Over the last few decades, the use of swine as an animal model for human diseases in biomedical research has been steadily increasing because of similarities between the two species. The gnotobiotechnique, on the other hand, has been developed further since the beginning of the 20th century (1 –3 ), stimulated by the need for an experimental model to study bacteria-host interactions in sterile laboratory animals, during the course of an infection with a defined pathogen. The combination of both aspects led to the development of a complex isolator system that made the delivery of piglets by cesarean section and their rearing in a self-contained unit possible, shielded from undesirable contaminating germs (4 ,5 ). In such a microbiologically well-defined environment, pathogen-host interactions can be studied without the influence of accompanying bacterial flora.