A reader wrote in with a question about a cat URI not getting better despite treatment…

I have a 6 month old cat named Sammy who started sneezing and having runny eyes right after I rescued him from the shelter. The vet gave him a shot and antibiotic drops a week ago but I’m worried because my cat’s URI is not getting better. Why didn’t the antibiotics work?


Dear Trevor,

I’m sorry to hear your new buddy is getting a rough start in life. Shelters expose cats to all kinds of bacteria, viruses, and parasites. Young cats who have never been exposed to any of these diseases are especially susceptible to catching something from the other cats in the facility.

Shelter Stress and Cat URI’s

Stress plays a role in a shelter cat’s health, too. Just think about it–Sammy was probably taken from the only home he’d ever known and put into a cage. With all the noise, new people and strange cats shelters can be pretty scary for kitties.

Stressed cats make extra hormones to boost immunity temporarily. After a while, this effect becomes detrimental as some white blood cells are decreased by long-term stress hormones. One study found that stressed shelter cats were 5.6 times more likely to contract an upper respiratory infection than unstressed cats in the same shelter (2).

I’m glad to hear you took Sammy to see your veterinarian. Although most feline upper respiratory infection cases are caused by viruses, they can lead to secondary bacterial sinus infections. Vets prescribe antibiotics for cats with thick nasal discharge or prolonged sinus symptoms. Antibiotics don’t do anything for the respiratory virus, but they can be helpful for a secondary bacterial infection.

Symptoms of Cat Upper Respiratory Infection

Clinical signs associated with cat colds can vary from mild occasional sneezing to severe eye and sinus lesions. Here are some of the symptoms you might see in a sick cat:

  • Sneezing
  • Watery, blood-tinged or thick nasal discharge
  • Nasal congestion and noisy breathing
  • Exaggerated swallowing
  • Open-mouth breathing
  • Drooling
  • Swollen membranes on/around eyes
  • Crusting around eyes
  • Watering, red eyes
  • Mouth or lip ulcers
  • Poor appetite

Infections Destroy Sinus Tissue

There is a group of diseases causing “cat flu,” or Upper Respiratory Tract Disease. The organisms responsible include feline calicivirus, feline herpesvirus and the bacterias Bordetella bronchiseptica, Chlamydophila felis, and Mycoplasma sp..(1) 

Feline upper respiratory viruses vary in their effect on a cat’s sinuses. Some cats experience extreme inflammation, ulceration of sinus mucous membranes, and even remodeling of the small bones inside the sinuses. These changes can lead to chronic upper respiratory symptoms even after the virus and bacteria are gone. With their new abnormal sinus anatomy, cats can develop recurrent bacterial infections, too.

Feline Herpes Virus (FHV) is one of the most common causes of URI in cats. Even after the initial symptoms clear, FHV can lie dormant in a cat’s system and become reactivated during times of stress. Reactivated viral infections can add to existing sinus problems.

Calicivirus is another common cause of feline URIs. The symptoms are similar to those seen with FHV but the eye symptoms are often less severe. Feline calicivirus may also cause painful ulceration of the lips or tongue. (2) 

After only a week of symptoms, Sammy still has a good chance to recover without long-term consequences. Start with another visit to your veterinarian to see if the situation has changed or if a new medicine should be considered.

yellow cat sneezing

You might be interested in how indoor cats get a cold

Natural Home Care for Cats with URIs

Some things you can try at home for a sick cat with an upper respiratory infection that’s not getting better with standard treatment:

  • Minimize stress. If you have other pets, make sure Sammy has a quiet, safe place to rest but don’t let him hide where you can’t monitor his condition.
  • Feline facial pheromone products like Feliway diffusers help cats acclimate to new homes. These nifty plug-in diffusers help cats feel less stressed and can make a noticeable difference over time.
  • Strong-smelling moist foods will encourage him to eat. The hunger drive of a cat depends on their sense of smell so when they have stuffy noses they tend to eat less.
  • Saline nose drops applied into his nostrils two or three times a day can help break up thick mucus so he can breathe better. Only use a few drops and skip this step if it is too stressful for him.
  • Use a humidifier in the area where he spends the most time. The mist can help moisten respiratory tissue and thin the mucous produced.
  • Probiotic supplements may help him get well sooner. A study found that cats with FHV who took an Enterococcus faecium probiotic (try FortiFlora for cats) did not feel as sick as those who didn’t take probiotics (1)
  • L-lysine nutritional supplements in the form of pastes or treats may help him fight off the virus more quickly. Skip this if it causes too much stress to get him to take it. Most cats I’ve come across will eat Enisyl-F Lysine Treats.

Next Steps for Chronic URIs

If symptoms are still present after three weeks of treatment, it’s time for some more aggressive intervention. You’ll definitely need your veterinarian’s input at this point.

Some of the next steps vets will take when cats with URIs are not getting better after several weeks include:

  • Examination under sedation to look for polyps in the ears and pharynx
  • Radiographs (x-rays) of the cat’s skull
  • Bacterial culture and cytology of sinus fluids
  • Biopsy of sinus tissue
  • Sinus flushing while the cat is under sedation

I hope Sammy feels better soon!

Dr. Thompson

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  1. Bannasch, M. J., & Foley, J. E. (2005). Epidemiologic evaluation of multiple respiratory pathogens in cats in animal shelters. Journal of Feline Medicine & Surgery, 7(2), 109-119.
  2. Berger, A., Willi, B., Meli, M. L., Boretti, F. S., Hartnack, S., Dreyfus, A., … & Hofmann-Lehmann, R. (2015). Feline calicivirus and other respiratory pathogens in cats with Feline calicivirus-related symptoms and in clinically healthy cats in Switzerland. BMC veterinary research, 11(1), 1-12.
  3. Lappin, M. R., Veir, J. K., Satyaraj, E., & Czarnecki-Maulden, G. (2009). Pilot study to evaluate the effect of oral supplementation of Enterococcus faecium SF68 on cats with latent feline herpesvirus 1. Journal of feline medicine and surgery, 11(8), 650–654.
  4. Tanaka, A., Wagner, D. C., Kass, P. H., & Hurley, K. F. (2012). Associations among weight loss, stress, and upper respiratory tract infection in shelter cats. Journal of the American Veterinary Medical Association, 240(5), 570–576.