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Most common illnesses for cats

Cats in general are healthy animals, but like any animal they can get ill so it is useful to know the common signs of illnesses. Please note that these points are for information only and should not be relied upon as a substitute for professional advice from your vet.


Older cats, around the age of 13, are most likely to suffer from hyperthyroidism. What happens is that too much thyroxine and tri-oidothyronine is produced by the thyroid gland. This tends to be due to a tumour in the gland, though in around 98% of cases these tumours aren’t cancerous.

Symptoms to look out for are sudden weight loss combined with an increase in appetite. You will also find that cats affected don’t tend to clean themselves as much, and therefore look more scruffy than usual. Some other symptoms to keep an eye out for are vomiting, panting, diarrhoea, hyperactivity and nervousness.

These symptoms are similar to renal disease - so be sure to know the differences. The treatment consists of radioactive iodine, anti-thyroid medication and the removal of the thyroid gland.

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Feline Immunodeficiency virus (FIV)

FIV is a contagious illness that can only affect cats and is normally passed through bites in cat fights – normally between males. The virus is carried in the blood and saliva of infected cats. It can cause a low white blood cell count and immune deficiency - making the cat more prone to catching illnesses and infections. It has been called the cat equivalent of human AIDS - but this can spread unnecessary panic among owners. There is currently no known cure for it but a test can check if your cat is carrying it.

It is a very slow-acting illness and many cats can live a normal lifespan while carrying FIV. Initial symptoms to look out for as the illness takes hold are swelling of the lymph nodes, anaemia and skin infections.

During the later stages of the disease your cat may suffer from diarrhoea, weight loss, mouth disease, urinary tract infections, ear canal infections, and be generally very ill.

To reduce the risks of your cat contracting FIV, it is a good idea to get him neutered as this will make him less likely to roam far from home and get into fights.


Diabetes for cats isn’t that different from diabetes in humans. Similarly, it is on the increase with around one quarter of one per cent of cats now having it. Cats with Type 1 diabetes require insulin treatment.

Type 2 diabetes in cats can be controlled through having less carbohydrates in their diet along with administering a hypoglycaemic drug. Type 2 diabetes can be caused by overeating. Hopefully, your cat will respond well to the diet and the diabetes can be controlled in that way. Symptoms of Type 2 diabetes are an increase in, or complete lack, of appetite; an increase in drinking or jaundice.

It is not completely known what causes diabetes, though a number of people think that it is the increase in dry food diets. Many people have started to feed their cats dry food as it is quick and easy, however it can contain high levels of sugar which can trigger diabetes.


This is probably one of the most serious and contagious viral diseases. It tends to be carried by humans and passed on to cats. It is advisable to get kittens vaccinated against distemper as soon as they are old enough. It’s a very fast-spreading disease which means you could spot the symptoms and three to five days later your cat may die. Owners may not even have time to notice the symptoms.

Some of the main symptoms of this disease are high fever, diarrhoea and vomiting. You may also find that your cat becomes very depressed and dehydrated. Due to these symptoms, septicaemia can often be caused by the bacterial infection spreading into the bloodstream. Sadly this will result in the death of your pet.

The best way to stop your cat from getting this disease is to prevent it by vaccination. Treatment such as fluid replacement and antibiotics can be offered to older cats that get the disease - but nothing can be offered to kittens.

Feline Leukaemia Virus (FeLV)

This is a serious, contagious cat illness which is NOT to be confused with FIV (listed above). There are two main ways in which cats can contract this illness: unborn kittens are infected if their mother carries the disease; cats can contract it from other cats where there is close physical contact, such as mutual grooming, sharing food bowls or biting. FeLV is also found in the tears, blood, nasal secretions and urine of infected cats.

Two to four weeks after contracting the virus, your cat may seem generally slightly unwell. Once your cat recovers from this initial period of ill health other symptoms may not show for some time - this could be a few weeks or even up to five years. Some cats will develop tumours while others may develop other problems including anaemia and other infections due to the cat's immune system being compromised.

You can get your cat checked for FeLV through a blood test carried out by a vet which is advised if you are looking to introduce a new cat to your home which already has other cats in it.

Upper Respiratory Infection (URI)

URI is a term that actually describes a number of infections that can be caused by four viruses, two of which are serious. These two are called Calicivirus and Rhinotracheitis (RHV). The other two viruses are mild and they are Pneumonitis and reovirus. Pneumonitis is milder than reovirus which leads to a mild fever. The main signs of these viruses are very much like a cold - sneezing, a runny nose and sore eyes.

During this virus a cat can lose its sense of smell and develop ulcers. Your cat may lose its appetite and lose weight as a result. This may lead to the cat becoming dehydrated and weak. RHV can cause ulceration in the front of the eye.

URI is much more serious than a cat cold and it is sometimes fatal for young cats and kittens. After the recovery of URI cats can still carry the disease due to their lymph nodes under their chin swelling and secondary infections can occur. To prevent your cat from getting this disease you are able to get them vaccinated.

Feline Lower Urinary Tract Disease (FLUD)

This is a term which is used for a number of lower urinary tract diseases which range from mild to serious. These can range from Cystitis - which is fairly mild - to total blockage which is a lot more serious.

Urinary infections have always been common in cats. As with diabetes, the number of cats having them has increased in step with the increased use of dry food in cat diets. This is due to dry food causing crystal formation and alkaline urine which means a cat needs to drink more than normal. If cats don't increase their uptake of liquid the infection is a likely result. An example of an infection is when the bladder becomes blocked. This can lead to a bacterial infection or inflammation due to the urine being an attractive environment for bacteria to form and multiply. This forms crystals or stones which cause the blockage. In some cases this blockage can lead to fatal kidney failure.

Feeding 'wet' cat food may help prevent the illness.

Feline Infectious Peritonitis (FIP)

FIP is when the peritoneum – the thin membrane that keeps the internal organs in the abdomen in place - inflames. This is similar to when humans get peritonitis. However, when cats get the disease it isn’t just the inflammation of the peritonitis. The capillary blood vessels also tend to inflate which causes a loss of fluid to those tissues.

The disease is invariably fatal. FIP can take two forms which are wet FIP and dry FIP. Wet FIP is when fluid builds up in the cat's chest lining and abdominal area. This can cause a number of symptoms such as: lack of eating, high fever, dehydration, weight loss and vomiting. You will notice that your cat is generally unwell. This form of the disease is particularly common in kittens. Dry FIP has the same early symptoms of wet FIP though without the fluid being produced. In a lot of dry FIP cases, the cat’s eyes may be affected becoming sore and red and in some cases bleeding. Cats suffering from dry FIP may also develop brain damage, kidney and pancreas problems, brain damage and around 10 to 20% develop FLV.

Sadly there isn’t a cure for either dry FIP or wet FIP. 

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