Genetic variation of Murray Valley encephalitis virus.

The genomes of 21 isolates of Murray Valley encephalitis virus (MVE) from Australia and Papua New Guinea were characterized and compared using RNase T1 oligonucleotide fingerprinting. Most Australian isolates grouped in clusters that were linked with a similarity coefficient of greater than 75%, indicating substantial homogeneity. Two isolates grouped as a cluster that linked with other isolates at a level of 67%. These two isolates, one from the north and one from the south-east of Australia were very similar and could demonstrate the movement of MVE between these areas. This notion is substantiated by genetic homogeneity of isolates from the Kimberley region and from south-eastern Australia. One Australian isolate (OR 156) and the Papua New Guinea isolate (MK 6684) were substantially different from each other as well as from the other isolates. No evidence was found for a poly(A) tract in the genome of MVE.