Common Feline Diseases

Acute inflammation of the mouth (stomatitis) and ulceration of the tongue (glossitis)

This can be caused by a variety of microorganisms, but commonly one of the ‘flu’ viruses is responsible. Both feline calicivirus (FCV) and feline herpes virus (FHV) will produce stomatitis but FCV does so more commonly.

FCV can produce mouth ulceration only. The ulcers appear typically on the upper surface and margin of the tongue, although they may occur on the gums, palate and nose. Sometimes the ulcers are associated with mild upper respiratory tract disease (cough/sneeze and some discharge from nose).

FHV (feline herpes virus) is a more severe disease with typical signs of upper respiratory disease, often involving inflammation of the pharynx (back of throat) and tonsils. The presence of tongue ulcers is rare.

In both cases the viral infection may predispose to superimposed bacterial infection. Since there are no usable antiviral drugs, treatment must consist of the use of antibiotics to control secondary infection. Attentive nursing of your cat with frequent removal of secretions is important. Offer your cat liquidised or pureed aromatic foods such as strongly flavoured fish. Sometimes we need to admit cats to put them on intravenous fluids.

Dental problems and gingivitis

True dental caries, the process of decay to which we humans are so susceptible, is very rare in the cat, though occasionally encountered in the back molars.

Dental calculus, also known as tartar, consists of mineral-impregnated bacterial plaque. Tartar is most common on the outer surface of the molars and premolars, it is more often found in cats fed on soft food.

Calculus sits at the junction of the gum with the tooth and, as this occurs, a niche is produced in which bacteria can flourish. As a consequence the gum becomes inflamed (gingivitis) and retracts from the base of the tooth. The gum may also become ulcerated, the retraction of the gum allows infection to track down the outside of the root (periodontitis) and a discharge of pus from around the teeth may result.

In early cases, all that is needed is for the cat to have tartar removed by scaling the teeth under general anaesthesia. In severe cases, teeth might need extracting and a course of antibiotics is prescribed.

Non-specific inflammation of the mouth and gums

Inflammation and ulceration:

Apart from the conditions mentioned above, there remains a large group of oral inflammatory conditions in the adult cat, which are unrelated to dental disease and which are extremely unresponsive to treatment. These conditions present with long-term inflammation of the lining of the mouth, little vesicles and ulcers being present in most cases. This affects most frequently the angles where the jaws meet at the back of the mouth although, less commonly, any other part of the mouth can be affected.

The cause is not fully understood; a number of bacteria have been isolated but their significance remains uncertain. FCV and FHV occasionally cause a short-lived inflammation of the mouth (see above) lasting two to three weeks, although we suspect that FCV may play a role in the chronic condition. It was also found that the condition is more common in pedigree cats (in these cases FCV was also more often isolated). There also is a strong association of FIV and non- specific inflammation, in fact very often if the cat is infected with both viruses then it will have more severe oral lesions.

FeLV (feline leukaemia virus) can also cause immunosuppression, which in turn can cause inflammation in the mouth. We often advise to have cats tested for FeLV/FIV (blood sample) and FCV/FHV (swab of mouth and conjunctiva) when we find chronic inflammation of the mouth.

Treatment consists of long-term antibiotics and anti-inflammatories and supportive therapy. There are some mixed reports on the use of interferon in cats, which is now readily available and used in cats that test positive for some of the viruses.

Despite the lack of involvement of dental disease, removal of the teeth sometimes helps. Cats do very well without any teeth if they are fed a soft diet.

Hyperthyroidism (overactive thyroid glands) is a very common disorder of older cats that is caused by the overproduction of hormones from the thyroid glands, which are found either side of the windpipe at the base of the neck. Thyroid hormones control your cat’s metabolism (or rate of bodily activity); in this disease the thyroid glands go into overdrive and produce too much hormone which means that your cat will burn up energy too rapidly. Untreated this disease can be fatal but fortunately in most cases this condition can now be successfully treated.

What causes the disease?

In the majority of cases (98%) the increase in thyroid production is caused by a benign tumour of the thyroid gland, however what causes this to develop is still not clear. In rare cases (2%) a malignant cancer known as a thyroid adenocarcinoma can also be the underlying cause, this is much more difficult to treat successfully.

What are the symptoms?

