Bot Fly Infestation in Ferrets

By PetMD Editorial on Jun. 4, 2010

Cuterebriasis in Ferrets

Cuterebriasis is a parasitic infection caused by the bot fly species Cuterebra. Also called myiasis, this type of infection affects mammals including ferrets. The female Cuterebra lays her eggs either in the grass (to be brushed by the fur of any outdoor animals walking by) or directly on the ferret. The warmth of the mammal’s body causes the eggs to hatch; the tiny maggots then burrow downward, headfirst, into the mammal’s skin, creating a hole.

Over time, the maggot will grow, causing a lump that can become as large as an egg to form in your ferret’s skin. In addition, the maturing maggot has mouthparts, which allows it chew and eat farther into your pet’s flesh as it grows. However, do not crush the lump in an attempt to kill the maggot, it will cause an allergic, sometimes fatal, reaction in your pet. It is best to take your pet to a veterinarian to surgically remove the maggot.

Symptoms and Types

Two black spots will be visible from the hole(s) created by the burrowing maggot, which are typically found on the neck, near the shoulder blades, or in the nose or mouth. These are spiracles at the tail end of the maggot through which it breathes and excretes waste products (a urine-like substance). The stress caused by this type of infection can lead to lethargy, fever, and loss of appetite (anorexia) in your ferret. And if the maggots accidentally migrate to the brain, it may cause:

  • Seizures
  • Depression
  • Blindness
  • Incoordination or unusual circling


Cuterebra bot fly maggot(s) that have infested your ferret.


You will need to give your veterinarian a thorough history of the ferret’s health, including the onset and nature of the symptoms and possible incidents that might have precipitated this condition. He or she will then perform a complete physical examination as well as a biochemistry profile, urinalysis, complete blood count, and an electrolyte panel, especially if the ferret has a fever or exhibits inappetence. If your ferret has cuterebriasis, the veterinarian should be able to see the hole in which the maggot lives in during the physical exam.


Your veterinarian will attempt to enlarge the holes and extract the maggot with forceps. Anesthetizing the ferret is often recommended, especially if the maggots are so embedded that they require surgical excision. It is important your veterinarian remove the entire maggot, as leaving any part of the maggot in your pet may cause a severe immune reaction.

Meanwhile, if the bot fly maggots have accidentally migrated to the brain, the ferret -- after being pretreated with anti-inflammatory drugs, antibiotics and allergy medication -- may be given Ivermectin to kill the parasite. However, the prognosis is guarded in these types of cases.

Living and Management

Once the maggot has been removed, the exposed hole will be slow to heal. It may also drain and cause the surrounding skin to slough off before the entire wound heals. Your veterinarian will provide you with proper medications to alleviate the pain.


If you live in a high-risk area, your veterinarian may recommend administering topical flea and tick medication such as Imidacloprid and Fipronil, which is thought to kill off the Cuterebra maggots. Keeping your ferret indoors may also reduce the risk of infection.

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