Intestinal worms are rarely a problem in ferrets. A baby ferret should have at least one stool sample checked for parasites when he is first adopted. The same test will identify several different parasites that shed eggs into the animal's stool. Roundworms are common in puppies and kittens but very rare in ferrets, therefore, ferrets need not be automatically treated for roundworms as other pets are.
Ferrets are commonly infected by 3 types of intestinal parasites in a biological group known as protozoans. Two species, Giardia lamblia and Cryptosporidium parvum, are potentially communicable to man. The third protozoans are coccidia, which do not infect humans, but are communicable to other carnivores, including, but not necessarily limited to, other mustelids, dogs, and cats.
Giardiasis is uncommon in ferrets, but has been known to occur in those that drink contaminated water or eat contaminated feed, especially uncooked offal. Although the cysts (the equivalent of eggs) may be found in the ferret's stool, the animal rarely shows any clinical signs related to the parasite. Humans suffer mild to severe diarrhea and abdominal pain when infected with Giardia, and there is a possibility that people could be infected by ferrets carrying this disease. However, this has never been reported, and giardiasis is uncommon in pet ferrets kept inside and fed commercial diets and clean water. Pet shop puppies often carry Giardia, which is communicable from them to ferrets in the same pet shop by way of the hands of the caretaker. The treatment for giardiasis is the same for animals as for people, and must be prescribed by a veterinarian.
Cryptosporidiosis is common in young ferrets fed uncooked offal. This parasite may be acquired from cattle, which often carry it. Human beings with cryptosporidiosis have mild to severe watery diarrhea and a flu-like syndrome. Although baby ferrets might infect people, this has never been reported. Ferrets do not usually have diarrhea associated with this infection. There is no effective treatment for cryptosporidiosis, but the person's or animal's immune system eventually eliminates the parasite. People who have AIDS or other immunodeficiency, or those on immunosuppressive drugs for allergies, arthritis, organ transplants, or cancer, should not handle baby ferrets. Even a kit that has never had raw beef products could get cryptosporidiosis from its mother. Kits eliminate the infection in a few weeks, and it is rarely found in an adult ferret.
Coccidiosis is common in ferrets, and sometimes causes bloody diarrhea in juvenile pets. There are many species of coccidia and usually each species infects a limited range of similar animals. For instance, coccidia of sheep and goats do not infect dogs, cats, or ferrets. Ferret coccidia will also infect dogs, cats, and probably similar animals like foxes or wolves, but not other types of animals such as cattle or sheep. Ferrets may be infected with coccidia at the breeding farm of origin or while in a pet shop when exposed to infected puppies or kittens. Adult animals rarely have coccidiosis because they become immune when young. Coccidia of ferrets do not infect humans.
Most of the time, even when a fecal sample is positive for coccidia oocysts (eggs), the parasite causes no obvious problem to the ferret. The oocysts shed in the stool do not become infectious for other animals for at least one day. Cleaning the litter box thoroughly each day helps to control the parasite and prevent re-infestation. To improve the pet's general health and prevent transmission of coccidiosis to other animals, the kit should be treated with one of several drugs available. Because of the life cycle of the parasite, treatment must be given for 10 consecutive days to eliminate coccidia from the gastrointestinal tract. A fecal sample should be checked about a week after the last dose to make sure treatment was effective.
A debilitated, dehydrated ferret with diarrhea due to coccidiosis may require hospitalization for a day for injections of electrolyte solutions. Replacing a poor quality diet with one or more ferret diets or premium cat foods helps sick kits recover more quickly.
See the Centers for Disease Control for more information on Giardia in People and Cryptosporidiosis in People.