Re: My dog killed a sick(?) rabbit
That's a lot of questions. Rabies comes to mind, not too many mammals are immune, but if your dog is up to date on his vaccinations I think he would be ok. Worms and other parasites are passed up the food chain, your feed store has worming medicine, and I'd worm him in a week or so just to be safe.
On diseases specific to rabbits I'm not much help. I've kept them, but they didn't get sick or have seizures. One died of kidney failure (he was 8 or 9 years old) and the other of fright - not a mark on him but he got out of his cage one night and I'm sure one of my dogs ran up to him. He was very skitzy.
I am not sure whether rabbits can get epilepsy but that sounds like what the described symptoms are. I doubt it would be transmissible if the dog ate the rabbit. Any sick wild rabbits around here wouldn't last long with coyotes and hawks about.
And then again, animals get old, if they don't get eaten. I have geriatric fish. They get tumors. They get heart disease if they get overweight. And these are fish. They also get ugly when they are really really old.
Stuck in Texas. Learning Permaculture in drought, flood and strange weather. The bees are still alive.