Echovirus-associated polyarthritis. Report of a case with synovial fluid and synovial histologic characterization.

A patient with fever, myalgias, and acute polyarthritis in whom echovirus 9 was isolated from throat and rectal swab specimens is described. All symptoms resolved spontaneously over a one week period except for the arthritis which required three months for complete recovery. A mildly inflammatory synovial fluid and histologic picture were observed. Attempts to isolate the virus from synovial fluid and synovium during acute illness were unsuccessful.