Antibody to togaviruses in the Northern Territory and adjoining areas of Australia.

Antibody to flaviviruses Murray Valley encephalitis (MVE) and Kunjin and to alphaviruses Ross River and Sindbis were found in many Aboriginal children and adults bled in central Australia in 1974 after several cases of MVE occurred there as part of a widespread epidemic. Antibody was also detected in sera taken in the period 1968 to 1973, but in a much lower proportion, suggesting both that the 1974 epidemic had caused frequent sub-clinical infection and that infection had occurred in the arid centre of Australia outside years of known togavirus activity. Evidence of frequent togavirus infection was found in sera from various species from monsoonal northern areas of Northern Territory and Western Australia, compatible with previous suggestions that togaviruses are enzootic or frequently epizootic in those areas.