Ferrets: Health Problems

Ferrets belong to the family Mustelidae. They are related to black-footed ferrets, weasels, and otters. The average life expectancy for a ferret is 8–10 years. Ferrets have several well-known but unique health problems. Understanding these problems and educating yourself about the symptoms of disease will allow you to better care for your pet and minimize future healthcare problems.

Adrenal Gland Disease

Adrenal gland disease may be the most common disease that affects ferrets. Adrenal gland disease occurs when the adrenal gland produces abnormally high amounts of hormones, often due to cancer in one or both adrenal glands. The excess hormones may cause one or all the following clinical signs: 

• Noticeable hair loss on the tail, rump, or spine
• Generalized itchiness with no history of fleas or mites
• Swelling of the vulva in females or the prostate gland in males

Prevention is possible with the use of a Suprelorin® hormone implant. Once symptoms are present, the Suprelorin® implant may reverse symptoms in mild cases. In advanced cases, your veterinarian will recommend surgery to remove the diseased adrenal gland.

Hypoglycemia (Low Blood Sugar)

Ferrets over three years of age that show signs of chronic lethargy (lack of energy), difficulty waking, or trouble walking may be exhibiting signs of low blood glucose levels, called hypoglycemia. In cases of severe hypoglycemia, many ferrets have seizures. This condition occurs when a cancerous growth of the pancreas, commonly known as insulinoma, creates excess insulin in the bloodstream.

Blood tests are needed to diagnose the specific cause of lethargy. If glucose levels are low, medical and/or surgical therapy is necessary to help the ferret maintain adequate blood glucose levels. Hypoglycemia is not curable, but with proper life-long treatment, many ferrets can live a normal life for up to two and a half years post-diagnosis. Surgery involves an abdominal exploratory procedure to visually examine the pancreas and remove cancerous nodules. Post-operatively, medications will be required to help maintain adequate blood glucose levels.

Neoplasia or Cancer

Ferrets can be affected by a variety of cancerous conditions. Skin growths are common on adult ferrets and are usually either basal cell carcinoma or mast cell tumors, but hemangiomas and squamous cell carcinoma have also been diagnosed. The most common cancerous condition amongst ferrets is lymphoma or lymphosarcoma. This condition is a cancer of the lymphoid system and causes enlargement or nodules on the lymph nodes, liver, and/or spleen. Most skin tumors are benign, whereas lymphoma is a metastatic (spreading) cancer that may spread from peripheral lymph nodes to the liver and/or spleen. Chemotherapy is an option for lymphoma.

Heartworm Disease

Like dogs and cats, ferrets are susceptible to heartworm disease. Heartworms are transmitted by mosquitos. In ferrets, the symptoms are generally severe. Affected ferrets are often weak, have difficulty breathing, and may have a distended abdomen. Radiographs (X-rays) may show fluid in the chest cavity and, if an ultrasound is available, live heartworms may be noted in the right side of the heart. Both the disease and treatment may be life-threatening, so prevention is the best plan, and is very simple. Administration of a monthly heartworm preventive is essential for every ferret, even indoor pets, that live in a region with mosquitoes.

Enlarged Spleen (Splenomegaly)

During a physical examination, your veterinarian may palpate (feel) for an enlarged spleen, especially if your ferret is older. While an enlarged spleen is not a sign of any one specific disease, it requires further investigation.

Enlargement of the spleen may be caused by inflammation, viral or bacterial infections, cancer, and/or heart disease. An enlarged spleen is a serious finding that requires laboratory testing to determine the cause. Occasionally, diagnostic tests are negative for any specific disease, in which case, the diagnosis is "benign hypersplenism" or "benign idiopathic splenomegaly". An abdominal ultrasound is extremely helpful in determining a potential cause for splenomegaly and a course of treatment.

