What is known about wobbly hedgehog syndrome etiology and how should affected hedgehogs be managed?

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Wobbly hedgehog syndrome (WHS) is a fatal, progressive spongy myelinopathy of unknown etiology, and management is entirely supportive — no treatment has been shown to alter disease course or survival. The etiology remains unconfirmed. Genetic, nutritional, and autoimmune causes have all been proposed.1 The consistent finding of inbreeding in captive US populations — a consequence of limited breeding stock following the 1991 import ban — is a suspected contributing factor, and WHS has never been reported in wild African pygmy hedgehogs.1 A viral cause has also been implicated: pneumonia virus of mice (PVM) was detected in one hedgehog with WHS-consistent white matter vacuolization, with 96.5% full genomic sequence homology to PVM strain 15, and PVM antigen was confirmed immunohistochemically in both brain and lung tissue of that animal.8 Histopathologically, WHS is characterized by bilateral, symmetrical status spongiosus of CNS white matter with myelin degeneration, axonal degeneration, reactive microgliosis, and mild astrocytosis — lesions most severe in the cerebellum, medulla oblongata, and cervical and thoracic spinal cord.3 Ultrastructurally, the primary event is splitting of the myelin sheath at the intraperiod line with subsequent focal expansion, disruption, dilatation, and phagocytosis.3 The clinical presentation is a progressive ascending paralysis. Early signs include gait abnormalities and proprioceptive deficits; late signs include ascending paralysis, self-mutilation, head tilt, circling, dysphagia, weight loss, and tremors.2 Disease typically affects animals under 2 years of age.1 Histopathologically confirmed prevalence in one referral population was 3.32%; earlier owner-survey data reported progressive paralysis in approximately 10% of companion hedgehogs.1 Definitive diagnosis requires postmortem histopathology. Antemortem diagnosis is presumptive, based on compatible clinical signs after ruling out differentials. The critical differentials are pri