Wet-tail or proliferative ileitis, is a disease in rodents kept in cages, mainly hamsters, but can include rabbits, gerbils, rats, and mice. It is caused by stress. Even with treatment, the animal can die within 24–48 hours. Baby hamsters are much more likely to get the disease than older hamsters. It commonly is found when the hamster is being weaned at about four weeks of age.