Mystery Disease in young ferrets

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Bruce Williams, DVM, DACVP
Chairman, Department of Telemedicine
Armed Forces Institute of Pathology
Washington, DC 20306-6000

Recently, a number of veterinarians and pathologists have observed a spike in mortality in young ferrets less than one year of age. Deaths occur in animals which appear to have overwhelming bacterial infections that are unresponsive to a wide range of treatments. Several unusual findings have linked animals autopsied on both the East and West coasts of the United States, and suggest that a new syndrome may have appeared in our pet ferret population.

This is not an epidemic situation, nor does the disease appear very contagious at this time. The condition is sporadic, and most commonly affects only a single animal in a household. Unfortunately, even with the highest levels of care, few animals have survived this condition once diagnosed.

Investigations on these cases to date have failed to disclose a cause for the condition. This is likely attributable to the slow progression of disease and the number of antibiotics, anti-inflammatory drugs and other treatments that are often used in a valiant attempt to keep the animals alive.

Recent postings on the FML and in other circles on this new syndrome have sparked a lot of interest in this "Mystery Disease". One approach that has not yet been tried is to obtain diagnostic samples from veterinarians and shelter operators prior to any attempted therapy. This may be in the form of surgical biopsy of abscessed skeletal muscle or lymph nodes, or necropsy tissue from animals that have been euthanatized without treatment.

The prospect of euthanatizing an animal without attempting treatment is loathe to all of us; however, the extended use of antibiotics and other drugs in these cases (even those to which the organism is not particularly sensitive to) likely lowers the concentration of the agent to an extent where we cannot successfully culture it, or view it under the microscope. There is no indication that antibiotics themselves are causing the problem - however it is very likely that they are masking the true culprit. Let me also clarify that this particular disease has not been linked to any breeder, pet store, distribution center, activity or anything at all at this point.

We are looking for tissue samples from animals less than 1 year of age who are exhibiting the following signs of acute disease:

Persistent high fever (greater than 104)
Markedly elevated white blood cell count
Discomfort or pain in the hind legs
Enlargement of one or more peripheral nodes
Cellulitis or abscessation of peripheral nodes or adjacent soft tissue

Proper collection of tissues is paramount. Surgical biopsies, such as enlarged lymph nodes, should be bisected and several touch imprints of the cut surface prepared and air-dried for cytologic examination and gram staining. Half of the tissue can then be placed in formalin; the other half should be immediately frozen for bacteriological examination. If an untreated animal is presented for autopsy, the widest range of tissues should be taken. Once again, equal halves can be formalin-fixed and frozen.

Screening of cytologic preps and formalin-fixed tissues will be performed to determine if further investigation (bacteriology, virology, etc.) is warranted on frozen tissue.

If you know of a current case that would fit these criteria, please contact me at williamsb@afip.osd.mil or 202-782-2392.

Bruce Williams, DVM