This book deals both with the epidemiologic background and the specific characteristics of vector-borne and emerging viral infections which may be spread all over the world due to today’s rapid transport of infected individuals or animal vectors. Detailed description of the situation with e.g. Dengue, Japanese encephalitis, Lassa, hepatitis, HIV and filoviruses helps to plan diagnostic approaches and to develop scenarios for the handling of patients suspected of carrying high hazard viruses.