Signs of Respiratory Infection in Cats

Signs of Respiratory Infection in Cats: What to Watch For

Upper respiratory infections (URIs) are among the most common illnesses in cats. Often called "cat colds," they're highly contagious between cats and can range from mild sniffling to serious illness requiring veterinary care. Knowing the signs — and understanding which ones are urgent — helps you act quickly and keep your cat comfortable.

What Causes Respiratory Infections in Cats?

The vast majority of feline URIs are caused by two viruses:

• Feline herpesvirus (FHV-1): Responsible for ~50% of cases. Most cats are exposed as kittens; the virus stays dormant and reactivates during stress or illness.
• Feline calicivirus (FCV): Responsible for ~40% of cases. Often causes mouth ulcers alongside respiratory symptoms.

Secondary bacterial infections (Chlamydophila, Bordetella, Mycoplasma) frequently complicate viral URIs, causing thicker, colored discharge and prolonged illness.

Common Signs of Respiratory Infection in Cats

Nasal Symptoms

• Sneezing: Often the first sign — frequent, repetitive sneezing bouts
• Nasal discharge: Starts clear, may become yellow or green as secondary bacterial infection develops
• Congestion: Noisy, labored nasal breathing; mouth breathing in severe cases
• Nasal crusting: Dried discharge around the nostrils

Eye Symptoms

• Eye discharge: Clear, yellow, or green discharge from one or both eyes
• Conjunctivitis: Red, swollen, inflamed eye tissue
• Squinting: Sensitivity to light or eye discomfort
• Eye crusting: Discharge drying around the eye

Mouth and Throat Symptoms

• Mouth ulcers: Painful sores on the tongue, gums, or palate (especially calicivirus)
• Drooling: Often due to mouth ulcers or difficulty swallowing
• Coughing: Less common than in dogs, but can occur
• Hoarse or changed voice

General Symptoms

• Lethargy: Reduced activity, sleeping more than usual
• Reduced appetite: Congested cats can't smell food well, suppressing appetite
• Fever: Temperature above 102.5°F (39.2°C). Use the iProven Pet Thermometer DTK-117Y for accurate at-home readings.
• Dehydration: From reduced drinking and fluid loss

How to Tell Mild from Serious

Which Cats Are Most at Risk?

While any cat can develop a URI, these groups are most vulnerable to serious illness:

• Kittens: Immature immune systems; can deteriorate rapidly
• Senior cats: Reduced immune function
• Unvaccinated cats: No protection against herpesvirus or calicivirus
• Shelter or multi-cat household cats: Higher exposure risk
• Immunocompromised cats: FIV-positive, FeLV-positive, or on immunosuppressive medications
• Flat-faced breeds: Persians, Himalayans — anatomical features make respiratory symptoms more severe

Supportive Home Care for Mild Cases

For mild URIs in healthy adult cats:

• Steam therapy: sit with your cat in a steamy bathroom 2–3 times daily to loosen congestion
• Clean nasal and eye discharge gently with a warm damp cloth or HICC PET Eye Wipes
• Warm wet food slightly to enhance aroma and encourage eating
• Keep your cat warm and stress-free
• Support immune health with Premo Pet Probiotic for Cats
• Monitor temperature daily with a pet thermometer

When to Call the Vet

Contact your vet promptly if your cat:

• Has difficulty breathing or is breathing with mouth open
• Has a fever above 104°F
• Stops eating for more than 24–48 hours
• Has thick colored discharge from nose or eyes
• Has mouth ulcers or significant drooling
• Is a kitten, senior, or immunocompromised
• Is getting worse after 5–7 days

Prevention

• Keep the FVRCP vaccine current — it protects against herpesvirus and calicivirus
• Quarantine new cats for 2 weeks before introducing to resident cats
• Reduce stress, which triggers herpesvirus reactivation
• Maintain good hygiene in multi-cat households

Final Thoughts

Recognizing the signs of respiratory infection early gives your cat the best chance of a quick, uncomplicated recovery. Most mild cases resolve with supportive home care, but knowing when to escalate to veterinary care is essential — especially for vulnerable cats. When in doubt, call your vet.