Cat Fleas, Ticks, Worms, lice & Mites

Most people land here after spotting scratching, flea dirt, a tick, or a sudden bout of vomiting or diarrhoea—and wondering if it’s “just a minor parasite” or something that needs a vet today. With cats, the same small hitchhikers can range from irritating to dangerous, especially for kittens, older cats, and anyone already unwell.

Below is a practical guide to the common parasites that affect cats—fleas, ticks, intestinal worms, lice and mites—how to recognise them, what’s happening in the background (life cycles), and the prevention steps that actually break the cycle.

Common parasites that affect cats

Cats host two broad kinds of parasites:

• External parasites that live on the skin or in the coat: fleas, ticks, lice and some mites.
• Internal parasites that live inside the body (often the gut): roundworm, hookworm and tapeworm.

Fleas

The cat flea (Ctenocephalides felis) is the most common. Fleas feed on blood and can trigger intense itch, skin inflammation, and secondary skin infections from over-grooming. In some cats, even a small number of bites can set off flea allergy dermatitis—an exaggerated reaction to flea saliva that causes persistent itch and scabbing, often around the back end and tail base.¹

Ticks

Ticks attach to the skin and feed on blood. In Australia, the paralysis tick (Ixodes holocyclus) is a key concern in affected regions because its toxin can cause weakness that climbs up the body and may progress to breathing difficulty. Any suspicion of tick paralysis is an emergency.^{2, 3}

Intestinal worms

Common intestinal worms in cats include:

• Roundworm
• Hookworm (can cause anaemia, especially in kittens)
• Tapeworm (often linked to swallowing fleas during grooming)

Signs vary. Some cats look completely normal while still shedding eggs, which is one reason routine worming matters.⁴

Lice

Lice are less common than fleas, but they do occur—usually in cats that are unwell, neglected, or living in crowded conditions. They cause irritation, a dry scruffy coat, and sometimes patchy hair loss. Lice are species-specific, so cat lice live on cats rather than spreading freely between different animal species.

Mites

Mites are tiny, but their effects can be obvious: itch, hair loss, scabs, and inflamed skin. Ear mites commonly cause debris and irritation in the ear canal, while other mites affect the skin more broadly. Diagnosis matters because treatment depends on the mite type.

Life cycles: why infestations keep coming back

Parasite control works best when it targets the life stage you can’t see.

Fleas: most of the problem is off the cat

Adult fleas live on the cat, but eggs drop into the environment—bedding, carpets, floor cracks, sheltered outdoor areas. Fleas develop through egg → larva → pupa → adult. Under typical household conditions, the full cycle often runs for weeks, and the cocoon stage can linger and “hatch” later when conditions suit (warmth, vibration, carbon dioxide). That delayed emergence is why fleas can seem to return out of nowhere after you thought you’d won.¹

Ticks: seasonal in many areas, but not always predictable

Ticks develop through multiple stages and spend much of their time off the host in the environment. In tick-prone areas, prevention and daily checks are more reliable than guessing the season.^{2, 3}

Worms: eggs and larvae spread quietly

Many intestinal worms spread via microscopic eggs passed in faeces, contaminating soil, litter trays, and outdoor areas. Cats can also become infected through hunting prey. Regular, vet-advised worming reduces both illness and ongoing contamination of the environment.⁴

Signs that suggest a parasite problem

Parasites don’t always announce themselves, but these patterns are worth noticing.

Skin and coat signs

• Persistent scratching or over-grooming (especially around the tail base and back legs with flea allergy)
• Flea dirt (black specks that smear reddish-brown when dampened)
• Scabs or “miliary” bumps along the back or neck
• Patchy hair loss, dry coat, or visible lice/nits
• Ear irritation: head shaking, scratching at ears, dark debris (often seen with ear mites)

Gut and general health signs (worms and heavy flea burdens)

• Vomiting or diarrhoea
• Weight loss or poor weight gain in kittens
• Pot-bellied appearance in kittens
• Lethargy or pale gums (possible anaemia—urgent in young animals)⁴

Red flags: seek urgent veterinary care

• Wobbliness, weakness, or breathing changes (possible tick paralysis)^{2, 3}
• Severe lethargy, collapse, very pale gums
• Kittens with diarrhoea, poor feeding, or rapid deterioration

Diagnosis: what vets actually look for

Diagnosis usually starts with a close inspection of the coat and skin (including a flea comb), plus targeted tests when needed:

• Skin exams to find fleas, flea dirt, lice, ticks, or patterns typical of flea allergy.
• Ear examination for ear mites and secondary infection.
• Faecal testing to identify worm eggs.
• Skin scrapings or other tests if mites are suspected.

