Viral infections of the central nervous system.

Viral infections of the central nervous system in the tropical countries of Asia and the Indian subcontinent are different from those of the Western and developed world. Many of the endemic and epidemic encephalitides that are prevalent in these regions, such as Japanese encephalitis, have characteristic findings on imaging, especially on magnetic resonance imaging, allowing a rapid diagnosis and differentiation from clinically similar syndromes. Other emerging viral infections in the region in recent years have posed new challenges. The contribution of neuroimaging to the management of these emerging infections is also discussed.