head shaking, scratching the ears, and dark brown, coffee-ground-like wax. They spread easily between cats and dogs. A vet can confirm with an otoscope or microscope and prescribe treatment for all pets in the household. See ears, eyes and teeth.

Heartworm

Spread by mosquitoes in warm regions (including much of the US). Cats are less commonly infected than dogs, but even a few worms can cause serious lung disease ("heartworm-associated respiratory disease") and there is no approved treatment for cats — so prevention is key where heartworm occurs. Ask your vet whether monthly prevention is recommended in your area.

Other parasites

• Giardia and coccidia/Isospora — single-celled parasites causing diarrhea, especially in kittens.
• Lungworm — in some regions, in cats that hunt snails, slugs or rodents.
• Toxoplasma gondii — see cats, babies and pregnancy.
• Ringworm — not a worm, but a fungal skin infection. See common health problems.

Indoor cats need protection too

Fleas hitch rides on people, dogs and visitors; mosquitoes get indoors; and kittens often arrive with worms. Indoor cats generally need less frequent treatment than hunters, but most still need a plan. Ask your vet.