If your cat is sneezing and sniffling, there can be lots of causes. But one thing to consider is feline calicivirus. This highly contagious virus is a common cause of respiratory disease in cats, especially if they haven’t been vaccinated against it. It’s most common in kittens, but cats of any age can contract this virus.
It’s Easy to Catch
Feline calicivirus is most commonly transmitted when a cat comes into direct contact with an infected cat. Virus particles can be found in saliva or nasal and eye discharges, so any objects that have been contaminated with these fluids, such as food bowls and bedding, can also serve as sources of infection.
The virus can live for up to a month in the environment, so it’s not surprising that infection is most commonly seen in places where there are large numbers of cats, such as shelters and breeding facilities.
Signs of Infection
After being exposed to the virus, cats may show signs of disease in about two to six days, and the signs can vary depending on the strain of virus. Often, cats will show classic signs of an upper respiratory infection, such as sneezing, nasal congestion, conjunctivitis (pink, inflamed eyes), and clear or cloudy discharge from the nose or eyes. Painful ulcers in the mouth can occur, which may lead to reluctance to eat and drooling. Lethargy, fever and enlarged lymph nodes are other signs that can occur. Cats can develop lameness due to joint pain; however, this occurs more frequently in kittens than in older cats.
Some infected cats may become carriers. Carrier cats may shed the virus intermittently and may or may not show signs of illness during those times.
A More Dangerous Strain
A very rare strain of calicivirus known as virulent systemic feline calicivirus or VS-FCV also exists. This strain is highly contagious and can be fatal, but the good news is there have been only a few reports of it in the U.S. since early 2000. VS-FCV causes severe generalized disease in which fever, depression and swelling of the limbs and/or face can occur. Cats can develop jaundice (yellowing of the eyes, ears, skin), and multiple organs can be affected. Older cats are most at risk.
Getting to a Diagnosis
After giving your cat a thorough physical exam, your veterinarian may make a presumptive diagnosis of calicivirus based on clinical signs and a medical history of possible exposure. A definitive diagnosis is not always necessary but may be recommended for a breeding cat or if an animal is not responding to treatment. To make a definitive diagnosis, samples from the nose, mouth or eyes can be submitted to a laboratory for testing to help isolate and identify the virus. Supportive Treatment
The virus will typically run its course for seven to 10 days. But infected cats can shed the virus for two to three weeks, so cats can be infectious to other cats and should be isolated. There is no specific treatment for the virus itself, but antibiotics and other medications may help address secondary infections and complications associated with the virus.
Treatment depends on the severity of disease, and your veterinarian can determine the best approach. Cats with only upper respiratory signs may require antibiotics, as well as gentle cleaning of the eyes and nose with a wet tissue or cotton ball. Periodically placing your cat in a warm, humidified environment, such as the bathroom during hot showers, can help to break up the nasal congestion. Cats with significant nasal congestion may have a decreased sense of smell. Since this can lead to a loss of appetite, a highly palatable food may help improve their food intake. Those with severe respiratory signs or other complications most likely require hospitalization for intensive care. If oral ulcers are present, pain medication and a soft diet may be recommended.
Help Prevent Infection
If your cat is current with her vaccines, she has likely been vaccinated against calicivirus. Although the vaccine can’t completely prevent your cat from getting disease, it usually helps reduce signs if your cat is exposed to calicivirus. This is similar to people who receive the flu vaccine. They are vaccinated against the known flu virus; however, they can still contract the virus but will typically not get as sick as someone who has not been vaccinated. Most veterinarians begin vaccinating kittens at about 6 to 8 weeks of age, followed by boosters every three to four weeks until the kitten is around 16 weeks of age. Boosters are usually given every one to three years after that, but your veterinarian will discuss the recommended vaccine schedule for your cat. Although vaccines are available that may help provide broader protection against other strains of calicivirus, such as the virulent systemic strain, they are generally used in shelters, where cats may be at a higher risk.
If you have any questions about calicivirus and your cat’s risk of infection, please have a conversation with your family veterinarian.