Neuroinvasive flavivirus infections.

Flaviviruses, including Dengue, West Nile, Japanese encephalitis, and Tick-borne encephalitis virus, are major emerging human pathogens, affecting millions of individuals worldwide. Many clinically important flaviviruses elicit CNS diseases in infected hosts, including traditional "hemorrhagic" viruses, such as Dengue. This review focuses on the epidemiology, symptomatology, neuropathology, and, specifically, neuropathogenesis of flavivirus-induced human CNS disease. A detailed insight into specific factors priming towards neuroinvasive disease is of clear clinical significance, as well as importance to the development of antiviral therapies and identification of key mechanisms involved in the (re)emergence of specific flaviviruses, including potentially novel or previously unrecognized ones, as neuroinvasive pathogens.