Poor Guy.

I've got some friends who live in Florida that have an occasional problem with bot flies and their horses.

I think they use a typical dewormer like ivermectin on all their horses to get them under control.

I do think its likely, if it really was a botfly, that your other animals could be infected and you may need to deworm them all.

Thank you for the advice Joepyeweed.
The only other animals we have are cats so far.
But we do plan on having cows/pigs/a horse. So I will keep a note of that dewormer in my horse book.
As for the other cats, i will try and check them over.
Thanks again.

I would call a vet and ask them. Maybe Meghane will post here, she always has the vet talk...

The botfly larvae lives in the intestines for awhile, so you may not see evidence of it by visual inspection. I'm not sure if they show up in stool samples, which is why I would talk to your vet...

I live in California and bot flies are a summer problem with horses. There are a few horse wormers that adress bots, ivermectin being one. The adult bot fly lays eggs on the horses legs. They are little orange spots, at that point you can scrape them off with a sharp object such as a knife or buy a bot scraper at the feed store. The flies migrate to the gut and stick to thee stomach walls. When they mature the are passed out of the horse in it's manure. They are big enough to see about 3/4 inch and look like a pine cone that hasn't opened. Where they become flys and the cycle starts over. These are horse bot flies there may be other types of bot flies. When you get your horse if you keep up on the worming you won't see bot flies.
I have found maggots in wounds on feral cats that I rescued. The maggots only eat dead flesh, something that I try to remember when I can't touch the cat because it is so gross. The cat is usally alright but has a bad scar. If I can touch the cat I wash the wound out and scrub all the maggots out. I wash it with proxide and put an antibodic ointment that won't kill a cat.

Talk with your vet for the best treatment or prevention. You wouldn't want to kill the larvae while it's still in the cat since that could lead to infection.
I wouldn't recommend randomly trying some type of med without knowing if it will truly prevent the bot in cats. What works well in one type of animal may kill another.

Sorry to hear the cat was put down since the bot is rarely fatal. Some people (farmers) choose to let it run it's cycle, the larvae leaves the body and the wound heals.......but there's no guarantee the outcome is good!

Here is a link that might be useful: bots

Thank you for all your advice! (especially for the future horse i may have one day!) I really feel bad now about putting down the kitten, knowing now that it wasn't going to be fatal...but it was just so horrifying what we saw, and the poor little kitty looked so awful :( . I'll make sure to try and check out the other kitten (if he doesn't go and hide when i walk in the barn) Thanks again!

You probably could have popped the grub out, irrigated the wound with saline and dusted with antibiotic powder.

It takes time to get the stomach to deal with some of the more extreme things we have to do to take care of animals.
(like squeezing anal glands in dogs).