Fig. 3

Summary of PRRSV RT-PCR results in farms where sows’ mass vaccination (SMV) was applied at PRRS stable status time (PS) (n = 58). Farms are displayed in rows and study weeks in columns. Cell codes: x/5: PCR positive pools/5 tested pools; T: negative PCR test and positive unstable status; T*: negative PCR test and positive stable status; SMV: Sows mass vaccination. Cell colors: Red cells: most recent testing PCR-positive; Dark green cells: most recent testing PCR-negative; Light green cells (SMV): SMV applied at PS without subsequent positive PCR test (n = 44): Blue cells (SMV): SMV applied at PS with subsequent positive PCR test related to field virus infection (n = 6); Orange cells (SMV): SMV applied at PS with subsequent positive PCR test with no ORF-5 nucleotide sequence available (n = 8)