Published by: Ingrid King. Last Updated on: February 10, 2023 by Crystal Uys
Feline calicivirus, or FCV, is a viral infection causing severe upper respiratory problems in cats. Entering through the cat’s eyes, nose, or mouth, this virus possesses symptoms similar to that of a common cold. As loving cat owners, it is important to be well informed of the causes, symptoms, and prevention of this fast-spreading infection to help keep our feline friends happy and healthy.
Frequently seen in animal shelters or within multi-cat homes, the FCV infection is typically spread amongst cats that are being housed together in large numbers or kittens with weak immune systems. Once the cat is infected with FCV, they may carry the virus in their bodies for life. “Approximately 10% of household cats exhibit this ‘carrier’ state and have the chance of becoming sick again during times of stress or other illness, although many will not” said Dr. Kathy Scott, lecturer at the College of Veterinary Medicine & Biomedical Sciences. “They may continue to shed the virus, however, putting other cats they are near at risk of developing the infection.”
Depending on the strain of the virus, infected cats can show a great variety of symptoms. Typical symptoms seen with FCV are similar to an upper respiratory infection, involving sneezing, nasal congestion, and conjunctivitis, with more severe cases exhibiting lethargy and poor appetite as well. “Some cats will develop severe gingivitis and oral pain that may be significant enough to cause the cat to not eat, while others may demonstrate lameness and fever,” Scott said. “Rarely, a severe variant of calicivirus (called FCV-associated virulent systemic disease or FCV-VSD) can develop and cause critical illness, multiple organ damage, and even death.” Luckily, this form is very rare and outbreaks can be controlled through strict isolation and quarantine.
Accurate diagnosis will help your veterinarian provide the best treatment possible, and is also important if the infected cat lives in a multi-cat household.. To diagnose FCV, the vet will evaluate the cat’s clinical symptoms and medical history in addition to laboratory testing. “A swab can be taken of the cat’s mouth or conjunctiva (a thin membrane of the eye), and tested for presence of the virus in those tissues,” Scott said.
Unfortunately, the treatment of FCV is challenging. There are currently no medications to completely eliminate the virus or eliminate the infection at a faster pace, so the best thing you can do for your furry friend is to provide them with the support and care they need to help them feel comfortable. Due to their stuffy noses and possible ulcers in their mouths, cats with FCV have a tendency to lose their appetite, so it is wise to provide them with soft, strong-smelling foods or pain medications that will make eating more comfortable. “We also recommend keeping their noses clean and sometimes using medications or vaporizers to help loosen the mucus in their noses, making it easier to breathe,” Scott said. “In more severe cases, antibiotics may be needed to stop the growth of bacteria that have overgrown as a result of the FCV infection, and if cats haven’t eaten in more than three days, they will probably require a short period of hospitalization to receive fluids and some form of nutrition.”
The most important measure you can take to reduce the likelihood of your cat contracting FCV is to ensure that their vaccinations are up to date at all times. “Although there is no vaccination that provides 100% protection, there is a vaccination available for FCV, and it is part of the ‘core’ vaccinations recommended by veterinarians to all cats,” Scott said. “This vaccine is likely to decrease risk of the development of upper respiratory infection, but, unfortunately, can’t protect against all strands of FCV, so cats still may become infected.” Though vaccinated cats still have a chance of becoming carriers if infected, they do have a lower chance of spreading the infection to other cats than those that are unvaccinated.
If coming down with an upper respiratory infection is miserable for us, imagine what it is like for our cats. Taking precautionary measurements to prevent them from coming down with FCV, as well as keeping an eye out for specific symptoms, can make a world of difference for both you and your feline friend.
This article is reprinted with permission from the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University.
Editor’s note: Sadly, I have had personal experience with the virulent version of this calici virus. In May of 2013, Amber contracted this virulent from of the virus, and she passed away less than two weeks after she started to get sick. At my request, her veterinarian at the time, Dr. Fern Crist, wrote a post about Amber’s progression for me in hopes of making cat guardians and veterinarians alike more aware that mutant caliciviruses are capable of creating disease scenarios such as Amber’s, and that this may be more common than we realize. Read Virulent Feline Systemic Calici Virus for more information.
Photo ©Robin Olson, Covered in Cat Hair, used with permission.
About the author
Ingrid King is an award-winning author, former veterinary hospital manager, and veterinary journalist who is passionate about cats.