The hepatitis E virus is best known as a waterborne pathogen that occasionally causes big outbreaks in Asia and Africa. But more recently, scientists have discovered that a strain named genotype 3 is a problem in Western countries as well, especially in Europe. An estimated 300,000 people get infected annually in Germany alone, and although the vast majority clears the infection easily and without symptoms, the virus persists in the liver of people with weakened immune systems, eventually killing them. Some people get infected through blood donations, but most infections come from eating contaminated pork. The big question now is how the hepatitis E virus can be stopped.