Ross River virus arthritis in Papua New Guinea.

In 1975 it was reported that antibodies to Ross River virus (RRV) were present in the sera of many population groups in Papua New Guinea. We describe here 3 cases of polyarthritis that occurred in Port Moresby, the capital of Papua New Guinea, during 1980-81 and in which the diagnosis of RRV infection was confirmed by serological tests, and 3 other cases in which serological tests suggested RRV infection but were not diagnostic. A possible case of fatal RRV encephalitis is also reported.