How do they get it?
Canine distemper is an airborne virus that can be transmitted from direct or indirect contact with an infected animal. Infected dogs shed this virus through their respiratory tract, urine and feces. Although dogs often recover from distemper, the disease is usually fatal in ferrets. Young, unvaccinated dogs in a rural setting are the principal carriers of the distemper virus. Distemper can be transmitted from your clothing, shoes, or from your skin for at least 8 hours after exposure. In other words, your ferret can become infected just by inhaling the virus from your skin or clothing. Since the incubation period can be as long as 10 days, always isolate any new dogs or ferrets brought into your household for a minimum of 14 days unless immunity to canine distemper (and other contagious illnesses) can be ascertained. Use caution and common sense when handling other dogs or ferrets.
When ferrets contract distemper, the virus multiplies in the lymphatic tissue surrounding the pet’s respiratory tract. It is for this reason that, early in the disease, distemper can be confused with human influenza to which ferrets are also susceptible.
The first signs are loss of appetite, lethargy and depression. Fever, skin rash and a clear to pussy eye and nose discharge soon follow. The characteristic rash of distemper in ferrets is present on the chin and between the rear legs. Many ferrets develop a dry cough, which soon becomes a moist cough as secondary bacterial pneumonia develops. Their eyes and nose become caked with brownish crusts and scabs. After this respiratory phase of the disease, the distemper virus invades the ferret’s nervous system causing twisted neck, cross-eyed gaze, muscular twitching, convulsions and incoordination. Some ferrets develop brown tarry stools and diarrhea. In some, the skin on the foot pads thicken and harden. The virus eventually infects the brain and causes convulsions, coma, and death. Many of these symptoms are never seen because the ferret will die first. Canine distemper is almost 100% fatal in ferrets within 12 to 42 days after exposure. Once they get the disease, euthanasia is usually recommended to prevent the spread of disease to other animals and to put the animal out of misery.
Yes, ferrets can survive major symptoms. But it is very rare, and they are never the same afterwards. Those few ferrets that have been reported to survive have done so with severe neurological damage. They can also suffer from recurring bouts of symptoms not dissimilar to chronic obstructive pulmonary disease – essentially a progressive lung disease with difficulty in breathing. One can try to support ferrets, sick with distemper, with antibiotics and intravenous fluids but there is little chance of their survival. Ferrets usually die 12-14 days into the diseases. A few will appear to be on the road to recovery only to develop nervous deterioration several weeks to months later. Most vets consider that the most humane thing to do is euthanize. Given the horrible nature of the disease, prevention should be the priority.
Kits receive some immunity from their mother, provided she was properly vaccinated. Studies suggest that at 6 ½ weeks of age, only 1/32 of the original maternal immunity is left. The actual length of protection is dependent upon the antibody level of the mother when the kits were born and the amount of colostrum (first milk) that each kit receives. To establish and maintain immunity, kits need a series of three shots at 6, 10, and 14 weeks followed by a yearly booster. Adults only need a yearly booster unless you are unable to establish that the ferret has had previous vaccinations. Two shots given three to four weeks apart are recommended for adult ferrets that have not previously established and maintained immunity. More recently, there is evidence that the immunity to distemper may last up to three years. Canine distemper vaccines are “live vaccines” (as opposed to a “killed vaccine” where the infectious agent has been inactivated in some way), which means that you should not vaccinate pregnant ferrets, ferrets with infections or ferrets with compromised immune systems. Ferrets with any of these conditions are at increased risk of becoming infected from the vaccine strain of the virus. Ferrets at high risk (those that go to shows, ferrets that are exposed to unvaccinated dogs, or those regularly exposed to new ferrets) should be vaccinated annually. Discuss your ferret’s risk of exposure and the risk of vaccine reactions with your veterinarian and work out your ferret’s vaccination regime.
Although vaccinating your ferret against canine distemper can save its life, there are risks involved. Ferrets have a high rate of moderate to severe vaccination reactions. Severe reactions usually occur within minutes of the vaccination, but delayed reactions are possible. The reaction can range from listlessness after the vaccination to full-blown anaphylaxis (life-threatening allergic reaction). Signs of anaphylaxis can include sneezing, vomiting, hives, itching, swelling, bloody diarrhea, cessation of breathing, or collapse. Be sure to stay at your vet for at least 30 minutes after any vaccination and watch for these symptoms. Anaphylaxis requires immediate care that a ferret owner cannot give. You may also want to ask your veterinarian (preferably one who specializes in ferrets) about pre-treating your ferret with an antihistamine prior to the vaccination.