Respiratory Diseases in Ferrets

Ferrets are susceptible to a variety of respiratory diseases. The symptoms of respiratory disease vary and can range from mild nasal discharge to severe respiratory distress. If you see any sign of abnormal breathing or discharge from the nostrils, contact a veterinarian familiar with ferret diseases.

Some respiratory diseases can be fatal. It is vital that your veterinarian determines the cause of your ferret’s respiratory disease so they can develop a treatment plan and determine a prognosis. Here are some of the most common respiratory diseases that may occur.

Distemper

Canine distemper is a paramyxovirus that can infect both dogs and ferrets. In dogs, canine distemper causes a severe and sometimes fatal illness. In ferrets, canine distemper is usually fatal. The virus is normally spread when an infected ferret or dog coughs or sneezes out infective virus particles that are then inhaled by a susceptible/unvaccinated ferret. The distemper virus can survive for up to three hours in the environment, so it can also be spread by contaminated hands, gloves, food/water bowls, and litter pans.

"In ferrets, canine distemper is usually fatal."

The key symptom of this disease is a purulent (pus-containing) discharge of the eyes and/or nose. However, the first sign in a ferret is often a rash on the chin or abdomen, followed by development of swollen and crusty skin around the eyes and muzzle. Most ferrets with distemper become lethargic and depressed. They may develop a cough or sneezing fits. Vomiting and diarrhea with melena (black, tarry stool due to intestinal bleeding) may occur in some ferrets. Neurological signs may occur in some ferrets, including seizures, incoordination, muscle tremors, and partial or full paralysis. Bacterial infections commonly occur secondary to distemper virus infections, most likely due to a compromised immune system in affected animals.

Initially, the symptoms of distemper are like influenza (flu). However, ferrets with distemper generally appear much sicker than those with influenza. Certain symptoms indicate distemper, such as hardening of the footpads. Treatment is rarely effective and the mortality rate is usually close to 100%. Supportive therapy may relieve discomfort and ease the animal's suffering, including antibiotic treatment, intravenous (IV) fluids, nutritional support, and placing in an oxygen tent.

Vaccination is essential in any animal that may be exposed to the disease. Unvaccinated ferrets and unvaccinated dogs are a potential source of exposure, as well as playgrounds or parks where unvaccinated pets may congregate. There are ferret distemper vaccines; multivalent canine vaccines are not recommended. Young ferrets should have three vaccination boosters in the initial immunization series at 4–6 weeks, 10–12 weeks, and again at 14–16 weeks of age. In subsequent years, the ferret should receive annual boosters.

Newer data shows that some ferrets produce an immunity to the vaccine that may last longer than one year. Many veterinarians recommend yearly “vaccine titer” testing to see if the vaccine is still producing adequate protection against the distemper virus. Ferrets can have adverse reactions (anaphylaxis) to both distemper and rabies vaccination. It is always worthwhile for owners to wait in the veterinary practice for 20–30 minutes post-vaccination to ensure that vaccine reactions, such as acute breathing or vomiting problems, do not occur.

Many veterinarians administer a diphenhydramine (Benadryl) injection before the distemper vaccine to decrease the risk of vaccine reaction. If problems do occur, your veterinarian can immediately administer an antihistamine and a steroid injection. Other vaccine reactions that may occasionally occur include a mild fever or diarrhea, but generally these are short-lived conditions. It is wise to hospitalize and monitor a ferret having such a reaction.

Influenza

Human influenza virus can affect ferrets, and infected ferrets can infect humans in close contact. Influenza generally causes sneezing and conjunctivitis (inflamed tissues around the eyeballs and eyelids), with a watery discharge from the eyes and nose (unlike the severe, purulent nasal and eye discharge seen with distemper). Other symptoms may include coughing, trouble breathing, fever, anorexia, and lethargy.

In otherwise healthy adult ferrets, involvement of the lungs is uncommon. However, young immunosuppressed ferrets can develop an infection of the bronchi or small air passages within the lungs (bronchitis or pneumonia). In such cases, antibiotics are essential to control secondary bacterial infections. These secondary infections can prove fatal to young ferrets. Intensive, supportive veterinary therapy is essential to prevent fatalities. Your veterinarian may prescribe a human influenza medication to help your ferret recover quicker. If there are humans in the house with fever and flu symptoms, they must stay away from the ferret until they have been without symptoms (and fever-free) for 24 hours.

Heartworm Disease

As in dogs and cats, heartworm disease can cause respiratory distress in a ferret. Heartworms are transmitted by mosquitos. Symptoms of heartworm disease include lethargy, weight loss, and moderate to severe difficulty breathing. Chest radiographs (X-rays) often show a large amount of fluid in the chest cavity. Diagnosis requires finding heartworms in the heart on a cardiac ultrasound or on an in-house heartworm blood test. 

It should be noted that in-house heartworm tests for ferrets are not highly accurate, so ultrasound is the better way to provide an accurate diagnosis. Treatment of heartworms in ferrets can be accomplished, but side effects of the treatment can be harsh and even fatal. The use of a monthly heartworm preventative is essential for any ferret living in any municipality where there are mosquitos.

Lymphoma

Lymphoma, a cancer involving the lymph nodes and lymphoid organs, can present as a respiratory problem if the tumor involves the thymus or the lungs. In these cases, the ferret may wheeze, be very weak, and/or be cyanotic (purple gums, nose, and sometimes feet). X-rays of the chest may show a mass in the chest cavity or tumors in the lung tissue. Blood work, ultrasound, or needle aspirates may be necessary to specifically diagnose the disease status and plan a treatment strategy. There are chemotherapy options for treating ferrets with lymphoma.

Cardiomyopathy

Cardiomyopathy is a disease of the heart muscle. There are two types of cardiomyopathies: dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). In both cases, the earliest signs include lethargy and exercise intolerance.

In DCM, the heart chambers become dilated and the muscles of the heart become thin-walled. These two factors make the heart unable to contract properly. Later stages of this disease may produce fluid build-up in the chest and/or abdomen. A ferret with DCM may show signs of mild to moderate respiratory distress.

HCM causes an extreme thickening of the heart muscle. It generally causes lethargy and mild respiratory distress as the heart is not pumping properly and not allowing for adequate oxygenation to the blood supply.

In both cases, chest X-rays, cardiac ultrasound, and echocardiogram are required to diagnose the condition. An accurate diagnosis is essential to determine the proper treatment for your ferret. Treatment options are available for both types of cardiomyopathy.

What else can cause respiratory disease in ferrets?

Bacterial and fungal diseases may affect ferrets, although not as commonly as the diseases mentioned. Blood tests, chest X-rays, and special testing (such as tracheal or lung washes) may be necessary to properly diagnose infectious respiratory disease in your ferret. Trauma can cause respiratory problems due to bleeding within the chest cavity or due to pneumothorax, in which air enters the space between the lungs and causes the lungs to collapse. Following any significant trauma, it is important to take X-rays to determine whether there are any problems in the chest.

Any symptom of respiratory distress, abnormal breathing patterns, or nasal discharge should be brought to the attention of a veterinarian familiar with ferret diseases as soon as possible. To find a veterinarian in your area that treats ferrets, to aemv.org and click “Find A Vet”.