Myofasciitis, or disseminated idiopathic myositis (DIM), is an emerging, noncontagious, progressive disease of domestic, primarily young (6 to 18 months of age) ferrets. The disease is characterized by acute onset of pain with reluctance to move, fever, leukocytosis with mature neutrophilia (12 to 100 ´ 103 WBC/µl), and failure to respond to medications. Some ferrets also display inappetence, vomiting, or diarrhea. Serum chemistry analysis is relatively unhelpful in diagnosis: Mild hypoalbuminemia and mild hyperglycemia are common. Occasionally, mild elevations in serum alanine transaminase or aspartate transaminase and bilirubin are seen; but, paradoxically, elevations in serum creatine kinase are rare. Gross lesions include white streaking in the muscles with marked atrophy. Unlike cases of nutritional atrophy, adequate fat stores are seen in cases of DIM. In addition, esophageal changes and splenomegaly are present. Diagnosis of DIM can be made presumptively based on history, clinical signs, laboratory values, and failure to respond to treatment. Definitive diagnosis is made by muscle biopsy. Histologic lesions consist primarily of moderate to severe suppurative to pyogranulomatous inflammation seen in all muscle groups. This inflammation sometimes extends into the subcutaneous or cavity adipose tissue. Draining lymph nodes may be enlarged. A number of drugs used to treat affected ferrets have failed, including several antibiotics, glucocorticoids, some NSAIDs, alpha interferon, cyclophosphamide, buprenorphine, and acyclovir. Various laboratory techniques, including cultures and polymerase chain reaction, have failed to detect bacterial, viral, or protozoal pathogens. The cause of DIM is still unknown, although the disease does resemble some of the acquired human immune-mediated inflammatory myopathies. The only common factor the authors have found in affected ferrets has been use of a commercial canine distemper vaccine that is no longer available.

COMMENTARY: An important article if you treat ferrets. The common clinical signs and diagnostic results covered are important to know in adding myofasciitis as a differential to your list of diseases of ferrets. Unfortunately, there is no treatment as yet.

Myofasciitis: An emerging fatal disease of the domestic ferret. Garner MM, Ramsell K. Exotic DVM 8:23-25, 2006.