Felicia B. Nutter
T. Augspurger
Tonie E. Rocke
L. Tomlinson
Nancy J. Thomas
M. K. Stoskopf
R. S. Larsen
2002
<p class="first"><strong>Objective</strong>—To characterize clinical features of avian vacuolar myelinopathy (AVM) in American coots.</p><p><strong>Design</strong>—Case-control study.</p><p><strong>Animals</strong>—26 AVM-affected American coots and 12 unaffected coots.</p><p><strong>Procedures</strong>—Complete physical, neurologic, hematologic, and plasma biochemical evaluations were performed. Affected coots received supportive care. All coots died or were euthanatized, and AVM status was confirmed via histopathologic findings.</p><p><strong>Results</strong>—3 severely affected coots were euthanatized immediately after examination. Seventeen affected coots were found dead within 7 days of admission, but 5 affected coots survived > 21 days and had signs of clinical recovery. Abnormal physical examination findings appeared to be related to general debilitation. Ataxia (88%), decreased withdrawal reflexes (88%), proprioceptive deficits (81%), decreased vent responses (69%), beak or tongue weakness (42%), and head tremors (31%), as well as absent pupillary light responses (46%), anisocoria (15%), apparent blindness (4%), nystagmus (4%), and strabismus (4%) were detected. Few gross abnormalities were detected at necropsy, but histologically, all AVM-affected coots had severe vacuolation of white matter of the brain. None of the control coots had vacuolation.</p><p class="last"><strong>Conclusions and Clinical Relevance</strong>—Although there was considerable variability in form and severity of clinical neurologic abnormalities, clinical signs common in AVM-affected birds were identified. Clinical recovery of some AVM-affected coots can occur when supportive care is administered. Until the etiology is identified, caution should be exercised when rehabilitating and releasing coots thought to be affected by AVM.</p>
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10.2460/javma.2002.221.80
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American Veterinary Medical Association
Clinical features of avian vacuolar myelinopathy in American coots
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