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Last month I had the incredible good fortune to meet, fall in love with, and ultimately adopt a sweet, tiny, smart-as-a-whip calico kitten who now goes by the name of Piper (more about her in a future post). Rescued from a kill shelter by a local rescue group, Piper came into my life with impeccable manners, a loving disposition, and an impossibly loud purr that, much to my delight, she uses often. However, like many kittens who spend time in a shelter environment, she also came with an additional bonus – a brewing upper respiratory infection.
Upper respiratory infections in cats are highly contagious, and are found most often in environments where 1) there are large numbers of cats together in close proximity, and 2) the environment is stressful. This is why they are so common in animal shelters, cat breeding facilities, and feral cat colonies. Once cats are exposed, the illness can lie dormant in their bodies until a stressful event triggers it to let loose.
These illnesses are often referred to as “kitty colds” or “cat flu”, which tends to give the impression that, like human colds, they really aren’t all that serious. However, in young kittens, unvaccinated cats, or those with a compromised immune system, they can have serious and long-lasting consequences.
What Causes Upper Respiratory Infections In Cats?
Upper respiratory infections, or URIs, can be caused by several different organisms (sometimes more than one at the same time), which is what makes them so tricky to diagnose.
The vast majority (over 90%) of URIs are the handiwork of 2 viruses:
Feline herpes virus (FHV)
Formerly known as “Feline viral rhinotracheitis”, FHV causes typical flu-like respiratory symptoms. Like all herpes viruses, FHV stays in the body long after the cat has recovered, and can reappear months or years later. It is so common that some researchers believe approximately one-third of all cats are carriers of this virus.
Feline calicivirus (FCV)

Calicivirus causes the usual respiratory symptoms, but in addition can cause extremely painful, ulcerating sores on the gums, tongue, lips, and nose. This is a tough little virus that’s difficult to kill. Cats with calicivirus can remain contagious for months after recovery. In most cases, calicivirus eventually leaves the body, but some cats can remain carriers for life.
Other organisms that can cause upper respiratory infections in cats include the parasitic bacteria mycoplasma, chlamydia, and bordetella.
Fortunately, these organisms are only contagious to other cats – they can’t be spread to humans or to other pets in the household.
How Are Upper Respiratory Infections Spread?
There are several ways cats can become infected with upper respiratory viruses:
- Direct exposure to the saliva, secretions from the nose or eyes, and possibly the urine and feces of an infected cat. Exposure can occur through sneezing and coughing, mutual grooming, napping together in close quarters, even hissing or spitting.
- Indirect exposure from viruses hitching a ride on toys, food and water bowls, bedding, grooming tools, litter boxes, and human hands and clothing.
- Exposure to cats who are carriers and are actively shedding the virus. Carrier cats harbor the virus in their bodies, and can “shed” the virus (release it back into the environment) even if they are not showing any signs of illness. Viral shedding can be triggered by any stressor, including moving to a new home, injury or illness, or the addition of a new family member (baby, dog, or another cat) to the household.
Symptoms Of URIs
Once a cat becomes infected with one of these microorganisms, symptoms generally show up within 2-10 days. They can include:
- Sneezing
- Congestion
- Nasal discharge (either clear and thin, or thick and colored brown, green, or yellow)
- Conjunctivitis (inflammation of the eyes, causing discharge and/or squinting)
- Fever
- Loss of appetite
- Lack of energy
Severity of these signs can vary considerably. In some cats (like Piper), they can be very mild and don’t last for long, but in other cases they can be quite severe and last for weeks.
Below is a photo of Piper during the worst part of her illness. Fortunately, she only had conjunctivitis in one eye, no nasal discharge, and very mild sneezing.
Piper was lucky; by the time she was exposed to the virus she had already started her vaccination series, which undoubtedly helped lessen the severity of her symptoms. Some kittens with URIs can become very sick, like this poor baby:

In the most severe cases, upper respiratory infections can cause coughing, drooling, painful corneal ulcers on the surface of the eye, and the aforementioned ulcers in the mouth and nose.
Why Are Upper Respiratory Infections In Cats So Hard To Treat?
Upper respiratory infections are notoriously difficult to treat and manage, for several reasons:
- They can be caused by many different types and strains of viruses and bacteria, and diagnosing which microorganism is the culprit is extremely difficult. There is no one simple test that can be run, so diagnosis is usually based purely on clinical symptoms.
