Advances in Infectious Encephalitis: Etiologies, Outcomes, and Potential Links with Anti-NMDAR Encephalitis.

Encephalitis results in substantial morbidity and mortality and is a challenging syndrome for clinicians to manage. The clinical presentation is heterogeneous, there is a broad range of causative agents, and specific treatments for many etiologies are lacking. Over the past decade, a number of novel infectious and autoimmune etiologies of encephalitis have been identified. Despite such advances, however, up to 50 % of encephalitis cases typically remain without an identified etiology. Moreover, few new vaccines and therapies have been developed. Here, we discuss recent advances in encephalitis, with specific focus on several areas: (1) the changing demographics of West Nile virus in the United States and the implications for vaccine development, (2) challenges in the diagnosis of herpesviral infections in immunocompromised individuals, (3) the identification of a potential link between herpes simplex encephalitis and anti-NMDA receptor encephalitis, and (4) the delineation of prognostic factors related to outcome in individuals with encephalitis.