AUSTRALIAN ENCEPHALITIS IN WESTERN-AUSTRALIA, 1978-1991

Objective: To review the various clinical manifestations of Murray Valley encephalitis (MVE) or Kunjin virus encephalitis in patients in Western Australia. Design: Review of clinical records, 1978 to 1991. Patients: Of 26 reported cases of Australian encephalitis, four were excluded from study because the patient's symptoms were not definitely associated with MVE virus or Kunjin virus infection. Two further cases of MVE were not reviewed as case records were not available. Of the remaining 20 patients, 18 had MVE and two had Kunjin virus encephalitis. Results: Sixteen cases were in the Kimberley, a tropical region where the viruses are endemic. Four were in the subtropical Pilbara and Gascoyne regions. Thirteen of the 20 cases were in Aborigines, of whom 11 were children. The seven non-Aboriginal patients were adults. Seventeen of 20 cases were in males. The range of neurological disease and outcome was similar to that in previously reported cases, with convulsions, brainstem disease or respiratory failure in severe and fatal cases, and involvement of the spinal cord, cranial nerve or cerebellum in the moderate cases. One mild case without neurological involvement was caused by Kunjin virus. Conclusions: The poor outcome in young Aboriginal children indicated that disease resulting from exposure early in life was more likely to be severe. The disease in adults, irrespective of racial background, was similar to that in cases reported previously from south-eastern Australia, but generally milder.