Detection of Ross River virus immunoglobulin M antibodies by enzyme-linked immunosorbent assay using antibody class capture and comparison with other methods.

An enzyme-linked immunosorbent assay based on antibody class capture was developed for the detection of Ross River virus-specific immunoglobulin M antibodies (RRV IgM). The assay was specific, reproducible and precise. When compared with conventional tests for the detection of RRV IgM, such as hemagglutination inhibition following sucrose density gradient centrifugation and indirect enzyme-linked immunosorbent assay, the class capture assay was more sensitive. In 186 sera which were collected from 39 patients with RRV infection over a period of 1-4 yr from onset of initial symptoms, RRV IgM persisted for at least 1-2 yr. Sera were tested both at a single dilution from which the results were expressed as a binding index and in a dilution series in which they were expressed as an antibody titre. Binding index values gave better discrimination between sera collected during acute and later phases of the disease and may be of greater value than antibody titres in the diagnosis of RRV infection.