This disease is almost exclusively seen in middle to old aged cats and is rarely seen in cats less than seven years of age. Most common signs are:

• Weight loss
• Ravenous appetite

Affected cats may also have:

• Increased urination and thirst
• Increased restlessness and irritability
• Rapid heart rate
• Unkempt coat
• Occasionally vomiting
• Diarrhoea
• Lying in cold places

In about 1 in 10 cases the symptoms are unusual and the opposite of what might be expected, such as depression, loss of appetite and physical weakness.

How can my vet diagnose hyperthyroidism?

Apart from recognising the above clinical symptoms, there are a number of other steps in making a diagnosis. The thyroid glands may feel lumpy or enlarged. Blood tests are usually taken to rule out other diseases of the liver or kidneys. Directly measuring levels of hormone in the blood may help to confirm the diagnosis but in some rare cases the hormone levels may be normal.

There are a number of potential reasons for this and usually a repeat test one month later will show elevated levels. If not additional tests may be required to confirm or rule out hyperthyroidism. The vet will also want to check your cat’s heart and may also check his/her eyes. An early diagnosis is important to prevent secondary complications and reverse the disease process.

Secondary complications

Thyroid hormones have effects on virtually all the organs of the body, and therefore it is not surprising that this disease can sometimes cause secondary problems that may need additional investigation and treatment.

The effect on the heart is to stimulate a faster heart rate and a stronger contraction of the heart muscle, over time the muscle of the heart enlarges and thickens leading to a condition called ‘hypertrophic cardiomyopathy’, if left untreated this will lead to heart failure. It means that in some cats with hyperthyroidism additional treatment may be required to control the secondary heart disease. However once the underlying hyperthyroidism has been controlled, the cardiac changes may often improve, or even resolve completely.

Hypertension (high blood pressure) is another potential complication of hyperthyroidism and can cause damage to several organs including the eyes, kidneys, heart and brain; if hypertension is diagnosed along with hyperthyroidism then drugs may be needed to control the blood pressure to reduce the risk of damaging other organs. As with heart disease, successful treatment of the hyperthyroidism may cause the high blood pressure to resolve and additional treatment may not be required permanently.

Kidney disease (chronic renal failure) does not occur as a direct result of hyperthyroidism, but the two diseases often occur together as both are common in older cats. Care is needed where both conditions are present, as hyperthyroidism tends to increase the blood supply to the kidneys, which may improve their function.

Thus blood results taken to assess kidney function in a hyperthyroid cat may show normal or only mild changes, but potentially more severe renal failure may be masked by the presence of hyperthyroidism. For this reason irrespective of what treatment is chosen for long-term management of the hyperthyroidism (see below), it is advisable to start on medical treatment (tablets) initially and to monitor the response with repeat blood and urine tests to look at thyroid and kidney function.

Just occasionally, successful treatment of the hyperthyroidism results in a dramatic decline in kidney function. If this is detected it may be necessary to reduce the dose of therapy so that the hyperthyroidism is not fully controlled but renal function is not too severely compromised.

Treatment

Because very few cats with hyperthyroidism have cancerous growths of the thyroid gland, treatment is usually very successful. The goal is to reduce the amount of thyroid hormone in the cat’s blood back to normal. This can be achieved in 4 ways:

a)  Medical Treatment

There are drugs available which block production of hormones by the thyroid gland. The medication is given one to three times a day.

Advantages

• Simple and does not require an anaesthetic
• Suitable for cats with severe kidney disease which might be made worse by the sudden drop in blood pressure which may occur after other types of treatment
• No dietary restrictions for your cat

Disadvantages

• Does not tackle the underlying problem and so treatment must continue throughout your cat’s life
• Difficulties in getting your cat to swallow tablets or liquid. Transdermal gels are available, but these require careful application and handling
• In some cats there are side effects ranging from tiredness to anaemia, skin irritation and liver changes.
• In the early stages your cat must be carefully monitored to make sure that the dose is right. This practice then advises 6 monthly thyroid hormone and kidney function blood tests to monitor therapy. The dosage of medication is likely to change over time as the tumour continues to grow
• Women of child bearing potential need to take precautions (gloves) when handling the tablets or their cats litter tray

b)  Surgical Treatment

The abnormal tissue can be surgically removed.

