[The hepatitis E virus, an unknown virus that reveals itself].

The first cause of acute hepatitis in the world is due to the hepatitis E virus (HEV). This infection has long been considered as a problem only affecting developing countries. However, since the identification of zoonotic forms at the end of the last century, it has become clear that this infection also affects industrialized countries. The recent renewed interest in HEV has revealed some particularities in this virus. Indeed, although considered as a non-enveloped virus, the HEV viral particle is surrounded by a lipid membrane in the bloodstream. In addition, HEV secretes abundantly into the bloodstream non-infectious forms of its capsid protein that could serve as an immunological bait. This review summarizes recent advances on this virus for which the number of diagnosed cases increases every year.