Emerging and re-emerging viruses affecting the nervous system

Emerging and re-emerging viruses may cause meningitis, encephalitis, meningoencephalomyelitis, encephalitis, Guillian-Barré-like-syndromes as well as strokes. Most important viruses belong to the family of Adenoviridae, Arbovirus, Arenaviridae, Herpesviridae, Picornaviridae, Paramyxoviridae as well as Togaviridae. Clinical presentation usually consists of a biphasic presentation. Non-specific febrile illnesses may be accompanied by rash, headache, arthralgia and myalgia. Thereafter focal neurological signs may evolve. Diagnostic strategies for the detection of emerging and re-emerging viruses may be difficult due to the short viraemic period. Pitfalls in serology may be due to antibody crossreactivity. Arboviruses are transmitted by arthropods. Aedes mosquitos are one of the vectors for arboviruses like Chikungunya-virus, Dengue-virus, Japanese-Encephalitis-B-virus and West-Nile-virus. Since the last centuries Aedes mosquitos have spread from their naturally habitat in Africa to America as well as Europe. The arboviruses risk profile depend essentially on the occurrence, the activity of the respective vector, this may be the key to fight the disease and its spread. Due to global shifts in the ecological balance but also as a result of more or less successful control measures, some diseases have become rarer, others are more common. The viruses persist in the respective vector months to years; in ticks they may persist for years and in mosquitoes 1 to 4 months. In order to survive bad climatic conditions unscathed, the viruses partially overwinter in arthropods.