Ferret Diseases


This cancer is not restricted to old ferrets. It also may occur in young animals. In many ferrets it tends to hide unnoticed with no signs for months or years and then suddenly appear in a variety of forms. It is a cancer of the lymphatic system, which is part of the body’s immune system. The cause is suspected to be a virus. Although much is still unknown, the theory is that the virus is initially transmitted from mother to kit where it may lay dormant for a long period before causing a problem. Transmission between adult animals may also possible, but the method of transmission is not completely understood. At this point in time it does not appear to be highly transmissible between adults.

Signs vary, and as already stated, many animals have no outward signs for a long period of time. Disease in these animals may be detected by abnormalities in the complete blood cell count. Noticeable changes in other animals may include any of the following signs; swollen lymph nodes, enlarged spleen (there are many causes of enlarged spleens, and in some cases it may be “normal”), wasting, lethargy, frequent illnesses (such as “colds”), poor appetite, difficulty breathing, chronic diarrhea or hind limb weakness.

The Diagnosis is made from a combination of a complete blood cell count and either a biopsy of a lymph node, a bone marrow biopsy, x-rays, or biopsies of other affected areas.

Treatment is achieved through chemotherapy, the details of which can be discussed with us. We have had about a 50% success rate with chemotherapy with life being prolonged for 6 months to 5 years post treatment. Most ferrets tolerate the therapy very well and have few side effects. Even those cases that are not good chemotherapy candidates may be helped to continue a quality life with the use of nutritional therapy and corticosteroids.


This is one of the most common cancers that we see. At least 50% or ore of the ferrets over three years of age will develop this disease. It is a caner of the beta cells of the pancreas (the cells that produce insulin). This cancer causes these cells to produce abnormally high levels of insulin. This increase in insulin has the effect of driving the sugar out of the blood stream and into the body’s cells at too rapid of a rate. This causes a dangerous decrease in the blood sugar level. The brain, which needs a constant large supply of sugar, then becomes sugar starved and begins behaving in an erratic manner. The abnormally functioning brain provides most of the signs that we have seen with insulinoma. Early in the disease, the body counteracts the sugar drop by producing more sugar from the liver, which then temporarily corrects the problem, so symptoms are very subtle. As the disease progresses, and the body is less able to cope with the situation, the signs become more severe and last longer.

Early signs of the disease are usually no more noticeable than seeing the ferret stare blankly into space for a few seconds and then return to normal. He may be a little more difficult to awaken from his naps. As the disease progressed, however, the signs become more specific and may include the following: drooling or salivating, pawing frantically at the mouth (all these sins are probably caused by a feeling of nausea when the sugar drops), extreme lethargy, seizures and finally a come and death. The diagnosis is based on a fasting blood sugar level. The pet should be fasted for a minimum of 4 to no longer than 6 hours. Occasionally it may also be necessary to run blood insulin levels at the same time.

Treatment depends on the stage of the disease and the overall condition of the pet. Usually, surgery is the first treatment choice. The tumor or tumors are removed and further medication may be unnecessary or at least delayed for some time. When surgery is not possible for whatever reason or in cases where the disease returns despite surgery, then medical management is indicated. This involves a good quality, high protein diet always available, and the use of protein snacks such as cooked meat and egg scraps or strained meat baby food. The addition of brewer’s yeast in the amount of 1/8 to ¼ tsp. of the powder or 1/8 to ¼ of a chewable tablet two times a daily with food has also been helpful to stabilize glucose levels. Brewer’s yeast contains chromium which is known as the glucose tolerance factor because it helps to stabilize blood glucose and insulin swings. No sugary treats should be given, as this may make the problem worse. When diet no longer controls the signs, then the pet may have to be put on corticosteroids and/or Proglycem which is an insulin blocking agent. Treatment will be for life.

If you should notice any of the signs listed above, especially the serious ones such as seizures and coma, you can help bring your pet out of these conditions by administering some honey and water by mouth until the pet is more alert or has stopped seizuring. Of course, contact you veterinarian and have your pet examined as soon as possible.

Adrenal Adenoma or Adenocarcinoma

This cancer is as common as insulinoma and frequently occurs along with it. This is a cancer of the adrenal glands, which are very tiny organs about the size of half a pea, located near the kidney. They produce very potent hormones that control a number of metabolic functions in the body. Ferrets may develop adenoma, which is the benign form of the disease (which means that it does not spread to other organs of the body) or adenocarcinoma, which is the malignant form. They may develop disease in either one or both glands.

Signs are fairly specific and are related to an overproduction of hormones, particularly abdrogens (precursors to the sex hormones…they act in the same manner as estrogen, progesterone and testosterone ). The most common sign seen is a hair loss over a portion or all of the body. The hair loss may come and go over a period of time. In spayed females, the vulva may swell as if they were in heat again. Other signs may include one or any combination of the following: intense itching, dry brittle haircoat, thin skin, red scaly skin, weakened muscles with hind limb or generalized weakness, increase in body odor (as if the pet was not neutered), anemia and lethargy. The diagnosis is based primarily on the signs. However if the diagnosis is in doubt, you veterinarian may recommend submitting a blood sample to a lab for hormone level evaluation.

The treatment of choice is the surgical removal of the affected adrenal gland. Since the disease and insulinoma frequently occur at the same time, insulinomas can also be removed. In cases where adenoma is diagnosed, and in the absence of insulinoma, a drug called Lysodren may be used to chemically destroy the overactive parts of the adrenal. This drug is not effective against adenocarcinoma.

Skin Tumors

Skin tumors in older ferrets should be surgically removed as soon as possible because of the possibility that some are malignant and can spread to other areas of the body. The most common type of skin tumor in the ferret is the mast cell tumor which appears as a round raised button-like lesion. They may be quite itchy and often have a crust of dried blood over the top. They are usually benign, but may metastasize to internal organs including the lungs.

Other common skin tumors are adenomas and adenocarcinomas. They are cancers of the skin glands and can occur anywhere. In males they occur frequently at the tip of the prepuce and appear as a bluish colored lump. Adenocarcinomas are highly malignant and should be removed as soon as possible.

Although ferrets in this country are plagued with a variety of illness as they get older, frequent examinations and laboratory testing as needed can greatly improve their chances of survival and prolong their lives in a quality manner. Enjoy your pet, give them love and attention and they will reward you with endless hours of laughter and love.

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