Combatting PRRSV: the new oral fluid IgM-IgA ELISA
Swine producers and veterinarians need both nucleic acid- and antibody-based tests to monitor PRRSV. PRRSV RT-PCR reflects virus circulation at the time of sample collection, whereas antibodies reveal the history of infection and immunity. In a recent report from scientists at Iowa State University, the new PRRSV oral fluid IgM-IgA ELISA was announced.Porcine reproductive and respiratory syndrome virus infection (or vaccination) stimulates the pig’s immune system to produce three types of antibodies: IgM appears within seven days of infection, IgA after seven days, and IgG at nine to 10 days of infection. The current PRRSV oral fluid ELISA is designed to detect IgG because it is present at a higher concentration and for a longer period of time than IgM or IgA. The PRRSV oral fluid IgG ELISA is very effective at monitoring maternal antibody levels in young pigs and the PRRSV immune status of growing pig populations.
The new PRRSV oral fluid IgM-IgA ELISA is designed to simultaneously detect both IgM and IgA, but not IgG. The two advantages of this new assay is that: (1) it is able to detect active infection in piglets with circulating maternal IgG antibody; and (2) can serve as a confirmatory assay in the event of “unexpected” results from other PRRSV tests, for example PRRSV RT-PCR or IgG ELISA.
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As reported by Iowa State University and National Hog Farmer