Cat Upper Respiratory Infection: Causes, Symptoms, and Care

What Is a Cat Upper Respiratory Infection?

Upper respiratory infection (URI) in cats is a group of infectious diseases affecting the nose, sinuses, and throat. Often referred to as "cat flu" or "cat colds," feline URI is one of the most common medical problems in cats, particularly in kittens, shelter cats, and multi-cat environments. While most cases are mild and self-limiting, URIs can become serious — especially in kittens, senior cats, or immunocompromised individuals.

The most common culprits are feline herpesvirus type 1 (FHV-1) and feline calicivirus (FCV), together responsible for approximately 90% of all feline URIs. Bacterial pathogens including Chlamydophila felis and Bordetella bronchiseptica also contribute, often as secondary infections. FHV-1 is particularly notable because it becomes latent (dormant) in nerve tissue after initial infection and can reactivate during periods of stress, causing recurrent episodes throughout the cat's life.

Causes and Risk Factors

URI-causing pathogens spread through:

Direct contact with eye, nose, or mouth secretions from infected cats
Airborne droplets from sneezing or coughing
Contaminated shared items — food bowls, water bowls, litter boxes, grooming tools
Human handlers (indirect transmission on hands, clothing)

Risk factors include:

Kitten or senior age
Multi-cat households and shelter environments
Stress (rehoming, new pets, changes in routine)
FeLV or FIV positive status
Incomplete vaccination history
Outdoor access with exposure to stray cats

Warning Signs and Symptoms

Feline URI symptoms are typically similar across different causative agents, though severity varies:

Sneezing — often repetitive and frequent
Nasal discharge — clear, then yellow or green as secondary infection develops
Eye discharge — watery to thick and crusty (conjunctivitis is common)
Red, squinting, or swollen eyes
Fever
Lethargy and reduced activity
Loss of appetite — cats largely smell their food; congestion removes this drive
Mouth ulcers — particularly with calicivirus; look for drooling or difficulty eating
Hoarse or absent meow (laryngitis)
Dehydration from reduced water intake

When to Go to the Vet Immediately

Many URIs can be managed with supportive home care, but veterinary attention is needed if your cat shows:

Complete refusal to eat or drink for more than 24–48 hours — cats can develop hepatic lipidosis (fatty liver disease) rapidly when anorexic
Breathing difficulty — open-mouth breathing in cats is always an emergency
Signs of severe dehydration
High fever or dramatic worsening after initial improvement
Eye symptoms that are worsening — herpetic eye disease can ulcerate the cornea
Any young kitten (under 8 weeks) with URI symptoms

Use the TailRounds AI Triage to assess whether your cat's symptoms require an urgent visit, and Book a vet appointment at Happy Paws if you are unsure.

At-Home Care and Monitoring

For mild to moderate URIs in otherwise healthy cats, home care can support a full recovery:

Steam therapy — bring the cat into the bathroom while running a hot shower for 10–15 minutes; the steam loosens nasal congestion
Clean the face gently — use a warm, damp cloth to remove discharge from around the nose and eyes twice daily
Encourage eating — warm wet food has stronger aroma; try different textures to find what the cat will eat
Ensure adequate hydration — offer water in multiple locations; a pet water fountain may encourage drinking
Keep the cat warm and comfortable
Isolate from other cats during active infection
L-lysine supplementation — may help reduce FHV-1 replication in some cats; discuss with your vet
Antiviral eye drops (cidofovir, idoxuridine) may be prescribed for herpetic eye disease

Log daily observations of food intake, discharge type and quantity, eye condition, and energy using the TailRounds Daily Log.

Prevention and Long-Term Management

Core vaccination is the primary prevention tool:

FVRCP (feline viral rhinotracheitis, calicivirus, panleukopenia) vaccine — a core vaccine given to kittens and adults on schedule
Vaccination does not fully prevent infection but significantly reduces severity
For FHV-1 carriers, stress management is key to preventing reactivation — stable routines, environmental enrichment, pheromone diffusers (Feliway)
Keep cats indoors to limit exposure to infected strays
Maintain good hygiene in multi-cat households — clean bowls and litter boxes frequently

Help Your Cat Breathe Easy with TailRounds

Daily monitoring is essential during a URI. Use the TailRounds Daily Log to track food intake, discharge, and eye condition. If symptoms worsen or your cat stops eating, Book a vet appointment at Happy Paws promptly. Find a Clinic Near You for specialist care, and check the TailRounds AI Triage for immediate symptom guidance.