- Most (over 90%) are caused by viruses, so antibiotics have no real effect other than to help prevent secondary bacterial infections.
- There is no way to determine if or when an infected cat is no longer contagious.
- Viruses can remain active and infective for up to 10 days on surfaces, and in the case of calicivirus, the only thing that will kill it is bleach solution. This makes it virtually impossible to disinfect all areas the cat has come into contact with.
- Some cats who are carriers remain so for life, and can experience repeated flare-ups of symptoms over the course of their lifetimes. There is currently no test available to determine if a cat is a carrier.
What You Can Do If Your Cat Develops An Upper Respiratory Infection
If your kitty develops an upper respiratory infection, know that the average illness typically lasts between 7 and 14 days, regardless of treatment. Since most of these infections are viral, antibiotics usually aren’t much help (and in some cases, may make the kitten or cat feel worse by causing digestive system upset).
Treatment for URI is generally based on providing supportive care and relief from symptoms while your kitty’s body fights the virus. However, if your kitten is very young, or you notice coughing, severe eye squinting, extreme weakness, or a refusal to eat, call your veterinarian immediately for advice.
For milder cases, here are things you can do to help nurse your kitten or cat through a URI.
- If you have multiple cats, separate the sick cat immediately and give her a warm, comfortable “quarantine” room, away from noise and drafts.
- Use a soft cotton ball soaked in warm water to wipe away any discharge from the eyes and nose. This prevents skin irritation, helps keep the nose clearer for breathing, and generally seems to make cats feel better.
- Offer soft, wet food (preferably with a strong smell) that has been warmed up to encourage your cat or kitten to keep eating. Cats with URIs are often unable to smell their food due to nasal congestion, which causes them to lose their appetite. Good nutrition and steady caloric intake will help them recover faster.
- If your cat is extremely congested and has difficulty breathing, use a humidifier or vaporizer to add moisture to the room. You can also take your cat into the bathroom, close the door, and run hot, steamy water in the shower.
- Keep your cat warm. This is especially important for kittens, who can’t efficiently regulate their body temperatures and can easily become chilled.
- Ask your veterinarian about giving your cat L-lysine, an amino acid that is thought to help boost the immune system by interfering with herpes virus reproduction in the body. Although there is still some debate as to whether L-lysine actually works, many cat parents and veterinarians have reportedly used it with good success.
- Keep your cat playing. Although your first instinct may be to try to keep your cat quiet at all times, short, gentle play sessions can actually help get your cat’s circulation going and improve her mood. I noticed this with Piper – she seemed to perk up quite a bit after playing for just a few minutes at a time. Just be careful not to overdo it.
For more serious cases, your veterinarian can prescribe antiviral medications or eye drops, decongestants, and immune supplements. Keep your veterinarian informed of your kitty’s progress, and don’t hesitate to call them if your cat or kitten is not improving or takes a turn for the worse.
Upper Respiratory Infections In Cats – S’not A Fun Experience
So how serious are these infections?
Upper respiratory infections can last anywhere from 1 to 4 weeks, and most cats and kittens fully recover. However, very young kittens, older cats, cats who have never been vaccinated, and those with a suppressed immune system (such as cats with FeLV or FIV) can develop life-threatening complications, including malnutrition (from being unable to eat), dehydration, and pneumonia. Permanent eye damage from corneal ulcers can cause blindness, and sometimes surgery is required to remove the damaged eye. Cats who remain carriers of the virus may experience occasional symptom outbreaks during times of stress, but these recurrences can usually be managed.
Since it’s virtually impossible to prevent your cat from being exposed to upper respiratory viruses, you can help lessen her chances of becoming sick by making sure she receives at least an initial round of FVRCP vaccinations. Although the vaccines may not completely prevent her from contracting the virus, they can help lessen the severity of the symptoms if she does become ill. Also, consider keeping your cat inside full-time and away from other potentially infected cats.
Although they are common, and most cats recover without long-term health effects, upper respiratory infections should never be taken lightly. It’s always better to err on the side of caution and talk to your veterinarian if you have any concerns during your cat’s illness and recovery from a URI.
Has your cat ever experienced an upper respiratory infection? Please share your story with us in the comments below!
