Expert: Dr. Louis N. Gotthelf - 7/18/2011

Question
I have two cats with fleas. When we got infested with the fleas, about 8 months ago and we attempted a combination pure chemical treatment: flea bomb, frontline on two of the cats and flea shampoo on the boy cat we had who had a bad reaction I feel due to an overdose and we had to put down. He already had something like hyperthyroidism for a number of years and was quite thin and once we had the fleas he was eating less and seemed to be in decline. My oversight and misuse of the shampoo pains me every day but I had had multiple vets before the fleas say his condition was hard to treat and that he had been silently suffering. The whole situation wreaked havoc on me and depressed me and we didn't follow up with frontline or any bombings. Now its summer, and these pests are still in big numbers. I sweep always and give them daily flea brushings in which i pull off and kill anywhere ranging from 3 to 20 off the seventeen year old and no more than 5 off the 13 year old. While we've had the fleas, the 17 year old has gotten thinner and seems to be developing hyperthyroidism because she eats plenty(we feed them primarily canned food and they stopped eating dry food when we got it in bulk)and she drinks and pees more and still poops regularly, just like the boy did for more than two years. In the past month now the 13 year old has been getting thinner, more sluggish, sleeping in the bath tub, barely eating if at all and just hovering over the water and taking bits at a time. I did the test of her scruff skin, pulling up the shoulder skin and it recedes a little slowly  which is a sign of dehydration. We are taking both cats to the vet tomorrow.Are there specific signals pointing to some condition in the younger hunger-striking cat? And anything about the 17 year old?

Answer
In older cats, there are many things that are possible including hyperthyroidism.  Have blood tests done on both to see if there is a problem developing.  As far as the fleas, Revolution seems to work best for cats, although it is a slower kill.  Advantage is OK, but it does not last on a cat that licks its skin.  Frontline does not work well on cats because cats do not have a lot of sebaceous glands, where the Frontline resides.