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Is your dog drinking like a fish, urinating frequently and losing weight?

Is your cat restless, nervous and getting thinner by the day, despite a huge appetite?

Diabetes and hyperthyroidism are just two of the common human diseases thought to be on the rise in the pet world.

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Diabetes

Human diabetes is on the increase, and Dr Stijn Niessen, of the Royal Veterinary College (RVC,) says the same trend can be seen in pet cats.

He suggests about one in every 200 pet cats now has type-2 diabetes, compared with some one in 900 just three decades ago.

"Cats are designed to be hunters - but now there are lots sitting in inner-city apartments getting little exercise and being fed frequently, often as a misplaced sign of affection," Dr Niessen says.

But he is quick to point out there are lots of fat cats that do not go on to develop diabetes.

In some cases, it is more about genetics than lifestyle.

When it comes to dogs, about three in every 1,000 have diabetes in the UK, according to the RVC.

Dogs do not get type-2 diabetes, but they are more likely than cats to have type-1 diabetes, where the body's immune system stops it from being able to produce insulin, a key hormone that helps store sugar safely.

In both cats and dogs (and sometimes monkeys, rabbits and even rats) with diabetes, owners often find their pets are constantly thirsty, urinating frequently and losing weight - diabetic symptoms humans and pets share.

Treatment can include giving insulin injections.

And some studies in cats suggest some can kick their diabetes into remission by getting rid of the extra pounds.

Thyroid problems

Hyperactive, restless cats that are losing weight despite eating ravenously may have hyperthyroidism.

Just like in humans, this condition occurs when the thyroid gland in the neck produces excess hormones.

One way to treat an overactive thyroid is to give the cat an injection of radioactive iodine.

The iodine ends up concentrated in the thyroid gland and emits radiation, killing overactive thyroid cells.

This is a good way to cure hyperthyroidism, but cats have to be kept in isolation for several weeks after as they are likely to be emitting radiation in their litter trays for some time.

Dogs, on the other hand, are more likely to suffer the opposite problem.

About four in every 1,000 pet dogs in the UK are seen by vets for underactive thyroids.

Owners might notice their pets are lazier and slower than usual and are piling on the pounds - some of the same symptoms humans with hypothyroidism share.

And just like with their human counterparts, thyroid hormone replacement therapy can help.

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Dogs on Viagra

Dogs who are breathless or even collapse suddenly may end up being given Viagra.

The drug is famous for helping men with erectile dysfunction.

But before doctors prescribed it for this, scientists were studying it to see if it could be used as a treatment for high blood pressure.

And vets now use it to treat pulmonary hypertension in dogs - high blood pressure in the lungs.

One tells me she is sometimes asked by owners whether they can just give their own pills to their pets.

But the answer is no.

The drugs are licensed and formulated separately for people and pets.

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Feline Immunodeficiency Virus

Feline Immunodeficiency Virus (FIV) attacks the cat's immune system, leaving it unable to fight off other infections.

In this way, it is similar to HIV in humans.

In the US, between 1.5% and 3% of otherwise healthy cats are infected with FIV.

Persistent fevers, a coat in poor condition and a loss of appetite are common in infected cats.

Inflammation of the gums and chronic infections of the skin, eyes, bladder, and upper respiratory tract are often signs too.

Epilepsy

According to Prof Holger Volk of the RVC, about one in every 100 dogs has epilepsy.

Cats also get the condition, but it is less common.

It can cause convulsions, but in some cases the symptoms are not as easy to spot.

Animals can be treated with anti-epileptic pills, but they do not work for every pet.

Prof Volk's early work suggests a diet rich in certain fatty acids might help.

And he is now conducting larger trials to see if these results stand up.

Scientists in his department have also looked at videos featuring either animals or humans with epilepsy having seizures.

And they concluded the animals often received more sympathy from onlookers.

But sympathy and empathy aside, Dr Volk and Dr Niessen both say studying common diseases in pets could ultimately help us learn more about the diseases we experience ourselves.