Calicivirus in Kittens & Mouth Sores

If your new kitten has a runny nose or eye discharge, he should see his vet to be tested for FCV.
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Adopting a kitten is exciting, but finding out your new pal came with a virus on board is frightening. Making sure you get your new pal vaccinated against FCV may prevent him from getting it or at least reduce the symptoms, possibly saving his life.

What is Feline Calcivirus?

Feline calcivirus (FCV) is a virus that affects Kitty's respiratory system and his mouth. According to the Cat Health Guide, 90 percent of upper respiratory infections are caused by FCV. It's contracted commonly in shelters where over 25 percent of the shelter population is infected. The disease will cause Kitty to have trouble breathing, sneezing, a runny nose, eye discharge, painful gums and mouth ulcers. It can be contracted if Kitty is around infected cats, whether or not they are showing any symptoms. FCV can take up to 10 days to show symptoms and some cats are simply carriers for the disease. When a cat is a carrier, he won't show any outward symptoms, but he still can pass the virus onto other cats. Kitty may stop eating due to loss of smell from severe congestion or pain in his mouth leading to dehydration. If left untreated, dehydration can be fatal to a small kitten.

Mouth Sores

Gingivostomatitis and caudal stomatitis are conditions where Kitty's mouth and gums become inflamed, painful and may bleed. These conditions are more prevalent in purebred cats than their mix-breed cousins. If Kitty has FCV, a reaction to the virus from his immune system may cause him to suffer these painful sores. You may notice Kitty avoiding his food dish and losing weight. When his mouth is swollen and full of painful lesions, it will be difficult for him to eat without pain.


If Kitty has the symptoms of FCV, he should visit his vet immediately. His vet can swab his nose and eyes to determine if he has FCV. If he also has mouth sores, his vet will do x-rays to determine how much damage there is in his jaw. Urinalysis also can tell the vet if he has heightened plasma protein globulin, indicative of stomatitis. The vet may biopsy the sores in Kitty's mouth just to make sure he doesn't have cancer.


Since FCV is a virus, the primary treatment is to support Kitty while the virus goes through its life cycle. If he's dehydrated, the vet may put him on an IV to give him fluids. If he hasn't eaten in three days, he'll need a feeding tube to make sure he's getting enough nutrients. The vet may put him on antibiotics to prevent him from contracting a secondary infection, like pneumonia while his immune system battles the FCV. Feeding him warmed food or strong-smelling food, like tuna, might encourage him to eat more if he's refusing due to a stuffy nose. His teeth and gums will need a good cleaning. While keeping Kitty's teeth clean and giving him anti-inflammatory medicine may ease the symptoms of the mouth ulcers, they usually don't give him relief long-term. The best treatment is to remove the affected teeth. According to the Pet MD website, removing the teeth just behind his pointy canines results in relief from painful mouth sores 60 percent of the time. (


Getting your kitten vaccinated against the disease will give him protection from the worse case scenario. While it may not give him a 100 percent chance of never contracting the disease, it will lessen the severity if he ever gets it. Kind of like the flu vaccine for humans, the FCV vaccine doesn't protect against all strains or mutations of the virus. At 10 weeks, he'll be able to get his first vaccination. At 14 weeks and one year he'll need booster shots. Then, he'll just need to be given a booster every three years to keep him protected. All healthy kittens should be vaccinated. Since a vaccine will prepare his immune system to fight the disease, waiting until he already is sick to get him vaccinated won't do him any good. Speak with his vet about a vaccination schedule.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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