Feline Calicivirus: Respiratory disease in cats

A viral disease called feline calicivirus (FCV) causes upper respiratory tract infections in cats. Although serious infections affecting the lungs, joints, and/or other organs can occur, infections most usually mimic a cold. Worldwide, this virus may infect cats and cause illness in both domestic and exotic cat species. Calicivirus is one of the most often identified infectious agents in cats with respiratory infections, despite the fact that a variety of viruses and bacteria can cause respiratory illness in cats. “Feline Upper Respiratory Infection” has details on a few other infectious agents that can result in an upper respiratory infection in cats.

The majority of the time, the virus is discovered in establishments that keep many cats, such breeding farms, shelters, and rescues. However, it may spread quickly in homes with a small number of cats. Although cats of any age can get the virus, kittens and young adults are often more at risk.

Causative agent:

The feline calicivirus, or FCV, is a member of the Caliciviridae virus family, which is a broad family of viruses that infects a variety of vertebrate species, such as sheep, frogs, rabbits, and reptiles. The Caliciviridae family also includes the human virus norovirus, which causes a short-lived but unpleasant gastrointestinal illness.

Different FCV strains are prevalent in both domestic and wild cats. Since the virus mutates often, new strains may emerge that are not entirely protected by current vaccinations. Different strains produce different degrees of sickness, most causing relatively moderate symptoms. The fact that outbreaks persist despite 40 years of FCV vaccination coverage is probably due to the virus’s capacity for mutation.

Occasionally, a mutant strain of FCV known as FCV-associated virulent systemic disease, or FCV-VSD, may appear on its own and cause an extremely serious illness including numerous organ damage or even death. In 1998, there was the first reported epidemic of FCV-VSD in Northern California. FCV-VSD outbreaks are atypical and uncorrelated with one another.

Virus transmission:

The majority of FCV cases occur in settings with several cats. In pet shops, shelters, and catteries, where 25–40% of cats could be carriers, a cat’s chance of exposure is increased.

The virus can spread by direct contact with an infected cat’s saliva, nasal mucus, or ocular discharge. It can also spread by aerosol droplets released by sneezing cats. The virus has also been found in blood, feces, and urine by lab tests. After infection, cats usually shed the virus for two or three weeks, but some go on to become long-term carriers and may shed the virus for months at a time.

FCV is a resilient virus that may endure up to a month on surfaces in specific conditions. People who come into contact with sick cats may unintentionally spread the illness.

Signs and symptoms:

Certain cats can get an infection without exhibiting any symptoms. If symptoms exist, they might be mild, moderate, or severe, with severe symptoms potentially leading to death. The most typical indications are:

• Sneezing
• Nasal discharge
• Ulceration of the surface of the nose (skin broken open)
• Conjunctivitis (eye inflammation)
• Eye discharge 
• An affected cat may also develop the following:
• Ulcers on the lip, tongue, or elsewhere in the mouth, often accompanied by drooling
• Fever
• Lethargy 
• Dehydration
• A lack of appetite brought on by severe mouth ulcers or nasal congestion
• More severe instances are linked to the following symptoms:
• Pneumonia accompanied with a cough or breathing difficulties
• Joint inflammation, resulting in edema or a limp in the afflicted joint or joints

Symptoms of vasculitis, an inflammation of the blood vessel walls that can cause multiple organ failure and death,

• Swelling in the face/legs 
• Skin wounds 
• Bloody nose 
• Bloody stool 

How Calcivirus transfer from one cat to another:

Cats who are infected with the calicivirus can transmit the virus through their eyes, nose, or saliva. Viral particles can travel several meters through the air when an infected cat sneezes. Although it is thought that the virus may also be excreted in feces or urine, this is not thought to be a significant cause of infection.

In a polluted environment, the virus may live for up to one week (and maybe longer in a chilly, wet place). Cats who are susceptible to infection can get the illness by ambient exposure to contaminated materials or direct contact with another affected cat.

Treatment:

While there isn’t a cure for the virus at this time, cat owners may provide supportive care while their pet’s immune system battles the illness. The majority of cats may heal at home, but those with serious illnesses could require careful nursing attention.

To assist cleanse the nasal passages, wipe the cat’s nose and eyes and use vaporizers and saline nose drops. Bromhexine is one medication that breaks down mucus, and it can also help lessen congestion. When necessary, opportunistic bacterial infections can be treated with broad-spectrum antibiotics; non-steroidal anti-inflammatory medicines can also help decrease fever and mouth discomfort.

Because of their mouth sores and congestion, cats frequently stop eating and lose their appetite. Strong-smelling, soft meals that can be briefly cooked to intensify their odor and blended to make them easier to swallow should be provided by owners. Cats that go more than three days without eating might need to be admitted to the hospital in order to get IV nourishment and hydration.

A cat who contracts FCV-VSD has to be given extensive care, which may entail intravenous fluids, antibiotics, and other therapies as required.

Prevention:

Although vaccinations cannot completely prevent FCV, they can significantly lessen the illness’s severity in the event that your cat is exposed. There are a number of nasal or injectable combination vaccinations that may be administered to prevent feline distemper, feline herpesvirus type 1, and feline panleukopenia virus. While vaccinations administered by injection may contain modified live viruses or inactivated ones, those administered by nasal delivery contain modified live viruses. After receiving the nasal vaccine, cats may sneeze for four to seven days.

Kittens should have a vaccination every three to four weeks once they are six to eight weeks old. The last booster should be administered when the kittens are 16 weeks old. Give the vaccination in two doses, spaced three to four weeks apart, if the cat is older than sixteen weeks. Boosters should be given to cats every three years, unless they live in a high-risk setting with other cats, in which case they should have a yearly revision. Boosters are necessary because cats that have recovered from a calicivirus infection might not be immune to other virus strains.

Research indicates that the nasal version of the vaccination provides faster viral protection, which might be useful in controlling epidemics in shelters.