Parasites are among the most common health problems in cats -- and even indoor-only cats are at risk. Fleas hitch rides on human clothing, mosquitoes carry heartworm through open windows, and intestinal parasites can be tracked in on shoes. Year-round prevention is the standard of care.
Table of Contents
External Parasites
Fleas
- The most common cat parasite worldwide
- Can cause: severe itching, flea allergy dermatitis, anemia (in kittens), tapeworm transmission
- Lifecycle: egg, larva, pupa, adult -- 95% of fleas are in the ENVIRONMENT, not on the cat
- One flea lays up to 50 eggs per day
Ticks
- Less common on cats than dogs but still a risk for outdoor cats
- Can transmit: cytauxzoonosis (often fatal in cats), Lyme disease (rare in cats), other tick-borne diseases
Ear Mites
- Extremely common in kittens and outdoor cats
- Dark, crumbly debris in ears, intense head shaking and scratching
- Highly contagious between cats
Internal Parasites
| Parasite | How Acquired | Symptoms |
|---|---|---|
| Roundworms | Mother's milk, contaminated soil, prey | Pot belly (kittens), vomiting, diarrhea, visible worms in stool |
| Tapeworms | Ingesting fleas or infected prey | Rice-like segments near tail/in stool |
| Hookworms | Contaminated soil, mother's milk | Anemia, weight loss, bloody stool |
| Heartworms | Mosquito bite | Coughing, breathing difficulty, sudden death (no treatment in cats) |
| Giardia | Contaminated water | Chronic diarrhea, weight loss |
Best Prevention Products
| Product | Covers | Application |
|---|---|---|
| Revolution Plus | Fleas, ticks, ear mites, roundworms, hookworms, heartworms | Monthly topical |
| Bravecto Plus | Fleas, ticks, heartworms, roundworms, hookworms | Every 2 months topical |
| Advantage Multi | Fleas, heartworms, roundworms, hookworms, ear mites | Monthly topical |
| Seresto Collar | Fleas, ticks | 8-month collar |
Critical Warnings
- NEVER use dog flea products on cats: Permethrin (common in dog products) is LETHAL to cats
- This is the #1 cause of feline insecticide poisoning
- Symptoms of permethrin toxicity: tremors, seizures, death
- If exposure occurs: emergency vet IMMEDIATELY
Indoor Cat Prevention
- Year-round flea prevention recommended even for indoor-only cats
- Heartworm prevention recommended in endemic areas (mosquitoes enter homes)
- Annual fecal exam to check for intestinal parasites
Frequently Asked Questions
My indoor cat has never had parasites -- does it still need prevention?
Yes -- prevention is far easier, safer, and cheaper than treatment. Fleas can enter on human clothing, shoes, and visiting pets. Mosquitoes carrying heartworm larvae enter through doors and windows. There is NO treatment for heartworm disease in cats (only prevention), making heartworm infection potentially fatal with no cure. Monthly prevention is inexpensive insurance against serious disease.