This matters because “itch” is not a diagnosis. A cat with fleas needs a different plan to a cat with mites, and a different plan again to a cat with allergic skin disease plus fleas as the trigger.

Treatment: what tends to work (and what to avoid)

Effective parasite treatment usually has two parts: treat the cat and interrupt the life cycle in the environment (especially for fleas).

Fleas

• Use a cat-safe flea treatment recommended by your vet, and keep to the schedule. Missing doses is a common reason infestations drag on.
• Treat every pet in the household (with the correct species-specific product).
• Clean the environment: hot-wash bedding, vacuum thoroughly (then empty the vacuum), and repeat regularly while you’re breaking the cycle.¹

Ticks (including paralysis ticks)

• Preventatives matter in risk areas—ask your vet what suits your cat.
• Daily tick searches are still recommended even when using preventatives, because no product is perfect.^{2, 3}
• If you find a tick, remove it promptly and contact a vet the same day. If there are any symptoms at all, treat it as urgent.^{2, 3}

Important: Never use dog tick products on cats. Some dog-only products can be toxic or fatal to cats.²

Worms

Worm treatment depends on the worm type and the cat’s age and lifestyle (indoor-only vs hunter). Many vets recommend routine control, with kittens needing more frequent dosing early on.⁴

Lice and mites

These usually require prescription or vet-directed products, and sometimes treatment of in-contact animals. If skin is broken or infected, additional medication may be needed.

Prevention: a simple routine that holds up over time

Parasite control is less about one perfect product and more about steady habits.

• Use parasite preventatives consistently (flea control year-round is common advice; tick control depends on region and risk).
• Check the coat regularly—especially after outdoor time, boarding, grooming visits, or contact with other animals.
• Keep bedding clean and vacuum areas where your cat sleeps, particularly during a flea outbreak.
• Worm routinely as recommended for your cat’s age and lifestyle.⁴

Natural remedies and “alternative” treatments: proceed carefully

Many home remedies for fleas and ticks don’t reliably break the life cycle, and some “natural” products can be unsafe for cats. Essential oils, for example, can be harmful to cats even in small amounts, and should not be applied unless a veterinarian has confirmed safety and dosing.

If you want a lower-chemical approach, a practical middle ground is often: vet-approved products used correctly, combined with environmental cleaning and regular physical checks. It’s quieter, steadier, and tends to work.

Common misconceptions

“My cat is indoors, so parasites aren’t a risk.”

Indoor cats can still get fleas (they hitchhike on people, visitors, or other pets) and can be exposed to worms or mites in certain circumstances. In tick areas, even indoor pets may be at risk if ticks come inside on clothing or other animals—daily checks are still recommended when risk is high.^{2, 3}

“If I can’t see fleas, there aren’t any.”

Fleas are good at hiding, and most of the life cycle is off the cat in carpets and bedding. Flea dirt, itch patterns, and recurring skin scabs can be the stronger clue.¹

“Herbal products are always safer.”

“Natural” doesn’t automatically mean safe for cats. Cats metabolise some substances differently, and certain oils and plant extracts can be toxic.

Regular vet check-ups and parasite control

Parasite prevention works best when it’s matched to the individual cat: age, weight, medical history, where you live, and whether they hunt or mix with other animals. Regular check-ups also help catch the quieter problems—worm burdens without obvious signs, low-grade skin inflammation, or a tick found late in the day.

References

1. Merck Veterinary Manual (Cat Owners) — Fleas of Cats
2. RSPCA Knowledgebase — How can I protect my dog or cat from tick paralysis?
3. University Veterinary Teaching Hospital Sydney — Tick paralysis
4. University Veterinary Teaching Hospital Sydney — Intestinal worms
5. healthdirect Australia — Toxoplasmosis
6. NHMRC — Toxoplasmosis fact sheet (Staying Healthy guidelines)
7. Better Health Channel (Victoria) — Toxoplasmosis
8. Merck Veterinary Manual — Fleas in Dogs and Cats (life cycle and control)