Found one little ginger near my flat on his own, very friendly about 3 months old, brought him straight to the Vet for a check up and first vaccines
Thought i will have a playmate for my other cat since they got on very well
After 2 days out of the blue he started sneezing and stopped eating. Back to the Vet who kept him in and put him on I.V
Deteriorated very quick and i had to make the decision to put him out of his misery 🙁
I still see the little one in front of my eyes
I’m so very sorry to hear about what happened to your little one. Kittens and puppies are very vulnerable to viral illnesses since their immune systems are so fragile. 🙁
I took in a foster kitten who supposedly just had a little sneeze and a drop or two of clear liquid from its nose. He was living in a closet so I had to take him (8 weeks old) bc I have a 1/2 bath where he could have his own space away from my big kitties. The first day I noticed green spots in his mucous when he sneezed in my tablet. I took him to a vets home, she wouldn’t let me in but told me she gave him an antibiotic shot and that she thought by looking that he had ring worm. I applied anti fungal Meds to his ears and neck area and kept him separate. But I held him often and let him sleep on my bed wrapped in his blanket. After 2 weeks he was getting better with L lysine and that shot. But I developed some very itchy spots on my chest, thought it was ring worm so I applied the anti fungal Meds, it got worse, more spots. Went to the MD, she said not ring worm, impetigo, which I have read is caused by staph or strep. My home is very clean and so am I, my doctor told me not to hug or hold my kitten. Could I have really gotten this from my kitten? The day it started I was at the beach and thought I had gotten some big bites, then went to a friends home, that isn’t very clean. I didn’t sit the entire time as I was cooking dinner. It just got worse after.. probably bc I touched the sore and then other parts of my body. Please tell me my kitten couldn’t have given me this and if he did what do I need to do for him??!! HELP!!
I still suspect my indoor cat caught a URI from ME 2 days after I started sneezing with a runny nose. Kiwi is a 10 month old kitten who came from shelter 6 months ago 24 hours after a vet pronounced him healthy. His only contact with with another cat (healthy–who has never been sick) was four months ago, and he hasn’t even touched a grocery cart or other fomite outside the home for weeks.
Initially he just sneezed a lot, then developed a clear watery discharge from one eye (which has resolved), but then developed a lot of nasal congestion and clear nasal discharge–just like me. His breathing seems normal, he still eats (like me!), but now spends more time in my bed. He coughs maybe twice/day, sneezes more often. He is now on sickness day 8, while I am on day 10 with minimal head/nasal congestion.
WHERE else could he have gotten a URI?
Hi Winifred! I must admit, I was very intrigued by your question and did quite a bit of research to see what recent studies said about transmitting flu to cats. When I worked in veterinary medicine, we were taught that there was no possibility of transmission of cold or flu viruses from humans to cats or dogs. However, there is now new research that shows that, although very rare, it is possible.
The virus that changed the game was the H1N1 virus (also known as the Swine Flu). In 2009, there was a documented case of a cat who contracted the virus from its owner, then subsequently developed pneumonia and unfortunately passed away. Since then, studies have shown that the H1N1 virus can attach to the respiratory tract of cats in a very similar way that it attaches in humans, and it’s believed that this cat, along with several ferrets, may have been victims of this flu. Which is not really surprising when you think about how effectively viruses can mutate. The parvo virus in dogs actually mutated from the panleukopenia virus in cats, and since viruses are frighteningly adaptable, it would certainly be possible that there was a virus strain that was able to make the jump from humans to cats.
The other possibility in your case is that, although rare, since certain viruses in dogs and cats can attach to our shoes, clothing, skin, or personal items (as you said, fomites) and be carried into the house (in theory, then infecting a dog or cat), it’s possible that Kiwi became exposed that way. However, since viruses are not usually very hardy once outside the host (with the exception of the parvo virus in dogs), I think it’s actually just as probable that Kiwi may have actually have contracted a virus directly from you. Unfortunately, we will probably never know for sure, but personally I do believe it could be possible.
How is Kiwi doing now? Hopefully better! If he isn’t improving, I would definitely let your vet know, just to be safe and make sure that there aren’t any complications developing. And hopefully you are feeling better too!!
