Even if you take the best possible care of her, your ferret is likely to become an unhappy host to a varied collection of parasites, either internal, external, or both. By knowing what to look for, you can help to eradicate most of these pests before they have the opportunity to harm your pet.
Routinely check your ferret's skin for signs of parasites, flea dropping (specks of hard, black "dirt") and dandruff. Also check her coat for lice eggs glued to the hair. Frequent or persistent scratching is a good indication that your ferret has a parasite problem.
Ear mites (Otodectes cynotis) are common in ferrets. You may have seen your ferret shaking her head or scratching her ears, but usually there are no signs. If, however, there is a severe infestation, you will notice inflammation of the external ear canal, severe itching and crusting, and there will be a brown waxy discharge from the ears. This discharge may also be the normal condition for some ferrets, and identification of ear mites by a veterinarian is necessary to be sure.
Fleas can be tracked down by the "dirt" they leave behind, even if you can't spot the fleas themselves. If you see hard, shiny drops of "dirt" on your ferret's skin, scrape some off and place the drops on a damp paper towel or tissue. If the dirt "bleeds" - shows red or pinkish - then your ferret has fleas.
Sarcoptic mange is not commonly found in ferrets. The symptoms, if these mites are present, include hair loss and severe itching at the site. Sometimes only the feet are affected, with the paws becoming inflamed, swollen, and crusted, and intense itching is present; in severe cases the foot can be lost (foot rot).
Ticks are easily diagnosed as they swell with blood and turn brownish white. If an engorged tick releases and drops to the floor, it can look almost like a rotting grape. To remove a tick, firmly pinch the skin around the tick and pull hard to extract the entire tick, including the head. Do not be afraid to take a bit of the ferret's skin and hair. This will make sure the tick's head is removed, and if left behind, the head can cause an infection. Put the extracted tick in a jar full of vinegar to kill it. (Flushing a tick down the toilet will not kill it.)
Botflies can cause cutaneous myiasis - cysts under the skin. Though this condition is not often seen in ferrets, in affected ones the larvae can be found in the neck region, readily seen through the swollen area and pore created for entry. "Fly strike" has been seen in ferrets that are kept outdoors. Kits at 4 to 5 weeks may be attacked, with eggs being laid on the face, neck, or flanks, and the larvae then bore into the skin, causing irritation. The resultant larvae infestation can cause lesions and sepsis or shock.
Internal parasites can pose a health risk to you as well as to your pet, and they are often difficult, if not impossible, to detect, except through blood tests and screenings performed by your veterinarian.
Parasites are most harmful to young kits and older debilitated ferrets. Prevention is key, so speak to your vet for instructions on how to safely use over-the-counter medications to worm your ferret as a matter of routine. If you see any symptoms, take your ferret to the vet immediately for a checkup.