Feline Upper Respiratory Infection in Cats

Feline upper respiratory infection is a common syndrome affecting the nose, throat, and sinuses. Pet parents often call it a “cat cold,” but it is usually caused by contagious infectious agents rather than the same viruses that cause colds in people. The most common causes are feline herpesvirus-1, also called feline viral rhinotracheitis, and feline calicivirus. Other organisms such as Chlamydia felis, Bordetella bronchiseptica, and Mycoplasma species can also play a role, especially in crowded cat settings.

Most cats develop sneezing, nasal congestion, watery or thick eye and nose discharge, and reduced appetite because they cannot smell food well. Some also develop fever, mouth ulcers, conjunctivitis, or noisy breathing. In many otherwise healthy adult cats, the illness is self-limiting and improves over one to three weeks. Even so, symptoms can be more serious in kittens, older cats, brachycephalic cats, and cats with underlying disease.

A feline URI spreads easily through saliva and secretions from the eyes and nose. Cats can catch it through direct contact, shared bowls or bedding, grooming, or contaminated hands and clothing. Stress, crowding, poor ventilation, and recent adoption or boarding can all increase risk. Vaccination helps reduce severity, but it does not prevent every infection.

See your vet immediately if your cat is breathing with effort, refuses food for more than a day, seems weak, or has severe eye pain or a cloudy eye. Those signs can point to dehydration, pneumonia, corneal ulceration, or another complication that needs prompt care.

Diagnosis usually starts with your vet taking a history and performing a physical exam. In many straightforward cases, the pattern of sneezing, eye and nose discharge, congestion, and recent exposure to other cats strongly suggests a feline URI. Your vet will also look for fever, dehydration, oral ulcers, conjunctivitis, and signs that the infection may have moved into the lower airways.

If symptoms are severe, recurrent, or not improving as expected, your vet may recommend additional testing. This can include PCR testing on swabs from the eyes, nose, or mouth to look for pathogens such as feline herpesvirus, calicivirus, Bordetella, Chlamydia felis, and Mycoplasma. In some cats, especially those that are very sick or have chronic disease, blood work may help assess hydration, inflammation, or other illness.

Chest X-rays may be recommended if your vet is concerned about pneumonia or another lower respiratory problem. Eye staining may be needed if there is squinting or a cloudy eye, because herpesvirus can be associated with corneal ulcers. Cats with repeated or unusually severe infections may also be tested for feline leukemia virus or feline immunodeficiency virus, since immune compromise can make respiratory disease harder to control.

Diagnosis is not always about proving one exact organism. In many cats, the practical goal is to determine how sick the cat is, whether complications are present, and which level of care makes sense for that individual pet and household.

More than one infectious agent can cause feline upper respiratory infection, but feline herpesvirus-1 and feline calicivirus are the leading causes. These viruses are highly contagious and common in the cat population. Secondary bacterial infection can develop on top of a viral infection, which may worsen discharge, prolong illness, or increase the need for medication. Chlamydia felis, Bordetella bronchiseptica, and Mycoplasma species are among the better-known bacterial contributors.

Cats usually become infected through direct contact with saliva or eye and nose secretions from another cat. Shared bowls, litter boxes, bedding, carriers, and human hands can also spread organisms between cats. According to VCA, infected cats may remain contagious during incubation and for up to about three weeks after signs begin, which is one reason outbreaks are common in shelters, foster systems, and multi-cat homes.

Risk is higher in kittens, senior cats, brachycephalic breeds, and cats under stress. Overcrowding, poor ventilation, transportation, boarding, recent adoption, surgery, and concurrent illness can all make infection more likely or more severe. Vaccination lowers the severity of disease but does not fully eliminate risk, especially because herpesvirus can remain latent in the body and flare later during stress.

Not every sneezing cat has a routine URI. Chronic nasal disease, dental disease, fungal infection, foreign material, asthma, pneumonia, and even heartworm-associated respiratory disease can mimic or complicate upper respiratory signs. That is why persistent or severe symptoms deserve a veterinary exam rather than home assumptions.

Prevention starts with vaccination, especially the FVRCP vaccine that covers feline viral rhinotracheitis, calicivirus, and panleukopenia. Vaccination does not prevent every case of upper respiratory infection, but it can reduce how severe the illness becomes. Kittens need a series of vaccines, and adult cats need boosters on a schedule your vet recommends based on age, lifestyle, and risk.

Good infection control matters just as much in many homes. If one cat is sick, separate food and water bowls, litter boxes, bedding, and grooming tools can reduce spread. Wash your hands after handling the sick cat, and clean surfaces that contact eye or nasal discharge. New cats should be quarantined before introduction, especially in multi-cat households.

Stress reduction also plays a real role. Herpesvirus can remain dormant and flare during stressful events such as moving, boarding, surgery, or social conflict between cats. Stable routines, adequate litter box access, good ventilation, and avoiding overcrowding can all help lower the chance of outbreaks.

Shelters, rescues, breeders, and foster homes need especially careful prevention plans because dense cat populations allow rapid transmission. Prompt isolation of symptomatic cats, vaccination protocols, sanitation, and minimizing crowding are key parts of control.

The outlook for most otherwise healthy cats with a mild upper respiratory infection is good. Many improve within one to three weeks, especially with supportive care and good hydration and nutrition. Cats with mild viral disease may recover without extensive treatment, though they can still feel miserable for several days because congestion interferes with eating and resting.

Recovery can take longer when bacterial infection, severe conjunctivitis, corneal ulcers, dehydration, or pneumonia are involved. Kittens and senior cats may decline faster because they have less reserve. Cats that stop eating are at special risk, since even short periods of poor intake can create additional medical problems.

Some cats, especially those exposed to feline herpesvirus, do not fully eliminate the virus. Instead, they become lifelong carriers with periods of remission and flare-up. These flare-ups may happen during stress or illness and can look like repeat “colds.” That does not always mean a new infection. It may reflect reactivation of latent virus.

Your cat’s long-term outlook is usually best when complications are treated early and future flare triggers are managed. If your cat has repeated congestion, chronic nasal noise, or frequent eye disease, ask your vet whether there may be chronic upper airway changes or herpes-associated recurrence that would benefit from a longer-term management plan.