the present invention relates to lawsonia intracellularis vaccines and methods for protecting against and diagnosing l . intracellularis infection . the products and processes of the invention are attainable , in part , as the result of an improved method for cultivating large scale supplies of l . intracellularis , including both a novel isolate of l . intracellularis of european origin and a method of preparing a lyophilized product containing the attenuated european isolate as vaccine product .