Advantages

• Treatment should permanently cure the disease so no need for further medication

Disadvantages

• NOT suitable for all cats, such as those with severe kidney disease or the very elderly.
• Your cat may need drug treatment for a few weeks beforehand to show that its kidneys will cope and to stabilise their condition before anaesthesia
• Requires a general anaesthetic which is always a slight risk, but more so in ill and elderly animals
• Possibility of damaging the parathyroid glands, which lie close to the thyroid and control the use of calcium in the body. For this reason often only one side is removed at a time. This makes it likely that a second operation would be required, typically within 18 months of the first
• Thyroid tumours can sometimes occur in the chest, making it difficult to locate and/or remove, this would result in the cat remaining Hyperthyroid, despite both Thyroid glands being removed.
• After surgery the cats should be carefully monitored for a couple of weeks to make sure there are no changes in blood calcium caused by parathyroid gland damage.

c) Radiation Therapy

An injection of radioactive iodine will destroy the abnormal thyroid tissue while leaving normal cells unaffected.

Advantages

• No anaesthetic required and very few unwanted side-effects.
• A single treatment will permanently cure the disease in 9 out of 10 cases and a second treatment will do the trick for the rest
• Radiation will also work in the rarer cases in which the tumour is malignant or where a portion of the thyroid tissue has broken away from the main gland and is normally missed during surgery

Disadvantages

• Availability: This is only available in a few referral centres
• Because of the need for limited handling, this method can be unsuitable for cats needing treatments for other serious conditions
• The cost of treatment and prolonged boarding can be high
• A small proportion of cats can become Hypothyroid (low levels of hormone) after treatment. Often no symptoms present, but a small number may need treatment
• Your cat will have to stay in complete isolation until the radiation level has died down, usually around four weeks. Cats can be sent home after the treatment in as little as 4 days, but it is usually closer to 14days. Strict handling rules would also have to be applied once home, usually for an additional 14 days, including no access to children, women of child bearing potential or pregnant women. Special precautions would need to be taken with the cat’s urine and faeces, and they must be kept indoors. Home management is not always achievable, in these cases the cat would need to remain at the referral centre for longer

d) Dietary management

A prescription diet with an extremely low Iodine content. Without Iodine the thyroid glands cannot produce the hormone and Thyroid tumours cannot over produce it.

Advantages

• No medication or invasive surgical treatments are required
• Your cat can be treated at home by a simple change of diet

Disadvantages

• Your cat can only eat the diet and nothing else, at all, ever. For cats in multi-cat households or who go outside this can be a problem. Even a small amount of other food can provide enough Iodine for the Thyroid to over produce Thyroid hormone.
• If your cat will not eat the diet, because they do not like it or become unwell, then it will not work
• It can take several months to work, although many cases respond in a few weeks
• The thyroid tumour is only prevented from producing hormone, it can continue to grow
• Periodic blood sampling to check how well the condition is controlled is still advised..

What is best for my cat?

The vets at the Park Veterinary Centre will help you make the decision on the best method of treatment for your cat after careful discussion in a consultation. There are a number of things to consider, your cat’s age, the severity of the condition, the presence or absence of other diseases and the risks of complications, etc.

Cost may also be a factor as both surgery and radiation treatment can involve initial expense. However, medication may prove to be costly in the longer term, especially as treatment has to be given for several years and your cat will need to have regular six monthly blood tests.

These tests will assess that the correct amount of medication is being given, and also ensure that your cat remains healthy, as it gets older despite its underlying disease.

As its name suggests, Feline Immunodeficiency Virus (FIV) is closely related to the Human Immunodeficiency Virus (HIV), responsible for causing AIDS in people. There is no cure for either disease, and the virus causes the gradual destruction of the white blood cells needed to protect the body against infectious diseases. However, the two viruses will only survive inside normal host species – in other words, there is no risk of humans catching FIV from a cat, or vice versa.

How does the virus spread?

Biting is considered to be the most important method of transmission of FIV. The saliva of an infected cat contains large amounts of virus and a single bite can result in transmission of infection. Infection can also occur by close social contact within a group of cats where there is no overt aggression, via the sharing of food bowls and mutual grooming. Infection may pass from mother to kittens during pregnancy (through placenta) or as a result of the mother licking her offspring or biting the birth cord. Unlike HIV there is no evidence FIV is sexually transmitted.

