Clinical cases of epidemic polyarthritis were observed in residents of the Port Stephens peninsula, New South Wales, during the 7 years 1965 to 1971, and serological confirmation of Ross River virus infection in such patients was obtained in 5 of these 7 years. Infection was most common in late summer and autumn. Although clinical cases were only found on the peninsula, serological surveys indicated that Ross River virus activity is generally prevalent on the central coast of New South Wales.
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Present address: Veterinary Research Station, Glenfield, N.S.W. 2167, Australia.