An ELISA for epidemiological studies of myxomatosis: Persistence of antibodies to myxoma virus in European rabbits (Oryctolagus cuniculus)

An ELISA (enzyme-linked immunosorbent assay) for detecting antibodies to myxoma virus was characterised in wild rabbits for use in epidemiological studies. Virus neutralisation assays and virus challenge were used to define sera from rabbits as positive or negative for myxoma-virus antibodies. En a group of naturally infected wild rabbits, antibodies to myxoma virus were readily detectable by ELISA each month for at least 12 months in all rabbits, including those where neutralising antibodies could no longer be detected. Maternally transferred antibodies could be detected in kittens born to immune does for approximately six weeks after birth. IgM antibodies to myxoma virus were detected by ELISA only during the active disease and recovery phase of myxomatosis. The ratio of IgM:IgG at a standard serum dilution provided an index of time since infection and a confirmatory assay for early myxomatosis, because the detection of IgM corresponded approximately with the onset of clinical signs. Rabbit antibodies to the orthopoxvirus, vaccinia, did not cross-react in the ELISA.