Apparently some parasites subtly change behaviour to make their host act recklessly: apparently that's how they spread - when their host gets eaten (!). You never should have seen a healthy mouse at all, far less got bitten. I wouldn't worry about it travelling in the bite though, you'd have to eat the mouse to get it, uhm, like your dog. I'd worry more about Lyme Disease from the bite though... (*Edit: but it comes from rats, not mice*)
(Apparently, a disproportionate number of people killed in traffic accidents are found to have a seemingly inactive and harmless parasite called toxoplasmosis as cysts in their brain, from eating uncooked pork. There is reason to suggest that it may be responsible for reckless behaviour or reduced reflexes as part of its life cycle to get its host killed. Isn't nature great? :-P)
Edit: although nothing much will bother a dog, they'll eat 1000 times worse in their lifetimes. Dirty stinking animals. :-x
