[Imported infections of the central nervous system : Migration and travel neurology]

The numbers of migrants, refugees and asylum seekers reached an unprecedented high in Europe in 2015 and 2016 but in 2019 they are back to the average numbers of the last 30 years. In contrast, frequencies of international and intercontinental travelers have continuously increased over the past decades and will continue to do so in the coming years. In 2018 more than 1.35 billion incoming travelers were reported worldwide by international organizations. Detailed knowledge of the epidemiology, transmission types, risk behavior and clinical presentation of acute and chronic central nervous system (CNS) infections enables timely diagnosis and initiation of potentially life-saving emergency treatment. Acute infections of the CNS, e.g. cerebral Plasmodium falciparum malaria or arboviral encephalitis, are seen most frequently and almost exclusively in travelers returning from tropical countries, whereas chronic CNS infections, e.g. tuberculous meningitis or neurocysticercosis, are typically seen in migrants and refugees. Beside CNS infections genetic diseases, environment-associated, nutrition-related, metabolic or cerebrovascular diseases also need to be considered when discussing differential diagnostic possibilities.