The Big Three 

We all worry about our feline companions becoming unwell, what we can do to reduce the risks, what the treatment options may be and what outcomes are to be expected

Viral diseases can be the toughest to treat as they don’t respond to antibiotics, and antiviral treatments are not guaranteed to be curative. Often the outcome can depend on the cat's own immunity. With that in mind, let's look at three viral diseases that can carry the most severe complications

Feline Leukaemia Virus (Felv)

This virus affects only cats, and if your cat becomes permanently infected there are risks of developing long lasting issues that can include anemia, reduced immunity and cancer. But disease may be very delayed in becoming apparent, this doesn’t mean it can’t be spread to others though.

Signs may include

• Fever
• Lethargy/Tiredness
• Reduced appetite
• Weight loss
• Recurrent skin, oral, intestinal or respiratory problems
• Pale gums

Cancers and anaemia are also seen with their own symptoms depending on the organs affected

Infection can be spread by prolonged social contact via the saliva, faeces, urine and milk

It is also commonly spread by fight wounds ( saliva is deposited into the wounds) and by mating. Cats that become pregnant whilst infected by the virus can also give birth to infected kittens

Outcome - depends on the immunity of the cat at the time of infection, three different things can happen

• The infection is effectively repelled and the cat recovers
• The infection is incompletely repelled and becomes dormant, this latent state can be triggered into active disease at a later time, especially if stressed
• The infection becomes firmly established and progressive disease will develop

Younger cats are more prone to developing progressive infections whereas resistance increases to this outcome as the cat ages

Diagnosis is by simple tests by your vet team, ( to detect the virus) Sometimes an unexpected positive or negative result will be followed up by a second test to an outside specialist laboratory. This is mostly because the virus is not continually circulating, it can become dormant, the test can only tell what is happening right NOW Remember also that several tests over a period of weeks/months may be needed to track the response to the infection, whether or not the virus has been eliminated.

Treatment sadly isn’t curative and is aimed at supporting your cat to maintain a good quality of life for as long as it is comfortable

This will include

• High quality diet to provide everything needed for a healthy immunity
• Raw food is discouraged as there is potentially some risk of infections
• Parasite control for fleas, ticks and intestinal worms All these place an extra strain on the immune system Immune strength needs to be directed at holding the virus in check
• Speedy treatment of any secondary bacterial infections such as chest infections, skin and oral infections
• Keeping the pet indoors This not only stops spread to other cats in the area as importantly reduces your own cat’s risk of exposure to other infections
• Chemotherapy for the treatment of solid cancers if they develop
• Blood transfusion if there is a marked anaemia
• Antiviral medications, though these can carry higher risks of unfavourable side effects

Prevention should always be the best and preferred choice. There are several very effective vaccines and is strongly encouraged, especially in younger cats, those that venture outdoors or are in contact with Felv positive cats within their own household Be responsible and do not allow an Felv positive cat freedom to roam Build a Cattio (Outdoor Enclosed Cat Run)

If your cat has successfully repelled the infection there are no long term risks

If there is latent infection you should take all the measures recommended to substantially help reduce the risks of developing active symptoms

If there is progressive infection, work closely with your vet to reduce the impact of the virus The quality of life can be very good for a period of time (often a long time with appropriate treatment of secondary complications)

Feline Immunodeficiency Virus (FIV)

FIV is a feline only virus that has a number of similarities to the human infection HIV. It affects the cells that are responsible for immunity. At some time, that can be several years after infection ( usually 2-5 years), the virus replicates more rapidly and destroys the ability to recover from otherwise simple infections. These simple infections can progress to serious illness

Signs are very variable but include

• Loss of appetite
• Weight loss
• Recurrent fevers
• Recurrent or chronic respiratory, intestinal, skin and oral infections
• Lethargy and tiredness
• Enlarged lymph nodded (glands)
• Cancers ( more rarely)
• Neurological signs

Infection is most commonly by cat bites when cat fights occur and so is much more common in unneutered male cats that roam freely. Cats of all ages are equally susceptible but it is often not diagnosed until 5-10 years of age as the virus replication accelerates. The saliva contains the virus, kittens from infected queens can be born carrying the virus. It isn’t yet clear if blood sucking parasites (fleas for example) can also spread the virus, or how great is the risk of spread by activities like mutual grooming. It is a fragile virus though and easily destroyed by cleaning of the environment, food and water bowls, grooming equipment and bedding etc.

Diagnosis is by a test at your local vet ( to detect response to the virus), though if there are concerns this may be followed up a few weeks later with a test sent to an outside specialist laboratory. An antibody (immune) response confirms the virus has been encountered and that the body is able to mount some fight against it, the level of this response does not predict how quickly or severe the disease will become over time Kittens born to an infected mother will test positive up to 5-6 months of age as they get the antibodies from mothers milk.