My cat Lennon is 12 years old, was diagnosed with Feline Herpes years ago while he was small and it only bothered his left eye. Now that he is older, when he has a bout with the Herpes, both eyes have discharge and poor fellow is so congested and can’t breathe thru his nose. He has been on an antibiotic for 10 days now (Amoxicillin and Clavulanale Potassium Oral Suspension). He is still having a tough time, sneezing with discharge and not able to breathe thru his nose. He cleared up for about 6 days and then started all over. Poor fellow has been sick now for almost 3 weeks with only those 6 days that he acted as though he felt better. I’m really running out of options and have him to 3 different vets. I’ve been told that you can not give felines decongestants?? I’m using baby saline spray. Any help would be appreciative.
what happened ? I have the same problem.Thanks Bob
I’m dealing with this right now in a new kitten we adopted from a shelter. He is so pitiful. He will eat and drink and play some so I have hope that he will recover but it’s so sad to have to keep him quarantined from our other two cats. I just hope they don’t end up sick. We are using the viralys powder in every cats food at the recommendation of our vet. We will see how it goes…
Hi Cari, how is your kitten doing now? Did the viralys help him?
I have a kitten just got her yesterday my daughter who is 13 has wanted to be a vet since kindergarten and picked the sickest cat of the sick litter all have upper respiratory infection and the person who found them with no knowledge was cleaning their eyes with peroxide never heard of such a thing luckily my kitten was not effected by the peroxide two of the kittens eyes were open when peroxide was applied so I assume they will end up blinded by it however I’ve done so much research on how to help my kitten recover I did give her the booster shot as soon as we walked in the door yesterday even though she is ill I made the judgement call to give it to her in hopes it will help me save her life she is very tiny very tiny and I’ve been giving her Prednisone to help her lungs out and all baby food warmed up if she takes it forcing Pedialyte doing all I can my son has a breathing machine so I use the hose peice and put it next to her to help her breathe better sit the Vic’s vapor rub tube next to her while she sleeps to help her as well she started yesterday with yellow discharge from her eyes today it is milky and clear at times too so I feel that means she is getting better she was very dehydrated that is getting better she finally did go number one and two today for the first time I feel I am helping her however I’m not sure if some of the things I am doin may not be too safe breathing treatment Prednisone heck even breathing in the Vic’s I’m unsure I got a booger sucker suck her nose a few times a day I’m doin what I believe will help her but I want to ensure I’m not actually hurting her in the long run I do know her meow has gotten louder more clear so I feel she is breathing better today then yesterday but without a large improvement I am counting myself on if I am helping her or not at this point
Hi Tabitha, do you know how old the kitten is? Unfortunately, very young kittens can crash very quickly even with the best of care, so the best thing you can do at this point is monitor her constantly and get her to a vet immediately if it appears she is struggling to breathe or not eating. When they are very young, they can dehydrate extremely quickly, so if she suddenly gets very weak I would get her to the vet as quickly as you can. I would also caution against giving her the Prednisone. Other than that, the suctioning her nose won’t hurt, and cleaning her eyes with cotton balls dipped in plain warm water to loosen the discharge will also make her feel much better. However, my best advice would be to contact your vet’s office directly and ask them for their help. They will be able to ask you additional questions over the phone to make sure the kitten is getting the best care possible. Good luck, I hope all goes well and this sweet little kitten feels better very soon!
We adopted a 4 month old kitty on August 2nd from a shelter; all vaccines and microchiped too. About 3 days later (she was in quarantine because she had just been spayed- but my husband let her out without telling me) started with goopy eyes and we threw away her toys. She unfortunately had already played with my other cat while I was away and my husband didn’t tell me. The vet saw her next day and gave her antibiotics and eye/nose drops. She finished her course of medicine yesterday. She was actually clear of gunk in her eyes 3 days after starting meds so I could see her improvement. I kept her isolated and cleaned her litter box 2x a day, swept up her area, even bleached the entire floor twice. Today while I was in her area cleaning, she got out and no one was around to grab her. She got under the stairs and was playing with my other cat. I climbed in and she got out. It was cat and mouse with onr adult and 2 cats playing hide and seek. I decided since she wasn’t looking terribly sick that I could go back to cleaning and she’d come out. She did and I put her back in isolation. I went to look at my other cat and noticed her eyes were leaking clear fluid. Instant panic attack! NO! How could she have gotten sick so quickly?! My new kitty has been in isolation for 12 days, course of meds finished, no visible symptoms, out for a bit and bam. I feel terrible and like this illness is never going to leave my home. I’m almost regretting bringing in a kitten to our home and possibly getting our other cat whose 1.5 years old and has been nothing but healthy, sick. What if this never goes away and just keeps happening? I have kids and worry that me kitty might have chlamydia. What if she gives it to my kids? What if I can’t get her healthy? I had a cat die of cancer last spring and my heart hurts thinking about having another sick cat. I feel selfish and regretful. Tell me this gets better. NONE of the cats I’ve had in my life have ever had a URI.