What happens to my cat if it is infected?

In the first few days after it is infected your cat may show signs of ill health, such as a slight fever, but this often goes unnoticed. Most cats recover from this early stage and appear perfectly healthy for months or even years. Eventually other signs develop as a result of the depressed immune system and an inability to fight infection.

These signs include lethargy, swollen glands, dull coat, fever, weight loss, inflammation of the mouth, discharging eyes, diarrhoea and if the nervous system is affected, behavioural changes, convulsions and dementia. Signs are more severe if the cat is also infected with Feline Leukaemia Virus (FeLV). Some forms of cancer, particularly lymphoma are more common in FIV infected cats.

How widespread is the infection and which cats are most at risk?

FIV is more common in some areas than others, depending on the population density and type of cats in the area (house cat/ stray/ farm cat). Entire males and feral cats are most at risk, as they are most likely to fight. Any cat can be infected at any age, but there is often several years between infection and development of clinical signs. Therefore the disease is most often seen in older cats between six and ten years.

How do I know if my cat is infected?

Until a cat starts to suffer from a series of infections as a result of its failing immune system, there is usually no reason to suspect that it is infected with FIV. An in-house blood test is available to detect antibodies to the virus in apparently healthy animals. The test is not 100% accurate, and a more complicated test looking for the virus itself can be used.

What can be done to help my cat if it is infected?

As there is no cure for the infection, treatment usually consists of supportive therapy, including antibiotics when required.

There is no vaccination available in the UK, and unfortunately when infected, cats are less likely to produce a good response to other vaccinations. Please discuss your cat’s individual vaccination needs with your vet.

 Will my cat’s lifestyle need to change?

Infected cats ideally should be confined indoors to prevent spread of the virus to other cats in the neighbourhood and to minimise the exposure of affected cats to infectious agents carried by other animals. Ideally infected cats are kept in single cat households, but cats that live in small stable groups are unlikely to fight.

Good nutrition and husbandry are essential to maintain good health in infected cats. A programme for routine control of parasites (fleas, ticks and worms) together with a routine vaccination programme should also be maintained. Six monthly checks with the vet are also recommended. Intact male and females should be neutered.

Feline infectious peritonitis (FIP) is a fatal disease of cats, caused by a type of feline coronavirus. Infection with coronavirus is actually very common in the UK cat population but most of the time it does not cause any problems, other than mild self-limiting diarrhoea. Uncommonly, the virus mutates (changes) within an infected cat, and it is this mutated form that causes the disease FIP.

How common is Feline Coronavirus?

Coronavirus is ubiquitous among cats and infection with the virus is particularly common where large numbers of cats are kept together. It is estimated that 25 to 40% of cats kept in multi-cat households, rescue and breeding colonies.

How are cats infected with coronavirus?

The virus is spread by the faecal-oral route, i.e. the virus is shed in faeces into the environment and cats become infected following ingestion when grooming or eating.

Most infected cats shed the virus in faeces for a variable period of time and then stop. The cat can then become re-infected from another cat and start shedding the virus again. In contrast, some cats shed the virus continuously.

Why has my cat developed FIP?

Although coronavirus is the cause of FIP, infection with coronavirus does not always mean the cat will go on to develop FIP. In comparison to the number of cats infected with coronavirus the number that develop FIP is very small. It is only when the virus mutates that FIP may develop.

The cause of viral mutation is unknown. The majority of cases of FIP develop in younger cats. A poorer immune response together with other stress factors such as rehoming, vaccination, neutering, or other concurrent disease may make younger cats more vulnerable to FIP. FIP can, however, develop in any age of cat and predisposing factors or risk factors are not always evident.

Genetics may also play a role in some cases, as purebred cats appear to be at greater risk. Sometimes particular lines of a breed have a high rate of developing FIP.

What are the signs of FIP?

There are no clinical signs that are unique for the disease. The classic form of the disease often termed ‘wet’ FIP is characterised by a build up of yellow fluid within the abdomen (resulting in abdominal distension) and/or chest (resulting in breathing difficulties). However the presence of this fluid is NOT diagnostic for FIP, and in additional large number of cases will not have any visible fluid build up. Initial clinical signs are often very vague, consisting of lethargy and loss of appetite.

