What is calicivirus? Can it spread to other cats?

Calicivirus is a contagious virus that causes respiratory or systemic symptoms in cats, typically spreading through direct contact or secretions. If you suspect infection, consult your vet and isolate the affected cat.

How does the vet confirm a calicivirus infection?

Common tests include a physical examination, blood work, and a PCR viral nucleic acid test. Secretion cultures or imaging may also be performed to assess for complications.

How long will my cat need to stay in hospital?

Hospitalisation length depends on how severe the illness is and whether oxygen therapy or IV fluids are needed — typically a few days to a week, based on your vet's assessment and test results.

What do I need to watch for at home after discharge?

Monitor your cat's temperature, appetite, and energy levels closely, and attend all follow-up blood tests as directed. Seek immediate veterinary care if breathing difficulties or worsening appetite loss occur.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Feline Calicivirus Infection in Cats: Symptoms, Diagnosis & Care [2025]

Feline calicivirus infection causes upper respiratory symptoms and oral ulcers. Signs include sneezing, nasal discharge, and mouth sores. Treatment is mainly supportive; secondary infections may require antibiotics.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ISFM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Persistent and marked rapid breathing or difficulty breathing
•Unconscious or unable to be roused, extremely unresponsive
•Gums or lips turning purple or noticeably pale and bloodless

Schedule a veterinary visit soon (within 24–72 hours)

•Noticeably lower energy and greatly reduced activity
•Persistent refusal to eat or clearly reduced appetite
•Persistent fever or body temperature higher than usual

01What Symptoms Signal Something Is Wrong?

Feline calicivirus commonly presents with changes in energy, appetite, and the respiratory or systemic state. Severity varies depending on the disease stage and any co-infections.

Lethargy, noticeably reduced activity, or loss of interest in play
Decreased appetite or refusing to eat and drink
Elevated body temperature — feels warmer than usual to the touch
Rapid breathing, panting, or visibly laboured breathing
Increased discharge from the eyes or nose, or yellowing of the gums or eyes
Localised swelling or abdominal distension

Seek emergency care immediately if you notice the following symptoms:

⚠️ Persistent and obviously rapid or laboured breathing
⚠️ Loss of consciousness or inability to be roused; extremely unresponsive
⚠️ Purple or visibly pale gums or lips

02How Can You Tell Something Is Wrong at Home? Key Observation Points and When to Seek Emergency Care

Observing and documenting key details at home helps your vet quickly assess your cat's condition and arrange the necessary tests.

Note the time symptoms first appeared and how they have changed
Take your cat's temperature daily and record the readings with timestamps
Track food intake, water consumption, and toilet habits
Record video of breathing and movement on your phone (front and side views)
Photograph any eye or nasal discharge, bleeding, or yellowing of the skin or eyes
Bring your notes and media to the appointment, or find a clinic that can run PCR tests

03How Does the Vet Make a Diagnosis? Common Tests Explained

Your vet will start with a physical examination and order blood tests, PCR, and imaging as needed to confirm infection and evaluate organ function.

Thorough physical examination

assessing breathing, mucous membrane colour, and temperature

Blood tests

CBC and biochemistry panel to evaluate organ function

PCR viral nucleic acid test

to confirm viral infection

Bacterial culture of secretions

to detect secondary bacterial infection

Imaging

chest and abdominal X-rays or ultrasound to assess for complications

Advanced imaging (CT)

used in complex cases or when a deep lesion is suspected

04How Is It Treated and How Do You Care for Your Cat Afterwards? Medications, Diet, and Home Care

Treatment centres on supportive care — including fluid therapy, warmth, and further interventions based on the cat's condition — with scheduled follow-up testing.

Supportive care: fluid therapy, keeping the cat warm, and nutritional support are the first priorities
Oxygen therapy and hospitalisation for observation if needed
If a secondary bacterial infection is present, the vet will decide whether antibiotics are required
Follow-up blood tests to monitor liver and kidney function and infection markers as directed by your vet
Monitor temperature, appetite, and energy levels at home after discharge
If symptoms worsen or there is any acute change, return to the clinic or seek emergency care immediately

05What Should You Prepare Before the Vet Visit? Key Information to Help Your Vet Pinpoint the Cause

Note the onset time and progression of symptoms for the vet's reference

List your cat's food intake, water consumption, and toilet habits over the past 24–72 hours

Prepare videos and photos of breathing and movement to show at the appointment

Write down any current medications, supplements, and vaccination records

Bring a secure carrier and book a clinic that can perform PCR and imaging tests

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.