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Infectious · Cats & dogs

Infectious diseases: cat and dog red flags

A source-linked overview of common infectious diseases, isolation clues, vaccine-preventable risks, and when not to wait.

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

Infectious diseases: cat and dog red flags

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

Care & observations

  • Separate sick pets from other animals, use dedicated bowls and litter areas, and wash hands after handling while arranging veterinary advice.
  • Prepare vaccine records, adoption or boarding dates, exposure history, and short videos of breathing, coughing, walking, or neurologic signs.
  • Keep food and water available if the pet can swallow normally, but do not force feed a weak, vomiting, or breathing-compromised pet.

Seek veterinary care now

  • Puppy or kitten with vomiting, diarrhea, refusing food, severe lethargy, dehydration signs, pale gums, breathing trouble, seizure, or collapse.
  • Any pet with neurologic signs, severe cough or breathing effort, bloody diarrhea, repeated vomiting, jaundice, severe weakness, or rapidly worsening feverish behavior.

Contact your veterinarian soon

  • Sneezing, cough, eye or nose discharge, mouth ulcers, reduced appetite, diarrhea, or lethargy after exposure to a shelter, boarding facility, grooming salon, or new pet.
  • Unclear vaccine history, missed boosters, positive infectious disease screening, or a household with multiple pets and one pet becoming sick.

What to avoid

  • Do not expose a sick or incompletely vaccinated pet to parks, boarding, grooming, adoption events, or other pets while signs are unexplained.
  • Do not use leftover antibiotics, antivirals, fever medicine, or human cold medicine; these can mask signs or harm pets.

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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