ADV
by Margaret Merchant
What? ADV? What is that? ADV stands for Aleutian Disease Virus. Well, that doesn't say much does it? Aleutian? What is that? Just the name alone is confusing.
Aleutian is part of a name. The Aleutian Islands are located at the western end of the Alaskan chain, formerly belonging to Russia. Russia ran fur trade through the area. So I think we could hazard a guess that the disease name is connected to this location. Aleutians Disease Virus is a virus that causes the disease Aleutians Disease. However, most people use the shorthand ADV to refer to both the disease and the virus.
ADV originated in minks, a cousin to the domesticated ferret, first documented in a strain of Aleutian mink. Although fatal in minks, it causes more a wasting, chronic disease in ferrets. That is what this article will focus on.
The virus itself is a parvo-virus. The strain that infects domesticated ferrets is thought to have mutated from the mink disease, and results in a less deadly form. Think of it being a cousin to the parvo-viruses that infect dogs and cats. It will not infect those animals, they are affected only by the species specific diseases such a canine parvo-virus or feline panleukopenia. In turn, those diseases will not infect a ferret.
The virus is a hardy virus, meaning it will live in the environment for some time. Infected animals do not constantly shed the virus, meaning the virus travels from their body through fluids and waste to the environment. The virus then sets up shop even in dry areas and will stay viable for long periods of time, at times for years. It is hard to rid an infected environment of the virus. You can carry it, as with any virus, on your clothes, shoes and other items if they come in contact with an infected ferret who is actively shedding the virus.
The virus will infect the ferret and possibly cause the disease within a couple of years. However, not all infected ferrets will succumb to the virus. Not all ferrets exposed will be infected either. There is currently no consensus regarding transmission. It is thought to be more readily transmitted via direct contact with a diseased ferret who is actively shedding, i.e. saliva, fecal, blood or urine exposure. Some experts believe it can also be transmitted via the environment, i.e. cages, clothing or people coming in contact with a diseased ferret who is actively shedding and then coming in contact with an unexposed ferret before proper sanitary procedures have taken place.
Aleutian disease is an auto-immune disease. In humans, example auto-immune diseases are lupus, AIDS, and rheumatoid arthritis. So this gives you an idea of the range of symptoms and severity the disease can have. Clinical signs include hind-end weakness, bloody stools, anemia, seizures or enlargement of the spleen or liver. NOT ALL SIGNS WILL PRESENT IN EVERY FERRET. Also many of the symptoms are indicative of other diseases such as e.c.e. or insulinoma. It is not possible to diagnose a ferret with ADV based on these symptoms alone. Some ferrets with active diease will not show any symptoms.
Testing is available for ADV, although reliability can be limited due to the disease going dormant. This fact leads many to recommend yearly testing on each ferret. The tests available are CEP or CIEP, ELISA, and PCR. All tests rely on one thing: viruses have small particles that are coated with proteins specific to the AD virus. Let's start with the simplest.
The ELISA test (Enzyme-Linked ImmunoSorbent Assay) is a saliva based test. It looks for a specific protein that is connected to the ADV. While it may be user friendly, the ferret will need to have active disease for this test to show positive. If the ferret isn't shedding the virus, you will not get a correct result. It might show negative when the ferret is positive. The company that provides this test recommends testing four times a year.
PCR (polymerase chain reaction) is a method were DNA is collected and then replicated artificially in the lab. This gives researches larger samples of material to test. You might have even heard the term on shows like C.S.I. While reliable, it only tests for one specific protein and so is limited by whether the disease is active or not.
CEP or CIEP (Counter-electrophoresis) uses blood immerse in special solutions and then applying electricity to the fluids. It detects several proteins associated with ADV and so will detect the disease in both it's active and dormant states.
Whew! Did we make it through that?
The hardest part of the disease is there is no treatment for the disease itself.
Only supportive treatments, such as steroids for inflammation.
There is currently no vaccine either. Prevention is your best bet. Be sure to
limit contact with ferrets you don't know about, or change clothing etc if you
do handle strange ferrets. If you adopt a ferret with unknown history, be sure
an quarantine for 2-4 weeks both for testing and to watch for any clinical signs
of the disease.
Basic good hygiene when going to a show will help prevent the disease from spreading. Don't contaminate your clothing by holding ferrets against it, and always sanitize your hands between holding ferrets.
If you do have a ferret positive for ADV, experts recommend keeping the infected animals separate from non-infected animals for the remainder of its life. Having separate play areas etc., along with good hygiene, will cut the chances of spreading the disease.
DON'T PANIC!! It isn't a plague just yet.
Remember:
Not all ferrets exposed will contract AD.
Not all ferrets infected with ADV will have active disease.
Use common sense when handling strange ferrets and when attending ferret shows.
Some good links for information:
FerretADV.com- This is a great easy to understand site with info on obtaining tests.
Dr. William's article on ADV- Fairly technical paper, but lots of details.
Aleutian Disease in Ferrets by Dr. Richard R. Nye- Older technical article directed towards veterinarians.