LGR5 and infection: The significant down-regulation of LGR5 transcript levels after the peak of L. intracellularis infection suggests that a reduction in the proliferation rate of LGR5-expressing ISCs, or a reduction in LGR5-expressing ISCs cell number, and/or as suggested previously, a significant attenuation of β-catenin/Wnt signalling, may occur at and/or after the height of infection (Fig 5D) [38].