Q: I have three guinea pigs that keep getting mites. I use wood shavings and hay that are dust free, so the only thing I could think of is that I bring them with fresh grass from outside. Can you help?

A:The mites are most likely to be mange mites (Sarcoptes) and they are not coming from the bedding or the grass.

Guinea pig mites can be present on a guinea pig with no symptoms at all, periodically, when the guinea pig is stressed, they can flare up enough to cause intense itching and skin rashes with hair loss.

These mites spread quickly between guinea pigs and they can infect you and your family too if you handle them. In humans they cause a very itchy rash. Take them to your vet who can confirm the diagnosis and prescribe a course of treatment.

Q: My four-month old Labrador, Fudge, is having problems with recurring water infections: the vet has found crystals in it.

After a course of antibiotics she improves, but the infection soon returns and she needs a special diet. My vet seems to be reluctant to carry out further tests and keeps giving us antibiotics.

Is there anywhere else I can go, or can I ask for a second opinion?

A: You are right to be concerned; Fudge is very young to have all these problems.

This could be an infection which is not clearing properly. Though it is more likely that the crystals (bladder stones) you mention are the cause. These are sharp and damage the bladder lining and make it easy for bacteria to cause further damage.

The special diet is designed to dissolve crystals or prevent new ones forming.

Some crystals will not dissolve, and this means an operation is necessary to remove them from the bladder, as well as more tests and possibly surgery.

If your vet is unwilling to take this further you need to ask for a referral.

Q: My cat doesn’t seem to like walking on the carpets. He just runs into a room and jumps on the first surface that he can find, which is normally high. Also, he spends a lot time staring at nothing and seems to be getting clumsy. Any ideas?

A:Cats often like to find places high up on which to perch, as it offers them a feeling of security.

Your cat may feel a little insecure in his new surroundings as there will very likely be other resident cats who object to him moving onto their patch.

Being at ground level may make him feel more prone to aggression from these other cats.

I see more and more cats suffering from a form of Alzheimer’s disease which often starts with bizarre behaviour patterns like some you mention.

I am not sure how old he is but this syndrome is more common in elderly cats.

It is worth a trip to your vet just to have him checked out.