Upper Respiratory Infections in Cats: The Feline Cold Explained

In this guide

Upper respiratory infections, often called cat flu, are one of the most common illnesses vets see, particularly in kittens, shelter cats and multi cat households. Understanding how they spread and what to expect can make a stressful few days much easier to manage.

What causes it

The vast majority of feline upper respiratory infections are caused by two viruses, feline herpesvirus and calicivirus, which together are responsible for around nine out of ten cases. Bacteria such as Bordetella, mycoplasma and chlamydia can cause infections on their own or take advantage once a virus has already weakened the airway, which is why nasal discharge often shifts from clear to thick yellow or green as an illness progresses.

Typical symptoms

• Sneezing and nasal congestion
• Discharge from the nose or eyes
• Red, watery or swollen eyes
• Mouth ulcers, more common with calicivirus
• Reduced appetite, since a blocked nose affects a cat's sense of smell
• Mild fever and lethargy

How it spreads

These infections are highly contagious between cats, spreading through direct contact, shared bowls and bedding, and airborne droplets from sneezing. This is why outbreaks move quickly through shelters, catteries and multi cat homes. Herpesvirus in particular can remain dormant in a cat's system for life after the first infection and resurface during stressful periods, such as boarding, a house move, or a new pet joining the household. Many Indian cat owners also notice flare-ups around the monsoon, when damp, humid conditions and sudden weather shifts seem to coincide with more upper respiratory symptoms, likely linked to the general stress and immune load that comes with seasonal change.

Treatment

Most uncomplicated cases run their course in about seven to ten days with supportive care at home, including keeping the eyes and nose gently wiped clean, encouraging eating with warmed, aromatic wet food, and ensuring good hydration. Vets may prescribe antibiotics if a secondary bacterial infection is suspected, along with eye drops for conjunctivitis and, in some cases, immune support. Kittens, senior cats and cats with other health conditions are more likely to need closer veterinary monitoring, since they have less reserve to cope with a prolonged illness.

Prevention

The FVRCP vaccine, a core vaccination recommended for all cats in India, protects against the main viral causes and significantly reduces both the risk and severity of infection. Keeping cats indoors, avoiding unnecessary exposure to unfamiliar cats, and isolating a newly adopted or visibly unwell cat from the rest of the household for the first couple of weeks all help limit the spread.

Article content © Ravi Teja. All rights reserved.