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NON-SUPPURATIVE MENINGOENCEPHALITIS IN A BRUSHTAIL POSSUM (Trichosurus vulpecula) (CASE 1411.1)
of mononuclear cells surround multifocal blood vessels within infection. The significance of the intranuclear inclusion bodies the brainstem, cerebral cortex and meninges (Fig 1c). Focally
within the liver of this possum is uncertain. CASE HISTORY
the meninges are markedly thickened with a mononuclear cell A ten year old female brushtail possum (Trichosurus infiltrate (Fig 1d).
Non-suppurative meningoencephalitis and choroiditis has been vulpecula) was submitted to a veterinary clinic with a reported in brushtail possums in Australia since 1985, when unilateral cataract, ataxia, poor weight and pale gums. The MORPHOLOGICAL DIAGNOSIS
the clinical syndrome of blindness and ataxia was first animal was thought to have ingested rodenticides and blood described as “wobbly possum syndrome”. A similar set of tests revealed anaemia (PCV 18 L/L). The possum was treated clinical signs and histological lesions has been identified in with amoxicillin and vitamin K, and it improved over the Extensive nonsuppurative meningoencephalitis brushtail possums in New Zealand, but the relationship following 2 weeks (the PCV increased to 35L/L). The possum Focally extensive acute cerebral haemorrhage and malacia between the two syndromes is uncertain. Although there has did not eat well, it began loosing weight, and its ataxia Multifocal eosinophilic intranuclear inclusion bodies - liver been speculation that “wobbly possum syndrome” in Australia progressed. The possum became dehydrated (PCV48 L/L, is likely to be associated with a viral pathogen, no aetiological GROSS PATHOLOGY
Gross post mortem examination revealed no significant REFERENCES (Abstracts on file)
findings. Formalin fixed tissues were submitted to the PERROTT M.R.F. MEERS J. COOKE M.M. WILKS C.R. (2000) A neurological syndrome in a free-living population of possums (Trichosurus vulpecula). [Journal article] New HISTOPATHOLOGY
Zealand Veterinary Journal. 48: 1, 9-15. 16 ref. Lesions are not evident within the following tissues: THOMPSON E.G. MCLEOD B.J. GILL J.M. (1999) The myocardium, ovary, oviducts/vagina, pancreas, spleen. prevalence of Wobbly Possum disease in a bush/farmland Liver: Hepatocytes contain small quantities of brown
environment. [Conference paper. Journal article] Proceedings cytoplasmic pigment. Multifocal hepatocytes contain of the New Zealand Society of Animal Production. 59: 233- eosinophilic intranuclear inclusion bodies and have O'KEEFE J.S. STANISLAWEK W.L. HEATH D.D. (1997) Kidney: Scattered renal tubules contain small quantities of
Pathological studies of wobbly possum disease in New mineral or cellular casts. Neutrophils are evident within Zealand brushtail possums (Trichosurus vulpecula). [Journal glomeruli. A small number of interstitial lymphoid aggregates article] Veterinary Record. 141: 9, 226-229. 19 ref. are evident within the renal interstitium.
Eye: The sample is fragmented. The retina is artefactually
separated from the choroid. No ganglion cells are evident
within the retina. The lens protein at the lateral aspects of the lens is liquefied. Lenticular epithelial cells have migrated to a Fig 1. Sections of brain tissue with foci of haemorrhage and position within the lenticular protein. The connective tissue malacia (a) and b)), and perivascular mononuclear cell cuffs surrounding the optic nerve contains a light infiltrate of (c) and d)). Clefts in the tissues are processing artefacts H & E mononuclear cells and a small number of neutrophils. The optic tract itself contains scattered mononuclear cells and 1 - 2 COMMENTS
cell layer perivascular cuffs composed of mononuclear cells. The lesions in the optic nerve and brain are most suggestive of Brain: An extensive tract of malacia and haemorrhage is
an acute to subacute viral infection. Eosinophils were not evident at the junction of the cerebral cortex and the dorsal evident within the inflammatory infiltrate within the nervous thalamus (Fig 1a). Blood vessels in this region exhibit
tissue and there is no other evidence of Angiostrongylus sp. or fibrinoid necrosis (Fig 1b). One to three cell layer thick cuffs
protozoal (Toxoplasma gondii or Neospora caninum) Case interpretation: Karrie Rose. Case construction: Damien Higgins

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