How likely is it that stress or new food causes loose stools?

Hi. My cats suffered with Tritrichomonas foetus which was horrible, but they were treated and got better. I introduced a new cat into the household (shelter cat that melted my heart...don't know what I was thinking) last night and took my other cats on a ride to the spay/neuter clinic today and back. (we missed our appointment and will go again tomorrow) When I got back my little girl Femmy had nasty loose stools. I only breifly introduced her to the new cat last night and he has been in another room. I am wondering if the stress of meeting him plus the stress of being put in the crate and for a car ride could have brought on the loose stools. She has been normal and fine for some time now.

My plan is to keep the new cat separated for a week or two before introducing all the cats further. He (new cat) seems to have loose stools as well, but I am not sure if it is the food change from shelter food or if he may have a parasite like giardia or if it is stress for him as well. In any case, I am going to have to take him to the vet soon.

My question is, how likely is it that either stress or new food could be causing the loose stools in either of them? I know that humans can get intestinal upset with stress....

Any kind of stress can be a trigger, and food changes are well known to cause some kitties problems.

I applaud you getting them to the vet as soon as you can. Re the shelter kitty, are you transitioning his food very slowly - when I got my two, I fed them their shelter food for a good two weeks at my house before I even started transitioning. And my boy has a delicate tummy in any event - there are certain foods that just don't agree with him.

BTW, and I know this may seem silly - at least for a long while, always greet your resident cats first, feed them first, and tell them that they are the loves of your life, that the new kitty is for them, and that you will never love them less.

And bless you for adopting.

I think that both stress and new food can definitely cause loose stools. My cat Wiggies is particularly sensitive to stress and has had diarrhea in response to stressful situations. And new food is well known to potentially cause upset tummies (not that it always does though).

Thanks for the imput. Yeah, I am going to try and make sure the other kitties feel loved still. I hope that everyones stools return to normal quickly. They weren't able to tell me what the new kitty has been eating so that I could slowly make the change. Hopefully his stools will adjust to the new food in no time. This is going to be quite a challenge. I hadn't thought about it, but the new kitty has such a different personality. I should have guessed by his build that he is an active cat. The other two are long haired munchkins and clearly are breed to be lie around kind of kitties. This guy is going to be the one to jump on and get into everything. He is like a dog with how much energy he has...like a little ADD cat. Hopefully he will not put off my other cats too much. They are also very playful with each other, but not nearly as athletic I think. Wish me luck. eek.

Keep us updated - and is it possible at your place to make/add some hidey holes or cat trees so that the cats can go to different levels in case anyone wants a little 'alone' time.

I always laugh at mine - I have two trees and it really does seem that both use them a lot - but they have their own times for picking the top spot. But there are definitely times when one wants to be in the front of the condo, and the other wants the back of the condo.