Ferrets are lively and amusing pets, but like most animals, they can carry diseases and pose hazards to people who handle them. Ferrets can carry bacteria and parasites such as Campylobacter, Salmonella, Giardia and Cryptosporidia in their intestinal tract and spread them to people cleaning their cages and litter boxes. Ferrets can also be carriers of ringworm fungus, fleas and scabies mites that can infect their handlers. Because of their inquisitive nature, ferrets can occasionally bite people, especially children who make sudden moves. Ferrets can be vaccinated against rabies, and rabies vaccinations are required for ferrets in King County beginning at four months of age. Rabies immunization must then be maintained with booster shots for the life of the animal.