We all know just how contagious COVID-19 is in humans. Here’s what you need to know about its variant in cats, the Feline Coronavirus (FCoV), and its supposed mutation, FIP, which is considered highly fatal.
COVID-19 and Feline Infectious Peritonitis (FIP) are both caused by coronaviruses: SARS-CoV2 and feline coronavirus (FCoV) respectively. SARS-CoV2 and feline coronavirus (FCoV) are completely different viruses, and the latter does not infect humans. However, in rare cases, SARS-CoV2 can infect cats. Even though a small number of pets worldwide, including cats and dogs, have been infected with the virus that causes COVID-19, the World Health Organization (WHO) notes that so far there has been no evidence that pets carry or transmit the virus. In addition, the World Small Animal Veterinary Association (WSAVA) hasn’t found “evidence that COVID-19 can be contracted from pets.”
Although both SARS-CoV2 and FCoV viruses are highly infectious, 97% of people exposed to COVID-19 recover, with a mortality median age of 80.5 years. When it comes to FCoV in cats, however, only about 90% of FCoV-infected cats recover from the infection. Unlike the human coronavirus that puts older human adults at a higher risk, FI—FCoV’s supposed mutation—affects young felines: mainly kittens and cats under 2 years of age.
FCoV and the Risks of FIP
FCoV is a highly common virus in domestic cat populations around the world (affecting even large cats in zoos). Infection is often subclinical or characterized by a transient gastrointestinal illness, including mild diarrhea and/or vomiting in kittens and newly infected adult cats. Why some cats are practically asymptomatic and others develop feline infectious peritonitis (FIP), which is considered to be a highly fatal multisystemic disease, is unknown but assumed to be caused by a more virulent mutation of FCoV.
Whenever the FCoV infection exists, so does the potential for the development of FIP. The probability of FCoV developing into FIP is about 10% in the feline FCoV infected population. In other words, an FCoV infected cat won’t necessarily suffer from FIP, and one should hope that it won’t.
There are two common forms of FIP: a ‘wet’ form and a ‘dry’ form. In both forms, the clinical signs vary depending on the involved organs, such as the peritoneum, pleurae, liver, kidneys, central nervous system (CNS), and eyes. FIP causes immune-mediated vasculitis, meaning that blood vessels of any organ can be affected with clinical signs resulting from the damage to the affected organ. In the ‘wet’ form the damage is greater and is more rapidly fatal than the ‘dry’ form.
Furthermore, in the ‘wet’ form, obvious thick yellow fluids build up in the cat’s belly or chest. The disease develops within 4-6 weeks from infection and has an extremely stressful effect on both cats and humans. In contrast, the ‘dry’ form’s clinical signs are usually vague, including weight loss, lack of energy, and appetite. The disease develops over a longer period, potentially even a year, but usually takes a toll within several weeks to a few months. Although both ‘wet’ and ‘dry’ forms have a history of nearly a 100% mortality rate, there are some new insights regarding the treatment and prevention possibilities of FCoV/FIP that are being further investigated.
Factors that Could Increase the Likelihood of FIP Development
While most cats recover from FCoV infection, some factors could increase the likelihood of FIP developing: these include a cat’s young age (in particular, kittens between 3 months to 2 years old), a genetic breed tendency, the cat’s immune status, stress levels and the dose and virulence of the virus, as well as high infection rates in the households, shelters, and catteries where there are several cats infected by FCoV and the shedding virus.
Furthermore, in crowded environments, such as catteries or shelters, in addition to the enormous exposure rate to FCoV, the cats’ stress levels are often very high, which makes shelter cats highly susceptible to the disease. Research has shown that most cats that develop FIP experienced high levels of stress before developing the disease. It is therefore recommended, if possible, to avoid causing stress in cats with FCoV antibodies. This includes rehoming, introducing a new kitten to the household, and neutering which can all be delayed until the cat has become antibody negative, or at least has experienced a significant drop in antibody titer.
FCoV/ FIP Prevention
Although new studies about treatment possibilities are becoming more available, prevention is still considered the best option. Particularly in purebred kittens and young cats which constitute 70% of all deaths to FIP, one of the acceptable preventative steps includes choosing an FCoV free kitten or cat. Kittens reared in a private home without any exposure to cats other than their mothers, or kittens from a coronavirus-free cattery are less likely to develop FIP.
If You Lose a Cat to FIP, When Is It Safe to Reintroduce an FCoV- uninfected Cat into Your Home?
Coronaviruses are fragile viruses, meaning that traces of the virus should disappear in a few hours to days. However, when covered by dried-up feces and cat litter, FCoV can remain infectious possibly up to 7 weeks; for this reason, it’s important to vacuum thoroughly and steam clean carpets, especially around the litter trays. After one to two months, it should be safe enough to let the cat enter the pet owner’s home.
Before the cat’s returning home, traces of the virus could be removed from the cat’s belongings by steam cleaning or using a common cleaning disinfectant. Decontamination of bowls, the cat’s litter box and bedding can be performed easily by using a dishwasher, a simple scrub, and a washing machine (at 60oC), respectively.
Testing a Cat’s Antibodies for FCoV
Feline coronaviruses (FCoV) are widespread in the feline population due to high contagious rates. With that being said, in order to make sure your cat is FCoV-free, an antibody blood test could be performed indicating exposure or infection. When screening cats for coronavirus antibodies, it is important you use a highly sensitive test kit that can detect all positive cats, not missing any. Due to its performance of 100% sensitivity (with a negative result indicating an FCoV/FIP-free cat), Biogal’s ImmunoComb Feline Coronavirus FCoV (FIP) Antibody Test Kit is highly recommended by Dr.Diane Addie (a renowned veterinary virologist whose Ph.D. and main focus of research is on feline infectious peritonitis (FIP)) in her published study comparing a variety of FCoV antibody tests.
Read more by visiting Dr. Diane Addie’s website to learn about how the FCoV infection can potentially turn into a life-threatening disease when it develops to FIP and what new preventative or treatment options are currently being investigated.