In some forms of the disease inflammatory lesions in the eye and nervous system can occur, resulting in visual disturbances and abnormal behaviour, a wobbly gait or tremors. The disease is usually rapidly progressive and ultimately fatal.

How is FIP diagnosed?

1. There is no specific test for FIP. If FIP is suspected, the veterinary surgeon will perform a thorough clinical examination. The more findings that are present that are consistent with FIP, the more likely the cat does have FIP.
2. Tissue samples can confirm a diagnosis, but often the cat is too sick for these to be undertaken and so in many cases a definitive test is only made on post-mortem
3. If any fluid is present within the chest, abdomen or both, analysis of this fluid is one of the most useful tests that can be performed. X-rays or ultrasound scans of the chest and abdomen are useful to detect small amounts of fluid when obvious clinical signs are lacking. This fluid can then be sampled under via ultrasound guidance. The presence of fluid in the abdomen does not confirm a diagnosis of FIP as other diseases can also lead to a build up of similar fluid. If the fluid is present in both the chest and the abdominal cavity, then FIP is even more
4. Routine blood tests are very helpful firstly in trying to exclude other causes for the clinical signs, and secondly to look for changes which may support a suspicion of FIP. Frequently the numbers of one type of white blood cell (lymphocytes) are low, there may be a mild anaemia, blood protein levels are usually very high, and sometimes blood bilirubin (pigment from old red blood cells) levels are high. All these changes are very non-specific and do not make a diagnosis of FIP, but help to increase suspicion of the disease.
5. Cats can be tested to see if they have been exposed to coronavirus by checking for specific antibodies. However, such a coronavirus blood test is of very limited use in diagnosis. This test does not distinguish between the coronavirus encountered commonly with few associated problems, and the mutated form that causes FIP. Furthermore, some cats with confirmed FIP are actually negative for antibodies, so it can not be used to exclude
6. In cats with neurological signs without other abnormalities, MRI scans of the brain and analysis of the fluid surrounding the brain and spinal cord can also be

Many of these abnormalities may not be present in the early stages of the disease but may become evident later. Thus some tests that give normal results may have to be repeated later.

Can FIP be treated?

Once clinical signs of FIP develop, it is usually fatal. Treatment is given to relieve symptoms. While there are a handful of anecdotal reports suggesting some success with newer antiviral drugs, studies have yet to show a proven benefit of any such treatments. In most cases euthanasia is recommended to avoid suffering.

Can you vaccinate against FIP?

There is no vaccine available in the UK. A vaccine is available in the USA but is does not appear to be particularly effective and can only be used in kittens over 16 weeks of age, by which time most kittens are infected with the virus anyway.

How can FIP be prevented and controlled?

1. Household Cats:

FIP is least common in household pets. The risk can be minimised by obtaining cats from a source with few cats and by keeping cats in small stable groups (less than five cats in a household). Minimising ‘stress factors’, such as rehoming, worming, vaccination and neutering happening all at once, or while the cat is suffering from other illness, may also help minimise the risk of the disease.

2. Breeding catteries with endemic FIP:

Total eradication of coronavirus infection from catteries is extremely difficult, as the virus is so ubiquitous.

A more practical approach is elimination of coronavirus infection in newly born kittens, providing the opportunity of re-homing kittens coronavirus free. If pregnant queens are isolated one or two weeks before they are due to kitten, and then the queen is kept in isolation with her kittens (whilst employing good hygiene procedures to prevent environmental spread), a substantial number of these kittens remain negative for coronavirus.

Following weaning, the queen can be removed and the kittens still kept isolated and tested at 12 to 16 weeks of age for coronavirus antibodies. If they are negative, the isolation procedure has been successful.

This procedure sometimes fails if the queen is shedding the virus and passes it on to her kittens. It is thought that this is less likely in queens over two years and can be helped by early weaning of the kittens (at five to six weeks of age when maternally derived antibodies are still protective) and removing the queen from the environment. Good hygiene is an important part of the control of spread of the virus to kittens. Although these procedures are successful, they require considerable commitment from the breeders.

