Another risk to rat owners is rat-bite fever. This is a rare disease among domesticated rats and is most often found in rats from large chain pet stores who breed their stock of rats in masses (usually with the intention of being snake food rather than pets) or from breeders who fail to take good care of their rats. This disease is fairly unnoticeable in the rat, but is characterized by the swelling of the site of the bite or scratch where it was contracted, a fever, vomiting and body aches. It is contracted by being bitten or scratched by an infected rat.