PRRS serology: A critical component of the diagnostic workup

Diagnostic notes are not peer reviewed ince the development of the indirect-fluorescent antibody (IFA) test in 1992, serologic profiling has been extremely valuable in improving the understanding of PRRS virus (PRRSV) patterns of transmission within infected farms. The IFA test detects IgG antibodies and indicates infection, not protection. IFA titers are initially detected 7–10 days post-infection and persist for up to 3–4 months. Recently, an ELISA test has been developed. It too measures IgG; however, ELISA antibodies are not detectable until 9–10 days post infection and persist for longer periods (at least 5–6 months). Both tests appear to be very useful when initially profiling an infected herd.