Ferrets can be infected with a variety of helminths, most commonly roundworms Toxacara canis or Toxascaris leonina. Protozoal infections may include Giardia and coccidia.
Ferrets are also susceptible to heartworm infections by Dirofilaria immitis. Because ferrets have a small heart, even 1 adult worm is sufficient to produce cardiac insufficiency, causing severe respiratory distress, ascites, and death. Typically, definitive diagnosis of heartworm disease is made at the postmortem examination. Treatment has been generally unsuccessful in suspected cases that had radiographic evidence of enlargement of the heart and enlarged pulmonary veins. Prevention with ivermectin products utilizing the canine dosages beginning at 3 months of age is recommended. It is possible to detect heartworms using the canine heartworm antigen test kit. Ferrets can be infected with Dipetalonema reconditum, which might be found on blood samples.
Infestation with Sarcoptes scabei may take two forms: 1) a patchy to generalized alopecia and intense itching associated with the mite, which can be found in skin scraping of affected areas, or 2) sarcoptic lesions which are limited to the toes and feet where feet are swollen, scabby, and if not treated, clawless. Diagnosis is made by scraping affected areas and observing the typical sarcoptic mite.
Treatment consists of application of sulfur ointment or lime and sulfur dips and washes, and trimming the claws and removing the scabs after softening them in warm water. Other topical treatments used for dogs have been used successfully on ferrets. Ivermectin is probably the most successful treatment available and has been successfully used to treat Sarcoptes in ferrets. Itchiness may be reduced by administration of corticosteroids.
Ferrets may also be infected with fleas and may be treated with mild flea products, similar to those used on cats. Ear mites (Otodectes cynotis) may be treated with ivermectin repeated in 2-3 weeks.
Public Health Significance: Humans may become bitten by fleas and infected with Sarcoptes scabei, which manifests as itch beginning in the areas of the skin having contact with the animal. The skin frequently becomes encrusted and excoriated as the disease progresses.