Aplastic Anemia

Aplastic anemia is a condition in which red blood cell production in the bone marrow is suppressed, resulting in a shutdown in production of new red blood cells. Bone marrow suppression may also suppress the production of white blood cells and platelets. This condition occurs in intact female ferrets (ferrets that are not spayed) that are not bred when they are in heat (in estrus; ready to breed). Sexually mature female ferrets that are not bred will stay in heat indefinitely, causing persistent high estrogen levels. High doses of estrogen suppress bone marrow function. This condition is rarely seen today, as most female ferrets are spayed before they are shipped to the pet store.

Signs of aplastic anemia include lethargy and pale mucous membranes, which can be easily observed by looking at the gums. When an intact female ferret is examined, her vulva will usually be swollen and enlarged, indicating persistent estrus or heat. Initial treatment to stabilize the ferret includes hormonal therapy to bring the ferret out of heat, antibiotics, iron supplementation, and vitamin B injection.

A ferret with severe anemia may need a blood transfusion to save her life. Once stabilized, the ferret should be spayed. Aplastic anemia is a serious and expensive disease to treat. Female ferrets should be spayed after they reach four to six months of age unless they are going to be bred at every heat cycle.

Heat Stroke

Ferrets, like dogs and cats, do not sweat like humans, so they are susceptible to extreme heat. Ferrets should be kept at an environmental temperature below 90°F (32°C). A ferret with heat stroke will show open-mouth breathing and an elevated rectal temperature (normal temperature is 100°F–104°F or 38°C–40°C).

Heat stroke is a life-threatening emergency. First aid involves rapidly cooling the ferret by wrapping the feet with towels soaked in cold water or fans, but be careful not to chill the ferret too much. If the ferret begins to shiver, stop the cooling process. If you suspect your ferret may be suffering from heat stroke, take it to the veterinarian immediately — do not delay. During the trip to the veterinarian, wrap the ferret’s feet in cool, wet towels, or transport it in an air-conditioned vehicle.

Your veterinarian will stabilize the ferret and slowly reduce its temperature using various medically safe procedures. Hospitalization is required after the temperature has been normalized to monitor vital signs and ensure that the ferret is stable.

Canine Distemper

Ferrets can be infected with canine distemper virus. This disease is usually fatal to ferrets. Clinical signs include loss of appetite; thick discharge from the eyes and nose; fever; thickened and hard skin on the footpads; and/or a rash on the chin, abdomen, or groin.

Treatment is supportive care, including fluids, antibiotics (for secondary bacterial infections), oxygen therapy, and maintaining nutritional intake. Since the symptoms of distemper and influenza are similar, you should attempt to get diagnosis and treatment from an experienced small mammal exotic veterinarian. A ferret infected with distemper will usually succumb to the disease within one to two weeks, whereas a ferret infected with the influenza virus should be better within one to two weeks.

To prevent this fatal disease, all ferrets at risk of exposure should be vaccinated. Discuss the risks of this disease with your veterinarian.

Human Influenza

Ferrets can both contract and spread human influenza, or flu. Symptoms are like those in people, and include runny eyes, runny nose, severe lethargy, and increased body temperature. Treatment consists of antibiotics (to prevent secondary bacterial infections), decongestants, and anti-viral therapy. Occasionally, hospitalization for supportive care such as fluid therapy or force-feeding by your veterinarian will be required. Never give your ferret any over-the-counter medications or prescription drugs without checking with your veterinarian first. Like dogs and cats, ferrets can be easily poisoned or killed with common human medications.

Coronavirus

Coronavirus infections in ferrets can show up in several different ways. The common SARS-CoV-2 (COVID-19) virus may be passed from humans to ferrets, but ferrets usually only show mild symptoms. Ferret enteric coronavirus is an intestinal disease that generally causes a greenish, mucoid diarrhea. This disease is commonly referred to as epizootic catarrhal enteritis (ECE). 

Ferret systemic coronavirus disease (FSCD) is a deadly form of ferret coronavirus infection. This infection mimics feline infectious peritonitis (FIP), a coronavirus infection that affects cats. Symptoms of FSCD include anemia, lethargy, diarrhea, and usually a palpable mass or thickening of the intestinal tract.