Often it is more appropriate to accept that there is endemic coronavirus infection and institute measure to try and minimise its impact. Considering that the virus is spread by the faecal-oral route, practical control measures that can be used include:

• Having at least one litter tray for every two cats located in easy to clean/disinfect area and kept away from food and water bowls to prevent cross
• Faeces should be removed at least once daily, accompanied by
• Cats should be kept in small stable groups of four or less, minimising cross-contamination within a household.
• Breeding programmes with more than 8-10 cats (including kittens) should not be undertaken in a normal household. Larger numbers require some purpose built facilities to enable proper hygiene and care to be maintained.
• Regular brushing of the coat, particularly of long-hair cats is desirable to reduce contamination with faeces and saliva
• Isolation of queens and their kittens can be recommended as a means to controlling spread of coronavirus to her young

Feline Leukaemia Virus (FeLV) is a serious and fatal disease affecting cats. About one in three cats that come into contact with the virus develop a permanent infection, which is almost always fatal. FeLV infection causes a wide range of symptoms and by weakening the body’s immune defences it can make cats more susceptible to other infectious conditions. FeLV can cause a variety of cancers including lymphoma and a true leukaemia that attacks the bone marrow.

How is the disease spread?

The Feline Leukaemia Virus is present in the bodily fluids of affected cats, most commonly on the saliva. The virus may be spread when cats groom each other, share the same food bowls or litter tray, sneeze on or bite another cat. Other less common but possible routes of infection are during sexual relations and between a mother and kittens, either within the womb or in the maternal milk.

Is my cat at risk of catching FeLV?

On average about one in every hundred cats has a persistent infection in which the active virus is permanently present in its body. The risks are much higher when several cats live under one roof, or in areas of high population density. The chances of being exposed to the virus increase with age.

However it is young animals that are most likely to be infected with the virus, and one in three of these animals will go on to develop the disease.

What are the effects of FeLV?

FeLV cats generally have a short life expectancy. Most cats die as a result of destruction of the white blood cells that are one of the main bodily defences against disease. This leaves the cat wide open to infection from any one of a range of other germs. FeLV can also cause anaemia, and a proportion of infected cats develop cancer.

The clinical picture can be very similar to those cats infected with Feline Immunodeficiency Virus (FIV). Symptoms include infertility, abortion, stillborn or very weak kittens, inflammation around the eyes, rapid weight loss, gut disease or nerve damage. An infected cat may appear healthy for several months, but about eight out of ten cats are dead within three years of being infected by the virus.

Can an infected cat be identified before it becomes ill?

FeLV must be suspected where your cat is affected by a succession of different disease conditions. There is a simple blood test to show whether or not your cat has had contact with the virus. However a positive result is not always disastrous – it may just mean that your cat has been infected but is now resistant.

Similarly a negative result is not an all clear – if the infection was recent your cat may not have reacted (produced antibodies) to the virus. Therefore we usually need to take 2 tests a few weeks apart to give more reliable information about your cats state of health.

Can FeLV be treated?

There is no way to stop an infection once it has become established. Medical treatments may make your cat more comfortable or help tackle other infections that may occur as a result of FeLV. Vaccines can reduce the likelihood of your cat contracting the disease. The vaccinations are given at 9 and 12 weeks of age, and annual boosters are required to maintain protection. Vaccination is no use if the virus has already infected your cat.

Are FeLV vaccines harmful?

The vaccines are very safe, but a reaction, such as lumps forming at the injection site, may occur in rare cases. If your cat is the only one in the household and spends ALL of its time indoors, there is no risk of contraction of the virus and vaccination for FeLV is unnecessary.

My cat has tested positive for FeLV – what should I do?

If two consecutive tests a few weeks apart show antibodies to FeLV it is safe to say that your cat is infected. A sick FeLV positive cat may be treated symptomatically, however euthanasia must be seriously considered if they do not enjoy a good quality of life. Healthy FeLV positive cats may continue to live in good health for a reasonable period of time.

They should be given the same level of care as an uninfected cat, but additionally should be shielded from cats with other diseases and stress should be kept to a minimum. They should be kept away from other cats in your home even if they have been vaccinated, and must NOT be allowed to wander outside. If it is impossible to keep your cats apart, it may be better to find it a new home where it is unlikely to pass infection on to other cats.

Should your cat pass away and you would like another cat, your new cat is unlikely to be at risk from lingering infection in the home. The virus does not live long outside an infected cat but to be safe all feeding bowls, litter trays etc should be replaced or washed with hot soapy water, and surfaces washed with a weak solution of bleach before introducing your new cat into the household.