Published in November 2017, this comprehensive and technical paper by Collins et al discusses the need for a highly efficacious live-attenuated vaccine capable of differentiating infected from vaccinated animals. It describes the potential link with Crohn’s disease and other human diseases which make MAP a concern as a zoonotic pathogen. It also references this website in describing the effect of MAP on the gut.
https://www.frontiersin.org/articles/10.3389/fvets.2017.00187/full