PetwellPET HEALTH REFERENCE
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Parasites · Cats & dogs

Parasite disease: fleas, ticks, mites, worms, coccidia, and heartworm

A parasite overview covering external and internal parasites, prevention records, household spread, and urgent warning signs.

Compiled by Petwell · Source content version 2.0.0
Source project update: 2026-05-13

Parasite disease: fleas, ticks, mites, worms, coccidia, and heartworm

Educational pet-health and visit-preparation reference. Not a diagnosis, prescription, dosage recommendation or substitute for a veterinarian.

Care & observations

  • Use species-appropriate prevention recommended by a veterinarian and keep dogs-only products away from cats.
  • Collect a fresh stool sample if diarrhea, visible worms, or weight loss is present and the pet is stable.
  • Treat all household pets only under veterinary guidance because product choice and timing differ by species and weight.

Seek veterinary care now

  • Cat exposure to a dog-only flea or tick product, tremors, seizure, severe weakness, pale gums, collapse, breathing trouble, or heavy parasite burden in a young pet.
  • Coughing, collapse, severe exercise intolerance, swollen belly, or breathing difficulty in a pet with heartworm risk.

Contact your veterinarian soon

  • Visible fleas, ticks, worms, chronic itching, ear debris, diarrhea, weight loss, missed prevention, or new pet with unknown parasite history.
  • Before starting prevention in very young, pregnant, sick, underweight, senior, or medicated pets.

What to avoid

  • Do not split doses, combine products, use livestock products, or use dog permethrin products on cats.
  • Do not rely on home remedies for worms, mites, ticks, fleas, or heartworm prevention.

MAKE YOUR OBSERVATIONS USEFUL

Bring a clear timeline to your vet

For the changes covered in this guide, note when they started, how often they happen, whether they are worsening and how they differ from your pet’s usual routine. List recent diet changes, medicines, travel or possible ingestion in time order. Add photos or a short video only when it is safe and will not delay care.

Open local health records

Sources & editorial context

Migrated from the Pet Vet Reference project with its bilingual content preserved. Cited organizations provide background resources and do not endorse this site. Source-based compilation is not individual clinical review; this page does not claim veterinarian sign-off.

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