Treatment may not be needed for many years after encountering the initial infection, and sadly none is curative for the virus. The strain of FIV virus and the cat’s own immunity can in some cases mean disease never develops. Concentrate on keeping the cat strong and healthy

• High quality diet
• Raw food is not recommended as there may be risk of other infections
• Maintain a good anti parasite regime with regular worm and flea prevention
• Speedy treatment of any other infections
• Keep infected cats indoors (with access to an enclosed outdoor run if you can) to prevent disease spread and reduce risks to your own cat of contact with other
• Take advice on what vaccinations are recommended by your vet for other diseases (Such as ‘Flu and Felv)
• Antiviral medications, if the side effect risks outweigh the severity of the disease

Prevention revolves around preventing exposure to infection. This means neutering male and female cats before they reach the age of sexual interest! Most infections are acquired through fighting as Romeo fights and roams looking for Juliet! If there are infected and uninfected cats in the same household then separate feeding and water bowls are advisable, as is regular deep disinfection of any shared litter trays and bedding.      If there is any intercat aggression within the household then it may be wise to keep the cats entirely separated. Do not let infected cats roam, keep them confined within the home or enclosed outdoor run.

There is currently no vaccine available against FIV in the UK

If a cat does become infected many years can pass without causing disease, some will never develop disease. The lack of disease doesn’t mean it can’t pass on the infection so constant vigilance to prevent spread is common sense.

Feline Infectious Peritonitis (FIP)

Finally some good news! FIP is caused by a coronavirus (Yes, the same group as Covid 19, but not passed to humans) that occurs worldwide. Despite being researched since 1963, until very recently it was inevitably a fatal infection once clinical signs developed. It does remain as one of those sometimes difficult to diagnose illness but there is now a specific treatment available. It is a very common virus in the intestines of cats, but disease is only seen in those cats where the virus has mutated (changed) and the cat’s own immunity has responded in a specific way to the changed virus. This may explain why some breeds have greater risks of developing disease, and where lots of cats come together (Feral cat colonies for example) so there are more opportunities for the mutated virus to spread, creating clusters of disease.

Signs vary greatly and are more common in younger cats but all cats are susceptible. Early signs are very non specific, common to all viral infections

• Fever
• Reduced appetite
• Lethargy/tiredness

Further signs may then develop days to months later, however at this stage many recover without treatment and never show signs of disease following exposure to this common virus.

Two forms of the disease are recognised if the infection does progress to disease. A positive test result at the early non-specific stage doesn’t mean a disease is caused by the coronavirus, or that it will happen, now or ever, only that the cat has been exposed. A positive result is useful though if there are signs consistent with FIP.

Wet or Effusive FIP is when the blood vessels are damaged and fluid that is thick and high in inflammatory protein leaks out into the chest or abdominal spaces. This can cause the belly to swell or/and difficulty breathing as the lungs become squashed by the fluid within a rigid rib cage.

Dry FIP can affect any organ in the body. Around a third of cats with this form show inflammation in the eyes or nervous system, resulting in bleeding or cloudiness in the eyes, a wobbly gait or seizures and weakness . But any organ can be affected and signs are then dictated by that organ with solid lumps being found in the belly, jaundice, vomiting or diarrhea and an overall lethargy and lack of appetite.

Infection occurs by exposure to faeces, either in the litter box or by mutual grooming and by an infected queen to her kittens in early life. Most commonly this is a benign virus and results in self limiting signs Remember it takes changes in the common coronavirus, individual immune response, stress and the amount of virus exposure for disease to develop in any individual.

Diagnosis depends on finding clinical signs that can be attributed to FIP, not on finding exposure to the virus by testing. If fluid is found on examination ( by a physical examination, ultrasound, x-ray) or lumps found in individual organs these will most likely also be tested to identify the virus

Treatment will only be needed if the individual cat develops signs consistent with either Wet or Dry FIP and show positive test results. Remember some breeds, age groups, higher risk groups or those undergoing stress such as neutering or rehoming need to be watched most for disease signs and receive speedy veterinary intervention Recent development of antiviral medications available in the UK since 2021 can now be expected to cure more than 85% of FIP cases. Rely on your vet to confirm the need for treatment. It is an extended and intensive treatment plan, and overuse may result in virus resistance in the future.

Prevention of exposure to benign or mutated corona viruses is best achieved by

• Maintaining excellent litter hygiene, and more litter boxes than cats in the house
• Keep food and litter areas separate
• Clean and disinfect frequently both food and water dishes
• Reduce stress where possible
• Keep cats in groups of 5 or less

A vaccine against FIP is available in some countries, but can only be given to kittens over 16 weeks of age, mainly reserved for use in breeding colonies By the time it can be used a large number of these kittens will already have been exposed, more options may eventually be developed.

Thanks to Jill the vet for taking the time to write this and for helping everyone who adopts through Catitude.