Central nervous system viral disease

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Central nervous system viral disease" – news · newspapers · books · scholar · JSTOR (May 2017) (Learn how and when to remove this message)

The central nervous system (CNS) controls most of the functions of the body and mind. It comprises the brain, spinal cord and the nerve fibers that branch off to all parts of the body. The CNS viral diseases are caused by viruses that attack the CNS. Existing and emerging viral CNS infections are major sources of human morbidity and mortality.

Virus infections usually begin in the peripheral tissues, and can invade the mammalian system by spreading into the peripheral nervous system and more rarely the CNS. CNS is protected by effective immune responses and multi-layer barriers, but some viruses enter with high-efficiency through the bloodstream and some by directly infecting the nerves that innervate the tissues.^[1]

Most viruses that enter can be opportunistic and accidental pathogens, but some like herpes viruses and rabies virus have evolved in time to enter the nervous system efficiently, by exploiting the neuronal cell biology. While acute viral diseases come on quickly, chronic viral conditions have long incubation periods inside the body. Their symptoms develop slowly and follow a progressive, fatal course.^{[citation needed]}