However, he was unable to isolate the pathogen—most likely because M. paratuberculosis sheds its cellular wall in humans and takes the form of a spheroplast, making it virtually undetectable under an optical microscope. Toutefois, il ne put isoler le pathogène, probablement parce que M. paratuberculosis se débarrasse de sa paroi cellulaire dans les humains, adoptant la forme d'une sphéroplaste, le rendant presque indétectable sous un microscope.
