Viral hemorrhagic fevers (VHFs) represent a collection of illnesses caused by several distinct viral families. While some types of hemorrhagic fever viruses can cause relatively mild illnesses, many of these viruses cause life-threatening diseases. The chapters of this book discuss the consequences of the Ebola outbreak in West Africa, the most frequency imported infection worldwide (malaria), the reservoirs of selected infectious diseases (often bats and fruit bats), the clinical symptoms of viral diseases and the most widely used diagnostic methods for the correct identification of the pathogen involved, and a discussion on Japanese encephalitis (JE) as an infectious disease caused by a virus transmitted by blood-sucking arthropods.