Could it be something OTHER than fleas?

I live with a 21 year old cat. Today he went to the vet, but I was unable to make the appointment. The vet said he is infested with fleas. Now, here's the thing: I have been trying to figure out what the wierd black stuff on his back has been for months....the thing is, I have looked, and never found, a flea. More telling, I think, as someone who has lived in homes where flea meds were unaffordable, is the fact that, despite sleeping UNDER THE BLANKETS WITH ME every night, I have never been bitten. Additionally, the only place this 'flea dirt' is, is on his back. There is ABSOLUTELY NOTHING othing on his tummy, where the fur is thickest and the skin is warmest, or his legs (even on the outside of hs thighs, which is RIGHT THERE and has much thicker fur, although less meat, bc he's an old man). I also don't see him scratch/twitch/start like he is being bitten, but I was just told that he may not get itchy if his immune system is giving up (although that does nothing as far as feeling the bites, so I don't know how much I buy that). He is still, despite his age, a pretty healthy cat with the exception of having kidney/thyroid problems for whick he takes methimazole. Otherwise he is still super cuddly, sassy, and full of personality. He isn't as fastidious about cleaning himself as he once was, particularly his back. So, is this simply a case of back specific, non-human biting fleas? Could it be something else, and if so is it something worrisome? Oh, I also gave him a dawn-water dip, which I have done before for foster dogs that were infested, and has always resulted in dead flea floaters... Nuthin, although his fur is much thicker than those I've done that to (if I had ever done it to a husky, I'd feel more confident that they would still shake loose--but particularly since he wanted no part of sitting calmly while submerged, I'm not sure much weight can be put on that). Either way, I did dose him with the flea meds, to be safe. Still. I would like to know if it isn't, in fact, fleas.   Thank you, and happy new year!

Hello!  Flea dirt and "flea dirt" are quite easy to differentiate from one another.  Dampen some white loo roll (damp, not soaking), take said 'flea dirt' or flea dirt and wipe it across the damp white stuff, pressing down.  Flea dirt leaves a red or brown track / stain behind it.  However, if this cat has been to the vets, there is likely no need:  there may be areas where not all vets are up to speed, but I would trust all vets to be able to identify flea dirt.  Fleas are nothing to be ashamed of although, in my experience, the vast majority of people who turn up with an animal with fleas, tell the vet that they have never seen a flea on their pet, which may explain why vets often appear not to take any notice.  Fleas actually live in carpets, vegetation and furnishings - it's only when they are really hungry, that they jump onto a passing animal. Their favourite place to hang out is often the top of the tail.  Cat fleas prefer visiting cats to humans, so the owners frequently go unbitten unless the infestation is really bad.  Either way, treating for fleas with a veterinary recommended flea treatment will help in the short term, but should be repeated at the intervals recommended by your vet, even cats with no apparently live fleas on them.  Was the cat otherwise found to be well?

My main niggling concern is that a poorly cat, previously untroubled by fleas, may also have something else going on.  Losing weight can be a first sign of this.  I expect that the vet also examined them and would have let the person know if they felt that other tests, monitoring or treatment was necessary.  I hope that something there helps.

A happy new year to you.