Ross River virus infection in the north-west outskirts of the Sydney basin.

In early 1997, 69 cases of Ross River virus infection were reported in the north-western outskirts of Sydney. This represents a substantial increase over the maximum of 12 cases reported in any one year since 1991. The majority of cases (71%) are thought to have been locally acquired. This is the first reported outbreak of Ross River virus infection in this area and highlights the need for metropolitan health services to be vigilant about a disease that has primarily been associated with rural and semirural areas in New South Wales.