Intrauterine infection with Mycobacterium avium subsp.paratuberculosis in pregnant cattle diagnosed with Johne's disease

[Abstract] Johne's disease (JD) is caused by infection with Mycobacterium avium subsp.paratuberulosis (MAP). We confirmed the intrauterine infection of MAP in 22 pregnant cattle diagnosed with JD in Hokkaido, Japan. MAP was isolated from the umbilical cord (3/22: 13.6%) or caruncle (6/22: 27.3%) derived from the pregnant dams. Furthermore, dams with MAP from which MAP was isolated were also found to have a high mount of MAP or detected bacterial load in their feces. Fetuses of the tested dams indicated positive polymerase chain reaction (PCR) results for the MAP gene (17/22:77.3%) in several tissues. MAP was isolated from the PCR-positive sites of dams detected with high levels of bacteria (6/22: 27.3%). These results indicate that MAP infection in pregnant cattle must be prevented as it is important for JD control.