Temporal patterns of diagnostic results in serial samples from cattle with advanced paratuberculosis infections.

As part of investigating diagnostic strategies for Mycobacterium avium subsp. paratuberculosis (Map), serial results from polymerase chain reaction (PCR) on extraintestinal tissues (blood, milk, and liver) were compared with those from more conventional detection methods including serum enzyme-linked immunosorbent assay (ELISA), fecal culture, and fecal PCR. Three cows previously identified as being subclinically infected with Map were selected for the study.