[Flavivirus infections: yellow fever, dengue fever and Japanese encephalitis].

Flavivirus infections, such as dengue fever, yellow fever and Japanese encephalitis, are untreatable. As a result of the high prevalence of dengue fever in endemic areas, it poses a substantial risk for travellers to those areas. When it comes to Japanese encephalitis and yellow fever, the risk for travellers is limited but the diseases are extremely serious, creating a dilemma for the physician when it comes to deciding whether to vaccinate against them. The vaccines against both potentially have side effects. The indications and contraindications for vaccination are described in detail.