Detection of viral ribonucleic acid and histologic analysis of inflamed synovium in Ross River virus infection

Objective. To document the histology of Ross River virus (RRV) arthritis and to examine inflamed synovium for vital RNA. Methods. Biopsy tissue from the inflamed knees of 12 patients with RRV infection was studied using conventional and immunostaining techniques. Reverse transcriptase-polymerase chain reaction technology was used to probe for the presence of vital RNA in the synovial biopsy samples and in serum. Results. Hyperplasia of the synovial lining layer, vascular proliferation, and mononuclear cell infiltration were the main histologic changes. RRV RNA was found in knee biopsy tissue that was obtained from 2 patients at 5 weeks after the onset of symptoms. Conclusion. RRV RNA was identified in inflamed synovium more than a month after symptoms began. Inflammation was apparent in the absence of detectable virus in the majority of patients.